Integrated crop protection and environment exposure to pesticides: methods to reduce use and impact of pesticides in arable farming

European Journal of Agronomy 7 (1997) 251–260

Integrated crop protection and environment exposure to pesticides: methods to reduce use and impact of pesticides in arable farming F.G. Wijnands* Applied Research for Arable Farming and Field Production of Vegetables, P.O. Box 430, NL 8200 AK, Lelystad, The Netherlands Accepted 14 July 1997

Abstract Prototypes of Integrated Farming Systems for arable farming are being developed in the Netherlands based on a coherent methodology elaborated in an European Union concerted action. The role of crop protection in Integrated systems is, additional to all other methods, to efficiently control the remaining harmful species, with minimal use of well selected pesticides. The overall aim of more sustainable farming systems is to reduce the exposure of the environment to pesticides in order to prevent short- and long term effects on all species over all the biosphere. An innovative approach to quantify this exposure of the environment to pesticides, based on molecular-chemical properties of the pesticides, is presented. The results of prototyping on an experimental farm in the Netherlands shows that not only drastic reductions in pesticide use are possible but that subsequent careful selection of pesticides can also lead to minimal environmental impact.  1997 Elsevier Science B.V. Keywords: Arable farming; Environment; Integrated crop protection; Integrated farming; Pesticides; Prevention; Farming systems research; Indicators; Pesticide risk evaluation

1. Introduction The use of pesticides in current arable farming systems is extremely high due to the almost exclusive choice for pesticides to correct structural problems in farm management such as insufficient crop rotation, susceptible varieties and high nitrogen inputs. The high pesticide use is only one symptom, however a major one, of the shortcomings of current farming in the European Union. Current farming is associated with a complex of environmental, agronomic and ecological problems. In reaction to these problems, Integrated Farming * Tel.: +31 320 291111; fax: +31 320 230479.

Systems have been developed as a coherent new vision on agriculture alongside other concepts such as ecological farming. Over the last 15 years these systems that integrate potentially conflicting objectives concerning economy, environment and agronomy are being developed on experimental farms all over Europe (Vereijken and Royle, 1989; Vereijken, 1994); in the last 5 years increasingly also in cooperation with commercial farms (Vereijken 1995, 1997). The methodology of designing, testing, improving and disseminating Integrated and Ecological Farming Systems for arable farming is elaborated in a 4 year European Union Concerted Action involving the leading research teams in Europe. This methodology is

1161-0301/97/$17.00  1997 Elsevier Science B.V. All rights reserved PII S1161-0301 (97 )0 0040-3

252

F.G. Wijnands / European Journal of Agronomy 7 (1997) 251–260

called prototyping and comprises five steps (Vereijken, 1994, 1995, 1997). After the objectives have been set (1) and transformed into a suitable set of multi-objective parameters (2), appropriate farming methods (comprehensive strategies built on different techniques) that sufficiently integrate the potentially conflicting objectives need to be developed or redesigned (3). Top priority is given to the design of a multifunctional crop rotation. Then nutrient management strategies need to be designed, followed by the design of soil cultivation strategies and the lay-out of an ecological infrastructure on the farm. All these methods are aimed at sustaining quality production with minimum external inputs and environmental hazards. In a theoretical prototype parameters and methods are linked as last check (4) before the testing in practice may start (5). Testing and improving the prototype in general and the method in particular continues until the objectives as quantified in the set of parameters have been achieved. This can either be done on experimental farms or on pilot farms. Dissemination of the results including implementation in practice concludes this approach. This paper is based on prototyping research on the Nagele experimental farm (Wijnands and Vereijken, 1992) in the Netherlands and elaborates the role of the farming method Integrated Crop Protection (ICP) in Integrated systems. This method is complementary to the methods that consider crop rotation, nutrient management, soil cultivation and ecological infrastructure, that were mentioned before. It will be shown how ICP can reduce the input of pesticides drastically. A new concept of quantifying the environmental burden due to pesticide use will be elaborated. This concept is called Environment Exposure to Pesticides (EEP). Minimising the latter is the basic aim for more sustainable farming systems in order to prevent short- and long term adverse effects on all species over all the biosphere. Results of the Nagele farm will demonstrate the perspective of this concept.

