秸秆还田配施氮肥对玉米产量和光合特性的影响

Effect of Straw Returning Plus Nitrogen Fertilizer on Grain Yield and Photosynthetic Performance of Maize

在前期研究中发现秸秆还田配施适量氮肥(180 kg·hm^(-2))模式可以显著提高玉米产量,然而在此模式下玉米产量提高的生理基础,尤其是光合性能方面还鲜有报道。基于11 a肥料定位试验,测定在玉米秸秆还田(SR)和不还田(NSR)条件下5种氮肥处理如N0(0)、N1(90 kg·hm^(-2))、N2(180 kg·hm^(-2))、N3(270 kg·hm^(-2))和N4(360 kg·hm^(-2))的玉米产量、SPAD值、净光合速率、蒸腾速率、胞间CO_(2)浓度、CO_(2)的导度及对水的导度等指标。结果表明:与NSR-N0相比,SR-N2处理对玉米产量和光合性能均有显著影响。SR-N2处理时的玉米产量比SR-N0和NSR-N0分别提高48.5%和71.1%。SR-N4处理时的叶绿素含量比SR-N0和NSR-N0分别提高10%和16.7%。SR-N2处理下的蒸腾速率和净光合速率分别比NSR-N0处理下提高42.2%和21.3%。SR-N2处理下的胞间CO_(2)浓度和CO_(2)的总导度分别比NSR-N0处理下降低7.2%和12%。SR-N2和NSR-N2处理下对水的导度比NSR-N0处理下分别增加35%和42%。说明在秸秆还田(SR)配施适量氮肥如N2(180 kg·hm^(-2))条件下玉米产量的提高归因于具有较高的叶绿素合成能力、较高的蒸腾速率、净光合速率和对水的总导度以及较低的胞间CO_(2)浓度、对CO_(2)的总导度。

In previous studies,we found that straw returning(SR)plus proper nitrogen fertilizer application(180 kg·hm^(-2))are helpful to enhance the grain yield of maize,however,the related physiological mechanisms,especially related photosynthetic performance of maize,still remain unknown.Under straw returning and non-straw returning(NSR)conditions,based on 11-year’s fertilizer positioning experiment,the maize indexes,inculding maize SPAD value,net photosynthetic rate,transpiration rate,intercellular CO_(2) concentration,the conductance to CO_(2) and to water in ear leaves,were measured under frive nitrogen(N)fertilizer levels of N0(0),N1(90 kg·hm^(-2)),N2(180 kg·hm^(-2)),N3(270 kg·hm^(-2))and N4(360 kg·hm^(-2)).Compared to NSR-N0,SR-N2 could significantly increase maize photosynthetic performance and yield.Under SR-N2 treatment,the yield was 48.5%and 71.1%higher than that under SR-N0 and NSR-N0,respectively.The SPAD value under SR-N4 was 10%and 16.7%higher than those under SR-N0 and NSR-N0,respectively.The transpiration rate and net photosynthetic rate under SR-N2 were 42.2%and 21.3%higher than that under NSR-N0 treatment,respectively.The intercellular CO_(2) concentration and the conductance to CO_(2) under SR-N2 were 7.2%and 12%lower than under NSR-N0,respectively.The water conductance under both SR-N2 and NSR-N2 was 35%and 42%less than under NSR-N0,respectively.So,the enhancement of maize yield under straw returning(SR)plus proper nitrogen fertilizer usage(180 kg·hm^(-2))results from the higher chlorophyll synthesis capacity,higher transpiration rate,net photosynthetic rate and total conductivity to water,lower intercellular CO_(2) concentration and lower total conductance to CO_(2).