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Erosion rates and nutrient losses affected by composted cattle manure application in vineyard soils of NE Spain
Catena 68 (2006) 177 – 185 www.elsevier.com/locate/catena
Erosion rates and nutrient losses affected by composted cattle manure application in vineyard soils of NE Spain M.C. Ramos *, J.A. Martı´nez-Casasnovas Department of Environment and Soil Science, University of Lleida, Alcalde Rovira Roure 191, E-25198 Lleida, Spain
Abstract Land preparation for mechanisation in vineyards of the Anoia – Alt Penede`s region, NE Spain, has required major soil movements, which has enormous environmental implications not only due to changes in the landscape morphology but also due to soil degradation. The resulting cultivated soils are very poor in organic matter and highly susceptible to erosion, which reduces the possibilities of water intake as most of the rain is lost as runoff. In order to improve soil conditions, the application of organic wastes has been generalised in the area, not only before plantation but also every 3 – 4 years at rates of 30 – 50 Mg ha 1 mixed in the upper 30 cm. These organic materials are important sources of nutrients (N and P) and other elements, which could reduce further fertilisation cost. However, due to the high susceptibility to sealing of these soils, erosion rates are relatively high, so a higher nutrient concentration on the soil surface increases non-point pollution sources due to runoff. The aim of this study is to analyse the influence of applied composted cattle manure on infiltration, runoff and soil losses and on nutrients transported by runoff in vineyards of the Alt Penede`s – Anoia region, NE Spain. In the two plots selected for the analysis, composted cattle manure had been applied in alternate rows 1 year previous to the study. In each plot soil surface samples (0 – 25 cm) were taken and compared to those of plots without manure application. The study was carried out at laboratory scale using simulated rainfall. Infiltration rates were calculated from the difference between rainfall intensity and runoff rates, and the sediment and total nitrogen and phosphorus were measured for each simulation. In addition, the influence of compost was investigated in the field under natural rainfall conditions by analysing the nutrient concentration in runoff samples collected in the field (in the same plots) after seven rainfall events, which amount different total precipitation and had different erosive character. Compost application increases infiltration rates by up to 26% and also increases the time when runoff starts. Sediment concentration in runoff was lower in treated (13.4 on average Mg L 1) than in untreated soils (ranging from 16.8 to 23.4 Mg L 1). However, the higher nutrient concentration in soils produces a higher mobilisation of N (7 – 17 Mg L 1 in untreated soils and 20 – 26 Mg L 1 in treated soils) and P (6 – 7 Mg L 1 in untreated soils and 13 – 19 Mg L 1 in treated soils). A major part of the P mobilised was attached to soil particles (about 90% on average) and only 10% was dissolved. Under natural conditions, higher nutrient concentrations were always recorded in treated vs. untreated soils in both plots, and the total amount of N and P mobilised by runoff was higher in treated soils, although without significant differences. Nutrient concentrations in runoff depend on rainfall erosivity but the average value in treated soils was twice that in untreated soils for both plots. D 2006 Elsevier B.V. All rights reserved. Keywords: Soil erosion; Nutrient losses; Vineyards; Compost; Mediterranean climate
1. Introduction The Mediterranean climate is characterised by a complex pattern of spatial and seasonal variability, with * Corresponding author. Tel.: +34 973702092; fax: +34 973 702613. E-mail address: [email protected] (M.C. Ramos). 0341-8162/$ - see front matter D 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.catena.2006.04.004
wide and unpredictable rainfall fluctuations from year to year and with frequent high-intensity rainfall events (Ramos, 2002), which increase the vulnerability of the Mediterranean region to erosion. Crop types and management practices also contribute to erosion processes. Vineyards are among the lands subject to the highest runoff and soil losses: 47– 70 Mg ha 1 year 1 in NW
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Italy (Tropeano, 1983), 35 Mg ha 1 year 1 in the Mid Aisne region (France) (Wicherek, 1991), 22 Mg ha 1 year 1 in the Penede`s– Anoia region (NE Spain) (Uso´n, 1998). Even higher soil losses have been associated with extreme rainfall events: 34 Mg ha 1 in a single extreme rainfall event in SE France (Wainwright, 1996) and 207 Mg ha 1 in the study area (Martı´nez-Casasnovas et al., 2002). These erosion processes are accelerated by changes in land use and in cropping patterns adapted for field mechanisation, which eliminate most traditional soil conservation measures. The traditional free-growing vines planted following contour lines and in bench terraces are being replaced with trained vines in rows perpendicular to the maximum slope gradient in most cases. Field mechanisation, which is taking place in some Mediterranean areas, has enabled significant soil movements to reduce slope gradients which, in many cases, has been carried out without preserving the topsoil. Sometimes the more fertile horizon is mixed and buried underneath poorer materials from deeper in the soil profile. This has enormous environmental implications, leading to changes in the landscape morphology and soil degradation. These movements are generating soils with poor structure and a very low organic matter content, which reduce the water holding capacity and increase runoff and erosion. The Anoia – Penede`s area, located in NE Spain, is a clear example of this situation. In order to improve soil conditions, the application of organic waste has been generalised in this area, not only before plantation but also every 3 – 4 years at rates of 30– 50 Mg ha 1 mixed in the upper 30 cm. Recycling these wastes via land application could lead to improvements in the physical properties of a soil, such as soil porosity, structure and water holding capacity (Tisdall and Oades, 1982; Oades, 1984; Hamblin, 1991; Oue´draogo et al., 2001). For this reason the application of organic waste or compost could be beneficial for soil conservation (Pinamonti and Zorzi, 1996), especially in degraded soils and soils susceptible to erosion. In addition, these organic materials are important sources of nutrients (N and P) and other elements, which could further reduce fertilisation costs. However, the intensification of agricultural systems and the use of organic waste to improve soil physical conditions have become a common practice, contributing to the build-up of soil P and N levels in specific areas to levels
rarely encountered in the past. As a result, there is an increase in potential P and N losses from these areas and an environmental risk of surface water pollution associated with runoff from fields to which organic waste has been applied. In addition, due to the high susceptibility to sealing of these soils, erosion rates are relatively high and consequently a higher nutrient concentration in the soil surface increases non-point pollution due to runoff. In the present study, the influence of a single application of composted cattle manure at a rate of 40 Mg ha 1 on vineyard soil from the Alt Penede`s –Anoia region, NE Spain, was evaluated, focusing on the changes in runoff and soil losses and on nutrients transported by runoff at laboratory and field scale.
