تعيين نياز نيتروژن و فسفرگندم ديم رقم سبلان در شرايط و آبياري تكميلي

Nitrogen and Phosphorus Requirements of Dryland Sabalan Wheat under Rainfed and Supplemental Irrigation Conditions

Wheat c.v. Sahalan nutrient requirement was estimated under tainted and supplemental irrigation conditions. The experiment was conducted in RCBD (split plot factorial) design with three replications. Main plots included three levels of irrigation namely: 10 (minted), lI (one irrigation at heading stage), and I2 (two irrigations at heading and milky stage). Subplots included fertilizer use in factorial combination, nitrogen levels of 0,60,120 kg N ha-1, and, phosphorus levels of t) and 61) kg P2O5 ha-1. The experiment was carried for 4 years during 1992-1996 at Mantgheh Dryland Station . Amount of water used in each irrigation was calculated based on moisture deficiency from F.C. in 100 cm soil profile depth. Nitrogen was split applied as urea (1/2 at planting and 1/2 at first irrigation) and triple superphosphate was applied at planting time. Results showed that irrigation had significant effects on wheat grain, straw yield and T.K.W increase at the 1";, probability level. Highest yield was obtained from II as 1843 kg ha-I . Decreasing soil moisture from F.C., increased the efficiency of supplemental irrigation. Regression equation showed that wheat nitrogen requirement in rainfed (10) and supplemental irrigation (I1) was 48 and 63 kg N ha-1, respectively and phosphorus requirement in (10) and (lI) was 20 and 28 kg P2O5 ha-1, respectively.