Gross Margin Research Articles

Economic Benefit to Gardeners and Retailers from Cultivating and Marketing Vegetables in Niamey, Niger

Little is known about the effects of season and marketplace on the return obtained by urban gardeners and retailers in West African cities from the cultivation and sale of amaranth, cabbage, lettuce and tomato. To fill this knowledge gap, measurements of yields and weekly price interviews were conducted in Niamey, Niger, during the rainy season (August–October) and the cool dry season (November–January) of 2007–08. Using gross margin (GM) analysis, net profits (NP) and returns (R) on investments were calculated. During the rainy season, farm-gate prices of tomato averaged 660 FCFA kg−1fresh matter, compared with 450 FCFA kg−1fresh matter (p < 0.05) in the cool dry season, while prices of amaranth, lettuce and cabbage were more stable across seasons (100 FCFA = 0.15 Euro). The estimated GM (FCFA per hectare and season) and R (FCFA per FCFA invested) were 5.83m (R = 12.78) for amaranth, 10.09m (R = 18.98) for cabbage, 5.90m (R = 12.21) for lettuce and 6.40m (R = 16.58) for tomato during the cool dry season, compared with 4.71m (R = 8.44, amaranth), 9.50m (R = 13.48, cabbage), 6.52m (R = 7.08, lettuce) and 15.17m (R = 23.46, tomato) in the rainy season. Inputs in terms of labour, fertilizers and seeds strongly affected returns. Cabbage and tomato market prices (per kg FM) averaged 804 FCFA and 832 FCFA in the rainy season, compared with 410 FCFA (p < 0.05) and 574 FCFA (p < 0.05) in the cool dry season. For amaranth and lettuce, the NP of market retailers depended only on marketplace, whereas the NP of cabbage and tomato strongly depended on season and marketplace. Reducing mineral fertilizer use would lower production costs and thus increase gardeners' profits; at the same time, it would reduce environmental hazards ensuing from urban vegetable production in Niamey

Managing for rainfall variability: long-term profitability of different grazing strategies in a northern Australian tropical savanna

Several grazing strategies are recommended to manage sustainably for rainfall variability in northern Australia, but there is little objective data on their profitability relative to less sustainable management systems such as heavy stocking. In 1997, a large cattle grazing trial was initiated in northern Queensland to quantify the relative performance of a range of grazing strategies in a variable climate. These strategies were (i) moderate stocking (MSR) stocked at the calculated long-term carrying capacity (LTCC), (ii) heavy stocking (HSR) at twice LTCC, (iii) rotational wet-season spelling (R/Spell) at 1.5 LTCC, (iv) variable stocking (VAR), with stocking rates adjusted in May based on available forage and (v) a southern oscillation index (SOI)-variable strategy, with stocking rates adjusted in November based on available forage and SOI-based seasonal forecasts. Rainfall varied over the 12-year trial period, with sequences of dry and wet years. Gross margins (GM) in the HSR were initially high but collapsed in drier years due to high costs and reduced product value. GMs only recovered in later years with a reduced stocking rate and increased rainfall. The VAR and SOI were also initially very profitable, but GMs plunged as rainfall declined due to reduced animal performance and the sale of poor-condition cattle. This sharp cut in stocking rates nevertheless allowed GMs to recover well in subsequent years. In the MSR, GMs remained relatively constant across most years due to low costs and a higher product value. The R/Spell also performed relatively well despite being compromised by an ill-timed fire, drought and the subsequent sale of poor-condition cattle. Net present value (NPV) after 12 years was highest in the VAR ($11 962/100 ha), followed by the MSR ($11 873/100 ha), the SOI ($11 167/100 ha) and the R/Spell ($10 665/100 ha). NPV was by far the lowest in the HSR ($6930/100 ha). Profitability also varied the most in the HSR, with a negative GM in 6 of the 12 years. Incorporating the costs of natural resource decline would further reinforce the case against heavy stocking. These results challenge the assumption that sustainable management in a variable environment is unprofitable.

