ECONOMIC AND ENVIRONMENTAL BENEFITS OF VARIABLE RATE APPLICATION OF NITROGEN TO CORN FIELDS: ROLE OF VARIABILITY AND WEATHER

The use of meta-response functions based on EPIC-generated data resulted in comparisons between variable (VRAT) and uniform rate application technologies for 36 simulated fields. VRAT was more profitable and less nitrogen was lost to the environment in most cases. When spatial variability was small, uniform rate application techniques were adopted. However, when nitrogen use is restricted, VRAT is used on all simulated fields.Precision farming, site-specific farming, spatial variability, nitrogen restriction, rainfall, EPIC, crop growth simulation model, meta-response functions, Environmental Economics and Policy, Research and Development/Tech Change/Emerging Technologies, Resource /Energy Economics and Policy,

ASSESSING SPATIAL BREAK-EVEN VARIABILITY IN FIELDS WITH TWO OR MORE MANAGEMENT ZONES

Farmers are interested in knowing whether applying inputs at variable rates across a field is economically viable. The answer depends on the crop, the input, their prices, the cost of variable rate technology (VRT) versus uninform rate technology (URT), and the spatial and yield response variability within each field. Methods were investigated for determining the range of spatial variability over which the return to VRT covers its additional cost compared with URT in fields with multiple management zones. Models developed in this article, or variants thereof, could be used to help farmers make the VRT adoption decision.management zones, nitrogen, precision farming, site-specific management, spatial break-even variability proportions, spatial variability, variable rate technology, yield response variability, Farm Management,

EVALUATING THE RETURNS TO VARIABLE RATE NITROGEN APPLICATION

Potential benefits of variable rate nitrogen application are illustrated and information needs identified. Lower costs of precision farming services, higher crop prices, and greater divergence in yield response potentials across management zones reduce the spatial variability required for profitable variable rate application. Information needs include identification and measurement of management zones within a field and estimation of management zone yield response functions, crop and input prices, and the cost of precision farming services.production economics, management zones, nitrogen, precision farming, spatial break-even variability proportions, variable rate applications, yield response variability, Crop Production/Industries,

Kharif Sorghum in Karnataka: An Economic Analysis

Sorghum, which once occupied more than 18 M ha of area in the country, has been on a continuous decline during the past two decades and has fallen down to 10.39 M ha. Most of the decline in area has occurred in kharif sorghum. This warrants critical examination of the changing scenario of kharif sorghum and identification of the reasons thereof. For the macro analysis, secondary data on various aspects of kharif sorghum have been used, whereas the farm survey data have been used to draw the inferences at the micro level with respect to changing scenario of kharif sorghum. The growth rates in area, production and productivity of kharif sorghum have been computed. The Herfindahl index has been computed to find out crop diversification in the sample districts of Dharwad and Belgaun. The deceleration in the kharif sorghum area in the overall period 1970-71 to 1997-98 and different sub-periods has been found due to the diversion of kharif sorghum area to more remunerative crops like oil seeds (groundnut and sunflower), and pulses. Belgaum district displayed a moderate degree of crop diversification compared to that of Dharwad district. Unfavourable prices, declining yields, inadequate credit and adverse climatic conditions have been identified as the major reasons for the replacement of kharif sorghum crop in the two sample districts. The net returns and benefit-cost ratio have been found low in the cultivation of kharif sorghum compared to those of its competing crops, viz. cotton, green gram and groundnut.Agricultural and Food Policy,

VARIABLE RATE NITROGEN APPLICATION ON CORN FIELDS: THE ROLE OF SPATIAL VARIABILITY AND WEATHER

Meta-response functions for corn yields and nitrogen losses were estimated from EPIC-generated data for three soil types and three weather scenarios. These metamodels were used to evaluate variable rate (VRT) versus uniform rate (URT) nitrogen application technologies for alternative weather scenarios and policy option. Except under very dry conditions, returns per acre for VRT were higher than for URT and the economic advantage of VRT increased as realized rainfall decreased from expected average rainfall. Nitrogen losses to the environment from VRT were lower for all situation examined, except on fields with little spatial variability.Corn, environment, meta-response functions, nitrogen restriction, precision farming, site-specific management, spatial variability, weather variability, Crop Production/Industries,

Economic Analysis of Post-harvest Losses in Food Grains in India: A Case Study of Karnataka

The post-harvest losses have been estimated at different stages in two major food grains, viz. rice and wheat in India. The time series data from 1982-83 to 2001-02 on area, production and productivity of the selected food grains have been subjected to growth rate analysis. The post-harvest losses have been estimated using the survey data collected from 100 farmers, 20 wholesalers, 20 processors and 20 retailers in each crop in Karnataka for the year 2003-04. Tabular analysis has been used to estimate the post-harvest losses at different stages, and functional analysis has been used to assess the influence of socio-economic factors on postharvest losses at the farm level. The increase in rice production in the study district of Shimoga has been mainly from increased area under rice. The increased rice output at the state level is the result of increased productivity and area, while at the national level it is the rise in productivity. The increased wheat output in the country has been due to increased wheat productivity. The postharvest losses at the farm level have been estimated to be 3.82 kg/ q for rice and 3.28 kg/q for wheat. The losses have been highest during storage in both the crops. The factors that influence the post-harvest losses significantly at the farm level have been identified and some policy implications have been highlighted

SPATIAL BREAK-EVEN VARIABILITY FOR CUSTOM HIRE VARIABLE RATE TECHNOLOGY ADOPTION

A theoretical model identified ranges of spatial variability required within multiple-land-class fields for economically viable variable rate technology (VRT) and the spatial variability required for maximum return to VRT. An example illustrated that return to VRT and the viable range of spatial variability increased for higher corn and nitrogen prices

ECONOMIC AND ENVIRONMENTAL BENEFITS OF VARIABLE RATE APPLICATION OF NITROGEN TO CORN FIELDS: ROLE OF VARIABILITY AND WEATHER

The use of meta-response functions based on EPIC-generated data resulted in comparisons between variable (VRAT) and uniform rate application technologies for 36 simulated fields. VRAT was more profitable and less nitrogen was lost to the environment in most cases. When spatial variability was small, uniform rate application techniques were adopted. However, when nitrogen use is restricted, VRAT is used on all simulated fields