密度对棉花冠层小气候影响及其与棉花相关生理特征和纤维品质的关系

The Effect of Different Density to Canopy-Microclimate and Quality of Cotton

为了探讨密度对棉花冠层小气候的影响,进一步研究密度与棉花生理特征和品质的关系,设计了5种不同密度（9万～27万株.hm-2）的田间试验。试验结果表明：不同冠层的透光率初花后迅速下降,各处理中A3（18万株.hm-2）处理透光率均变为最高。空气温度花期20 cm处冠层以A3处理空气温度最高,吐絮后规律性不明显。花期相对湿度较高且变化较小,以A3处理的相对湿度最为稳定,变化最小。吐絮期,不同冠层相对湿度变化趋势基本一致,早、晚的相对湿度较高,处理间规律性不明显。A3处理皮棉产量最高,LAI高峰出现在盛铃期,吐絮时仍保持在2.5~2.6。8月14日左右棉花第10果枝叶开始衰老,5 d后第8果枝叶开始衰老,其A3处理能维持较长时间的正常生理状态。不同处理棉花纤维品质无显著差异,密度增加能增进纤维品质,但密度大于A4（22.5万株.hm-2）后,又对纤维品质产生负效应。

In order to study the effects of different density to the micro-climate of cotton canopy and the relationship between cot-ton physiology characteristic and its quality,we has designed five kinds of different densities in field study.The results indicated that the transmittance of different crown level after first flowering dropped rapidly,in different crown level the transmittance A3（180000 plants per hectare） became the highest.In the flowering season air temperature was the highest by A3 when the crown level was 20 cm.After the boll opening,the regularity was not obvious.In the flowering season relative humidity was high,but its change was small.The relative humidity was the stablest by A3,and the change was the smallest.The change was big by oth-er treatments.In the boll opening period,change tendency of relative humidity was consistent basicly in different crown levels,the relative humidity was a little higher in the morning and evening,the regularity was not obvious among different treatments.The yield of ginned cotton in A3 was the highest,the LAI peak appeared during the cotton bolling period,it still maintained 2.5~2.6 at the boll opening stage.The leaves of tenth fruit branches senesced in August 14th,after 5 days began the eighth fruit branches,A3 could maintain the normal physiological condition longer.Cotton textile fiber quality of different treatments had no significant difference,the increasing of the density could promote the fiber quality,but it had negative effect on the fiber quality beyond the density of A4（225000 plants per hectare）.