| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Wageningen University, Farm Management Group Hollandseweg 1, 6706 KN Wageningen The Netherlands
Corresponding author:
Paul Berentsen; e-mail:
Paul.Berentsen{at}wur.nl.
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONSACKNOWLEDGEMENTSREFERENCES |
|---|
Key Words: environment • economy • policy
Abbreviation key: MINAS = Mineral Accounting System, MTAS = Manure Transfer Agreement System, Nmin = mineral nitrogen
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONSACKNOWLEDGEMENTSREFERENCES |
|---|
To tackle these problems, the Dutch government developed policies from 1987 to the present. Until 1998, excessive use of animal manure was regulated by application standards. In 1998, the Mineral Accounting System (MINAS) was introduced to reduce surpluses of nitrogen (N) and phosphate (P2O5) (Aarts et al., 2000). Starting in 2002 the Manure Transfer Agreement System (MTAS) was added as an additional policy to avoid leaching of nutrients from animal manure.
Normative modeling at farm level is one way to determine the effects of management measures on the environment. The effect of management measures on the environment was studied by Rotz et al. (1999), Dunlap et al. (2000), and Kohn et al. (1997). Policy-oriented studies are especially prevalent in EU countries where the EU pressure on national governments to decrease nitrate leaching to ground water is high (Berentsen et al., 1992; Rigby and Young, 1996; Van der Ven, 1996; Van Huylenbroek et al., 2000). Because strict environmental policies that apply to agriculture are relatively new, empirical research on the effect of policies on farm management and the environment is relatively scarce. For Dutch dairy farming an in-depth analysis of the first years’ effects of MINAS was reported by Ondersteijn (2002).
The objective of this modeling study was to determine the effects of adapting to current environmental policies for dairy farms that differ in intensity. Moreover, the environmental effectiveness of applying two policies in order to achieve one goal is examined.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONSACKNOWLEDGEMENTSREFERENCES |
|---|
The Mineral Accounting System is a farm gate balance approach. Farmers are required to account for nutrient flows that enter and leave the farm through the farm gate. The difference between input and output is the nutrient surplus. As MINAS aims to decrease losses to the soil, the N surplus is corrected for gaseous losses like ammonia emission from stables. The final surplus is expressed per hectare and compared to standards expressing surpluses per hectare that are considered acceptable. The amounts of N and P2O5 exceeding the acceptable surpluses are penalized with a levy per kg of N and P2O5 respectively. As from the introduction of MINAS in 1998, acceptable surpluses and levies were gradually tightened till final standards will be used in 2003 (Table 1
). As can be seen from Table 1, acceptable surpluses differ depending on the use of the land and for N also on the vulnerability of the land concerning leaching. MINAS has a number of shortcomings like not including atmospheric N deposition, biological fixation of N and P2O5 fertilizer as inputs to the system. However, MINAS is considered a step forward in environmental policy because the resulting N surplus is a better indicator for nutrient contamination of ground water than nutrient input via manure (Schröder et al., 2003). A whole-farm balance approach has the advantage of giving autonomy to farmers to determine how and where they will reduce their surpluses (Hanegraaf and Den Boer, 2003), but application standards leave only a very limited number of measures farmers can take to comply with the standards.
|
for the application standards for 2003). If a farm produces more N in manure than can be applied to the farm land according to the standards, the farmer has to have a manure transfer agreement with any farmer with excess "application room," showing that this farmer is willing to apply the surplus of manure on his land. However, there is no direct link between the obligation to have a manure transfer agreement and actual disposal of manure (Ministry of Agriculture, 2001). A farmer is not required to dispose manure and he will not do so as long as he can apply the manure on his own land within the acceptable surpluses of MINAS. As in the Netherlands, many farms have a shortage of "application room", manure transfer agreements are scarce, so manure producers have to pay for agreements. MTAS was introduced in 2002. For 2002, only 85% of the N manure production on farms had to be covered by application of manure on the own farm and, if necessary, by manure transfer agreements. For 2003, the amount increases to 95%. For 2002, manure transfer agreements covered 91 million kg of N, which is 20% of the total N manure production in the Netherlands (Van Staalduinen et al., 2002). A first indication for an average price paid is €0.78 per kg N (Van der Kamp, 2002). This price is paid for the agreement only, not for disposal of manure. The price a manure producer has to pay for disposal of manure varies between €8.50 and €15.50 per metric ton of manure (Philipsen et al., 2001).
The Dairy Farm Model
The model that is used to determine the effects of the environmental policies is a whole farm linear programming model. The objective function maximizes labor income (i.e., the remuneration for family labor and management that is left after all other costs have been paid).