2. Material and methods 2.1. Study area The study area is located in the Alt Penede`s– Anoia region, NE Spain (X: 400300; Y: 4592700), between the Anoia and Llobregat rivers. Vineyards represent the main land use in the area (about 80% of the cultivated area), being cultivated with the soil bare during most of the year. The area has a Mediterranean climate (dry sub-humid) with an average annual rainfall of about 550 mm, mainly concentrated in spring and autumn. In most cases, the rainfall intensity is higher than 100 mm h 1 during short time periods (Ramos, 2002), which causes major erosion problems, nutrient losses and alterations of the soil surface. The soil moisture regime is xeric and the soil temperature regime is thermic. The annual average temperature is about 15 -C. 2.2. Plot characteristics, soil sampling and nutrient loss assessment The study was conducted on two vineyard plots planted 12 years ago. Similar management practices are applied on these two plots, but while one plot maintains the original soil profile (undisturbed soils: UD), the other one was the result of major land-levelling works before plantation (disturbed soils: D), in which more than 2.5 m of soil was cut from the upper part of the plot and used to fill the lower part. According to Keys of Soil Taxonomy (Soil Survey Staff, 1998), the soils are classified as Typic Calcixerepts
Table 1 Characteristics of the surface soil (0 – 25 cm) of the selected plots included in the study Soil
UD(U) UD(T) D(U) D(T)
pH
7.8 8.2
CE(1:5) (dS m 1)
CaCO3 (%)
OM (%)
Total N (g kg 1)
Total P (mg kg
0.23 0.39 0.18 0.29
52
0.9 1.8 0.4 1.8
0.7 1.6 0.3 1.2
332 787 417 855
34
Texture (USDA) 1
)
Clay (%) 8.6 12 80
Silt (%)
Fine sand (%)
Coarse sand (%)
42.7
30.9
18.5
43
37
UD(U)—untreated undisturbed soil; UD(T)—treated undisturbed soil; D(U) untreated disturbed soil; D(T)—treated disturbed soil.
M.C. Ramos, J.A. Martı´nez-Casasnovas / Catena 68 (2006) 177 – 185
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Table 2 Runoff rates and sediment concentration obtained after the rainfall simulation carried out in soils of both plots Plot
Time to runoff (min)
Time to constant runoff rate (min)
Runoff (mm)
Runoff rate (%)
Infiltration rate (%)
Sediment concentration (g L 1)
Total sediment (kg m 2)
UD(T) UD(U) D(T) D(U)
7.6 5.1 2.0 1.4
25 15 20 12
22.4 31.4 26.5 45.3
50.0 60.7 72.8 86.0
50.0 39.3 27.2 14.0
13.41 16.80 13.43 23.41*
0.336 0.666 0.452 1.016*
UD(U)—untreated undisturbed soil; UD(T)—treated undisturbed soil; D(U) untreated disturbed soil; D(T)—treated disturbed soil. * Significant differences at 95% confidence level.
and Haplic Xerarents (in the UD plot) and Typic Xerorthents (in the D plot). Vineyards have bare soil for most of the year. The 25-cm upper layer is ploughed several times during the growing season (at least five times from November to June) to eliminate weeds, favour infiltration and force the vines to root deeper. Composted cattle manure was applied to this field 1 year prior to this study at a rate of 40 Mg ha 1 wet weight (28% moisture) in alternate rows. This compost contains in its matrix N and P at concentrations of 22.6 T 0.6 Mg g 1 and 1411 T11 Mg kg 1, respectively. In each field plot, soil surface samples (0 –25 cm) were taken in both treated and untreated soils. Plots, 0.30 m*0.20 m*0.15 m (deep) filled with air-dry soil aggregates < 8 mm diameter were subjected to an 80 mm h 1 simulated rainfall composed of 2.5 mm diameter drops of deionised water
falling freely from drippers 2.5 m above the soil surface. Runoff water was collected at 5-min intervals for 40 min. The eroded soil in suspension and the total volume were measured for each simulation. Water intake rates were calculated from the difference between rainfall intensity and runoff rates. The intensity was calibrated just before and after each simulation. All simulations were done in triplicate. The average of the three replications is shown. Sediment concentration in runoff was determined in aliquots of runoff, which were decanted and dried at 105 -C, and then weighed. For runoff water analysis, an aliquot of each sample was filtered (0.45 Am pore diameter) to analyse dissolved reactive phosphorous (DRP). Other unfiltered acid-digested aliquots were used for total Kjeldahl nitrogen (TKN) and total phosphorous (TP) determinations. P was measured following the method proposed by Murphy and
Fig. 1. Evolution of runoff with time, for soils with and without compost: (a) disturbed plot; (b) undisturbed plot (D(T): disturbed treated, D(U): disturbed untreated; UD(T): undisturbed treated, UD(U): undisturbed untreated).
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Riley (1962), while total N was determined by a distillation procedure (American Public Health Association, 1998). Additional aliquots were used to determine NO3 – N (using a Merkoquant Nitrat-test) and NH4 – N (using a RQflex Ammonium-test). Runoff nutrient concentrations were used in conjunction with runoff water volumes to calculate mass losses of nutrients for each soil. For field assessment, Gerlach type sediment and runoff collectors were installed at the same points at which the samples were taken. At each location one collector was located in the row with added compost and another in an untreated soil. Runoff samples were collected after the main rainfall events throughout the year 2000. An aliquot of the collected runoff samples was filtered and air-dried in order to evaluate sediment concentration. An unfiltered aciddigested sample was used for total phosphorous (TP) and total Kjeldahl nitrogen (TKN) determinations, following the methods explained above. At the same positions, the base infiltration rate was evaluated from rainfall simulation, with the same equipment used in the laboratory. The collectors used in the field allow us to have information about nutrient concentration in runoff at each specific location but not about erosion rates, because they are not installed in delimited plots. However,
an estimation of total nutrient losses for each event was obtained by considering the differences in the base infiltration rate, measured in the field at the same position in soils with and without compost, and assuming that rainfall falling at higher intensity cannot infiltrate and runs off. Rainfall was recorded at 1-min intervals in the experimental field using a tipping-bucket system linked to a datalogger. From these records, the total rainfall amount and intensity were analysed, and the rainfall kinetic energy and the erosivity of each storm were calculated. Kinetic energy was evaluated using the relationship between kinetic energy and rainfall intensity obtained for the experimental area (Ramos, 1999), and the erosivity of the rainfall was estimated according to the erosivity R factor proposed by Wischmeier and Smith (1978), defined as the product of kinetic energy multiplied by the maximum intensity in 30-min periods (R = KE*I30) for each rainfall period. 2.3. Statistical analysis A statistical analysis (Duncan’s mean test and one-way analysis of variance) of runoff volume, sediment concentration in runoff and nutrient losses was done to evaluate
Fig. 2. Evolution of sediment concentration in runoff for treated and untreated soil: (a) undisturbed plot, (b) disturbed plot (D(T): disturbed treated, D(U): disturbed untreated; UD(T): undisturbed treated, UD(U): undisturbed untreated).
M.C. Ramos, J.A. Martı´nez-Casasnovas / Catena 68 (2006) 177 – 185
181
Table 3 Nutrient losses by runoff in treated and untreated soils for both plots (Ns: total nitrogen mobilised during the rainfall simulation; Ps: total P mobilised during the 40 min of rainfall simulation Plot
Total N (mg L
1
)
Total P Concentration (mg L
UD(T) UD(U) D(T) D(U)
15.04 5.19 26.32 7.42
8.93 1.99 19.08 7.09
Mass loss in runoff 1
)
Particulate P (%)
Dissolved P (%)
Ns (kg ha
80.85 91.20 85.71 93.15
21.27 8.80 14.29 6.84
3.37 1.73 6.95 3.18
1
)
Ps (kg ha
1
)
1.43 0.90 5.04 3.20
UD(U)—untreated undisturbed soil; UD(T)—treated undisturbed soil; D(U) untreated disturbed soil; D(T)—treated disturbed soil.
significant differences between treated and untreated soils, using the multi-range test and the Statgraphics 5.1 program.