Effect of including genetic progress in milk yield on evaluating the use of sexed semen and other reproduction strategies in a dairy herd

The objective of this study was to explore the importance of including genetic progress in milk yield when evaluating different reproductive strategies in a dairy herd by simulation modeling. The model used in this study was SimHerd V, a dynamic and mechanistic Monte Carlo simulation model of a dairy herd including young stock. A daily increasing trend describing genetic milk yield potential of the sire population was included in the model. The inaccuracy of assuming that replacement heifers have the same (milk yield) potential as the cows present in the herd was hereby dealt with. Improving estrus detection rate from 0.45 to 0.80 increased gross margin (GM) per cow-year by €20 when genetic progress was not included in the model. When genetic progress was included in the model, then the same improvement in estrus detection decreased the GM per cow-year by €7.4. This reduced effect was explained by a lower replacement rate in consequence of the improved estrus detection and thereby a slower genetic progress in the herd. There was a reduced effect of including genetic progress on GM when surplus heifers were sold selectively based on breeding values. Repeated insemination with sexed semen on the superior half of all heifers reduced GM by €8 per cow-year when genetic progress was not included and increased the GM by €16 per cow-year when genetic progress was included in the model. Including genetic progress reduced the losses caused by lower conception and estrus detection rates and had a minimal effect with regard to postponing first insemination. This study has proven that it is important to include genetic progress in decisions on reproduction strategies in a dairy herd.

Efecto de la incorporación del poroto soya procesado a la dieta de gallinas de postura sobre la producción y la calidad del huevo

The objective of this work was to produce local information with regard to the inclusion of full fat toasted soybean (FFTSB) or extruded (FFESB) in the diet of laying hens, evaluating their effects on: egg production (EP), feed intake (FI), body weight (BW), egg weight (EW), egg mass (EM), efficiency of feed utilization (EFU), mortality (M), and the externa/ and internal egg quality parameters. In addition, gross margin (GM) and alimentary cost of the kg of egg produced (ACek) were determinated. The experiment was can-ied out for 16 weeks with 216 white Leghorn Lohman hens 26 weeks old at the beginning of the trial, randomly distributed in 3 treatments of 72 birds each one. The treatment 1, control, was fed a diet without FFTSB or FFESB; the treatments 2 and 3, included 20% of FFTSB or FFESB, respectively, all diets were formulated isoproteinic and isoenergetic. The data were subjected to the analysis of variance according to a model of fixed effects type 1 and Tukey test was used to compare differences among individual mean. The results pointed out that the FFESB treatment was superior for EP, EM and shell strengh to fracture, but on the other hand it obtained the less EFUs of the study, associated to a greater FI. The FFTSB treatment showed no differences with the Control Soybean Meal treatment for: BW, EP, EW, EM, FI, EFU (kg feed/doz. eggs), and cracked, broken and shell less eggs, specific gravity, shell deformation capacity, shell thickness, albumen: yolk ratio (weight and volume), Haugh units and yolk color, but was less efficient for EFU (kg foodlkg of eggs) than this treatment. Regarding the economic results, the FFESB treatment generated the biggest GM followed by the FFTSB treatment that in addition obtained the smallest ACke. Finally, the data pointed out that the use of FFESB or FFTSB in practical diets for laying hens may allow producers and feed milis to formulate diets with these alternative plant protein sources when their availability and prices be competitive.

