Nitrogen and carbon mineralization in soils amended with biofumigant or non-biofumigant plant materials

G Model

ARTICLE IN PRESS

INDCRO-8048; No. of Pages 8

Industrial Crops and Products xxx (2015) xxx–xxx

Contents lists available at ScienceDirect

Industrial Crops and Products journal homepage: www.elsevier.com/locate/indcrop

Nitrogen and carbon mineralization in soils amended with biofumigant or non-biofumigant plant materials Rosa Marchetti a,∗ , Luca Lazzeri b , Lorenzo D’Avino c , Gilda Ponzoni a a Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria, Unità di ricerca per la suinicoltura (CRA-SUI), Via Beccastecca 345, 41018 San Cesario sul Panaro, Modena, Italy, b Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria, Centro di ricerca per le colture industriali (CRA-CIN), Via di Corticella, 133, 40128, Bologna, Italy c Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria, Centro di ricerca per l’agrobiologia e la pedologia (CRA-ABP), via di Lanciola 12/A, 50125 Cascine del Riccio, Firenze, Italy

a r t i c l e

i n f o

Article history: Received 2 July 2014 Received in revised form 28 February 2015 Accepted 28 April 2015 Available online xxx Keywords: Brassicaceae Defatted seed meals Green manure Nitrogen mineralization Carbon mineralization

a b s t r a c t Biofumigant plant materials from Brassicaceae are rich in nutrients and could represent an interesting source of organic nitrogen for crops, when used as soil amendments. In this study, we evaluated in two laboratory experiments the nitrogen and carbon mineralization in soil amended with glucosinolatecontaining (Brassica carinata defatted seed meals and Brassica juncea green manure) or non-containing (carinata crop residues, and sunflower) plant materials. In the first experiment, two soils of contrasting texture (a loam and a silty clay) were amended with carinata defatted seed meals, B. juncea green manure, carinata crop residues and un-amended control. In the second experiment, a loam soil amended with carinata and sunflower defatted seed meals obtained by mechanical and solvent extraction were compared. The amount of mineralized nitrogen at the end of a 3-month incubation period was on average 56.6% of the added nitrogen in soil amended with carinata seed meals, and 39% in soil amended with B. juncea green manure, whereas nitrogen immobilization occurred in soil amended with carinata crop residues. Inorganic nitrogen release was faster in soil amended with carinata defatted seed meals. These results were related to carbon to nitrogen ratio in the plant materials. The soil type did not affect N mineralization of the amendments. No negative effect on mineralization could be attributed to the presence of glucosinolates or to the oil extraction method. Biofumigant defatted seed meals from carinata, used as soil amendments, release interesting inorganic-nitrogen amounts into soil and could therefore substitute chemical nitrogen fertilizers for crop nutrition. © 2015 Elsevier B.V. All rights reserved.

1. Introduction Green manure of Brassicaceae containing glucosinolates is able to play a biofumigant effect in soil and has been utilized for the biological control of some soilborne plant pests and nematodes (Matthiessen and Kirkegaard, 2006; Curto et al., 2008; Larkin and Griffin, 2007). It represents a natural alternative approach to the use of chemical fumigants, such as metam sodium (Pinkerton et al., 2000; Rowe and Powelson, 2002; McGuire, 2004) or methyl bromide (Lazzeri et al., 2004; Mattner et al., 2008), which entered in phase-out several years ago. The utilization of biofumigant green

Abbreviations: DSMs, defatted seed meals. ∗ Corresponding author. Tel.: +39 059926268; fax: +39 059928371. E-mail addresses: [email protected] (R. Marchetti), [email protected] (L. Lazzeri).

manure crops can be partially or totally replaced by glucosinolatecontaining defatted seed meals (DSMs) (Handiseni et al., 2013), that are by-products of Brassicaceae seed defatting and biodiesel industry. Defatted seed meals can be more easily managed than green manure in field applications, because they are less subject to constraints in timing of incorporation into soil and the amounts to be incorporated can be quantified more easily. The decline in soil organic matter in many Mediterranean semiarid agricultural areas is associated with a decrease in soil fertility (Moreno-Cornejo et al., 2014). Whether acting as biofumigants or not, DSMs as well as green manure may improve soil fertility (Moore, 2011; Mohammadi and Rokhzadi, 2012) through incorporation of large organic matter amounts potentially suitable as nutrient sources for crops (Kumar and Goh, 2000; ThorupKristensen et al., 2003). Organic carbon (C) and organic nitrogen (N) mineralization are tightly linked processes. While the influence of crop residue char-

http://dx.doi.org/10.1016/j.indcrop.2015.04.062 0926-6690/© 2015 Elsevier B.V. All rights reserved.

Please cite this article in press as: Marchetti, R., et al., Nitrogen and carbon mineralization in soils amended with biofumigant or non-biofumigant plant materials. Ind. Crops Prod. (2015), http://dx.doi.org/10.1016/j.indcrop.2015.04.062

G Model

ARTICLE IN PRESS

INDCRO-8048; No. of Pages 8

R. Marchetti et al. / Industrial Crops and Products xxx (2015) xxx–xxx

2

Table 1 Selected chemical characteristics (mean ± standard deviation) of the plant materials used in the experiments. DM: dry matter; FW: fresh weight. Parameter

Brassica juncea green manure

Carinata defatted seed meals

Carinata crop residues

(Mechanical pressing) Moisture, % FW Total C, % DM Kjeldahl N, % DM Ashes, % DM C/N Oil, % DM Glucosinolates, ␮mol g−1 DM

75.2 ± 1.8 43.4 ± 0.4 2.5 ± 0.2 9.9 ± 1.6 17.5 Tr 10.7 ± 0.6

6.6 ± 1.5 47.9 ± 0.1 6.1 ± 0.8 6.6 ± 0.3 7.9 10.8 ± 0.1 90.3 ± 2.0

6.6 ± 0.8 47.0 ± 0.3 0.6 ± 0.2 7.5 ± 0.9 75.7 Tr Tr

Sunflower defatted seed meals (Mechanical pressing/hexane)