designed for three specific regions in the Netherlands and laid out on experimental farms with region-specific crop rotations and cropping systems (Wijnands and Vereijken, 1992). From 1990 to 1993 the tested prototypes were evaluated on commercial farms in a national pilot farm network (Wijnands, 1992; Wijnands et al., 1995). The Integrated prototype for the Central Clay area will serve here as example. The small farm size (25– 50 ha) in this region encourages farmers to grow cash crops in short rotations needing heavy inputs. Potato is the most profitable crop, followed by sugar beet and vegetables such as onion and cabbage. Cereals are financially less attractive but are needed as break crops. Most rotations are for only 3 or 4 years. Consequently, beet and potato cyst nematodes (Heterodera spp and Globodera spp) cause serious problems, forcing farmers to fumigate soil regularly as a curative or preventive measure. The Integrated prototype for the Central Clay area has been developed since 1979 on the ‘Development of Farming Systems’ experimental farm at Nagele (central clay region). The farm size is 72 ha and the soil is heavy sandy marine clay (24% clay). Three farming systems were studied until 1991: Integrated, Conventional (rotations see Table 1) and Ecological. In 1991 the experimental layout was drastically Table 1 Crop rotations of the different systems and periods at the experimental farm at Nagele Integrated and Conventional 1986–1990

Integrated and Experimental 1991

Year

Crop

Year

Crop

1

1

One-half ware, one-half seed potato Sugar beet

3

One-half ware, one-half seed potato One-half dry pea, one-quarter carrot, one-quarter onion Sugar beet

4

Winter wheat

4

2

2

3

2. Material and methods 2.1. Prototypes of integrated systems in the Netherlands Integrated prototypes for arable farming were

Experimental, advanced integrated.

One-half carrot, one-half onion (experimental: one-half carrot, one-half chicory) Winter wheat (Experimental: one-half winter wheat, one-half sugar barley)

F.G. Wijnands / European Journal of Agronomy 7 (1997) 251–260

revised. Because of the promising results of the Integrated prototype (Wijnands and Vereijken, 1992; economically the Integrated system was competitive with the Conventional reference system) and the subsequent progress in policy (Ministry of Agriculture, Nature Management and Fisheries, 1990, 1991), the Conventional reference system was no longer needed. It was therefore replaced by a demonstration-Integrated prototype meeting the policy aims of 2000. Subsequently a new Integrated prototype (Experimental) was designed, aimed at further reductions in inputs of pesticides and nutrients (rotations; see Table 1). Concerning the farming methods that are used in the Integrated system the following specifications can be given. Concerning the Multifunctional Crop Rotation: a potato cropping frequency of 1:4 is considered as an acceptable compromise between a more sound rotation (1:5 or 1:6) and more profitable short rotations (1:3) with more biotic stress and therefore requiring more inputs. The Integrated Nutrient Management strategy applied is based on the environmental safe and agronomic efficient use of manure as a basic source of nutrients and organic matter and is aimed at minimum losses. For more details on Ecological Infrastructure Management and the economic aspects see Wijnands (1994). The ICP strategy that was followed will be elaborated in Section 2.2. 2.2. Integrated crop protection The role of crop protection in an Integrated system is, additional to all the other methods, to efficiently control the residual harmful species, with minimal use of well selected pesticides. ICP focuses on the real problems, namely the residual ones, after all other methods are designed and optimised. Consequently this means that in the design of the multi-objective methods Multifunctional Crop Rotation and Integrated Nutrient Management, all crop protection aspects are taken into consideration. This concerns for instance the choice of the (inter)crops, their frequency and sequence as well as the spatial aspects of the crop rotation (Vereijken, 1994). Moreover a well balanced Ecological Infrastructure Management should enhance the stability of the system. When designing an Integrated Nutrient Management strategy, the interaction between weeds, pests and dis-

