Wheat Response to N Application Method Under Some Irrigation Systems at North Delta

Abstract

N4" and 100 % soil application "N5") on wheat (var. Sakha 93) yield, N uptake, N use efficiency and soil available N remained after harvesting. The main results could be summarized as follows: 1-Surface irrigation system (I1) and N1 treatment achieved the highest values of wheat grain and straw yields, while the lowest values were recorded with subsurface drip irrigation system and N4 treatment. 2-I1 and N2 treatment gave the highest 1000 kernel weight, while I6 and N4 treatment gave the lowest value. 3-The highest values of N uptake, and N use efficiency were recorded with I1 and N1, while, the lowest values were achieved under I6 and N5. The opposite trend was observed with available nitrogen remained in soil after wheat harvest. This means surface irrigation and N fertigation increase the ability of wheat plants to N uptake from the soil and consequently increase yield. 4-The response of wheat grain yield to N application method under surface drip irrigation could be expressed by equations 1 and 2 as follow:-YSoil app = 3107.4 (N soil app.) + 56.1 (R 2 = 0.9973), (1) Yfert = 2756.2 (N fert.) + 31.7 (R 2 = 0.9991),(2) While, equations 3 and 4 summarized the response of grain yield to different N treatments under sub-surface drip irrigation as follow:-Yfert = 2478.1 (N fert.) -33.298 (R 2 = 0.9992), (3) YSoil app = 2064.3 (N soil app.) + 70.15 (R 2 = 0.9913 ), (4) Where: YSoil app = the estimated wheat grain yield (kg fed -1 ) according to the contribution ratio of N soil application. Yfert = the estimated wheat grain yield (kg fed -1 ) according to the contribution ratio N fertigation method. N soil app.= N soil application ratio (%). N fert = N fertigation ratio (%). From equation 1, 2, 3 and 4 it could be concluded that nitrogen fertilizer is preferable to add as soil application with surface drip irrigation, while N fertigation method has to be used with sub-surface drip irrigation.