(Mechanical pressing)

7.7 ± 1.2 47.5 ± 0.4 5.4 ± 0.3 6.9 ± 0.4 8.9 0.8 ± 0.1 Absent

8.3 ± 0.4 42.7 ± 0.3 4.7 ± 0.4 6.4 ± 0.2 9.1 12.8 ± 0.2 Absent

Tr = traces.

acteristics on rate and extent of soil inorganic N availability and CO2 –C release is well known (Mary et al., 1996; Trinsoutrot et al., 2000), information on the influence of biochemical composition, and particularly glucosinolate effect, on N and C mineralization of Brassicaceae defatted seed meals is still scarce. Fresh organic matter decomposition also depends on the soil type. In particular, the soil pore size distribution influences the accessibility of organic substrates to soil organisms (Hassink, 1992). Thomsen et al. (1999) found a high correlation between CO2 release from crop residue decomposition and water retained in soil pores with diameters >0.2 ␮m. Little is known on C and N mineralization patterns of different DSMs when incorporated into soils with different texture. The most critical point in the management of organic amendments as N sources is the difficulty to predict the right time for their incorporation into soil, depending on the pattern of N release (Mohanty et al., 2011). Green manure from leguminous crops releases N early after incorporation, and high amounts of clover N are generally mineralised within a month (Båth, 2000) whereas, on the contrary, crop residues may reduce soil inorganic N availability, due to N immobilization in microbial biomass. Knowledge on C and N mineralization dynamics in soils amended with glucosinolatecontaining plants or DSMs is not yet well established. Improvement in this knowledge should help in estimating the most suitable incorporation time, in tune with the nutrition needs of the crops. The organic C and N mineralization in soil is carried out by several groups of microorganisms. The effect of glucosinolatecontaining plant materials on their activities has been the subject of debate. Glucosinolates are responsible for allelochemical effects (Brown and Morra, 1997), even if their toxicity varies with the type of degradation product and the type of organism involved (Brown et al., 1991; Scott and Knudsen, 1999; Bending and Lincoln, 2000; Reardon et al., 2013). A better understanding of the relationship between type of amendment and type of involved organisms could help to explain these seemingly contradictory results. The overall objective of this study was to evaluate the fertilizing contribution of biofumigant DSMs in terms of available N for crops. Nitrogen and C mineralization in soil amended with carinata DSMs was compared with that in soil amended with other plant materials usable as soil amendments: B. juncea green manure and carinata crop residues. Glucosinolate-containing B. juncea was chosen because it is recognized as the most effective species in biofumigant green manuring (Lazzeri et al., 2003), whereas carinata crop residues were included because, though deriving from a biofumigant crop, are nearly glucosinolate-free, and may be assimilated to crop residues commonly used as soil amendments. Two soils of contrasting texture, a loam and a silty clay, were included in the evaluation to investigate the response variability due to soil textural class. The variability in DSMs N and C mineralization due to different glucosinolate and oil content was also tested by comparing carinata glucosinolate-containing and sun-

flower glucosinolate-non containing DSMs obtained with different oil extraction technologies. 2. Materials and methods 2.1. Plant materials and soils Three types of DSMs were tested (Table 1): a meal obtained from seeds of Brassica carinata A. Brown (common names: carinata, Ethiopian mustard) and two DSMs from Helianthus annuus L. (sunflower). The carinata DSMs were obtained by mechanical oil extraction after a patented procedure aimed at optimizing isothiocyanate release over time (Lazzeri et al., 2010; Lazzeri et al., 2011), and purchased from Agrium Italia S.p.A. (Livorno, Italy). The sunflower DSMs were obtained by pressing extraction at the Scaramagli plant in Ferrara, Italy, or by pressing/hexane extraction at Italcol S.p.A. (Castelfiorentino, Firenze, Italy). B. juncea L. Czern. sel. ISCI99 (common name: Indian mustard) and carinata crops were grown in small plots at the CRA-CIN experimental farm of Budrio (Bologna, Italy; 44◦ 32 13 N, 11◦ 29 40 E, altitude 29 m. asl). At full flowering time, B. juncea plants were harvested, immediately taken to the laboratory and finely cut in a grinder mill just before incorporation into soil. Carinata seeds were harvested at seed technological maturity. After seed removal, crop residues were dried at 65 ◦ C and milled at 1 mm. Selected analytical parameters for characterization of the plant materials are reported in Table 1. Soil samples were collected in the top 0.2-m soil profile, at Bovolone, Verona (BV soil), San Cesario sul Panaro, Modena (SCe soil), and Pisa (PI soil). These sampling sites are located in experimental farms of selected CRA research centers (BV and SCe soils, in the Po Valley) and of Pisa University (PI soil, in Tuscany). Selected soil characteristics are reported in Table 2. 2.2. Experimental design and microcosm incubations Mineralized N and C were measured in 2 laboratory experiments, organized in randomized complete block designs with 3 (Exp. I) or 4 (Exp. II) replications. Experiment I (Exp. I). Mineralized N and C were measured in a loam (BV) and a silty clay (SCe) soil amended with carinata DSMs, B. juncea green manure and carinata crop residues. The amounts of amendments corresponding to those adopted in the current field practice were incorporated into soil (Table 3). Experiment II (Exp. II). Mineralized N and C were measured in a loam soil (PI) amended with carinata DSMs in comparison with sunflower DSMs produced by mechanical pressing or mechanical pressing/hexane extraction. In this experiment, the comparison was based on the same amount of incorporated N (100 kg N ha−1 ). The incorporation of fresh organic matter into moist soil on a volume basis (gram fresh weight L−1 moist soil) entailed the supply of

Please cite this article in press as: Marchetti, R., et al., Nitrogen and carbon mineralization in soils amended with biofumigant or non-biofumigant plant materials. Ind. Crops Prod. (2015), http://dx.doi.org/10.1016/j.indcrop.2015.04.062