Economics and environmental analysis of Mediterranean greenhouse crops

The aim of this paper is to show that intensive agriculture, as greenhouse crops that produce a high level of environmental pollution, both by nitrogen fertilization as pesticides used, may be distributed based on weighted goal programming using utility functions, in a way as to decrease the pollution, maintaining benefit and lowering risk, based on, to change the crop alternatives employed. To prepare this model, accounts were tracked on 46 (year 2006 to 2007) and 49 greenhouses (year 2007 to 2008), in which 16 crops were rotated, these being representative in percentage terms of the distribution of crops in the area. The data obtained were gross margin (GM), irrigation water consumption (W), nitrate consumption (N), labour needed (L) and toxicity level (TL) through the use of plant protection products. The utility function obtained shows that the objectives considered by the average farmer are gross margin, risk (R) and labour. This study has also considered other scenarios such as minimum W, minimum N and minimum TL. Comparing the actual situation with all the scenarios studied, it is observed that these scenarios are better in terms of economics and environment. The scenarios they want to achieve are environmental objectives, like W, N and TL. They have a limited distribution of crops. Also, it was observed that the greenhouse crops studied have consumption of water, nitrogen and labour close to the optimal. With planning, the crops would achieve the utility function, thereby reducing the environmental pollution and improving the gross margin and the risk of farmers. Key words: Toxicity, nitrogen, water, gross margin, risk, labour.

Effect of irrigation uniformity on the profitability of crops

Abstract There are numerous models capable of simulating crop behavior under different water stress conditions. However, none of them takes into account the effect of irrigation water uniformity on yield. The model developed simulates the uniformity effect on yield and the repercussion on gross margin (GM). The application of the model to a maize crop in Albacete (Spain) indicates that for the same irrigation depth, an increase in uniformity of water in the soil (CU) corresponds to a 4% increase in yield for the common irrigation strategy in the area, and a 6.8% increase in yield for the optimal irrigation schedule established by the model. Values of percentage of adequately irrigated area (a) between 50 and 80% appear to be adequate for values of CU > 80%. This effect has special relevance on the GM mainly when designing the irrigation strategy of areas with limited water resources. This leads to improvement of CU from 75 to 95% for the common irrigation depth applied to maize and may increase GM up to 27%. For small irrigation depths, the effect of CU on GM is reduced. The maximum GM is reached at ET a /ET m

ECONOMIC FEASIBILITY AND BIOLOGICAL PRODUCTIVITY OF COCONUT-BASED AGROFORESTRY MODELS IN SRI LANKA

This study evaluates the economic feasibility and biological productivity of coconut-based agroforestry models designed for coconut smallholders. Coconut Research Institute of Sri Lanka has developed and established twenty-six agroforestry models in farmers' fields. Of them, four models were selected for this study. They were: mixed farming for Wet Zone (model 1), mixed cropping for Wet Zone (model 2), mixed farming for Wet Intermediate Zone (model 3) and catch cropping in young replanted coconut for Wet Intermediate Zone (model 4), established at Gaspe, Hanchapola, Katuneriya and Thulawala, respectively. Input and output data for several years, for each model, were used in the evaluation. Annual Gross Margins (GM) payback period, Net Present Value (NPV) and Benefit-Cost Ratio (BCR) were employed for the economic analysis. Biological productivity of the models was. determined employing Land Equivalent Ratio (LER) and Relative Yield Total (RYT). NPVs of agroforestry models were higher than the monocrop, suggestingthe higher net worth of the agroforestry models in the long run. Othereconomic indicators also showed that agroforestry models were moreprofitable than coconut monoculture. In all models, LER exceeded unity,indicating the yield advantage with agroforestry over coconut monocultures.However, RYT values indicated that there were negative interactionsbetween component crops of certain models, which can be attributed to thecompetition that occurs between crops.

