Bogachan Benli

A non-linear model for farm optimization with adequate and limited water supplies: Application to the South-east Anatolian Project (GAP) Region

Abstract This paper develops a non-linear optimization model for the determination of optimum cropping pattern, water amount and farm income under adequate and limited water supply conditions. The objective function of the model is based on crop water-benefit functions. The model is solved using Ms Excel Solver package for conditions existing in South-east Anatolian Region of Turkey. The model gives the optimal distribution of crop areas, irrigation water needs of crops and total profit for the farm under adequate and limited water supplies. The problem was also solved by a linear programming (LP) model, in order to indicate the difference between non-linear programming (NLP) and linear programming models. After the examination of NLP and LP model solutions, it can be seen that, the NLP model can give higher farm income values than the LP model under deficit irrigation conditions. Also, in some capacity levels, with the NLP model, instead of two different irrigation volume applications for one crop, the best irrigation volume ratio has been calculated.

Performance of Penman-Monteith FAO56 in a Semiarid Highland Environment

Reliable estimates of evapotranspiration are essential for irrigation and water resources planning and management. Although several methods are available for computing reference evapotranspiration ( ETo ) , the provision of complete and accurate climate data is often a problem. Therefore, weighing lysimeter data from a semiarid highland environment were used to evaluate the performance of six commonly used reference evapotranspiration estimation methods with different data requirements (Penman-Monteith-FAO56, Priestley-Taylor, Radiation-FAO24, Hargreaves, Blaney-Criddle, Class A pan). The lysimeter experiments were conducted at Ankara Research Institute of Rural Services in Turkey, during the April–October cropping seasons of the years 2000–2002. The average ETo for the three seasons, computed from the lysimeter data, was 964 mm. The Penman-Monteith-FAO56 method was also evaluated for cases where relative humidity, wind speed, solar radiation, or all three parameters would be missing. This resulted in a t...

Yield gap analysis: modelling of achievable yields at farm level

This chapter quantifies the potential yields and yield gaps between the potential and the actual yields obtained by the farmers for the major rainfed crops grown in the selected countries in South and South East Asia (India, Thailand and Vietnam), SSA and the West Asia and North Africa (WANA) region, where food security is increasingly threatened because of expected increase in population and degradation of natural resources. This analysis is expected to help identify the opportunities and constraints for yield improvement with the implementation of the improved crop production and natural resource management technologies for the rainfed regions.