G Model INDCRO-8048; No. of Pages 8

ARTICLE IN PRESS R. Marchetti et al. / Industrial Crops and Products xxx (2015) xxx–xxx

3

Table 2 Selected properties of the soils used in the experiments. In parentheses, the sampling locations. Soil Parameter

BV (Bovolone)

PI (Pisa)

SCe (San Cesario)

Textural class (USDA) Sand % Silt % Clay % Bulk density, g cm−3 Water content at wilting point, %vol Water content at field capacity, %vol Available water content, %vol Organic C, g kg−1 Kjeldahl N, g kg−1 Inorganic N, mg kg−1 pH Ca carbonate, g kg−1 C/N CEC, cmol(+) kg−1

Loam 46.4 40.2 13.4 1.14 8.2 20.4 12.2 7.1 0.80 18.7 8.3 29 8.9 16

Loam 46 40 14 1.36 9.4 22.3 11.1 6.3 0.80 22.5 8.0 78 7.9 19

Silty clay 8.5 44.7 46.8 1.00 25.9 40.0 14.1 15.6 1.78 4.4 8.2 28 8.8 27

different amounts of dry matter per kilogram of dry soil. Details on the experiments are given in Table 3. The method proposed by Drinkwater et al. (1996) was used for the soil incubations, in both experiments. Soil moisture was adjusted with distilled water to bring the soil to 75% available water content. The corresponding moisture values (on a volume basis), calculated as the sum of soil moisture at wilting point plus soil moisture at 75% available water content, were 17.4%, 17.7% and 36.5% for the BV, PI and SCe soil, respectively. The vials were placed in plastic boxes. Measurements were performed at the start of the experiments and after 7, 14, 28, 60, and 90 days of incubation. The boxes, closed by lids, were kept in the dark in a laboratory incubator at 30 ◦ C. Once or twice per week, the vials were aerated and the moisture losses were checked by weighing and adjusted with distilled water at 75% available water content. At each date of measurement, the CO2 –C release was measured (except at time 0), and selected vials (3 or 4 for each treatment, depending on the experiment) were removed from the incubator and stored at −20 ◦ C until analysis for inorganic N extraction and measurement.

dried samples according to Page et al. (1982). Available water content was estimated from particle size distribution and organic matter content using a pedotransfer function (Saxton and Rawls, 2006). Soil inorganic N (inorganic N = NO3 − N + NO2 − N + NH4 − N) was extracted from the frozen soil samples, after thawing them at room temperature, by using 2 mol L−1 KCl (soil/solution ratio 1:5) and measured colorimetrically with an automatic analyzer (AutoAnalyzer 3; Bran + Luebbe GmbH, Norderstedt, Germany) according to Keeney and Nelson (1982). The net mineralized N over time was determined according to Drinkwater et al. (1996) after subtraction of the baseline inorganic N, that is the amount of inorganic N already present in soil after amendment, at the start of the experiment. The mineralized C was determined according to Rice et al. (1996) as cumulative CO2 –C released over time after subtraction of the air CO2 –C amount. Values were expressed as milligrams of inorganic N or CO2 –C released per kilogram of dry soil, or per gram of added N or C. 2.4. Data analysis and statistical procedures

2.3. Chemical analyses Dry matter, ash, total N, oil, and glucosinolate contents of the plant materials were determined using the methods reported in Lazzeri et al. (2011). The total C content was evaluated by multiplying the organic matter content by the factor 0.51. This factor was obtained by series of measurements of total C content on the same plant materials, using an elemental analyzer (LECO, CHN Truspec), according to the American Society for Testing Materials (ASTM D5373). Soil texture, pH, cation exchange capacity (CEC), and organic C, Kjeldahl N, and Ca carbonate contents were determined on air-

For each soil, values of mineralized N or C in the un-amended soil were subtracted from each treatment to remove the soil contribution, assuming no priming effect in the soil. When N immobilization occurred (negative values of mineralized N), N remineralization was estimated by subtracting the amount of N mineralized after 4 weeks per unit weight of N or C to that mineralized after a 3-month incubation (Mary et al., 1996). Analysis of variance (ANOVA) was performed using the PROC MIXED procedure of the SAS statistical package (Littell et al., 1996). Multiple comparisons of the means were carried out using the SAS LSMEANS statement. Factor and factor-interaction effects were

Table 3 Amounts of amendments incorporated into soil. FW: fresh weight. Soil

Treatment

Amount g FW L-1 moist soil

Amount t FW ha-1

Dry matter g kg-1 dry soil

Experiment I Loam (BV); Silty clay (SCe)

Carinata defatted seed meals

1.79

2.5

Carinata crop residues

5.7

8

B. juncea green manure

36

50

1.59 (BV) 2.01 (SCe) 5.14 (BV) 6.49 (SCe) 8.62 (BV) 10.90 (SCe)

Carinata defatted seed meals Sunflower defatted seed meals (mechanical pressing) Sunflower defatted seed meals (mechanical pressing/hexane)

0.79 0.79 0.79

1.1 1.1 1.1

Experiment II Loam (PI)

0.78 0.83 0.83

Please cite this article in press as: Marchetti, R., et al., Nitrogen and carbon mineralization in soils amended with biofumigant or non-biofumigant plant materials. Ind. Crops Prod. (2015), http://dx.doi.org/10.1016/j.indcrop.2015.04.062

G Model INDCRO-8048; No. of Pages 8

ARTICLE IN PRESS

315B Treatment means followed by equal letters are not significantly different at P < 0.05 according to the LSD test. Lowercase letters compare treatments, uppercase letters compare soils.