253

eases and soil fertility, and the plant nutritional status are taken into account. The ultimate objective of the Integrated and Ecological systems with respect to pesticides is the same: zero use and zero negative impact on environment and ecology. However whilst an Ecological system radically abandons pesticide use and consequently produces under label for higher prices on special markets, Integrated systems still use pesticides since production for the world market does not allow to radically abandon pesticides. However also for Integrated systems the target can only be zero use of pesticides. This is a major challenge for agronomy and crop protection science. First of all the use of pesticides in an Integrated approach can be minimised by putting maximum emphasis on prevention (resistant varieties, cultural measures such as adapted sowing date and row spacing). Whenever a disease, pest or weed population occurs a correct interpretation of the need for control (guided control systems, thresholds, signalising systems, etc.) can prevent unjustified use of pesticides. Secondly all available non-chemical control measures (mechanical weed control, physical and biological control) should optimally be integrated in effective and manageable control strategies. Pesticides are only necessary in very specific cases. They always have to be integrated in crop- and location specific control strategies. Application methods are preferred that lead to a minimum use, such as seed treatment and row- or spotwise application. The latter techniques require careful integration of chemical and mechanical techniques when applied in weed control. Appropriate dosages and when possible a curative approach (field- and year specific) further reduce the input. The residual required pesticide use then requires a careful selection of pesticides to avoid disturbance of non-target organisms (selectivity) and to minimise the exposure of the environment to pesticides.

3. Pesticides 3.1. Behaviour and impact Current agriculture depends to a great extent on pesticides. It is estimated that world wide some 2.5

254

F.G. Wijnands / European Journal of Agronomy 7 (1997) 251–260

million t of pesticides are applied annually in agricultural crops. Pesticides can be described as the only group of toxic chemicals which are intentionally dispersed in the environment (The Pesticides Trust UK, information leaflet). Only a fraction of the pesticides gets in contact with its target organisms (directly or indirectly). Pimentel (1995) estimates that in the case of pests, only 0.4% of the pesticide contacts its target pest. Inevitably a large part of the applied pesticides become part of the abiotic environment. Pesticides may volatilise into the air, runoff or leach into surface- and groundwater, be taken up by plants or soil organisms or remain in the soil, depending on pesticide properties, climatic and crop conditions, soil type and ‘infrastructure’ (slope of fields, nearness of surface water, hydrology, etc.). The environment thus gets exposed to a certain pesticide load. The combination of pesticide properties and ‘environmental’ conditions determines the ‘persistence’ of the compounds (adsorption, degradation, photolysis, etc.). Pesticide behaviour in soil (persistence and leaching to groundwater) has been studied extensively and is relatively well known. The total seasonal losses in runoff rarely exceed 5–10% of the total amount applied (Leonard, 1990). The fraction removed by leaching is probably less than 5–10% (Taylor and Spencer, 1990) however both runoff and leaching have a very significant impact on water quality causing world wide serious concern over the past three decades. Volatilisation is the major cause of pesticide loss. Volatilisation losses up to 80–90%, within a few days after application, have been reported (Taylor and Spencer, 1990). A recent study in the Netherlands (in the framework of the evaluation of the crop protection policy) estimates that some 50% of the total pesticide use volatilises (Multi-Year Crop Protection Plan, 1996). The fate of pesticides in the atmosphere is relatively unknown. However by atmospheric transport and deposition (global distillation) many pesticides may be distributed all over the earth (Gregor and Gummer, 1989; Atlas and Schauffler, 1990; Schomburg and Glotfelty, 1991; Simonich and Hites, 1995). Pesticides unavoidably cause ecological effects, since no pesticide is specifically toxic to only one species. Consequently the presence of pesticides in the abiotic environment is potentially a threat for all involved biota (non-target). The magnitude and dif-

ferentiation of this threat is only very partially known and quantified. Pesticide toxicity for humans and some mammals is relatively well known. Much less is known about the effects on other biota, the so-called ecotoxicity. A proper evaluation of the ecotoxicity of a substance is virtually impossible since it involves thousands of different species that react differently when exposed to a certain substance. It not only involves direct toxicity but also mid- and long term effects on, for instance fertility, vitality and population dynamics. This knowledge calls for a radical strategy. A preventive strategy that aims at minimising any potential effect of pesticides on biota. Therefore the exposure of the environment to pesticides should be minimised. This should be reached by minimising the pesticide requirements of farming systems (e.g. by ICP, see Section 2.2) and consequently careful selection of pesticides taking into account the extent to which the environment gets exposed to pesticides. The use of pesticides is currently often quantified as number of treatments, as kg active ingredients or as a relative number expressing the ratio used dose/recommended full field dose. These parameters only quantify use and cropping technique. In Section 3.2 the quantification of pesticide properties in terms of potential presence in the environment will be elaborated. 3.2. Environment exposure to pesticides EEP is quantified by taking into account the active ingredient properties and the amount used. EEP-air = active ingredient (kg/ha) × vapour pressure (VP at 20–25°C) (Pa). EEP-soil = active ingredient (kg/ha) ×50% degradation time (DT50) (days). EEP-groundwater = EEP-soil (kg days/ha) × mobility of the pesticide (−). Mobility = Kom; Kom = partitioning coefficient of the pesticide over dry matter and water fraction of the soil/organic matter fraction of the soil. The properties of active ingredients of pesticides, i.e. VP, DT50 and Kom, are known under standardised conditions, since this is required for the approval procedures (Linders et al., 1994). For instance the ratio DT50/Kom in the Netherlands is used in model studies to establish the leaching risk as part of the approval procedures.