Profitability Analysis Of Natural Rubber Tapping In Southern Nigeria

The study was a conducted to analyse cost and returns to rubber tapping in Southern Nigeria .Structured questionnaires were administered to a random sample of 129 tappers . Data collected were analysed using descriptive statistics and budgetary technique. The result indicated that males dominated rubber tapping, all of the tappers were literate for they have one form of formal education or the other and all of them were trained before tapping. A mean of 387 trees were tapped per day with output per man day of 14.02 kg and an annual output of 2,550.53 kg of dry rubber respectively. The result of the budgetary analysis show that total revenue (TR) and gross margin (GM) and net farm income (NFI)/ hectare were of N148,592.50,159.50 , N102,953.58 and N 14,214.11 respectively. The study also identified rubber plantation management problems which include, poor maintenance of plantations, irregular wage payment, inadequate transport, inadequate housing near plantation and inadequate salary/ wage. The study recommended an increased wage package, prompt payment of wages, provision of transport and maintenance of plantation to overcome the identified problems.. Keywords : Profitability, natural rubber, Southern Nigeria JORIND Vol. 5 (2) 2007: pp. 17-17

Determinants and Uses of Farm Income from the Cassava Enterprise in Ondo State, Nigeria

The on-going campaign for increased production of cassava rests on peasant farmers for its success. One obstacle is the unavailability of credit for farm expansion and the need for farmers to prudently utilize income from the farm firm. The study therefore examines the determinants and uses of income generated from cassava cultivation. Descriptive statistics, budgetary analysis and multiple regression models were the tools utilized for data analysis. Empirical results show that cassava cultivation is profitable in the study area with gross revenue (GR), gross margin (GM) and net farm income (NFI) per hectare of N95,700.00, N90,133.74 and N88,319.18 respectively. NFI was determined by size of cassava farm, quantity of hired labour used, amount of capital invested on farm and the variety of cassava cultivated. These factors were significant at either 5% or 1% level and positively influenced income. Income generated was put to a variety of uses with family food consumption, children's school needs and purchase and maintenance of household assets accounting for about 40.0%, 28.2% and 7.7% respectively. Only 13.2% of income, considered insufficient for a reasonable farm expansion bid, was re-invested into the cassava enterprise. It is recommended that a special credit window be opened for cassava farmers if the desired boost in cassava production is to be achieved and sustained.

Financial modelling of the potential cost of ovine Johne's disease and the benefit of vaccinating sheep flocks in southern New South Wales

To develop an enterprise gross margin (GM) model that predicts the on-farm financial impact of ovine Johne's disease (OJD) for various sheep enterprises in Australia. In addition, to estimate the benefits and costs of control through the use of the Gudair vaccination, including a breakeven point. Data for the model was gained from an observational study conducted over a 3-year period from 2002 to 2004 using sheep from 12 OJD-infected flocks from southern New South Wales. Flocks ranged between 3500 and 20,000 sheep, with owner estimates of 5% or greater OJD mortality at the start of the study. A GM model was developed to predict the on-farm financial impact of OJD for various sheep enterprises in Australia, comparing non-infected, infected (status quo) and infected (vaccination) disease scenarios. Vaccination breakeven points are achieved within 2 to 3 years for breeding enterprises if OJD mortalities are high, rising towards 7 years for a Merino ewe enterprise if OJD mortalities are low. The GM model demonstrates the returns to investment of vaccination for Australian sheep producers with OJD-infected flocks.

Power Producer Production Valuation

The ongoing developments in the electricity market, in particular the establishment of the Prague Energy Exchange (PXE) and the associated transfer from campaign-driven sale to continuous trading, represent a significant change for power companies. Power producing companies can now optimize the sale of their production capacities with the objective of maximizing profit from wholesale electricity and supporting services. The Trading Departments measure the success rate of trading activities by the gross margin (GM), calculated by subtracting the realized sales prices from the realized purchase prices and the production cost, and indicate the profit & loss (P&L) to be subsequently calculated by the Control Department. The risk management process is set up on the basis of a business strategy defining the volumes of electricity that have to be sold one year and one month before the commencement of delivery. At the same time, this process defines the volume of electricity to remain available for spot trading (trading limits).