– – 1762A – – – – – –

41.9A

349bc 0.152b 1648a 2831a 21b 365a 3b 54b 4.72 0.27

51.9b

322c 0.050b 919b 1931b −4c −10c 2.85 0.04

7.5e

−741c

−313b

– 273c

446A –

– 0.357a – 243c

– 1007B

1033d 1253c – 67a

– –

– 554a – 38a

–

– 318a

– 12.4B

37.2c 71.2a – 0.89

– –

Un-amended soil Carinata defatted seed meals Carinata crop residues B. juncea green manure Mean SCe

– 0.107

454a 0.149b 1697a 2014b 24b 416a 3a 21b 3.74 0.214

23.5d

458a 0.059b 1036b 1270c −12c −858a −1034d 2.26 0.032

−22.3f

−15a

– 426ab – 0.179b – 298c 215f 528e – 70a – 579a – 39a – 318a 10.8e 37.8c – 0.7

Un-amended soil Carinata defatted seed meals Carinata crop residues B. junceagreen manure Mean BV

– 0.085

mg g-1 added C d-1 mg kg-1 dry soil mg kg-1 dry soil mg g-1 added C mg g-1 added N mg g-1 added C mg g-1 added N g kg-1 dry soil g kg-1 dry soil

mg kg-1 dry soil

Mineralized C after 3 months and model parameters C0 Mineralized N after 3 months C0 k CO2 -C

After a 4-week incubation, the mineralized N per kilogram of dry soil was higher in the soils amended with carinata DSMs than in the un-amended soil and in the soil amended with B. juncea green manure (Exp. I; Table 4). In soils amended with carinata crop residues the mineralized N was lower than that of the un-amended control (SCe soil), or it was negative (BV soil). In all treatments, the mineralized N was mainly nitrate-N. At the start of the incubation the ammonium-N content (Fig. 1) was higher in the soil amended with B. juncea green manure than in the other treatments; it increased just after incorporation in the soil amended with carinata DSMs. In both cases, however, ammonium-N nearly disappeared within two weeks from the start of the experiment. In both soils, 4 weeks after the start of the experiment, the amount of N mineralized was on average 31.8% of the added N for carinata DSMs, and only 3.7% for B. juncea green manure. In the soils amended with carinata crop residues the net inorganic N content decreased between 74 and 103% of the added N, depending on the soil. Clearly, N immobilization occurred, also involving the inorganic N released by the bulk soil. Three months after the start of incubation, the amount of mineralized N was on average 56.6% of the added N for carinata DSMs, and 39.1% for B. juncea green manure, whereas the amount of net N immobilized in the soil amended with carinata crop residues was 85.8% of the added N in the loam and 31.3% in the silty clay soil. The amount of mineralized N per gram of added C was on average 38.5 mg for carinata DSMs and 3 mg for B. juncea green manure, after 4 weeks. It was on average 68.5 mg for carinata DSMs and 22.5 mg for B. juncea green manure, after 3 months. Negative values were measured for the carinata crop residues. Lower negative values for net N mineralization in soil after 3 months, in comparison with those after 4 weeks, mean that a remineralization occurred during the incubation period (Fig. 2) in soils amended with carinata crop residues. A remineralization occurred also in the soil amended with B. juncea green manure, as the net N mineralized in this soil per gram of added N or C was much higher 3 months after the start of the incubation than after 4 weeks. Cumulative CO2 –C release values, fitted to a first-order kinetic model, gave rise to models all with F values with P < 0.0001. The highest C mineralization potential per kilogram of dry soil (C0 ) was measured for the soils amended with B. juncea green manure, the lowest for the soils amended with carinata DSMs, without significant differences in the mineralization rate constants, apart from the case of carinata DSMs in the SCe silty clay soil, presenting a higher k value. The amount of potentially mineralizable C, C0 , in milligram per kilogram of dry soil, was proportional to the amount of added C. However, when considering C0 in milligram per gram of added C, no differences were detected between treatments, within each soil type.

Mineralized N after 4 weeks

3.1. Defatted seed meals vs green manure and crop residues

Added C

3. Results

Added N

where: C0 , potentially mineralizable C; k, mineralization constant rate; t, time.

Treatment

ReleasedCO2 –C = C 0 [1−e−kt ],

Soil

considered significant at P < 0.05. The Fisher’s LSD test (P < 0.05) was used to compare treatment mean values. On the basis of a preliminary inspection of the plots, a first order kinetic model was chosen to fit data of CO2 –C release for each replication of each treatment. Fitting was performed by means of a non-linear regression procedure, using the SAS package. The kinetic model form was:

Table 4 Net N and C mineralization in two soils of contrasting texture amended with carinata defatted seed meals, in comparison with carinata crop residues and B. juncea green manure (Exp. I). Values per unit weight of added N or C, as well as the parameters of the first order kinetic model of C mineralization, were calculated after removal of N mineralized or CO2 –C released by the un-amended soil. C0 : potentially mineralizable C; k: C mineralization rate constant.

R. Marchetti et al. / Industrial Crops and Products xxx (2015) xxx–xxx

4

Please cite this article in press as: Marchetti, R., et al., Nitrogen and carbon mineralization in soils amended with biofumigant or non-biofumigant plant materials. Ind. Crops Prod. (2015), http://dx.doi.org/10.1016/j.indcrop.2015.04.062

G Model

ARTICLE IN PRESS

INDCRO-8048; No. of Pages 8

R. Marchetti et al. / Industrial Crops and Products xxx (2015) xxx–xxx

a)

20 15 10 5

25

NH4-N, mg N kg-1 dry soil

NH4-N, mg N kg-1 dry soil

25

5

0

b)

20 15 10 5 0

0

20

40 60 Days of incubaon

80

100

0

20

40 60 Days of incubaon

100

80

Fig. 1. Soil ammonium-N (NH4 -N) content (including soil and plant amendment contribution) during incubation of BV loam (a) and SCe silty clay (b) soils amended with carinata defatted seed meals (black dots), carinata crop residues (black triangles), B. juncea green manure (white squares) vs un-amended control (white dots).