F.G. Wijnands / European Journal of Agronomy 7 (1997) 251–260

These rather simple calculations do not take into account any division of the compounds over the three compartments of the abiotic environment nor do they relate to the period of the year and the crop conditions (soil cover) during application. EEP quantifies the maximum risk of environment exposure to pesticides and can be used to evaluate pesticide use or to select pesticides. Of course any additional knowledge of ecological effects should be taken into consideration. EEP can be quantified per pesticide, but also be summarised as EEP per crop (sum of EEP per pesticide) or EEP per farm (weighted average of EEP per crop with respect to area). Comparative surveys of available pesticides provide the basis for rational pesticide choice. Evaluation of pesticide use implies quantification of the EEP-water, -air and -soil per pesticide, per crop and per farm. Pesticides then can be ranked by calculating their relative contribution to the EEP per farm (Table 7). This provides a rational basis for targeted improvement in EEP. EEP targets should be achieved by: (1) substitution of the highest ranking compounds by non-chemical measures or lower ranked pesticides, or (2) reducing the used amount by a more appropriate dose or by bandspray or spotwise treatments.

4. Results The results of crop protection in terms of pesticide use and EEP of the Nagele experimental farm over the period 1986–1990 are presented, including an outlook

Table 2 Average marketable crop yields (t/ha) in the Integrated and Conventional farming system at Nagele in different periods Crop

Ware potato Seed potato Sugar beet Winter wheat Pea Winter carrot Sown onion

1986–1990

1992–1995

Conventional

Integrated

Integrated

54.4 33.9 64.3 7.6 5.0 52.2 40.6

54.6 34.3 60.2 6.7 4.7 52.2 31.0

53.1 32.0 59.2 9.7 – 69.3 45.3

255

into the period 1992–1996. The crop rotation in both periods is given in Table 1. Yields of the crops in the Conventional and Integrated systems were in general similar, with exception of winter wheat and sown onion (Table 2). For ware potato (cultivar value), seed potato (cultivar value), sown onion (quality) and sugar beet (sugar content and extractability) higher product prices were achieved in the Integrated system. Prices of produce for the other crops were similar in both systems. The costs of pesticides and fertilisers were lower and the costs of seeds and tubers were higher in the Integrated system. The final gross margin per crop was higher in the Integrated system, still with exception of winter wheat and sown onion. At farm level, costs of machinery and labour were slightly higher in the Integrated system, but these did not fully remove the financial advantage of the higher gross margins. As a result the net surplus of the Integrated system was slightly higher than that of the Conventional system (Wijnands and Vereijken, 1992). More details about the physical and financial results of the various systems have been reported by Bos et al. (1992). The yields of the 1992–1995 period show considerable improvement in yields of wheat (cultivar and N-management), onion (N management) and carrot (cultivar and Nmanagement) in the Integrated system. For all crops, the yield levels are now similar to the average ‘conventional’ yields of the region (Conventional no longer available at the experimental farm). 4.1. Pesticide use Table 3 specifies the number of ICP interventions. Compared to the Conventional system the annual input of pesticides in kg active ingredients/ha in the Integrated system was reduced by 65%, excluding nematicides and by 90% if nematicides are included (Table 4). The largest reduction in active ingredient use was realised by substituting dichloropropene (DCP), a soil fumigant used to control potato cyst nematodes in the Conventional system, by non-chemical measures such as the use of appropriate cultivars based on detailed monitoring techniques. Herbicide input in the Integrated system was largely replaced by mechanical control and by band spraying or low dose techniques (Tables 3 and 4).

