种植密度对南疆匀播冬小麦根系时空分布的影响

Effects of Planting Density on Spatiotemporal Distribution of Root System of Uniformly Sowed Winter Wheat in Southern Xinjiang

为明确匀播冬小麦根系对种植密度的响应,以多穗型冬小麦品种新冬22号为材料,设置了123万、156万、204万、278万、400万株/hm^(2)共5个种植密度,研究了根长密度、根表面积、根系直径、根干质量密度时空分布。结果表明,新冬22号根长密度、根系表面积、根干质量密度均在抽穗期达到最大值,均呈先增加后降低的趋势,越冬期123万株/hm^(2)处理的根长密度、根表面积和根干质量密度均大于其他处理。拔节期、抽穗期、成熟期根长密度、根表面积均由高到低依次为156万株/hm^(2)处理、204万株/hm^(2)处理、123万株/hm^(2)处理、278万株/hm^(2)处理、400万株/hm^(2)处理。5种不同密度处理下0~60 cm土层根系分布最多,占总根长的95.13%~97.84%,说明匀播冬小麦根系主要分布在0~60 cm,随深度的增加根系急剧减少。越冬后,0~40 cm土层的根系增长速率最为显著,拔节后40~100 cm土层根系显著增多。越冬期高密度条件下匀播冬小麦根量较大;拔节至抽穗期根系生长最旺盛,各处理由高到低依次为156万株/hm^(2)处理、204万株/hm^(2)处理、123万株/hm^(2)处理、278万株/hm^(2)处理、400万株/hm^(2)处理,匀播条件下新冬22号根系集中分布在0~60 cm土层。

To determine the response of roots of uniformly sowed winter wheat to the planting density in South Xinjiang area,multiple spike type winter wheat varieties of Xindong 22 were used as material,five planting density were designed,which were 123×10^(4),156×10^(4),204×10^(4),278×10^(4)and 400×10^(4)plants/hm^(2).The root length,root surface area,root length density and root dry weight were investigated.Results showed that root length density,root surface area and root dry mass density of Xindong 22 reached the maximum value at heading period,showing the trend of firstly enhance and then reduce.At overwintering period,treatment of 123×10^(4)plants/hm^(2)showed greater root length density,root surface area and root dry mass density than other treatments.Root length density and root surface area at jointing stage,heading period and mature period were in the order of 156×10^(4)plants/hm^(2)treatment>204×10^(4)plants/hm^(2)treatment>123×10^(4)plants/hm^(2)treatment>278×10^(4)plants/hm^(2)treatment>400×10^(4)plants/hm^(2)treatment.Under 5 different density treatments,0-60 cm soil layer had the most root system distribution,accounting for 95.13%-97.84%of the total root length,showing that evenly sowing winter wheat root system was mainly distributed in 0-60 cm,the root system reduced sharply with the increase of soil layer.After wintering,increasing rate of root system at 0-40 cm soil layer was the most significant.After jointing,increasing rate of root system at 40-100 cm soil layer was the most significant.Root amount of uniformly sowed winter wheat was relatively great under high-density condition at overwintering period.Root system grew the most vigorously from jointing stage to heading stage,showing the order of 156×10^(4)plants/hm^(2)treatment>204×10^(4)plants/hm^(2)treatment>123×10^(4)plants/hm^(2)treatment>278×10^(4)plants/hm^(2)treatment>400×10^(4)plants/hm^(2)treatment.Under uniform sowing,root system of Xindong 22 was mainly distributed at 0-60 cm soil layer.