3. Results and discussion 3.1. Soil characteristics The characteristics of the studied soils are presented in Table 1. In both plots, soils have a relatively high silt + fine sand content (> 50%) and a very low organic matter content
(0.8 –1.9% in the plot with the original soil profile, and 0.16 – 0.53% in the land-levelled plot). Despite the increase in organic matter, 1 year after compost application the improvement in soil aggregate stability was very low (Ramos and Martı´nez-Casasnovas, 2003). The method applied to analyse aggregate stability included different disaggregation processes (slaking, cracking and mechanical breakdown), and significant improvements were only found against slaking and cracking, but not against mechanical breakdown, which is the process that takes place by drop impact. Montenegro and Malago´n (1990) indicated that aggregate stability increases with organic matter content,
Fig. 3. Relationship between nutrient concentration and sediment concentration in runoff: (a) P; (b) N.
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particularly when it is less than 2%. However, this was not the case. Calcium carbonate content ranges from 34% to 52 %, and pH varies from 7.8 to 8.2. Total N ranged from 0.3 g kg 1 in the levelled plot to 0.7 g kg 1 in the undisturbed plot, and P ranged from 417 Mg kg 1 in the levelled plot to 332 Mg kg 1 in the undisturbed plot. The concentration of N and P was nearly doubled 1 year after of the compost application. 3.2. Runoff rates and nutrient concentrations at laboratory scale 3.2.1. Runoff rates The runoff rates and sediment concentrations obtained after the rainfall simulation carried out at 80 mm h 1 in each plot, in treated and untreated soils, are presented in Table 2. Significant differences in infiltration rates can be observed between the two plots and between treated and untreated soils within a plot. For the undisturbed plot, runoff rates represented about 60.7% of the rainfall in untreated soils and 50% in treated soils, but very few differences were
found in the time used to reach the minimum infiltration rate (Fig. 1). However, in the disturbed plot, higher runoff rates were observed, representing up to 86% of the rainfall in untreated soils and 72.8% in treated soils. The maximum runoff rates were reached after only 15 min of rainfall in untreated soils, while in treated soils the maximum occurred after 20 or 25 min of rainfall (Fig. 1). Base infiltration improved from 15 mm h 1 in untreated soils to 20 mm h 1 in treated soils in the undisturbed plot and from 10 to 15 mm h 1, respectively, in the disturbed plot. There were also differences in the sediment concentration in runoff between plots and treatments (Fig. 2). The eroded material showed some fluctuations during the first step of the simulation, but after the first minutes tended to decrease until it reached a constant value. In the disturbed plot, the average sediment concentration was 23 g L 1 in untreated soils vs. 13.4 g L 1 in treated soils, whereas in the undisturbed plot the concentrations were significantly lower: 16.8 g L 1 in untreated soils and 13.4 g L 1 in treated soils (Table 2). These values represented soil losses of 0.336 and 0.666 kg m 2, respectively, for treated and untreated undisturbed soils,
Fig. 4. Relationship between nutrient concentration in runoff and soil nutrient concentration: (a) P; (b) N.
M.C. Ramos, J.A. Martı´nez-Casasnovas / Catena 68 (2006) 177 – 185 Table 4 Rainfall characteristics of the analysed periods: total rainfall ( P); KE (kinetic energy); R factor (= KE*MaxI30) Data
P (mm)
KE (MJ ha
9/1 27/3 22/5 27/7 16/9 4/10 4/12
30.8 22.5 57.6 57.8 200.8 24.8 46.4
2.6 3.2 3.1 11.3 38.1 20.3 4.28
1
)
R factor (MJ ha
1
mm h
1
183
can be 75% to 90% of the P transported in runoff. The results are summarised in Table 3. The increase in total P and total N concentration was associated with the higher runoff sediment concentration, as is confirmed by the correlation between particulate phosphorous and total nitrogen and the sediment concentration in runoff (Fig. 3). The rate of dissolved phosphorous increased in runoff in treated vs. untreated soils, but was not significantly correlated with the sediment concentration in runoff. However, N dissolved fractions correlated with the total sediment in runoff. There was also good correlation between the particulate phosphorous in runoff and the total soil P concentration, and between N mobilised by runoff and the total soil N concentration (Fig. 4). Taking into account the observed concentrations and the total runoff volume in each simulation, the total amount of N and P mobilised was evaluated. The results indicated that in treated soils the quantity of N mobilised by runoff is nearly twice that occurring in untreated soils. For P, the amount of nutrient mobilised by runoff in treated soils was about 1.6 times higher than in untreated soil. Mass loss due to a high intensity rainfall (75 – 80 mm h 1), such as that used in the study, which is recorded very often in the study area in short time periods, could imply nutrient losses of about 7 kg ha 1 of N and 5 kg ha 1 of P in a single event, while in untreated soils it would be about 3.2 kg ha 1 of N and P. Those values for one event are higher than the annual losses of N and P found by different authors in rainfed crops, which have been presented as those giving the maximum rates.
)
26.07 26.07 121.8 319.7 624.0 243.2 110.2
while erosion rates in disturbed soils were 0.452 and 1.016 kg m 2 for treated and untreated soils, for the 40-min periods and under the intensity used in the experiment. Significant differences were observed between the two plots and also between treated and untreated soils within the plots, the effect of compost being greater in the disturbed soils. 3.2.2. Nutrient concentration in runoff Due to the high runoff rates, some nutrients are mobilised and transported by runoff, linked to soil particles and dissolved. The average nitrogen and phosphorus concentration in runoff is presented in Table 3. Due to the application of compost, which had large quantities of these two nutrients, nutrient concentrations in treated soils are much higher than in untreated soils, and taking into account that the sediment concentration in runoff was higher in the treated soils, the nutrient concentration in runoff was also higher. For nitrogen, the differences between treated and untreated soils ranged between 15.0 and 5.2 Mg L 1 for the undisturbed plot, and between 26.3 and 7.4 Mg L 1 for the disturbed plot. The fractions presented as nitrate and ammonium were very low. Similar results were observed for phosphorus concentrations. In this case, the differences ranged from 8.9 to 2 Mg L 1 in the undisturbed plot and from 19.1 to 7.1 Mg L 1 in the disturbed plot. In the untreated soils, most of the P transported was linked to soil particles (more than 90%). However, in the treated soils the dissolved fraction increased by up to 21% of the total P mobilised. This result is in agreement with that reported by Schuman et al. (1973), who point out that the particulate P
3.3. Runoff rates and nutrient concentrations at field scale Runoff was collected after seven rainfall periods throughout 2000. The rainfall characteristics are included in Table 4. The analysed events had erosivities (R = Kinetic energy*I30max) ranging from 26 to 624 MJ ha 1 mm h 1, the most erosive being those recorded in autumn. Nutrient concentrations in the runoff samples collected after those rainfall events are presented in Table 5. It is confirmed that also under natural conditions N and P concentrations in runoff are much higher in treated than in
Table 5 Nutrient concentration in runoff collected in treated (T) and untreated (U) soils of two vineyard plots (undisturbed: UD) and disturbed (D) under natural rainfall Rainfall period
9/1 27/3 22/5 27/7 16/9 4/10 3/11
Undisturbed plot (UD)
Disturbed plot (D)
N concentration in runoff (mg L 1)
P concentration in runoff (mg L 1)
N concentration in runoff (mg L 1)
U
T
U
T
U
T
U
T
6.8 3.4 18.9 13.7 5.0 13.6 10.7
17.1 18.4 26.2 14.7 8.6 14.7 33.5
3.5 10.4 2.6 2.8 4.9 10.5 3.7
14.6 13.8 3.1 6.5 10.2 32.2 11.2
11.2 4.4 11.5 2.4 1.04 5.1 10.6
17.6 5.8 28.2 5.1 2.2 6.8 38.2
2.2 1.5 2.2 1.3 12.6 9.4 3.2
6.3 2.7 6.3 3.1 25.9 10.2 7.5
P concentration in runoff (mg L 1)
184
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Fig. 5. Estimated total nitrogen and total phosphorous lost by runoff under natural rainfall in seven events of different erosive character in treated and untreated soils: (a) undisturbed plot; (b) disturbed plot.