256

F.G. Wijnands / European Journal of Agronomy 7 (1997) 251–260

Table 3 Number of interventions for crop protection (n/crop) in the Conventional and Integrated farming system (1986–1990) at Nagele Weeds

Conventional Integrated

Pest/diseases

Mechanical

Thermal

Chemical

Total

Chemical

0.9 2.0

– 0.2

2.6 1.5

3.5 3.7

4.2 1.9

Total

7.7 5.6

the most recent period (1992–1996). The reduction in fungicide use is mainly based on the substitution of the ‘old’ compounds used to control Phytophthora infestans by a new low active ingredient compound called fluazinam. The reduction in herbicide use is based on a further increased and optimised use of mechanical techniques and appropriate dosage herbicide systems Compared to the Conventional system of 1986– 1990 the reduction percentage increased. In absolute terms the level of pesticide use is very low (Fig. 2). Does this also mean that the environmental impact of the Integrated system is much lower with respect to pesticides?

Per herbicide application, the amount of active ingredient used was 25–50% less. The labour demand increased because the band spraying and mechanical interventions took more time than full field herbicide spraying. In seed and ware potato crops it was not necessary to use herbicides for weed control. Growing winter wheat at wider inter-row spacing (26 cm) enabled herbicides to be replaced by mechanical control. Fungicide input was reduced by using resistant cultivars, moderate nitrogen supply, control thresholds and decision support systems. The largest reduction at farm level was achieved in potato (Table 4 and Table 5). Fungicide input in onion was largely reduced by supervised control based on monitoring initial infestation by Botrytis squamosa and weather conditions (Table 4). Growth regulators were only used in sown onions to inhibit sprouting during storage. Insecticide input was minimal due to low insect pressure and the use of control thresholds, reduced dose techniques and band spraying. Fig. 1 shows the further decrease in pesticide use in

4.2. Environment exposure to pesticides Active ingredient input and EEP were quantified for the Conventional and Integrated system in 1988, and to demonstrate the progress that was made also for the Integrated system in 1992 (Table 6). From the Conventional 1988 system (representative for 1986–

Table 4 Annual input of pesticides (kg active ingredients/ha) in the Integrated and Conventional farming system (1986–1990) at Nagele

Ware potato Seed potato Sugar beet Winter wheat Pea Winter carrot Sown onion System average

Herbicides

Fungicides

Insecticides

Growth regulator

Nematicides

Total

Integrated

Conventional

Integrated

Conventional

Integrated

Conventional

Integrated

Conventional

Integrated

Conventional

Integrated

Conventional

0.1a 2.0a 1.3 1.2 2.1 1.4 2.7 1.4

2.5a 4.5a 3.8 3.7 3.3 3.5 9.0 4.0

8.9 4.3 0.0 0.3 0.6 0.0 2.5 2.0

19.6 13.9 0.0 2.3 1.1 0.7 8.6 5.5

0.0 0.3 0.1 0.0 0.2 1.3 0.0 0.2

0.4 0.8 0.3 0.1 0.4 3.7 0.1 0.5

– – – 0.0 – – 1.8 0.1

– – – 0.6 – – 2.3 0.3

– – – – – – – –

104.6 135.8 – – – – – 29.7

9.0 6.6 1.4 1.6 2.9 2.7 7.0 3.7

124.1 155.1 4.1 6.7 4.8 7.9 20.0 40.0

F.G. Wijnands / European Journal of Agronomy 7 (1997) 251–260

257

Table 5 Number of interventions (n/crop) and fungicide input (kg active ingredients/ha) for Phytophthora infestans control in the Integrated and Conventional farming system (1986–1990) at Nagele Ware potato

Seed potato

Integrated Conventional Integrated Conventional Interventions 6.3 Active 8.9 ingredients

