Interaction of water deficit and mulch on the yield and water use efficiency in basil using elasticity theory

One of the ways to reduce water consumption and increase water productivity is to simultaneous use mulch and deficit irrigation. For studying the effect of mulch and different levels of irrigation on water use efficiency of Basil, a split plot experiment based on randomized complete block design was conducted. The experimental treatments consisted of four different irrigation levels; and two soil factors in two seasons of cultivation. The elasticity theory was used to determine the maximum product yield and water productivity. In the theory of elasticity, marginal water consumption efficiency index and elasticity index are determined by deriving from the production function. The results of the first season showed that in the conditions of maximum yield, the yield of the product in mulched soil was about 19% higher than the normal soil, while water consumption was reduced by 28% in the mulch, and in total about 50% of water productivity has increased. In deficit irrigation condition, the best dry matter yield, water requirement and water productivity were 118 gr/m2, 67 mm and 67.1 gr/lit in soil covered with mulch respectively; while these values for uncovered soil were 96.7 gr/ m2, 80.2 mm and 21.1 gr /lit respectively. The results in the second season of cultivation were similar to those of the first cultivar and indicated that the yield of the product, water requirement and water productivity in the mulch was increased. The results of the experiment showed by applying mulch on the soil surface and using deficit irrigation strategy, water use efficiency and yield productivity of basil increased.