不同密度对南疆杂交棉冠层和田间小气候的影响

Effect of Different Densities on Hybrid Cotton Canopy and Field Microclimate in South Xinjiang

选用‘兆丰1号’，设置4种种植密度。重点观察各处理在南疆的群体冠层结构和微环境气候指标。结果表明，密度对棉株平均果节长度和果节数影响最大，对单株各部位结铃数的影响顺序为下部〉中部〉上部。在盛营期、盛花期和盛铃期，冠层内温度在14：00—16：00时达最高，且相对湿度达最低，其日平均温度分别为31．3～32．1℃、29．3～30．5℃和26．5～27．1℃，日平均相对湿度分别为42．2％～43．5％、57．3％～61．0％、48．6％～51．4％，光截获率分别为0．34～0．50、0．57～0．63和0．52～0．61。随生育进程推进，冠层温度和光截获率先升后降，并以盛花后期（7月25日）最大，分别达32．9～34．7℃和0．56～0．63。冠层相对湿度先降后升，并以初铃期（8月4日）达最低值45．1％～48．0％，冠层内风速除盛蕾期较高外，在盛铃后期（8月17日）有峰值。密度对各指标的影响程度为光截获率〉风速〉相对湿度〉温度。随密度增加，温度、相对湿度和群体光截获率呈上升趋势，群体光漏射率和反射率呈下降趋势，冠层内风速在密度为19．5×10^4～25．5×10^4株／hm^2时较大。提出了南疆种植‘兆丰1号’适宜密度的冠层指标。

Four-planting density test were conducted in south Xinjiang to obtain canopy structure and microenvironment climate indexes of hybrid cotton ＇Zhaofeng 1＇ The results showed that planting density strongly influenced fruiting branch internode length and node number, and its effect on bolls were various in the sequence of lower〉central〉upper. At full bud stage, full flowering and full boll stage, the canopy temperature was the highest and the canopy relative humidity was the lowest, the daily average temperature was 31.3-32.1 ℃, 29.3-30.5℃ and 26.5-27.1 ℃, respectively, relative humidity were 42.2%-43.5%,57.3%-61.0% and 48.6%-51.4% respectively, light interception rate were 0. 34-0. 50,0. 57-0. 63 and 0.52-0.61 respectively. As growth process, canopy temperature and light interception showed a increasing-downward trend with the maximum of 32.9-34.7 ℃ and 0.56-0.63 respectively at late full flowering（July 25）. The canopy relative humidity a downward-increasing trend with the minimum of 45.1 % -48.0 % at late full boll stage （August 4）, wind speed within the canopy was the largest at late full boll stage（August 17） besides at full bud stage. The order of influence of density to microclimate indexes was light interception rate〉 wind speed〉 relative humidity〉 temperature. As densities increasing, temperature, relative humidity and light interception rate showed a rising trend while transmittance and reflectance had a downward trend. Under the density of 19.5 × 10^4 -25.5 × 10^4 plant/hm^2 , there was larger wind speed within the canopy. The canopy indexes of ＇Zhaofeng 1 ＇under suitable density were proposed.