BIOLOGICAL EVALUATION OF BARKI SHEEP UNDER TWO DIFFERENT BREEDING SEASONS

SUMMARY The present study was conducted to investigate the impact of breeding season on the productivity and profitability of Barki flock. Simulation technique was used based on technical coefficients derived from statistical analysis of the basic data. Basic data utilized in this study were obtained from the accumulated records collected over 34 successive breeding seasons from 1972 to 2005 of Barki sheep flock raised at Maryout Research Station. Biological criteria considered were number of ewes lambed per ewe joined, (EL/EJ), number of lambs born per ewe joined (LB/EJ), number of lambs weaned per ewe joined (LW/EJ), kilogram weaned per ewe joined (KGW/EJ). Deterministic technical coefficients were used to create two simulated flocks of two different breeding seasons. Economical indicators were gross margin (GM) per flock and per ewe, marginal rate of return (MRR), cost of one kg of meat produced and benefit/cost ratio (B/C). The overall least squares means for EL/EJ, LB/EJ, LW/EJ and KGW/EJ were 78 %, 80 %, 61 % and 11.9 kg, respectively. Analysis of variance showed that autumn breeding season flock was significantly higher than summer breeding season flock in all studied traits. Flock applying autumn breeding season achieved higher gross margin per flock, per ewe, B/C and lower variable cost per one kg of meat produced than flock applying summer breeding season ( LE 47703 vs. LE 30699), (LE 95.5 vs. LE 61.8), (1.35 vs. 1.25) and (LE 14.6 vs. LE 15.8), respectively. While, MRR was LE 2.40.

Dynamics and developmental trends of smallholder pig production systems in North Vietnam

This study analyses developmental trends, and the driving forces behind them, in smallholder pig production systems in the marginalized mountainous areas of North-west Vietnam. Fieldwork was conducted from 2001 to 2002 in a total of 64 households in four villages in North Vietnam of varying remoteness. Data on developments in pig production were derived from structured household interviews and analysed by loglinear models. The findings of Rapid Rural Appraisal on historical developments are also presented. Spreadsheet models were developed simulating four production alternatives: demand-driven pig production with higher-yielding Vietnamese Mong Cai sows or resource-driven production with lower-yielding local Ban sows, generating offspring either through purebred boars of the respective breed or with higher-yielding Large White boars. Starting from the base models of the four genotype/production system combinations, the following scenarios were tested: (1) increased performance through improved management, (2) modification of end products, and variation of (3) input costs and (4) end-product prices. Evaluation variables were gross margin (GM) and net benefit (NB) of pig production. Results show a rapid transition process from subsistence to increasingly market-oriented production, beginning even before the reforms of 1986 (Doi Moi) but gaining considerable momentum afterwards. Differentiation of production systems was observed in regions that differed in remoteness and environmental conditions. In the base model, improved Large White × Mong Cai pigs yielded the highest GM and local Ban pigs the lowest; Large White × Ban pigs yielded the highest NB and Mong Cai pigs the lowest. Under a scenario of considerably increasing feed costs, Large White × Ban pigs became more beneficial than Large White × Mong Cai pigs based on GM as the decision criterion. Modelling results are compared with current conditions in the Vietnamese pig sector. The probability of local Ban pigs becoming a beneficial production alternative is critically discussed, as is the methodological approach of the study.