11.4 19.5

2.6 4.2

5.4 12.0

1990) to the Integrated 1988 system the input of pesticides was strongly reduced over all crops (Table 6). In 1992 (representative for 1992–1996) the Integrated system reduced the pesticide input even further, again over all crops. The main cause of the drastic decline in EEP-air, water and -soil going from the Conventional 1988 system to the Integrated 1988 system is that DCP, the soil fumigant used to control potato cyst nematodes, has been replaced by non-chemical measures. DCP is extremely volatile and used in high dosages (80–110 kg active ingredients/ha). The major change going from the Integrated 1988 system to the Integrated 1992 system again occurs in the potato crop. The dithiocarbamates and fentin acetate, fungicides against late potato blight (Phytophthora infestans), were replaced by fluazinam, a new low dosage compound. From the Conventional 1988 system to the Integrated 1992 system the EEP-air, -water and -soil

Fig. 1. Annual input of pesticides (kg active ingredients/ha) in different systems and periods (I, Integrated; C, Conventional; X, Experimental) at Nagele.

Fig. 2. Reduction (%) in input of pesticides (kg active ingredients/ ha) of the Integrated (I) (1986–1990) and the I and Experimental (X) farming system (1992–1996) in comparison to the Conventional farming system (1986–1990) at Nagele.

were reduced by ..99, 96 and 98%, respectively. The active ingredient use was reduced by ‘only’ 95% (including nematicides). The basis for the reduction in EEP is ICP. However the beneficial effect of selecting pesticides based on EEP is large as is apparent from the foregoing, especially in EEP-air. Table 7 presents, as an example the pesticides used in the Integrated 1992 system ranked according to their share in the farm average EEP-soil. Fluazinam is present at position 1 and 3 on the list, in ware-and seed potato (32%), respectively. It is used full field, to prevent late blight in potatoes, however in a low dosage system based on the higher resistance of the cultivars cropped in the Integrated system. Then herbicides used in band-spray appropriate dosage systems in sugar beet are present at position 2, 5, 11 and 14 (23%). To reduce the EEP further, harrow treatments might replace the last one or two low dose herbicide applications in sugar beet. Other compounds, that would decrease EEP are not available yet. Then glyphosate is used to control spot-wise perennial weeds in different crops (6, 9, 10; 12%). Pirimicarb and propiconazole are used in winter wheat (10%). However, the crop growth stage during application will largely prevent these compounds to reach the soil. Other compounds on the list contribute only marginally to the EEP-soil per farm.

258

F.G. Wijnands / European Journal of Agronomy 7 (1997) 251–260

Table 6 Pesticide use (kg/ha, active ingredients) and Environment Exposure to Pesticides (EEP)-air, -water and -soil by crop for the Conventional and Integrated farming system at Nagele in different years EEP-aira

Active ingredients

Ware potato Seed potato Winter wheat Sugar beet Sown onion Averagec a

1988

1992

1988

Conven- Integtional rated

Integrated

Conventional

196.8 187.7 5.1 2.1 23.4 60.3

7.2 3.5 1.0 1.8 3.8 2.9

156 152 141 1.1 7.4 86

9.1 6.4 2.6 0.4 9.8 4.5

EEP-waterb

EEP-soilb

1992

1988

1992

1988

Integrated

Integrated

Conven- Integtional rated

Integrated

Conventional

Integrated

Integrated

0.9 0.9 1.5 0.1 3.8 1.3

0.5 0.3 0.4 0.4 0.7 0.4

3493 3218 162 103 722 1170

82 66 10 55 47 46

196.6 187.5 5.0 3.0 23.4 60.5

9.7 6.4 2.6 0.4 9.8 4.6

2.0 1.4 0.4 1.6 2.1 1.4

376 185 25 15 401 129

1992

In log (106 × EEP-air); bsee text; ccropping plan.

5. Discussion The presented approach clearly distinguishes three phases in pesticide use: (1) the use (characterised by number of applications and kg active ingredients/ha);

(2) the exposure of the environment to pesticides (quantified by the EEP) and; (3) the effects on biota. The presented approach focuses on the first and second step. The governmental approval procedures for pesticides guarantee that the ‘worst’ pesticides

Table 7 Ranking of pesticides based on share in farm level EEP-soil for the Integrated farming system (1992) at Nagele Product