untreated soils: the nutrient concentration is on average twice the value in treated than in untreated soils for both total N and total P, although it depends on rainfall characteristics. By considering the differences in the base infiltration rate, measured in the field at the same position in soils with and without compost, and assuming that rainfall falling at higher intensity cannot infiltrate and runs off, nutrient losses for each event were estimated. This information is summarised in Fig. 5 for 7 events. It is observed that in both plots total P losses are higher in treated than in untreated soils: 1.84 and 1.57 times higher on average in treated vs. untreated soils for the undisturbed and the disturbed plot, respectively. Total N losses were also higher in treated than in untreated soils in the disturbed plot (1.4 times higher in treated vs. untreated soils), but there were no significant differences in the undisturbed plot for all the analysed events, although in some of them we found soil loses higher than twice in treated than in untreated soils. A significant linear regression was also observed between P losses and rainfall erosivity estimated by the R factor (KE*I30) in treated and untreated soils in both plots. However, the relationship between N losses and the erosivity was not significant.
4. Conclusions Composted cattle manure applied to the soils showed a positive effect, improving infiltration and decreasing runoff volumes by up to 20%. This involves beneficial effects for soils that are highly degraded due to land-levelling works
and a reduction in the cost of fertilisation. Although the total of soil particles mobilised by runoff decreases with compost application due to the higher nutrient concentration in the surface layer, where the compost is mixed, the nutrient concentration in runoff increases. Therefore, the total amount of N and P mobilised by runoff, which can reach streams, will reduce surface water quality. In the present study, the N and P concentrations in runoff generated in treated soils were nearly twice those in untreated soils for the rainfall recorded in the study area. These results suggest the need to find alternative waste or products to improve soil properties in order to avoid the presence of high surface nutrient concentrations which lead to water pollution. Acknowledgements This study was financially supported by the Spanish Government (Comisio´n Interministerial de Ciencia y Tecnologı´a: CICYT), project REN2002-00432/GLO. References American Public Health Association (APHA), 1998. Standard Methods for the Examination of Water and Wastewater, 19th ed. APHA, Washington, DC. Hamblin, A., 1991. Sustainable agricultural systems: what are the appropriate measures for soil structure? Aust. J. Soil Res. 29, 709 – 715. Martı´nez-Casasnovas, J.A., Ramos, M.C., Ribes-Dasi, M., 2002. Soil erosion caused by extreme rainfall events: mapping and quantification in agricultural plots from very detailed digital elevation models. Geoderma 105 (1 – 2), 125 – 140.
M.C. Ramos, J.A. Martı´nez-Casasnovas / Catena 68 (2006) 177 – 185 Montenegro, H., Malago´n, D., 1990. Propiedades fı´sicas de los suelos. IGAC, Bogota´. 813 pp. Murphy, G., Riley, J.P., 1962. A modified single solution method for the determination of phosphate in natural waters. Anal. Chim. Acta 27, 31 – 36. Oades, J.M., 1984. Soil organic matter and structural stability: mechanisms and implications for management. Plant Soil 76, 319 – 337. Oue´draogo, E., Mando, A.M., Zombre´, N.P., 2001. Use of compost to improve soil properties and crop productivity under low input agricultural system in West Africa. Agric. Ecosyst. Environ. 84, 259 – 266. Pinamonti, F., Zorzi, G., 1996. Experiences of compost use in agriculture and in land reclamation projects. In: De Bertoldi, M., et al. (Eds.), The Science of Composting: Part I. Blackie, Glasgow, UK, pp. 517 – 527. Ramos, M.C., 1999. Rainfall intensity – kinetic energy relationship for NE Spain. Nuovo Cim. 22, 668 – 675. Ramos, M.C., 2002. Differences of the characteristics of the storms recorded along the year in a Mediterranean climate. Intensity and kinetic energy. In: Mugnai, A., Guzetti, F., Roth, G. (Eds.), II Plinius Conference on Mediterranean Storms, Publi GNDCI, vol. 2547, pp. 431 – 440. Ramos, M.C., Martı´nez-Casasnovas, J.A., 2003. Cambios en las propiedades fı´sicas y quı´micas por aplicacio´n de compost en suelos altamente degradados por movimientos de tierras. In: Bienes, R., Marque´s, M.J. (Eds.), Control de la erosio´n y degradacio´n del suelo. I
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Simposio sobre control de la erosio´n y conservacio´n de suelos. Forum Calidad, pp. 275 – 278. Schuman, G.E., Spurner, R.G., Piest, R.F., 1973. Phosphorous losses form four agricultural watersheds on Missouri Valley Loess. Proc.-Soil Sci. Soc. Am. 37, 424 – 427. Soil Survey Staff, 1998. Keys to Soil Taxonomy, 6th edition. U.S. Departament of Agriculture, Soil Conservation Service, Washington, DC. Tisdall, J.M., Oades, J.M., 1982. Organic matter and water stable aggregates in soils. J. Soil Sci. 33, 141 – 163. Tropeano, D., 1983. Soil erosion on vineyards in the Tertiary Piedmontese basin (northwestern Italy): studies on experimental areas. Catena, Suppl. 4, 115 – 127. Uso´n, A., 1998. Medidas de control de la erosio´n en suelos de vin˜a de las comarcas Anoia – Alt Penede`s (Barcelona): efectividad y viabilidad. PhD thesis, University of Lleida, Lleida, p. 260. Wainwright, J., 1996. Infiltration, runoff and erosion characteristics of agricultural land in extreme storm events, SE France. Catena 26, 24 – 47. Wicherek, S., 1991. Viticulture and soil erosion in the North of Parisian Basin. Example: The Mid Aisne Region. Z. Geomorphol. N.F., Suppl.bd. 83, 115 – 126. Wischmeier, W.H., Smith, D.D., 1978. Predicting Rainfall Erosion Losses. A Guide to Conservation Planning, Agricultural Handbook, vol. 537. US Department of Agriculture, Washington, DC.
