松嫩平原西部膜下滴灌玉米基于叶龄指数的适宜追氮量研究

【目的】膜下滴灌玉米种植模式在松嫩平原西部大面积推广,研究该模式下不同叶龄追施不同氮肥量对玉米的干物质积累、 氮肥利用及产量形成的影响,可为建立该种植模式玉米施肥制度提供理论依据。【方法】 在底施N 60 kg/hm2、 P2O5 90 kg/hm2和K2O 120 kg/hm2的条件下,设置4个追施尿素态氮肥水平处理: 0(N0)、 40(N40)、 90(N90)和140(N140)kg/hm2,于叶龄指数为30%、 45%、 60%和75%时,随滴灌进行追施,以不追肥为对照(CK)。测定了不同处理玉米叶片光合效率、 干物质积累和运转以及产量,计算了氮肥的利用率。【结果】随着玉米生育进程,在一定施肥范围内(0~150 kg/hm2),玉米产量、 叶面积指数、 叶绿素含量、 干物质积累、 植株氮素积累、 氮肥利用率、 氮肥农学效率及氮收获指数均随施氮量的增加而增加,当氮肥超过一定数量时(200 kg/hm2),各指标增加不明显,甚至下降。在叶龄指数为45%时追施90 kg/hm2氮肥处理,叶面积指数及叶绿素含量分别为6.92和2.69 mg/g,籽粒产量为11957.89 kg/hm2,干物质积累量、 花后同化物输入籽粒量及花后同化物对籽粒的贡献率分别为423.76 g/plant、 14451.50 kg/hm2和85.86%;氮肥利用率、 氮肥农学利用率分别为69.10%和38.38 kg/kg,显著高于其他处理(P0.05)。【结论】在松嫩平原西部膜下滴灌种植模式下,在玉米叶龄指数为45%时追施90 kg/hm2氮肥,可显著提高光合利用率,改善玉米生育后期的氮素吸收和干物质积累并增加产量,提高玉米对氮肥的吸收利用效率。

Suitable amount of N topdressing based on leaf age index of maize using mulched drip irrigation technology in Western Songnen Plain

【Objectives】 The mulched drip irrigation technology has been extended in the production of maize in Western Songnen Plain. Studying the suitable N fertilizer application amount and leaf age of maize under this technology system will provide a theoretical basis for efficient water and fertilizer efficiency and high-yield maize production.【Methods】 At the basal fertilizer levels of N 60 kg/hm2, P2O5 90 kg/hm2 and K2O 120 kg/hm2, four topdressing levels of N 0, 40, 90 and 140 kg/hm2 were top dressed at the leaf age index of 30%, 45%, 60% and 75%, respectively. Drip irrigation equipment was used for the fertilization. The photosynthetic efficiencies, the dry matter accumulation and the grain yields of corn in different growth stages were measured, and the N efficiencies were calculated. 【Results】Along with the advancement of maize growth process, the grain yield, leaf area index, chlorophyll content, dry matter accumulation and nitrogen accumulation of maize, nitrogen utilization efficiency, nitrogen agronomic efficiency and nitrogen harvest index are increased with the raising of nitrogen application rate in a certain range (0-150 kg/hm2) of nitrogen application. When the nitrogen usage exceeds a certain amount (200 kg/hm2), there were no more increases or even fallen in the above items tested. In the treatment of topdressing at the leaf age index of 45% and the nitrogen application rate of 90 kg/hm2, the grain yield reaches to 11957.89 kg/hm2, the leaf area index and chlorophyll content are 6.92 and 2.69 mg/g, the dry matter accumulation amount, post-anthesis assimilate inputs to grains, and contribution of post-anthesis assimilates to grains are 423.76 g/plant, 14451.50 kg/hm2, and 85.86% respectively. And the nitrogen utilization efficiency and nitrogen agronomic efficiency are 69.10% and 38.38%. All the mentioned items are significantly higher than those in the other treatments(P0.05).【Conclusions】 In Western Songnen Plain under the mulched-drip irrigation condition, the suitable N topdressing amount is 90 kg/hm2, and preparatory leaf age for the practice is at leaf age index of 45%.