Four weeks after the start of the incubation, N mineralization was on average much higher in the SCe silty clay than in the BV loam soil (Table 4). However, when referring the mineralized N to the amount of added N or C, differences between soils became less evident. Only for carinata crop residues, N immobilization was lower in the silty clay soil than in the loam soil. Nitrogen remineralization in soil amended with carinata crop residues and B. juncea green manure started earlier in the SCe silty clay than in the BV loam soil (Fig. 2). Carbon mineralization per kilogram of dry soil at the end of the incubation period was much higher in the SCe silty clay than in the BV loam soil (1762 mg kg−1 dry soil in SCe vs 1007 mg in BV, on average). However, no differences in C0 per gram of added C were detected between plant materials within each soil. In contrast, the C0 value per gram of added C in the silty clay soil was on average 71% of that in the loam soil. 3.3. Defatted seed meals glucosinolate and oil content After a 4-week incubation, there were no differences in mineralized N between DSMs containing or non-containing glucosinolates. Mineralized N varied between 49.0 and 55.6% of the added N (Exp. II, Table 5). At the end of the incubation period, the amount of mineralized N had not changed, in comparison with that measured after 4 weeks. This means that the low amount of incorporated organic N had completely mineralized within a month. The mineralized N varied between 56 and 63 mg per gram of added C, 4 weeks after the start of the incubation, and between 46 and 69 mg, 3 months after the start of the incubation. Even though the N mineralized in the soil amended with sunflower seed meals defatted by mechanical pressing (with higher oil content) was lower than that in the soil amended with sunflower meals defatted by the combination of mechanical and solvent extraction, differences were not significant.

Nmin, mg N kg-1 dry soil

300

a)

250 200 150 100 50 0

The amount of organic C mineralized in 3 months was the same for the compared treatments, as well as the potentially mineralizable C, C0 , either referred to the weight unit of dry soil or to the amount of added C. The model F values were less satisfactory than those in the first experiment, as the probability P of F being higher than the critical F value varied between 0.0045 and 0.038. This could be because the fitting to a first-order model was applied to data of the whole incubation period, whereas the CO2 –C release occurred mainly in the first month of incubation. In the following 2 months, the CO2 –C release from the amended soils was linear and parallel to that from the control soil (data not shown). 4. Discussion 4.1. Amendment effect The amount of N mineralized after 4 weeks may be considered as an index of readily available N for crops (Doran and Parkin, 1996). After 4-week incubation, net N mineralization in soil amended with carinata DSMs was higher and faster than in soils amended with carinata crop residues and B. juncea green manure. Therefore, carinata meals seem a more suitable N source when the need exists of a timely N availability for crops. The amount of N mineralized in soils amended with carinata (31.8% of the added nitrogen, in Exp. I; 55.6% in Exp. II) was analogous to that reported by Galvez et al. (2012) for 0.5% rapeseed (B. napus) meal incorporated into an alkaline and a slightly acidic soil. They found 126 mg inorganic N kg−1 soil on average (41.9% of added N), after a month of incubation, without significant differences between soil types. These results can be explained in terms of C to N ratio (Trinsoutrot et al., 2000; Trinsoutrot et al., 2000): the carinata DSMs had a C to N ratio (7.9) lower than that of carinata crop residues (75.7) and B. juncea green manure (17.5; Table 1). On the contrary, no relationship was found between mineralized N and added N or C, in agreement with Frankenberger and Abdelmagid (1985) and other authors. 300

Nmin, mg N kg-1 dry soil

3.2. Soil type

b)

250 200 150 100 50 0

0

20

40 60 Days of incubaon

80

100

0

20

40 60 Days of incubaon

80

100

Fig. 2. Soil inorganic-N (Nmin) content (including soil and plant amendment contribution) during incubation of BV loam (a) and SCe silty clay (b) soils amended with carinata defatted seed meals (black dots), carinata crop residues (black triangles), B. juncea green manure (white squares) vs un-amended control (white dots).

Please cite this article in press as: Marchetti, R., et al., Nitrogen and carbon mineralization in soils amended with biofumigant or non-biofumigant plant materials. Ind. Crops Prod. (2015), http://dx.doi.org/10.1016/j.indcrop.2015.04.062

G Model

ARTICLE IN PRESS

INDCRO-8048; No. of Pages 8

R. Marchetti et al. / Industrial Crops and Products xxx (2015) xxx–xxx

494a 0.132a 183a 61a 540a

591a

574a 0.126a 212a 46a 405a

636a

687a 254a 69a 616a

314b 677a

0.062a

62a 0.042 −

551a 41.0a 0.37

56a 0.042 −

490a 38.5a 0.37

63a 556a 17.9b 41.3a 0.37 0.042 − +

Un-amended soil Carinata (mechanical pressing) Sunflower (mechanical pressing) Sunflower (mechanical pressing/hexane)

Treatment means followed by equal letters are not significantly different at P < 0.05 according to the LSD test.

C0 mg g−1 added C k d−1 C0 mg kg−1 dry soil CO2 -C mg kg−1 dry soil mg g−1 added C mg g−1 added N mg kg−1 dry soil g kg−1 dry soil g kg−1 dry soil

mg g−1 added C

mg g−1 added N

Mineralized C after 3 months, and model parameters Mineralized N after 3 months Added C Added N Glucosinolate

Mineralized N after 4 weeks

No relationship was found between N and C mineralization, also in agreement with other authors, as the highest extent of N mineralization was found in soil amended with carinata DSMs, despite the higher amount of CO2 –C released from the soil amended with B. juncea green manure. The higher CO2 –C release detected after a 3-month incubation from the soil amended with B. juncea could be due to the moisture contribution of the fresh organic matter, when incorporated into soil. Water supplied with fresh tissues increases the water content of the soil, with effects on soil respiration (Cook and Orchard, 2008). After 3-month incubation, N mineralization in soil amended with B. juncea green manure varied between 36.5% and 41.6% of the added N, depending on the soil, and was in the range of values reported for green manure of glucosinolate-containing or noncontaining plant materials by other authors. Chaves et al. (2004), 4 months after the incorporation of rye grass (Lolium perenne L.) and white mustard (Sinapis alba L.) green manure in soil, measured an amount of mineralized N in the range of 16.2–54.9% of the total N. The extent of N immobilization by carinata crop residues (between 4 and 15 g N kg−1 added C, depending on soil type and time of measurement) was included in the range reported by Trinsoutrot et al. (2000). They examined 47 types of crop residues and found that N immobilization after incorporation occurred in 96% of the cases, and it varied between 1 and 33 g N kg−1 of added C. A remineralization occurred in the soils amended with crop residues in the later period of incubation (Fig. 2), equal to 176 mg N g−1 of added N in the BV loam soil, and to 428 mg N g−1 of added N in the SCe silty clay soil. This late remineralization may have important consequences in the agricultural practice, as green manure incorporation could be considered a way to delay the release of inorganic N in soil for the subsequent crops. 4.2. Soil effect