Erosion rates and nutrient losses affected by composted cattle manure application in vineyard soils of NE Spain M.C. Ramos *, J.A. Martı´nez-Casasnovas Department of Environment and Soil Science, University of Lleida, Alcalde Rovira Roure 191, E-25198 Lleida, Spain
Abstract Land preparation for mechanisation in vineyards of the Anoia – Alt Penede`s region, NE Spain, has required major soil movements, which has enormous environmental implications not only due to changes in the landscape morphology but also due to soil degradation. The resulting cultivated soils are very poor in organic matter and highly susceptible to erosion, which reduces the possibilities of water intake as most of the rain is lost as runoff. In order to improve soil conditions, the application of organic wastes has been generalised in the area, not only before plantation but also every 3 – 4 years at rates of 30 – 50 Mg ha 1 mixed in the upper 30 cm. These organic materials are important sources of nutrients (N and P) and other elements, which could reduce further fertilisation cost. However, due to the high susceptibility to sealing of these soils, erosion rates are relatively high, so a higher nutrient concentration on the soil surface increases non-point pollution sources due to runoff. The aim of this study is to analyse the influence of applied composted cattle manure on infiltration, runoff and soil losses and on nutrients transported by runoff in vineyards of the Alt Penede`s – Anoia region, NE Spain. In the two plots selected for the analysis, composted cattle manure had been applied in alternate rows 1 year previous to the study. In each plot soil surface samples (0 – 25 cm) were taken and compared to those of plots without manure application. The study was carried out at laboratory scale using simulated rainfall. Infiltration rates were calculated from the difference between rainfall intensity and runoff rates, and the sediment and total nitrogen and phosphorus were measured for each simulation. In addition, the influence of compost was investigated in the field under natural rainfall conditions by analysing the nutrient concentration in runoff samples collected in the field (in the same plots) after seven rainfall events, which amount different total precipitation and had different erosive character. Compost application increases infiltration rates by up to 26% and also increases the time when runoff starts. Sediment concentration in runoff was lower in treated (13.4 on average Mg L 1) than in untreated soils (ranging from 16.8 to 23.4 Mg L 1). However, the higher nutrient concentration in soils produces a higher mobilisation of N (7 – 17 Mg L 1 in untreated soils and 20 – 26 Mg L 1 in treated soils) and P (6 – 7 Mg L 1 in untreated soils and 13 – 19 Mg L 1 in treated soils). A major part of the P mobilised was attached to soil particles (about 90% on average) and only 10% was dissolved. Under natural conditions, higher nutrient concentrations were always recorded in treated vs. untreated soils in both plots, and the total amount of N and P mobilised by runoff was higher in treated soils, although without significant differences. Nutrient concentrations in runoff depend on rainfall erosivity but the average value in treated soils was twice that in untreated soils for both plots. D 2006 Elsevier B.V. All rights reserved. Keywords: Soil erosion; Nutrient losses; Vineyards; Compost; Mediterranean climate
1. Introduction The Mediterranean climate is characterised by a complex pattern of spatial and seasonal variability, with * Corresponding author. Tel.: +34 973702092; fax: +34 973 702613. E-mail address: [email protected] (M.C. Ramos). 0341-8162/$ - see front matter D 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.catena.2006.04.004
wide and unpredictable rainfall fluctuations from year to year and with frequent high-intensity rainfall events (Ramos, 2002), which increase the vulnerability of the Mediterranean region to erosion. Crop types and management practices also contribute to erosion processes. Vineyards are among the lands subject to the highest runoff and soil losses: 47– 70 Mg ha 1 year 1 in NW
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M.C. Ramos, J.A. Martı´nez-Casasnovas / Catena 68 (2006) 177 – 185
Italy (Tropeano, 1983), 35 Mg ha 1 year 1 in the Mid Aisne region (France) (Wicherek, 1991), 22 Mg ha 1 year 1 in the Penede`s– Anoia region (NE Spain) (Uso´n, 1998). Even higher soil losses have been associated with extreme rainfall events: 34 Mg ha 1 in a single extreme rainfall event in SE France (Wainwright, 1996) and 207 Mg ha 1 in the study area (Martı´nez-Casasnovas et al., 2002). These erosion processes are accelerated by changes in land use and in cropping patterns adapted for field mechanisation, which eliminate most traditional soil conservation measures. The traditional free-growing vines planted following contour lines and in bench terraces are being replaced with trained vines in rows perpendicular to the maximum slope gradient in most cases. Field mechanisation, which is taking place in some Mediterranean areas, has enabled significant soil movements to reduce slope gradients which, in many cases, has been carried out without preserving the topsoil. Sometimes the more fertile horizon is mixed and buried underneath poorer materials from deeper in the soil profile. This has enormous environmental implications, leading to changes in the landscape morphology and soil degradation. These movements are generating soils with poor structure and a very low organic matter content, which reduce the water holding capacity and increase runoff and erosion. The Anoia – Penede`s area, located in NE Spain, is a clear example of this situation. In order to improve soil conditions, the application of organic waste has been generalised in this area, not only before plantation but also every 3 – 4 years at rates of 30– 50 Mg ha 1 mixed in the upper 30 cm. Recycling these wastes via land application could lead to improvements in the physical properties of a soil, such as soil porosity, structure and water holding capacity (Tisdall and Oades, 1982; Oades, 1984; Hamblin, 1991; Oue´draogo et al., 2001). For this reason the application of organic waste or compost could be beneficial for soil conservation (Pinamonti and Zorzi, 1996), especially in degraded soils and soils susceptible to erosion. In addition, these organic materials are important sources of nutrients (N and P) and other elements, which could further reduce fertilisation costs. However, the intensification of agricultural systems and the use of organic waste to improve soil physical conditions have become a common practice, contributing to the build-up of soil P and N levels in specific areas to levels
rarely encountered in the past. As a result, there is an increase in potential P and N losses from these areas and an environmental risk of surface water pollution associated with runoff from fields to which organic waste has been applied. In addition, due to the high susceptibility to sealing of these soils, erosion rates are relatively high and consequently a higher nutrient concentration in the soil surface increases non-point pollution due to runoff. In the present study, the influence of a single application of composted cattle manure at a rate of 40 Mg ha 1 on vineyard soil from the Alt Penede`s –Anoia region, NE Spain, was evaluated, focusing on the changes in runoff and soil losses and on nutrients transported by runoff at laboratory and field scale.
