Determining Optimal Single Irrigation Amount and Planting Date of Five Wheat Varieties at Rainfed Condition
2005
Tavakoli, Alireza | Zad Hassan, Esmail | Atarilor, Jalil | Khorsandi, Hadi
In order to investigate the effects of planting date and single irrigation on yield increasing and stability, this experiments was conducted as split split plot arranged in a randomized complete block design (RCBD) with three replications during 2000-2004 for rainfed wheat varieties at main station of Dryland Agricultural Research Institute (DARI) at Maragheh. The treatments included three planting (sowing) date (early, normal and late), three levels of single irrigation (Rainfed, 50mm and 100mm only at planting time) and five wheat varieties. Observations were included: grain, straw and biological yields, harvest index, productivity degree, plant height, kernel number per spike, spike number per.m-2, thousand kernel weights, spike length and water productivity. Yields of rainfed conditions varied with seasonal rainfall and its distribution, with all main factors having significant effects. Results of path analysis showed that increase in grain yield was resulted from increase of plant height and spike number per.m-2 respectively. Optimum program of single irrigation was 100mm at early, 75mm at normal and 50mm at late planting time. V3 wheat variety was better than other varieties. At this single irrigation program obtained maximum water productivity (11.3 – 21.3 kg.mm-1) and so maximum net benefit. Limit of benefitability for optimum program of irrigation was determined as 4187, 5384 and 2642Rial.m.-3 water respectively, or ratio of irrigation and water cost to price of crop was less than 2.43, 3.12 and 1.53 respectively. Keywords: single irrigation, planting (sowing) date, wheat varieties, rainfed, yield and yield components, path analysis, correlation coefficient, net benefit, water productivity
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