The central element in the model is a dairy cow, calving in February, with a fixed milk production. A minimal ratio is required between the number of young stock and the number of dairy cows to guarantee replacement of dairy cows. Surplus heifers can be sold. The feeding part of the model consists of four parts. The dairy cows and young stock are fed separately, and a division is made between summer, when cows and young stock can graze, and winter, when livestock are kept indoors. For dairy cows, feeding constraints reflect demand and supply of energy and protein, DMI capacity, and demand for fiber in the ration. Milk production, energy requirements and feed intake capacity in the summer and winter periods are determined using formulas of Groen (1988). For protein, the DVE/OEB system is used (Tamminga et al., 1994). Protein requirements are calculated using formulas of the Central Bureau for Livestock Feeding (1995). Because dietary requirements of young stock are usually less complicated, constraints on feeding pertain to only energy and protein. Feed for dairy cows and young stock consists of grazed and conserved grass and maize silage produced on the farm, three types of purchased concentrates that differ in protein content, dried beet pulp, and purchased maize silage.
The land can be used for growing grass or maize silage. Grass can be produced in the model at five rates of mineral nitrogen (Nmin) from fertilizer and manure (100, 200, 300, 400 and 500 kg per ha per yr) to include decreasing marginal production with increasing Nmin rates. Grass can be used either for grazing by dairy cows and young stock or for mowing for silage to be fed to either category of stock. The area of grassland and division between grazing and mowing is dependent on the interactions among animal requirements, season of the year, price of concentrates and price and availability of other forages. These interactions are all considered in the optimization process. To maintain the quality of grass a minimum percentage of mowing is necessary. This is modeled by requiring a minimum amount of grass silage of 2 kg DM per cow per day in the winter ration.
Modeling of maize production is less complex. Above an optimal nutrient rate, production response to nutrients is low (Aarts and Middelkoop, 1990) so that only one nutrient rate is used. Maize silage can be grown as summer or winter feed for dairy cows, or as winter feed for young stock.
Nutrients for plant production can be supplied by fertilizer or by manure. The model estimates MINAS balances for N and P2O5 at the farm level based on nutrient inputs and outputs. For a more detailed description of the model see Berentsen and Giesen (1995).
The initial farm situation is specified by the right-hand side values for land, milk quota and family labor and by farm-specific coefficients representing milk production per cow and grass production per hectare.
Typical Farms
Choice of farms is based on a report called Typical Dutch (Reijneveld et al., 2000). In this report specialized dairy farms in the Netherlands are clustered according to region, soil type and intensity. Farm data used for clustering are from 1997 and 1998. More than half of the specialized dairy farms in the Netherlands are located on sandy soil where environmental problems are highest. Consequently, averages of different intensity clusters on sandy soil were chosen as typical farms. The different classes of intensity, based on yearly milk production per hectare, were 10,000 to 12,000 kg/ha, 12,000 to 15,000 kg/ha and > 15,000 kg/ha. Fixed assets and productivity characteristics of the resulting farms are in Table 2. These data were used to model the farms. Because average productivity of maize silage appeared to differ only slightly among the farms, the average gross production of 85,050 MJ NEL was used for all farms.
|
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONSACKNOWLEDGEMENTSREFERENCES |
|---|
The Low Intensity Farm (11,300 kg milk quota/ha)
In all situations, the numbers of dairy cows and young stock on this farm are 58 and 44 respectively. These numbers are determined by the available milk quota and milk production per cow and by the fixed replacement rate respectively.
In general, land use and dairy cow rations in the base situation are determined as follows. The amount of grass silage is minimized in the winter ration because costs of ensiling are relatively high and because grass production per ha is lower than silage maize production per ha. The uptake of fresh grass in summer by grazing is maximized because it is a cheap source of energy and protein (no harvesting costs). The maximum is determined by the DMI capacity of the cows and by the minimum requirement of 4 kg DM from maize silage in summer. An additional amount of concentrates fulfils the requirement for energy. The high amount of grass in the summer ration results in a high surplus of protein in the ration. For the winter ration, requirements for energy, rumen degradable protein, and intestine digestible protein fine-tune the composition of the ration and influence Nmin use on grassland. Higher use of Nmin results in higher protein concentrations in grass. Nmin use is also influenced by the required production of grass and together these factors determine the area of grassland. The rest of the area is used for maize silage.