2. Material and methods 2.1. Study area The study area is located in the Alt Penede`s– Anoia region, NE Spain (X: 400300; Y: 4592700), between the Anoia and Llobregat rivers. Vineyards represent the main land use in the area (about 80% of the cultivated area), being cultivated with the soil bare during most of the year. The area has a Mediterranean climate (dry sub-humid) with an average annual rainfall of about 550 mm, mainly concentrated in spring and autumn. In most cases, the rainfall intensity is higher than 100 mm h 1 during short time periods (Ramos, 2002), which causes major erosion problems, nutrient losses and alterations of the soil surface. The soil moisture regime is xeric and the soil temperature regime is thermic. The annual average temperature is about 15 -C. 2.2. Plot characteristics, soil sampling and nutrient loss assessment The study was conducted on two vineyard plots planted 12 years ago. Similar management practices are applied on these two plots, but while one plot maintains the original soil profile (undisturbed soils: UD), the other one was the result of major land-levelling works before plantation (disturbed soils: D), in which more than 2.5 m of soil was cut from the upper part of the plot and used to fill the lower part. According to Keys of Soil Taxonomy (Soil Survey Staff, 1998), the soils are classified as Typic Calcixerepts
Table 1 Characteristics of the surface soil (0 – 25 cm) of the selected plots included in the study Soil
UD(U) UD(T) D(U) D(T)
pH
7.8 8.2
CE(1:5) (dS m 1)
CaCO3 (%)
OM (%)
Total N (g kg 1)
Total P (mg kg
0.23 0.39 0.18 0.29
52
0.9 1.8 0.4 1.8
0.7 1.6 0.3 1.2
332 787 417 855
34
Texture (USDA) 1
)
Clay (%) 8.6 12 80
Silt (%)
Fine sand (%)
Coarse sand (%)
42.7
30.9
18.5
43
37
UD(U)—untreated undisturbed soil; UD(T)—treated undisturbed soil; D(U) untreated disturbed soil; D(T)—treated disturbed soil.
M.C. Ramos, J.A. Martı´nez-Casasnovas / Catena 68 (2006) 177 – 185
179
Table 2 Runoff rates and sediment concentration obtained after the rainfall simulation carried out in soils of both plots Plot
Time to runoff (min)
Time to constant runoff rate (min)
Runoff (mm)
Runoff rate (%)
Infiltration rate (%)
Sediment concentration (g L 1)
Total sediment (kg m 2)
UD(T) UD(U) D(T) D(U)
7.6 5.1 2.0 1.4
25 15 20 12
22.4 31.4 26.5 45.3
50.0 60.7 72.8 86.0
50.0 39.3 27.2 14.0
13.41 16.80 13.43 23.41*
0.336 0.666 0.452 1.016*
UD(U)—untreated undisturbed soil; UD(T)—treated undisturbed soil; D(U) untreated disturbed soil; D(T)—treated disturbed soil. * Significant differences at 95% confidence level.
and Haplic Xerarents (in the UD plot) and Typic Xerorthents (in the D plot). Vineyards have bare soil for most of the year. The 25-cm upper layer is ploughed several times during the growing season (at least five times from November to June) to eliminate weeds, favour infiltration and force the vines to root deeper. Composted cattle manure was applied to this field 1 year prior to this study at a rate of 40 Mg ha 1 wet weight (28% moisture) in alternate rows. This compost contains in its matrix N and P at concentrations of 22.6 T 0.6 Mg g 1 and 1411 T11 Mg kg 1, respectively. In each field plot, soil surface samples (0 –25 cm) were taken in both treated and untreated soils. Plots, 0.30 m*0.20 m*0.15 m (deep) filled with air-dry soil aggregates < 8 mm diameter were subjected to an 80 mm h 1 simulated rainfall composed of 2.5 mm diameter drops of deionised water
falling freely from drippers 2.5 m above the soil surface. Runoff water was collected at 5-min intervals for 40 min. The eroded soil in suspension and the total volume were measured for each simulation. Water intake rates were calculated from the difference between rainfall intensity and runoff rates. The intensity was calibrated just before and after each simulation. All simulations were done in triplicate. The average of the three replications is shown. Sediment concentration in runoff was determined in aliquots of runoff, which were decanted and dried at 105 -C, and then weighed. For runoff water analysis, an aliquot of each sample was filtered (0.45 Am pore diameter) to analyse dissolved reactive phosphorous (DRP). Other unfiltered acid-digested aliquots were used for total Kjeldahl nitrogen (TKN) and total phosphorous (TP) determinations. P was measured following the method proposed by Murphy and
Fig. 1. Evolution of runoff with time, for soils with and without compost: (a) disturbed plot; (b) undisturbed plot (D(T): disturbed treated, D(U): disturbed untreated; UD(T): undisturbed treated, UD(U): undisturbed untreated).
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Riley (1962), while total N was determined by a distillation procedure (American Public Health Association, 1998). Additional aliquots were used to determine NO3 – N (using a Merkoquant Nitrat-test) and NH4 – N (using a RQflex Ammonium-test). Runoff nutrient concentrations were used in conjunction with runoff water volumes to calculate mass losses of nutrients for each soil. For field assessment, Gerlach type sediment and runoff collectors were installed at the same points at which the samples were taken. At each location one collector was located in the row with added compost and another in an untreated soil. Runoff samples were collected after the main rainfall events throughout the year 2000. An aliquot of the collected runoff samples was filtered and air-dried in order to evaluate sediment concentration. An unfiltered aciddigested sample was used for total phosphorous (TP) and total Kjeldahl nitrogen (TKN) determinations, following the methods explained above. At the same positions, the base infiltration rate was evaluated from rainfall simulation, with the same equipment used in the laboratory. The collectors used in the field allow us to have information about nutrient concentration in runoff at each specific location but not about erosion rates, because they are not installed in delimited plots. However,
an estimation of total nutrient losses for each event was obtained by considering the differences in the base infiltration rate, measured in the field at the same position in soils with and without compost, and assuming that rainfall falling at higher intensity cannot infiltrate and runs off. Rainfall was recorded at 1-min intervals in the experimental field using a tipping-bucket system linked to a datalogger. From these records, the total rainfall amount and intensity were analysed, and the rainfall kinetic energy and the erosivity of each storm were calculated. Kinetic energy was evaluated using the relationship between kinetic energy and rainfall intensity obtained for the experimental area (Ramos, 1999), and the erosivity of the rainfall was estimated according to the erosivity R factor proposed by Wischmeier and Smith (1978), defined as the product of kinetic energy multiplied by the maximum intensity in 30-min periods (R = KE*I30) for each rainfall period. 2.3. Statistical analysis A statistical analysis (Duncan’s mean test and one-way analysis of variance) of runoff volume, sediment concentration in runoff and nutrient losses was done to evaluate
Fig. 2. Evolution of sediment concentration in runoff for treated and untreated soil: (a) undisturbed plot, (b) disturbed plot (D(T): disturbed treated, D(U): disturbed untreated; UD(T): undisturbed treated, UD(U): undisturbed untreated).
M.C. Ramos, J.A. Martı´nez-Casasnovas / Catena 68 (2006) 177 – 185
181
Table 3 Nutrient losses by runoff in treated and untreated soils for both plots (Ns: total nitrogen mobilised during the rainfall simulation; Ps: total P mobilised during the 40 min of rainfall simulation Plot
Total N (mg L
1
)
Total P Concentration (mg L
UD(T) UD(U) D(T) D(U)
15.04 5.19 26.32 7.42
8.93 1.99 19.08 7.09
Mass loss in runoff 1
)
Particulate P (%)
Dissolved P (%)
Ns (kg ha
80.85 91.20 85.71 93.15
21.27 8.80 14.29 6.84
3.37 1.73 6.95 3.18
1
)
Ps (kg ha
1
)
1.43 0.90 5.04 3.20
UD(U)—untreated undisturbed soil; UD(T)—treated undisturbed soil; D(U) untreated disturbed soil; D(T)—treated disturbed soil.
significant differences between treated and untreated soils, using the multi-range test and the Statgraphics 5.1 program.
