不同灌水量和密度对无膜棉光合特性及产量的影响

Effects of Different Irrigation Amounts and Densities on Photosynthetic Characteristics and Yield of Membrane-Free Cotton

【目的】研究灌水量和种植密度对滴灌无膜棉光合特性和产量的影响。【方法】以“中619”为供试材料,设置两因素裂区田间试验,其中灌水量为主区,分别为3000 m^(3)/hm^(2)(W_(1))、4500 m^(3)/hm^(2)(W_(2))和6000 m^(3)/hm^(2)(W_(3));密度为副区,分别为29.24×10^(4)株/hm^(2)(M1)、26.32×10^(4)株/hm^(2)(M_(2))、23.92×10^(4)株/hm^(2)(M_(3))和21.93×10^(4)株/hm^(2)(M_(4)),分析无膜棉群体叶面积指数(LAI)动态、光合指标变化及产量差异特征。【结果】盛花期是无膜棉LAI及光合功能最大期,随密度和灌水量增加,LAI增加,W2M3处理的LAI变化较平稳,后期LAI较高,W_(3)M_(1)处理LAI表现最高,但盛花期后下降速度快;适宜灌水及合理密度有利于叶片光合功能提高,其中盛花期W_(2)M_(3)、W_(2)M_(4)和W_(3)M_(3)处理的Pn、Gs和Tr较高,Ci较低,且日变化中的光合“午休”不明显,其最大值分别为29.10~32.15μmolCO_(2)/(m^(2)·s)、0.91~1.07 mol/(m^(2)·s)、12.78~13.87 mmolH_(2)O/(m^(2)·s)和112.1~131.0μmolCO_(2)/(m^(2)·s),产量达6890.71~7496.79 kg/hm^(2)的较高水平。W3M4处理的LAI及光合指标虽然较高,但后期下降过快,而W1M1各项指标均表现最低,灌水及密度过高或过低均不利于叶片光合功能的提高;灌水量与密度对叶片生长及光合指标的影响具有互作效应,且密度效应高于水分效应。【结论】较适宜的灌水量及种植密度范围为4500~6000 m^(3)/hm^(2)和21.93×104~23.62×10^(4)株/hm^(2),当灌水量5034.73 m^(3)/hm^(2)、种植密度24.63×10^(4)株/hm^(2)时的产量最高为7508.82 kg/hm^(2)。

【Objective】To study the effects of irrigation amount and planting density on photosynthetic characteristics and yield of drip irrigation membrane-free cotton.【Method】Field tests designed by the two-factor split zone were carried out with"medium 619"as the test material,the main area was irrigation amount,which was 3,000 m^(3)/hm^(2)(W_(1)),4,500 m^(3)/hm^(2)(W_(2))and 6,000 m^(3)/hm^(2)(W_(3)),respectively;the sub-area was density,which was 29.24×10^(4)/hm^(2)(M_(1)),26.32×10^(4)/hm^(2)(M_(2)),23.92×10^(4)/hm^(2)(M_(3))and 21.93×10^(4)/hm^(2)(M_(4)),respectively,to study the dynamics of membrane-free cotton population leaf area index(LAI),photolysis indicators and yield differences.【Results】Full-blooming stage was the maximum period of filmless cotton LAI and photolysis function,and the LAI increased with density and irrigation amount.The LAI change of W_(2)M_(3)treatment was more stable and higher in the later stage.The LAI of W_(3)M_(1)treatment was the highest,but it decreased rapidly after the full flowering stage.Suitable irrigation and reasonable density were beneficial to the improvement of photosynthetic function of leaves.The treatments W_(2)M_(3),W_(2)M_(4)and W_(3)M_(3)had higher Pn,Gs and Tr and lower Ci at full flowering stage,and the diurnal photosynthetic"midday depression"was not obvious,and its maximum values were 29.10-32.15μmolCO_(2)/(m^(2)·s),0.91-1.07 mol/(m^(2)·s),12.78-13.87 mmolH_(2)O/(m^(2)·s)and 112.1-131.0μmolCO_(2)/mol,respectively,and the yield reached a high level of 6,890.71-7,496.79 kg/hm^(2).Although the LAI and photosynthetic index of W_(3)M_(4)treatment were higher,they decreased too fast in the later stage,while the W_(1)M_(1)showed the lowest,indicating that too high or too low irrigation and density were not conducive to the improvement of photosynthetic function of leaves.The effects of irrigation amount and density on leaf growth and photosynthetic index had interaction effect,and the effect of density was higher than that of water.【Conclusion】Through analysis,the suitable irrigation amount and planting density in this region are 4,500-6,000 m^(3)/hm^(2)and 21.93×10^(4)-23.62×10^(4)/hm^(2).The highest yield is 7,508.82 kg/hm^(2)when the irrigation amount is 5,034.73 m^(3)/hm^(2)and the planting density is 24.63×10^(4)/hm^(2).