Treatment

Table 5 Net N and C mineralization in a loam soil amended with glucosinolate-containing or non-containing defatted seed meals extracted by mechanical pressing or mechanical pressing/hexane (Exp. II). Values per unit weight of added N or C, as well as the parameters of the first order kinetic model of C mineralization, were calculated after removal of N mineralized or CO2 –C released by the un-amended soil. C0 : potentially mineralizable C; k: C mineralization rate constant.

6

Even though the dynamics of soil organic matter decomposition in soil are complex, due to the contribution of different pools, a direct relationship between soil N content and mineralized N has long been recognized (Stanford and Smith, 1972). The un-amended SCe silty clay soil showed higher N and C mineralization values than the BV loam, due to higher soil N and C contents. This soil, at 75% available water content, had also a higher water content in comparison with the loam (36.5% vs 17.4%, v/v). Soil texture and water content have been reported as factors influencing the CO2 –C release from soil (Thomsen et al., 2003). However, in the amended soils of Exp. I, the amount of mineralized C per gram of added C was higher in the loam (446 mg C g−1 added C, on average) than in the silty clay soil (315 mg C g−1 added C, on average). This behavior could be attributed to a higher physical, chemical or structural protection of the organic matter in the fine-textured soil (Krull et al., 2001). 4.3. Glucosinolate effect When dealing with the glucosinolate effect on N mineralization, the evidence of a nitrification inhibition is recurrent. Brown and Morra (2009) measured higher amounts of NH4 –N in soils amended with plant tissues containing high glucosinolate concentrations as compared to soils amended with tissues containing no or low glucosinolate concentrations. Wang et al. (2012) found ammonium accumulation in soil after incorporation of B. juncea DSMs at high rates of incorporation (2.5%). Snyder et al. (2010), using labeled 15 N, measured an increase in soil NH4 –N and a delay and reduction in CO2 –C release after soil amendment with 2% DSMs of high-glucosinolate species of Brassicaceae. In contrast, we did not find any nitrification inhibition in soil amended with glucosinolatecontaining DSMs in comparison with non-glucosinolate containing plant materials. This discrepancy may be due to the kind and

Please cite this article in press as: Marchetti, R., et al., Nitrogen and carbon mineralization in soils amended with biofumigant or non-biofumigant plant materials. Ind. Crops Prod. (2015), http://dx.doi.org/10.1016/j.indcrop.2015.04.062

G Model INDCRO-8048; No. of Pages 8

ARTICLE IN PRESS R. Marchetti et al. / Industrial Crops and Products xxx (2015) xxx–xxx

amount of meal incorporated. In fact, the other authors used B. juncea DSMs, instead of carinata, and incorporated higher amounts of materials than those incorporated in our experiments (0.18% in Exp. I, and 0.078% in Exp. II; Table 3). At these rates, the amount of N mineralized in the soil with glucosinolate-containing carinata DSMs was even higher, even though not significantly, than the amount of N in the soil amended with sunflower DSMs. The reasons may be searched in a different composition of these materials, and this issue certainly deserves further research. Even though in our experiments glucosinolate-containing DSMs did not seem to affect the nitrifier population, this however does not exclude that other soil processes and organisms may negatively be affected, such as plant roots. Lower crop yields were observed (Mazzoncini et al., 2015 this issue) when using DSMs as soil amendments, which could be due to some phytotoxicity effect, more than to a reduced N availability. 4.4. Oil content effect A higher amount of residual oil remains in DSMs extracted by mechanical pressing than in those obtained by a combination of pressing and solvent extraction. As lipids are a powerful energy source for organisms, consequences could be expected on microbial N transformations after lipid incorporation into soil. Perucci et al. (2006) observed a strong increase in soil respiration after amendment of a silty clay soil with moist olive husks, whereas Frankenberger and Abdelmagid (1985) did not find any correlation between N mineralized and lipid content in soil amended with fresh residues of leguminous crops. In our experiment, no significant differences among treatments was detected. As the amount of organic matter incorporated into soil was low, it may be worth further research to better understand the relationship among type of meal, oil content and N mineralization. 5. Conclusions These results show that carinata and sunflower DSMs may give a higher contribution to the soil N availability than green manure and crop residues, both in absolute (g kg−1 soil) and in relative terms (g kg−1 added N). As N mineralization in soil amended with carinata was also faster than in the other treatments, it seems easier to match inorganic N release with the crop N needs when using carinata instead of green manure or crop residues as a source of N for crop nutrition. Moreover, it is more advantageous from a practical point of view to manage dry material instead of fresh and voluminous organic matter, as it could be when using crop residues and green manure. The soil amendment with glucosinolate-containing carinata DSMs and green manure at the rates usually adopted in the agricultural practice should not have any detrimental effect on N mineralization, although the possibility exists of a phytotoxic effect on the crop roots when isothiocyanate release is not managed properly. The amendment of soil with fresh organic matter enriches it with nutrients, whereas the supply of chemical fertilizers does not. These results confirm the improvement of soil fertility due to organic matter incorporation and endorse interesting perspectives for use of plants and DSMs in a correct soil management to increase soil fertility. This aspect is awaited in order to cover a strategic option, considering the request of the European Commission for a more sustainable use of pesticides in agriculture. In fact the EU Directive 2009/128/EC focuses on the importance of non-chemical alternatives to conventional crop protection products. The materials studied in this work not only can be considered as innovative materials useful for this aim, but they are also characterized by a clear fertilizing potential.