Table 3 shows the resulting land use and composition of the rations for the 11,300 kg intensity farm. Comparison of the land use with the land use in reality (Table 2) shows a smaller area of grassland in favor of a greater area of maize silage. The MINAS balances show an N-surplus of 197 and a P2O5-surplus of 6 kg/ha. Total revenues of €163,001 and total costs of €142,755 result in a labor income of €20,246. Marginal values of land and milk quota show the increase of labor income if one hectare of land respectively 1000 kg of milk quota is added to the farm. Conversely, marginal values show the amount of money that the farm can afford to pay annually to acquire these production factors without decreasing labor income.
|
). The N input is decreased by decreasing N fertilizer use on grassland. Given the lower marginal productivity at higher N rates, this decreases N surpluses per kg of produced grass. The resulting shortage of feed is replenished by purchasing extra concentrate. This is low protein concentrate as the summer ration is balanced for protein requirements. Furthermore, this fine-tuning results in a greater share of maize silage in the summer ration. The consequence is a greater area of maize silage. MINAS-P2O5 is not a problem with this low intensity keeping in mind that P2O5 fertilizer is not included as an input. Costs that differ are costs of ensiling roughage (+€1000), concentrate costs (+€1600), and fertilizer costs (-€1000). As a result, labor income decreases by €1600. As MINAS is land based, the intensity becomes more important when including MINAS. This is shown by the marginal values of land and milk quota. Under MINAS, land becomes more valuable while the value of milk quota decreases. The marginal value of the acceptable N surplus shows the marginal cost of realizing the acceptable N surplus. It shows that for this farm it is cheaper to decrease the N surplus than to pay levy. This means that the levy of €2.30 is prohibitive in this case.
Adding MTAS means that manure transfer agreements have to be made for 549 kg of N (Table 3). MTAS pushes the farm plan in the direction of more grassland because MTAS application standards of grassland are higher. To stay within the acceptable N surplus dried beet pulp enters the summer ration. The very low protein content of dried beet pulp compensates for extra protein supplied with the increase of fresh grass. As the P2O5 content of dried beet pulp is also very low, the P2O5 surplus decreases. Total costs increase by €600. This is mainly due to manure transfer agreements (€430). The rest is the result of the changes in the farm plan. Finally, like MINAS, MTAS increases marginal value of land and decreases marginal value of milk quota.
The Medium Intensity Farm (13,400 kg milk quota/ha)
Given the area of land, available milk quota, milk production per cow and replacement rates, the numbers of dairy cows and young stock are 55 and 40 respectively. Due to the higher intensity of this farm, more roughage production per hectare is required. This is the reason that the Nmin level on grassland is as high as 400 kg in the base situation (Table 4). Cow rations are highly comparable with that of the previous farm. Labor income for this farm is €6000 higher. This higher income is the result of a higher total milk production leading to higher revenues. On the costs side the lower number of cows (with a higher production per cow) leads to lower costs directly attributable to the number of animals, like costs of housing, health care, breeding, etc. The smaller land area and the lower numbers of animals results in zero costs for variable, non-family labor. These costs were around €1500 for the previous farm. Finally, due to the smaller land area, costs of purchased feed (concentrates) are higher, but this effect is moderate because productivity of grassland is considerably higher on this farm. Summarizing, the economic effect of higher plant and animal productivity and a 2% higher milk quota outweighs the economic effect of a 14% greater land area by €6000. Both the marginal values for land and quota are higher than on the previous farm. In general, the marginal value for land increases with increasing intensity (land is becoming more scarce) while the marginal value for milk quota decreases. However, due to the higher plant and animal productivity both marginal values are higher in this case.
|
Inclusion of both MINAS and MTAS does not change the farm plan or the MINAS-balances. Labor income decreases by €781 due to costs of manure transfer agreements.
The High Intensity Farm (19,000 kg milk quota/ha)
For this farm, the numbers of dairy cows and young stock are 63 and 48 respectively. Due to the high intensity and the high requirement for grass this farm uses the major part of the land as grassland (Table 5). Comparison with the farm characteristics (Table 2) shows that, contrary to the previous farms, this farm has a much smaller area of maize land than in reality. Purchasing some 10 ha of maize silage compensates for the shortage of roughage. Rations are highly comparable with those of the previous farms. The high intensity of the farm results in relatively high MINAS-surpluses. Labor income is comparable with that of the previous farm. Apparently, from an economic point of view a 12% higher milk quota compensates for a 21% smaller area, as animal and plant productivity are almost the same.
|
Adding MTAS-2003 does not change the farm plan nor the MINAS balances. The only effects are economic. Labor income decreases by €2559, which are the costs of the manure transfer agreements.
Sensitivity Analysis
A number of uncertain factors should be considered. The first one has to do with the location of the farms. So far it was assumed that farms were located on common sandy soil. An alternative, worst case scenario for farms as far as environmental policy is concerned, would be to assume that farms are located on sandy soils vulnerable for leaching of N. Secondly, there is uncertainty about prices of goods and services that are influenced heavily by environmental policy, like prices of manure transfer agreements and of manure disposal. Extra calculations for the situation with MINAS-2003 and MTAS-2003 were done to determine the sensitivity of the results for changes in these factors. New results are compared to those in the final situation of the previous calculations.
