Document Type : Research Paper
Authors
1
Assis. Researcher. Agri. and Food Sc. Dept. Fars Technological & Environmental Research Center (FTERC), Shiraz, Iran
2
Assoc. Prof. Irr. Dept. College of Agri. Shiraz University
Abstract
This experiment was conducted to investigate the effect of water stress at different growing stages of cowpea. A complete randomized block design with five treatments in four replications was used on a silty clay loam soil under furrow irrigation. The treatments consisted of one control (without water stress) and four treatments with water stress at, respectively, vegetative, flowering, pod forming, and pod filling stages. Soil moisture was measured weekly by neutron meter before each irrigation. Evapotranspiration was calculated using water balance method. The water requirement was supplied based on difference between soil moisture and field capacity. Seed yields in the control and stress treatment at vegetative stage were, respectively, 2384 and 2170 kg.ha-1, without significant difference. The amounts of water supply were, respectively, 946 and 828 mm. Seed yields of the treatments with water stress at flowering, pod forming, and pod filing stages were 1782, 1760, and 1700 kg.ha-1, respectively, being significantly lower than the first two treatments. The amounts of water supplied to these three treatments were 820, 898, and 789 mm, respectively. According to the results, cowpea tolerates water stress for two weeks at vegetative stage, but, the same water stress experienced at flowering, pod forming or pod filling stages decreases the number of seeds per pod, the average weight of one seed, and total seed yield. Relations found between the seed yield with the amount of water supply and seed yield with evapotranspiration are presented in the main text.
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