7

Acknowledgements This work was granted by the Ministry of Agricultural, Food and Forestry Policies within the framework of the project “Sistema Integrato di Tecnologie per la valorizzazione dei sottoprodotti della filiera del Biodiesel” (VALSO) MiPAAF (D.M. 17533/7303/10 del 29/04/2010) and coordinated by CRA-CIN of Bologna. We thank Anna Orsi, Lidia Sghedoni and Lorena Malaguti for laboratory analyses and assistance.

References Båth, B., 2000. Matching the availability of N mineralised from green-manure crops with the N-demand of field vegetables. In: Doctoral thesis. Uppsala, Swedish University of Agricultural Sciences. Bending, G.D., Lincoln, S.D., 2000. Inhibition of soil nitrifying bacteria communities and their activities by glucosinolate hydrolysis products. Soil Biol. Biochem. 32, 1261–1269. Brown, P.D., Morra, M.J., McCaffrey, J.P., Auld, D.L., Williams, L., 1991. Allelochemicals produced during glucosinolate degradation in soil. J. Chem. Ecol. 17, 2021–2034. Brown, P.D., Morra, M.J., 1997. Control of soil-borne plant pests using glucosinolate-containing plants. Adv. Agron. 61, 167–231. Brown, P.D., Morra, M.J., 2009. Brassicaceae tissues as inhibitors of nitrification in soil. J. Agric. Food Chem. 57, 7706–7711. Chaves, B., De Neve, S., Hofman, G., Boeckx, P., Van Cleemput, O., 2004. Nitrogen mineralization of vegetable root residues and green manures as related to their (bio) chemical composition. Eur. J. Agron. 21, 161–170. Cook, F.J., Orchard, V.A., 2008. Relationships between soil respiration and soil moisture. Soil Biol. Biochem. 40, 1013–1018. Curto, G., Lazzeri, L., Dallavalle, E., Santi, R., 2008. Management of Meloidogyne incognita (Kofoid et White) Chitw in organic horticulture. Redia XCL, 81–84. Directive 2009/128/EC of the European Parliament and of the council (21.10.09). A framework for Community action to achieve the sustainable use of pesticides, Off. J. Eur. Union, 309, 71–86 (24/11/09). Doran, J.W., Parkin, T.B., 1996. Quantitative indicators of soil quality: a minimum data set. In: Doran, J.W., Jones, A.J. (Eds.), Methods for Assessing Soil Quality. SSSA Madison, WI, US, pp. 25–37. Drinkwater, L.E., Cambardella, C.A., Reeder, J.D., Rice, C.W., 1996. Potentially mineralizable nitrogen as an indicator of biologically active soil nitrogen. In: Doran, J.W., Jones, A.J. (Eds.), Methods for Assessing Soil Quality. SSSA Spec. Publ. 49, Madison, WI (USA), pp. 217–229. Frankenberger Jr., W.T., Abdelmagid, H.M., 1985. Kinetic parameters of nitrogen mineralization rates of leguminous crops incorporated into soil. Plant Soil 85, 257–271. Galvez, A., Sinicco, T., Cayuela, M.L., Mingorance, M.D., Fornasier, F., Mondini, C., 2012. Short term effects of bioenergy by-products on soil C and N dynamics: nutrient availability and biochemical properties. Agric. Ecosyst. Environ. 160, 3–14. Handiseni, M., Brown, J., Zemetra, R., Mazzola, M., 2013. Effect of Brassicaceae seed meals with different glucosinolate profiles on Rhizoctonia root rot in wheat. Crop Prot. 48, 1–5. Hassink, J., 1992. Effects of soil texture and structure on carbon and nitrogen mineralization in grassland soils. Biol. Fert. Soils 14 (2), 126–134. Keeney, D.R., Nelson, D.W., et al., 1982. Nitrogen-inorganic forms. In: Page, A.L. (Ed.), Methods of soil analysis Part 2. , 2nd ed. Agron. Monogr. 9. ASA and SSSA Madison, WI, pp. 643–698. Krull, E., Baldock, J., Skjemstad, J., 2001. Soil texture effects on decomposition and soil carbon storage NEE. In: Workshop Proceedings, 18–20 April, pp. 103–110. Kumar, K., Goh, K.M., 2000. Crop residues and management practices: effects on soil quality soil nitrogen dynamics crop yield, and nitrogen recovery. Adv. Agron. 68, 197–319. Larkin, R.P., Griffin, T.S., 2007. Control of soilborne potato diseases using Brassica green manures. Crop Prot. 26, 1067–1077. Lazzeri, L., D’Avino, L., Ugolini, L., De Nicola, G.R., Cinti, S., Malaguti, L., Bagatta, M., Patalano, G., Leoni, O., 2011. Bio-based products from Brassica carinata a Braun Oil and Defatted Meal by a Second Generation Biorefinery Approach. In: I 19th European Biomass Conference and Exhibition Proceedings, Berlin, Germany. Lazzeri, L., Leoni, O., Manici, L.M., Palmieri, S., Patalano, G. 2010. Use of Seed Flour as Soil Pesticide. USA Patent n 749 (7) 549. Lazzeri, L., Malaguti, L., Cinti, S., Baruzzi, G., 2003. I sovesci di piante biocide nella rotazione. Colture Protette 1, 53–56. Lazzeri, L., Matthiessen, J., Morra, M.J., Palmieri, S., Rollin, P. (Eds.), 2004. Agroindustria, 2 (2/3), ISCI, Bologna, p. 189. Littell, R.C., Milliken, G.A., Stroup, W.W., Wolfinger, R.D., 1996. SAS system for mixed models. SAS Inst. Inc., Cary, NC. Mary, B., Recous, S., Darwis, D., Robin, D., 1996. Interactions between decomposition of plant residues and nitrogen cycling in soil. Plant Soil 181, 71–82. Matthiessen, J.N., Kirkegaard, J.A., 2006. Biofumigation and enhanced biodegradation: opportunity and challenge in soilborne pest and disease management. Crit. Rev. Plant Sci. 25, 235–265.