Assuming that farms are located on vulnerable sandy soil means that acceptable N surpluses go down (see Table 1). For the high intensity farm there is no effect on farm management and environmental results. This farm was already paying levies and it pays €2200 more levy. Both other farms further decrease the N level on grassland and buy more concentrates and maize silage (the 13,400 kg intensity farm) to stay within the acceptable N surpluses. The effect on labor income is €2500 and €2000 for the low and for the medium intensity farm, respectively. The effect is higher for the first farm because of the lower animal and plant productivity.
If the price of manure transfer contracts would be doubled, there is a higher area of grassland used as the N application standards for grassland are higher than for arable land. However, changing arable land to grassland is limited by MINAS that requires fine-tuning of the rations especially with regard to protein requirement and supply. So, all farms slightly increase the area of grassland. On the high intensity farm this is accompanied by a further decrease of the Nmin level on grassland. The result is a decrease of the amount of N under the manure transfer agreement. Labor income decreases by €230, €700 and €2425 for the three farms respectively. Effects on MINAS surpluses are negligible.
Increasing the price of manure disposal by 20%, which results in the high end of the range of manure disposal prices as given by Philipsen et al. (2001), only influences the high intensity farm as this is the only farm that disposes manure. There is no effect on farm plan. The only effect is an income decrease by €1022 due to the higher costs of manure disposal.
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONSACKNOWLEDGEMENTSREFERENCES |
|---|
MINAS-2003 is fully effective as far as the two less intensive farms are concerned in the sense that N surpluses are brought down to the acceptable level. Given the intensity of these farms, P2O5 surpluses are not a problem. For the high intensity farm, MINAS-2003 is not fully effective as it shows to be economically profitable to pay levies on N surplus instead of further decreasing N surpluses. This conflicts with the basic idea of the government that levies should be prohibitive (Brinkhorst and Pronk, 1999), which means that it should not be economically attractive to pay levies instead of decreasing surpluses. Margin analysis shows that in this particular case with a manure disposal price of €13.00 per metric ton, the levy on unacceptable N surpluses should be 20% higher to become prohibitive.
MTAS-2003 does affect farms, but not in the sense that environmental results improve. On the low intensity farm, the farm plan shifts towards more grassland because the manure application standards for grassland are higher. On the other two farms, the farm plan already shifted towards more grassland as a result of MINAS. For these farms there is only an economic effect. For the high intensity farm, MTAS results in a further decrease of labor income by 9%. As the decrease of income is not accompanied by better environmental results, MTAS merely functions as a mechanism to transfer income from livestock farmers to arable farmers.
Changing the ration in order to meet herd nutritional requirements with less N-input through purchased feed appears to be helpful to reduce manure N excretion and consequently N surpluses (see also Rotz et al., 1999 and Dou et al., 1996). In the model that was used here, it is assumed that cows could exactly be fed according to protein standards. This can be realized if animals are fed individually. However, if cows are group fed, for example, roughage, it is often impossible to feed exactly according to protein standards. This means that, in practice, generally a surplus of protein is fed as a kind of safety margin. On average, this means extra consumption of protein and consequently higher N surpluses. As a result it will take more effort and more costs to meet the acceptable surpluses. A safety margin of 100 g of intestine digestible protein per day (6 to 7%) and 200 g rumen degradable protein (Berentsen et al., 1996) means that labor income decreases by an extra €1350 and €2584 for the medium and high intensity farms, respectively, as a result of the environmental policies. On the low intensity farm, there is hardly any influence.
The farm data used in this research, including the data on productivity, are from 1997 to 1998. Since then, animal and plant productivities have improved. Productivity improvement means a better input/output ratio and this includes a more efficient use of nutrients and lower surpluses (Tamminga, 1992; Berentsen and Giesen, 1997). The consequences for 2003 calculations will be that it will take lower costs to meet the acceptable surpluses.
|
CONCLUSIONS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONSACKNOWLEDGEMENTSREFERENCES |
|---|
Contrary to MINAS, the Manure Transfer Agreement System has little effect on farm management. The higher application standard of grassland is an incentive for more grassland. Income effects depend strongly on intensity, measured in animals per hectare. On intensive farms, income decreases by €2600 due to MTAS. There is no benefit to the environment by applying MTAS in addition to MINAS.
|
ACKNOWLEDGEMENTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONSACKNOWLEDGEMENTSREFERENCES |
|---|
Received for publication July 1, 2002. Accepted for publication August 22, 2002.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONSACKNOWLEDGEMENTSREFERENCES |
|---|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