Typea

Active ingredients

Methodb

Crop

Share farm level %c

Cumulative share in farm level

1 2 3 4 5

Shirlan Goltix Shirlan Pirimor Betanal Progress

F H F I H

FF RT FF FF RT

Ware potato Sugar beet Seed potato Seed potato Sugar beet

22 11 10 7 7

22 33 43 50 57

6 7 8 9 10 11

Roundup Royal MH-30 Tilt Roundup Roudnup Betanal Tandem

H GR F H H H

SPOTW FF FF SPOTW SPOTW RT

Sugar beet Sowed onions Spring barley Sowed onions Chicory Sugar beet

7 5 3 3 3 3

64 69 72 75 78 81

12 13 14 15

Chloor-IPC Kerb Pyramin Flow Chloor-IPC

H H H H

Fluazinam Metamitron Fluazinam Pirimicarb Ethofumesate + desmedipham + fenmedipham Glyphosate Maleine-hydrazide Propiconazole Glyphosate Glyphosate Ethofumesate + fenmedipham Chlorpropham Propyzamide Chloridazon Chlorpropham

RT RT FF RT

Sowed onions Chicory Sugar beet Chicory

3 2 2 2

84 86 88 90

Ranking

a

GR, growth regulator; F, fungicide; H, herbicide; I, insecticide. FF, full field; RT, row treatment; SPOTW, spotwise. c Share in farm level in % = [(EEP by pesticide × crop share in farm area)/(EEP by farm)] ×100; Crop share in farm area = area of one crop/ total area of farm. b

F.G. Wijnands / European Journal of Agronomy 7 (1997) 251–260

from an environmental and ecological point of view are not approved. ICP enables a minimum use of pesticides. EEP is a useful instrument to select then within the range of approved pesticides. EEP in combination with ICP enables a quantitative approach to a stepwise, targeted reduction in pesticide use and environmental impact. Van der Werf (1996) reviewed different approaches to evaluate pesticide impact on environment and biota. The reviewed methods show considerable differences in the parameters that are considered to asses environmental impact. From this review that includes the proposed approach in this article it is clear that EEP is the only approach that takes volatilisation of pesticides into account. It is also the only one that ‘on purpose’ does not consider effect on biota, since an overall comprehensive assessment is virtually impossible. Overall quantitative scores of ‘ecosafety’ therefore may easily lead to unjustified classification of a pesticide as being safe. The more radical approach of EEP enables a basic approach towards prevention. The volatilisation losses are obviously the largest ones and thus have to be taken into account when trying to reduce environmental impact. It can be argued, whether the parameter VP is the best to account for volatilisation losses. Henry’s law constant (Kh, the ratio of the VP to the water solubility) might also be an appropriate criterion for the volatility of a pesticide. However in a recent study in the Netherlands VP was also chosen in the model calculations as most simple and accurate prediction parameter (Multi-Year Crop Protection Plan, 1996). Both DT50 and Kom are in fact exponentially related to the leaching risk. Nevertheless by using the straight forward ratio DT50/Kom the risk of leaching is estimated properly. The presented approach might be extended to consider all involved processes, however the risk of loosing the simple and user-friendly character of EEP should be taken seriously. The Integrated prototype as designed, tested and improved on the Nagele experimental farm for the Central Clay conditions proved to have good perspectives in terms of minimising pesticide input and environment exposure to pesticides. ICP and pesticide selection based on EEP proved to be effective. Since the economic perspectives of the Integrated prototype are equal to those of the current ‘conventional’ farm-

259

ing systems, large scale implementation in practice inevitably should be the next step