EVALUATION OF CROP-DAIRY PRODUCTION SYSTEM IN NILE DELTA

SUMMARY A linear programming (LP) model was applied to evaluate crop-dairy production system in small mixed farms in the Nile Delta through the impact of Food Sector Development Program (FSDP) of the Ministry of Agriculture and Land Reform. The LP model considered land, labor, large ruminant genotypes, cropping pattern and available cash resources (ACR) as factors affecting production of this system. Technical coefficients of the LP model were estimated from a survey data collected from 492 farmers in five different governorates, Damietta (DAM), Daqahleia (DAQ), Gharbeia (GHA), Kafr El-Sheikh (KEL) and Menoufeia (MEN), during the period from 1993 to 2001. Two districts were sampled within each governorate, one with farmers collaborating with FSDP, who got at least one training package (C1) and another with non-collaborating farmers (receiving no training packages (control group)) (C0). The objective function of LP model was to determine the optimum combination of crops and dairy production, which maximizes the gross margin (GM) of the farm, which enhances the return per feddan (RPF) and the return per animal (RPA). One LP model with three runs was tested. The first run (base run) was to simulate the actual situation, the second (LP1) to avoid the unacceptable solution for the base run while the third (LP2) to get feasible solution for the district that had no feasible solution. Results suggested that, in base run solution, farmers in general should combine cultivating berseem in winter with rice in summer plus keeping buffalo before FSDP package adoption. While, after FSDP package adoption the farmers should combine cultivating cash crops with berseem in winter , rice in summer and crossbred cattle in district C1 in MEN and in both district in DAQ, while other districts should keep exotic cattle. The FSDP improved GM, RPF and RPA by about 9 %, 5% and 11%, respectively in base run, by about 10%, 7% and 10%, respectively, in LP1 and by about 8%, 3% and 10%, respectively in LP2. In conclusion LP model showed that, both land and available cash resources were the limiting resources while labor was not. In mixed dairy production system in Nile delta, dairy animal activities contribute substantially, about 25%, to the total farm gross margin.

27: Pharmacoeconomic Model for the Treatment of Acute Asthma: A Comparison of Racemic Albuterol Vs. Levalbuterol

To quantify the pharmacoeconomic gross margin (GM) impact comparing racemic albuterol (ALB) versus levalbuterol (LEV) in the emergency department (ED) treatment of patients presenting with acute asthma based on number-needed to treat (NNT), volume (V), per diem revenue (PD$), length of stay (LOS), indigency rate (IR), and daily cost of care (DCOC).

Effects of pasture improvement on productivity, gross margin and methane emissions of a grazing sheep enterprise

Improving the availability and digestibility of pasture typically increases the enteric methane emission (g/day) produced by ruminants, but reduces the methane yield per unit of meat or wool produced. On Australian farms, sowing of improved pastures is associated with an increase in stocking rate (animals/ha) to manage the sward and repay sowing costs. This increase in animal numbers complicates the calculation of changes in whole-farm enteric methane emissions associated with pasture improvement. The GrassGro™ model was used to simulate the changes in annual methane, meat, wool and gross margin (GM), resulting from sowing improved pasture on a 100 ha cross-bred lamb farm at Cowra, NSW. Simulations used 45 years of local weather data with stocking rates on unimproved and improved pastures of 3.5 and 9 ewes/ha, respectively. Farm methane production and sales of wool and LW were increased 2.3-, 2.7- and 3.1-fold by sowing 100% of the farm area to improved pasture. GM was increased almost four-fold and the annual variation in GM reduced. Consequently, while annual enteric methane emissions on sustainably managed pastures are greater if the pasture is improved, the proportionally greater increase in farm GM and profit far exceeds the potential value of extra emissions.

Applying science as a tool for dairy farmers

Dairy Systems Monitoring (DSM) was developed out of response from dairy farmers for a benchmarking tool that made fair and equitable comparisons between farms. This benchmarking system is used by the clients to improve their productivity and profitability. The dairy farm simulation model UDDER is used to simulate the farm system. The input information is milk production from fencepost, and monthly data from the farm, including, areas, stock numbers, supplements, crops and nitrogen (N). The model is then calibrated to simulate the farms production, revised and validated monthly. There has been a successful uptake of this program. Currently 50 farms are involved. Dairy Systems Monitoring has generated change in the systems of participating farmers. Dairy Systems Monitoring has proven to be an effective tool to demonstrate the impact of a range of new technologies on farm systems. The tool is used on an ongoing basis to simulate and compare different operating strategies. It has the ability for clients to compare themselves to simular farms. A key benchmark that is analysed is the feed harvested. For every additional 1 tonne of dry matter (DM) harvested, the gross margin (GM) increases by $339/ha. The question this poses for participants is "how do we harvest more pasture"? Is it by growing more pasture, or improving management to harvest more of the existing pasture growth? Dairy Systems Monitoring is an effective extension tool to highlight the impact of new technologies or management practices on the client's farm program. Keywords: benchmarking, dairy farm programmes, feed harvested, gross margins, UDDER model

