引黄灌区套种玉米种植密度与施N量的最佳耦合效应

Research on the Optimum Effect of Plant Density and Nitrogen Applied Quantity in Interplanting Maize and Wheat in the Area Irrigated by the Yellow River

通过对麦玉套种下肥、密耦合效应的研究,表明增加种植密度和施氮量能显著提高玉米单产水平,种植密度60 000～67 500株/hm2、施氮量337.5～450 kg/hm2是高产的较佳组合。随着种植密度增加,千粒重、穗粒数显著降低,穗长、穗粗、穗行数下降,秃尖增长,但种植密度与株高、穗位、出籽率无相关性;随着种植密度的进一步增加植株茎秆变细、变弱,抗倒伏能力降低,空秆率增加。增施氮肥能有效增加千粒重和单穗粒数,穗长、行粒数以及株高、穗位均随着施氮量的增加而增加,但施N量在337.5 kg/hm2以上时,继续增施氮肥穗长与行粒数不再增加;施N量与出籽率之间呈正相关,与穗行数、秃尖长、基茎粗、倒折率、空秆率无相关性。

Research on the coupling effect of fertilizer and density in the maize showed that increasing the plant density and nitrogen applied quantity could improve the yield evidently. It is a better combination when the plant density is 60,000-67,500 individual line/hm^2 and meanwhile the nitrogen applied quantity is 337.5-450 kg/hm^2. With the increasing of plant density, 1000 kernel weight and each spike kernel number is decreased distinctly, the spike length, width and row number in each spike was also decreased, while the bald needle was increased at the same time. The plant density had no pertinence with the plant height, spike location and the seed ratio. When the plant density further increased, the plant culm become thin and slender, so it was liable to lodge more easily, vacant stalk ratio increased more. With the increasing of Nitrogen applied quantity, 1000 kernel weight and each spike kernel number is also decreased distinctly, the spike length, row number in each spike, plant height and spike location was also increased. When the Nitrogen applied quantity was more than 337.5 kg/hm^2 , the spike length and row number in each spike would not increased even much more fertilizer was used. Nitrogen applied quantity had positive correlation with seed ratio, but had no pertinence with row number in each spike, bald needle length, plant culm width, the lodged stalk ratio and vacant stalk ratio.