Acknowledgements The author cordially thanks Dr. Boesten, Ir. Spoorenberg and particularly Dr. Vereijken for the support in developing the concept of Environment Exposure to Pesticides. References Atlas, E.A. and Schauffler, S., 1990. Concentration and variation of trace organic compounds in the north pacific atmosphere. In: D.A. Kurtz (Editor), Long Range Transports of Pesticides. Lewis, Chelsea, MI, pp. 161–183. Bos, A., Janssens, S.R.M. and Krikke, A.T., 1992. Analysis of economic results. In: H.H. Cheng (Editor), More Sustainable Farming Systems for Arable Farming. Themaboekje nr. 14, PAV, Lelystad, pp. 126–181 (in Dutch). Gregor, D.J. and Gummer, W.D., 1989. Evidence of atmospheric transport and deposition of organochlorine pesticides and polychlorinated biphenyl’s in Canadian arctic snow. Environ. Sci. Technol., 23: 561–565. Leonard, R.A., 1990. Movement of pesticides into surface waters. In: Pesticides in the Soil Environment. Soil Science Society of America Book Series, No. 2, Madison, WI, pp. 303–349. Linders, J.B.M.J., Jansma, J.W., Mensink, B.J.W.G. and Ottermann, K., 1994. Pesticides: Benefaction or Pandora’s Box, A Synopsis of the Environmental Aspects of 243 Pesticides. Report no. 6791014. National Institute of Public Health and Environmental Protection, Bilthoven, 201 pp. Ministry of Agriculture, Nature Management and Fisheries, 1990. Agriculture Structure Memorandum. Government decision (in Dutch). Ministry of Agriculture, Nature Management and Fisheries. DS, The Hague (essentials available in English). Ministry of Agriculture, Nature Management and Fisheries, 1991. Multi-Year Crop Protection Plan. Government decision. (In Dutch). Ministry of Agriculture, Nature Management and Fisheries. SDU, The Hague (essentials available in English). Multi-Year Crop Protection Plan, 1996. Multi-Year Crop Protection Plan. Evaluation emission 1995, background document. IKC-L. Ede, 127 pp. plus annexes (in Dutch). Pimentel, D., 1995. Amounts of pesticides reaching target pests: environmental impacts and ethics. J. Agric. Environ. Ethics, 8: 17–29. Schomburg, C.J. and Glotfelty, D.E., 1991. Pesticide occurrence and distribution in fog collected near Monterey, California. Environ. Sci. Technol., 25: 155–160. Simonich, S.L. and Hites, R.A., 1995. Global distribution of organochlorine compounds. Science, 269: 1851–1854. Taylor, A.W. and Spencer, W.F., 1990. Volatilisation and vapor transport processes. In: H.H. Cheng (Editor), Pesticides in the

260

F.G. Wijnands / European Journal of Agronomy 7 (1997) 251–260

Soil Environment. Soil Science Society of America Book Series, No. 2, Madison, WI, pp. 213–269. The Pesticides Trust UK, information leaflet. Eurolink Business Centre, 49 EFFRA Road, London, SW2 1B2, UK. Vereijken, P., 1994. 1. Designing Prototypes. Progress Reports of Research Network on Integrated and Ecological Arable Farming Systems for EU- and Associated Countries (concerted action AIR3-CT927705). AB-DLO, Wageningen, 87 pp. Vereijken, P., 1995. 2. Designing and Testing Prototypes. Progress Reports of Research Network on Integrated and Ecological Arable Farming Systems for EU- and Associated Countries (concerted action AIR3-CT927705). AB-DLO, Wageningen, 76 pp. Vereijken, P., 1997. A methodical way of prototyping integrated and ecological arable farming systems (I/EAFS) in interaction with pilot farms. In: M.K. van Ittersum and S.C. van de Geijn (Editors), Proceedings of the 4th ESA Congress, Elsevier, Amsterdam. Vereijken, P. and D.J. Royle, 1989. Current status of Integrated arable farming systems research in Western Europe. IOBC/ WPRS Bull., XII: 5.

Werf van der, H.G.M., 1996. Assessing the impact of pesticides on the environment. Agric. Ecosyst. Environ., 60: 81–96. Wijnands, F.G., 1992. Introduction and evaluation of integrated arable farming in practice. Neth. J. Agric. Sci., 40: 239–250. Wijnands, F.G., 1994. Focus on IAFS prototyping in Nagele experimental farm (NL1). In: P. Vereijken (Editor) 1. Designing Prototypes. Progress Reports of Research Network on Integrated and Ecological Arable Farming Systems for EU- and Associated Countries (concerted action AIR3-CT927705). AB-DLO, Wageningen, pp. 79–84. Wijnands, F.G. and Vereijken, P., 1992. Region-wise development of prototypes of Integrated arable farming and outdoor horticulture. Neth. J. Agric. Sci., 40: 225–238. Wijnands, F.G., van Asperen, P., van Dongen, G.J.M., Janssens, S.R.M., Schro¨der, J.J. and van Bon, K.B., 1995. Innovatiebedrijven geı¨ntegreerde akkerbouw, beknopt overzicht technische en economische resultaten. PAGV-verslag nr. 196. PAV, Lelystad, 126 pp. (in Dutch with English summary and tables and figures).