3. Results and discussion 3.1. Soil characteristics The characteristics of the studied soils are presented in Table 1. In both plots, soils have a relatively high silt + fine sand content (> 50%) and a very low organic matter content
(0.8 –1.9% in the plot with the original soil profile, and 0.16 – 0.53% in the land-levelled plot). Despite the increase in organic matter, 1 year after compost application the improvement in soil aggregate stability was very low (Ramos and Martı´nez-Casasnovas, 2003). The method applied to analyse aggregate stability included different disaggregation processes (slaking, cracking and mechanical breakdown), and significant improvements were only found against slaking and cracking, but not against mechanical breakdown, which is the process that takes place by drop impact. Montenegro and Malago´n (1990) indicated that aggregate stability increases with organic matter content,
Fig. 3. Relationship between nutrient concentration and sediment concentration in runoff: (a) P; (b) N.
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M.C. Ramos, J.A. Martı´nez-Casasnovas / Catena 68 (2006) 177 – 185
particularly when it is less than 2%. However, this was not the case. Calcium carbonate content ranges from 34% to 52 %, and pH varies from 7.8 to 8.2. Total N ranged from 0.3 g kg 1 in the levelled plot to 0.7 g kg 1 in the undisturbed plot, and P ranged from 417 Mg kg 1 in the levelled plot to 332 Mg kg 1 in the undisturbed plot. The concentration of N and P was nearly doubled 1 year after of the compost application. 3.2. Runoff rates and nutrient concentrations at laboratory scale 3.2.1. Runoff rates The runoff rates and sediment concentrations obtained after the rainfall simulation carried out at 80 mm h 1 in each plot, in treated and untreated soils, are presented in Table 2. Significant differences in infiltration rates can be observed between the two plots and between treated and untreated soils within a plot. For the undisturbed plot, runoff rates represented about 60.7% of the rainfall in untreated soils and 50% in treated soils, but very few differences were
found in the time used to reach the minimum infiltration rate (Fig. 1). However, in the disturbed plot, higher runoff rates were observed, representing up to 86% of the rainfall in untreated soils and 72.8% in treated soils. The maximum runoff rates were reached after only 15 min of rainfall in untreated soils, while in treated soils the maximum occurred after 20 or 25 min of rainfall (Fig. 1). Base infiltration improved from 15 mm h 1 in untreated soils to 20 mm h 1 in treated soils in the undisturbed plot and from 10 to 15 mm h 1, respectively, in the disturbed plot. There were also differences in the sediment concentration in runoff between plots and treatments (Fig. 2). The eroded material showed some fluctuations during the first step of the simulation, but after the first minutes tended to decrease until it reached a constant value. In the disturbed plot, the average sediment concentration was 23 g L 1 in untreated soils vs. 13.4 g L 1 in treated soils, whereas in the undisturbed plot the concentrations were significantly lower: 16.8 g L 1 in untreated soils and 13.4 g L 1 in treated soils (Table 2). These values represented soil losses of 0.336 and 0.666 kg m 2, respectively, for treated and untreated undisturbed soils,
Fig. 4. Relationship between nutrient concentration in runoff and soil nutrient concentration: (a) P; (b) N.
M.C. Ramos, J.A. Martı´nez-Casasnovas / Catena 68 (2006) 177 – 185 Table 4 Rainfall characteristics of the analysed periods: total rainfall ( P); KE (kinetic energy); R factor (= KE*MaxI30) Data
P (mm)
KE (MJ ha
9/1 27/3 22/5 27/7 16/9 4/10 4/12
30.8 22.5 57.6 57.8 200.8 24.8 46.4
2.6 3.2 3.1 11.3 38.1 20.3 4.28
1
)
R factor (MJ ha
1
mm h
1
183
can be 75% to 90% of the P transported in runoff. The results are summarised in Table 3. The increase in total P and total N concentration was associated with the higher runoff sediment concentration, as is confirmed by the correlation between particulate phosphorous and total nitrogen and the sediment concentration in runoff (Fig. 3). The rate of dissolved phosphorous increased in runoff in treated vs. untreated soils, but was not significantly correlated with the sediment concentration in runoff. However, N dissolved fractions correlated with the total sediment in runoff. There was also good correlation between the particulate phosphorous in runoff and the total soil P concentration, and between N mobilised by runoff and the total soil N concentration (Fig. 4). Taking into account the observed concentrations and the total runoff volume in each simulation, the total amount of N and P mobilised was evaluated. The results indicated that in treated soils the quantity of N mobilised by runoff is nearly twice that occurring in untreated soils. For P, the amount of nutrient mobilised by runoff in treated soils was about 1.6 times higher than in untreated soil. Mass loss due to a high intensity rainfall (75 – 80 mm h 1), such as that used in the study, which is recorded very often in the study area in short time periods, could imply nutrient losses of about 7 kg ha 1 of N and 5 kg ha 1 of P in a single event, while in untreated soils it would be about 3.2 kg ha 1 of N and P. Those values for one event are higher than the annual losses of N and P found by different authors in rainfed crops, which have been presented as those giving the maximum rates.
)
26.07 26.07 121.8 319.7 624.0 243.2 110.2
while erosion rates in disturbed soils were 0.452 and 1.016 kg m 2 for treated and untreated soils, for the 40-min periods and under the intensity used in the experiment. Significant differences were observed between the two plots and also between treated and untreated soils within the plots, the effect of compost being greater in the disturbed soils. 3.2.2. Nutrient concentration in runoff Due to the high runoff rates, some nutrients are mobilised and transported by runoff, linked to soil particles and dissolved. The average nitrogen and phosphorus concentration in runoff is presented in Table 3. Due to the application of compost, which had large quantities of these two nutrients, nutrient concentrations in treated soils are much higher than in untreated soils, and taking into account that the sediment concentration in runoff was higher in the treated soils, the nutrient concentration in runoff was also higher. For nitrogen, the differences between treated and untreated soils ranged between 15.0 and 5.2 Mg L 1 for the undisturbed plot, and between 26.3 and 7.4 Mg L 1 for the disturbed plot. The fractions presented as nitrate and ammonium were very low. Similar results were observed for phosphorus concentrations. In this case, the differences ranged from 8.9 to 2 Mg L 1 in the undisturbed plot and from 19.1 to 7.1 Mg L 1 in the disturbed plot. In the untreated soils, most of the P transported was linked to soil particles (more than 90%). However, in the treated soils the dissolved fraction increased by up to 21% of the total P mobilised. This result is in agreement with that reported by Schuman et al. (1973), who point out that the particulate P
3.3. Runoff rates and nutrient concentrations at field scale Runoff was collected after seven rainfall periods throughout 2000. The rainfall characteristics are included in Table 4. The analysed events had erosivities (R = Kinetic energy*I30max) ranging from 26 to 624 MJ ha 1 mm h 1, the most erosive being those recorded in autumn. Nutrient concentrations in the runoff samples collected after those rainfall events are presented in Table 5. It is confirmed that also under natural conditions N and P concentrations in runoff are much higher in treated than in
Table 5 Nutrient concentration in runoff collected in treated (T) and untreated (U) soils of two vineyard plots (undisturbed: UD) and disturbed (D) under natural rainfall Rainfall period
9/1 27/3 22/5 27/7 16/9 4/10 3/11
Undisturbed plot (UD)
Disturbed plot (D)
N concentration in runoff (mg L 1)
P concentration in runoff (mg L 1)
N concentration in runoff (mg L 1)
U
T
U
T
U
T
U
T
6.8 3.4 18.9 13.7 5.0 13.6 10.7
17.1 18.4 26.2 14.7 8.6 14.7 33.5
3.5 10.4 2.6 2.8 4.9 10.5 3.7
14.6 13.8 3.1 6.5 10.2 32.2 11.2
11.2 4.4 11.5 2.4 1.04 5.1 10.6
17.6 5.8 28.2 5.1 2.2 6.8 38.2
2.2 1.5 2.2 1.3 12.6 9.4 3.2
6.3 2.7 6.3 3.1 25.9 10.2 7.5
P concentration in runoff (mg L 1)
184
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Fig. 5. Estimated total nitrogen and total phosphorous lost by runoff under natural rainfall in seven events of different erosive character in treated and untreated soils: (a) undisturbed plot; (b) disturbed plot.