Please cite this article in press as: Marchetti, R., et al., Nitrogen and carbon mineralization in soils amended with biofumigant or non-biofumigant plant materials. Ind. Crops Prod. (2015), http://dx.doi.org/10.1016/j.indcrop.2015.04.062

G Model INDCRO-8048; No. of Pages 8 8

ARTICLE IN PRESS R. Marchetti et al. / Industrial Crops and Products xxx (2015) xxx–xxx

Mattner, S.W., Porter, I.J., Gounder, R.K., Shanks, A.L., Wren, D.J., Allen, D., 2008. Factors that impact on the ability of biofumigants to suppress fungal pathogens and weeds of strawberry. Crop Prot. 27, 1165–1173. Mazzoncini, M., Antichi, D., Tavarini, S., Silvestri, N., Lazzeri, L., D’Avino, L. 2015 Effect of defatted oilseed meals applied as organic fertilizer on vegetable crop production and environmental impact. This issue. McGuire, A.M., 2004. Mustard green manures replace fumigant and improve infiltration in potato cropping system. Agroindustrial 3, 331–333. Mohammadi, K., Rokhzadi, A., 2012. An integrated fertilization system of canola (Brassica napus L.) production under different crop rotations. Ind. Crops Prod. 37, 264–269. Mohanty, M., Sammi Reddy, K., Probert, M.E., Dalal, R.C., Subba Rao, A., Menzies, N.W., 2011. Modelling N mineralization from green manure and farmyard manure from a laboratory incubation study. Ecol. Modell. 222, 719–726. Moore, A.D., 2011. Fertilizer potential of biofuel byproducts, Last accessed on 29/06/14 http://cdn.intechopen.com/pdfs-wm/20070.pdf Moreno-Cornejo, M., Zornoza, J., Faz, A., 2014. Carbon and nitrogen mineralization during decomposition of crop residues in a calcareous soil. Geoderma 230-231, 58–63. Page, A.L., Miller, R.H., Keeney, D.R., 1982. Methods of Soil Analysis. Part 2, 2nd ed. Agron. Monogr. 9. ASA and SSSA, Madison, WI. Perucci, P., Dumontet, S., Casucci, C., Schnitzer, M., Dinel, H., Monaci, E., Vischetti, C., 2006. Moist olive husks addition to a silty clay soil: influence on microbial and biochemical parameters. J. Environ. Sci. Health Part B: Pestic. Food Contam. Agric. Wastes 41, 1019–1036. Pinkerton, J.N., Ivors, K.L., Miller, M.L., Moore, L.W., 2000. Effect of soil solarization and cover crops on populations of selected soilborne plant pathogens in Western Oregon. Plant Dis. 84, 952–960. Reardon, C.L., Strauss, S.L., Mazzola, M., 2013. Changes in available nitrogen and nematode abundance in response to Brassica seed meal amendment of orchard soil. Soil Biol. Biochem. 57, 22–29.

Rice, C.W., Moorman, T.B., Beare, M., et al., 1996. Role of microbial biomass carbon and nitrogen in soil quality. In: Doran, J.W. (Ed.), Methods for Assessing Soil Quality. SSSA Spec. Publ. 49. SSSA, Madison, WI, pp. 203–216. Rowe, R.C., Powelson, M.L., 2002. Potato early dying: management challenges in a changing production environment. Plant Dis. 86, 1184–1193. Saxton, K.E., Rawls, W.J., 2006. Soil water characteristic estimates by texture and organic matter for hydrologic solutions. Soil Sci. Soc. Am. J. 70, 1569–1578. Scott, J.S., Knudsen, G.R., 1999. Soil amendment effects of rape (Brassica napus) residues on pea rhizosphere bacteria. Soil Biol. Biochem. 31, 1435–1441. Snyder, J.A., Johnson-Maynard, J.L., Morra, M.J., 2010. Nitrogen mineralization in soil incubated with 15N-labeled Brassicaceae seed DSMs. Appl. Soil Ecol. 46, 73–80. Stanford, G., Smith, S.J., 1972. Nitrogen mineralization potentials of soils. Soil Sci. Soc. Am. Proc. 36, 465–472. Thorup-Kristensen, K., Magid, J., Jensen, L.S., 2003. Catch crops and green manures as biological tools in nitrogen management in temperate zones. Adv. Agron. 79, 227–302. Thomsen, I.K., Schjønning, P., Jensen, B., Kristensen, K., Christensen, B.T., 1999. Turnover of organic matter in differently textured soils: II: microbial activity as influenced by soil water regimes. Geoderma 89, 199–218. Thomsen, I.K., Schjønning, P., Olesen, J.E., Christensen, B.T., 2003. C and N turnover in structurally intact soils of different texture. Soil Biol. Biochem. 35, 765–774. Trinsoutrot, I., Recous, S., Bentz, B., Linères, M., Chèneby, D., Nicolardot, B., 2000. Biochemical quality of crop residues and carbon and nitrogen mineralization kinetics under nonlimiting nitrogen conditions. Soil Sci. Soc. Am. J. 64, 918–926. Wang, A.S., Hu, P., Hollister, E.B., Rothlisberger, K.L., Somenahally, A., Provin, T.L., Hons, F.M., Gentry, T.J., 2012. Impact of Indian mustard (Brassica juncea) and flax (Linum usitatissimum) seed meal applications on soil carbon, nitrogen, and microbial dynamics. Appl. Environ. Soil Sci., 14, Article ID 351, 609, Hindawi Publishing Corporation.

Please cite this article in press as: Marchetti, R., et al., Nitrogen and carbon mineralization in soils amended with biofumigant or non-biofumigant plant materials. Ind. Crops Prod. (2015), http://dx.doi.org/10.1016/j.indcrop.2015.04.062