Processed Sweetpotato in the Household Economy of North-Eastern Uganda

The study was conducted in north-eastern Uganda to assess the status and market potential of processed sweet potato namely, Inginyo and Amukeke. Primary data was obtained using formal survey techniques. Descriptive techniques were used to describe the status quo. Regression analysis was used to estimate the strength of the factors that influence the quantity of fresh tubers processed. Gross margin analysis was used to estimate the profitability of processed sweet potato. All farmer respondents process sweet potato primarily for household food security. Peeling and slicing were the most labour intensive activities. Lack of time, insufficient labour and lack of a market were reported as the main bottlenecks. Only the quantity of Ingiyo processed, quantity of cassava chips processed and the price of Amukeke were found to significantly influence the quantity of Amukeke processed. Gross Margin (GM) analysis, indicate that currently farmers do not make profit by engaging in sweetpotato processing. The current strategy aimed at minimizing the cost of sweetpotato processing is worthwhile. Investing in improved storage facilities is also a good short term strategy. However, the long-term solution lies with demand expansion including creation of sweetpotato products with a wider consumer appeal. The possibility of using sweetpotato flour in the baking industry also needs serious research and promotion. Keywords: Amukeke, Inginyo, Sweet Potato, Cassva Chips, North-East Uganda Eastern Africa Journal of Rural Development (2001) 17, 35-50

The Dutch Mineral Accounting System and the European Nitrate Directive: implications for N and P management and farm performance

Agricultural nutrients can be a significant source of groundwater pollution. This paper studies the possible effects on farm management of a newly introduced policy instrument to control nitrogen and phosphorus pollution of groundwater bodies in The Netherlands. Ecological, technical, political, as well as financial issues, associated with the agricultural nutrient pollution problem, are considered. In response to the concern of the European Community (EC) for pollution of groundwater, The Netherlands implemented the Mineral Accounting System (MINAS), which focusses on nutrient (nitrogen and phosphorus flows) on individual farms, and taxes farms whose nutrient surplus exceeds a defined limit. To investigate the implications of MINAS for individual farm performance, financial and nutrient bookkeeping data of 194 farms, distributed over five farm types, were collected from 1997 through 1999. This paper shows that nutrient management performance of farmers varied largely between and within farm types, not only in absolute figures but also in terms of nutrient efficiency. The study also indicated that levies or taxes for excess nutrient surpluses could be high, ranging from ▪179 ha −1 for arable farmers to ▪404 ha −1 for mixed dairy and intensive livestock producers. These levies would reduce gross margin (GM) by 8% on average and can threaten continuity on an individual farm level. Therefore, current performance has to change considerably for farmers to be able to make the final surplus standards in 2003. Furthermore, as a consequence of objections of the EC to the Dutch policy, application standards for manure were introduced. This study showed that this does not prove to guarantee safe nutrient management as well as MINAS does, but will impact financial performance more, due to higher manure disposal costs.

DIRECT PRODUCT PROFITABILITY AND RETAIL SHELF‐SPACE ALLOCATION MODELS

Given an assortment of k products, a retailer must make an important decision on the percentage of space allocated to each of them. Optimization models for this problem have previously shown that an item's space should not simply be given in proportion to its sales or its gross margin (GM). Calculations of Direct Product Profitability (DPP) have improved upon the GM concept, but the present paper is the first (of which we are aware) to integrate the DPP approach into a shelf‐space optimization model.