Document Type : Original Article
Authors
1
Soil and Water Department, Faculty of Agriculture, Cairo University, 12613, Giza, Egypt.
2
Atomic Energy Authority, Nuclear Research Center, Soil and Water Research Department, Abou-Zaabl, Egypt
3
Agronomy Department, Faculty of Agriculture, Cairo University, 12613, Giza, Egypt
4
Soil Department, Faculty of Agriculture, Damietta University, Egypt.
Abstract
Two field experiments were conducted under two different soil texture located in two sites. Tracing the nitrogen status in wheat plants – soil - environment system using 15N technique under different water regimes was the aim of this investigation. Three nitrogen rates (100, 80 and 60% of the recommended rate with 5% 15N atom excess labeled ammonium sulfate) through two mode of application (Mode A; nitrogen fertilizer rate splitting into three doses: 25, 25, 50% of added rates at seedling, tillering and jointing, respectively, and Mode B; splitting N rate into two doses: 35 % at seedling and 65% at tillering) conjugated with three water regimes (100, 75 and 50% of crop water requirement (CWR)) were applied under clay loam and loamy sand soils conditions. Wheat grain and straw yields were declined by 16.4 and 4.4% in clay loam soil, and by 34.6 and 20.7% in loamy sand soil as water regime reduced from 100 to 50% CWR, respectively. Application of 80% of the recommended N rate recorded the highest grain yield under Mode A, whereas 100% N rate recorded the highest straw yield under Mode B in both soil textures. The moderate rate of N fertilizer (80%, corresponding to 142.4 and 190.4 kg N ha-1 in clay loam and loamy sand soil, respectively) applied with mode A under 75% water regime (4017.7 and 4200.8 m3 applied irrigation water per hectare in clay loam and loamy sand soil, respectively) recorded the highest N uptake by plant, nitrogen use efficiency (NUE) and consequently wheat yield.
Keywords
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