untreated soils: the nutrient concentration is on average twice the value in treated than in untreated soils for both total N and total P, although it depends on rainfall characteristics. By considering the differences in the base infiltration rate, measured in the field at the same position in soils with and without compost, and assuming that rainfall falling at higher intensity cannot infiltrate and runs off, nutrient losses for each event were estimated. This information is summarised in Fig. 5 for 7 events. It is observed that in both plots total P losses are higher in treated than in untreated soils: 1.84 and 1.57 times higher on average in treated vs. untreated soils for the undisturbed and the disturbed plot, respectively. Total N losses were also higher in treated than in untreated soils in the disturbed plot (1.4 times higher in treated vs. untreated soils), but there were no significant differences in the undisturbed plot for all the analysed events, although in some of them we found soil loses higher than twice in treated than in untreated soils. A significant linear regression was also observed between P losses and rainfall erosivity estimated by the R factor (KE*I30) in treated and untreated soils in both plots. However, the relationship between N losses and the erosivity was not significant.
4. Conclusions Composted cattle manure applied to the soils showed a positive effect, improving infiltration and decreasing runoff volumes by up to 20%. This involves beneficial effects for soils that are highly degraded due to land-levelling works
and a reduction in the cost of fertilisation. Although the total of soil particles mobilised by runoff decreases with compost application due to the higher nutrient concentration in the surface layer, where the compost is mixed, the nutrient concentration in runoff increases. Therefore, the total amount of N and P mobilised by runoff, which can reach streams, will reduce surface water quality. In the present study, the N and P concentrations in runoff generated in treated soils were nearly twice those in untreated soils for the rainfall recorded in the study area. These results suggest the need to find alternative waste or products to improve soil properties in order to avoid the presence of high surface nutrient concentrations which lead to water pollution. Acknowledgements This study was financially supported by the Spanish Government (Comisio´n Interministerial de Ciencia y Tecnologı´a: CICYT), project REN2002-00432/GLO. References American Public Health Association (APHA), 1998. Standard Methods for the Examination of Water and Wastewater, 19th ed. APHA, Washington, DC. Hamblin, A., 1991. Sustainable agricultural systems: what are the appropriate measures for soil structure? Aust. J. Soil Res. 29, 709 – 715. Martı´nez-Casasnovas, J.A., Ramos, M.C., Ribes-Dasi, M., 2002. Soil erosion caused by extreme rainfall events: mapping and quantification in agricultural plots from very detailed digital elevation models. Geoderma 105 (1 – 2), 125 – 140.
M.C. Ramos, J.A. Martı´nez-Casasnovas / Catena 68 (2006) 177 – 185 Montenegro, H., Malago´n, D., 1990. Propiedades fı´sicas de los suelos. IGAC, Bogota´. 813 pp. Murphy, G., Riley, J.P., 1962. A modified single solution method for the determination of phosphate in natural waters. Anal. Chim. Acta 27, 31 – 36. Oades, J.M., 1984. Soil organic matter and structural stability: mechanisms and implications for management. Plant Soil 76, 319 – 337. Oue´draogo, E., Mando, A.M., Zombre´, N.P., 2001. Use of compost to improve soil properties and crop productivity under low input agricultural system in West Africa. Agric. Ecosyst. Environ. 84, 259 – 266. Pinamonti, F., Zorzi, G., 1996. Experiences of compost use in agriculture and in land reclamation projects. In: De Bertoldi, M., et al. (Eds.), The Science of Composting: Part I. Blackie, Glasgow, UK, pp. 517 – 527. Ramos, M.C., 1999. Rainfall intensity – kinetic energy relationship for NE Spain. Nuovo Cim. 22, 668 – 675. Ramos, M.C., 2002. Differences of the characteristics of the storms recorded along the year in a Mediterranean climate. Intensity and kinetic energy. In: Mugnai, A., Guzetti, F., Roth, G. (Eds.), II Plinius Conference on Mediterranean Storms, Publi GNDCI, vol. 2547, pp. 431 – 440. Ramos, M.C., Martı´nez-Casasnovas, J.A., 2003. Cambios en las propiedades fı´sicas y quı´micas por aplicacio´n de compost en suelos altamente degradados por movimientos de tierras. In: Bienes, R., Marque´s, M.J. (Eds.), Control de la erosio´n y degradacio´n del suelo. I
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Simposio sobre control de la erosio´n y conservacio´n de suelos. Forum Calidad, pp. 275 – 278. Schuman, G.E., Spurner, R.G., Piest, R.F., 1973. Phosphorous losses form four agricultural watersheds on Missouri Valley Loess. Proc.-Soil Sci. Soc. Am. 37, 424 – 427. Soil Survey Staff, 1998. Keys to Soil Taxonomy, 6th edition. U.S. Departament of Agriculture, Soil Conservation Service, Washington, DC. Tisdall, J.M., Oades, J.M., 1982. Organic matter and water stable aggregates in soils. J. Soil Sci. 33, 141 – 163. Tropeano, D., 1983. Soil erosion on vineyards in the Tertiary Piedmontese basin (northwestern Italy): studies on experimental areas. Catena, Suppl. 4, 115 – 127. Uso´n, A., 1998. Medidas de control de la erosio´n en suelos de vin˜a de las comarcas Anoia – Alt Penede`s (Barcelona): efectividad y viabilidad. PhD thesis, University of Lleida, Lleida, p. 260. Wainwright, J., 1996. Infiltration, runoff and erosion characteristics of agricultural land in extreme storm events, SE France. Catena 26, 24 – 47. Wicherek, S., 1991. Viticulture and soil erosion in the North of Parisian Basin. Example: The Mid Aisne Region. Z. Geomorphol. N.F., Suppl.bd. 83, 115 – 126. Wischmeier, W.H., Smith, D.D., 1978. Predicting Rainfall Erosion Losses. A Guide to Conservation Planning, Agricultural Handbook, vol. 537. US Department of Agriculture, Washington, DC.