摘要
【目的】膜下滴灌（drip irrigation under mulch film,DI）技术由于其高效节水的特点在新疆大面积推广使用,然而近期发现应用滴灌技术进行灌溉的作物根系出现了早衰,影响了地上部生长及产量的形成。本研究探讨了目前膜下滴灌技术体系棉花根系生长发育、空间分布的动态变化规律及地上部响应。【方法】采用田间试验方法,设置膜下滴灌、漫灌（flood irrigation under mulch film,FI,对照）两处理,采用Monolith法分7次采集根系,DT-Scan软件测定根系长度,分析不同生育时期棉花根系在土壤空间中的变化特征,同时采集地上部样品并分器官测定干物质量。【结果】滴灌棉花根系表现出明显的浅层分布趋势：从播种后96 d开始,距地表10cm范围内的根系长度明显大于漫灌处理,而30—60 cm土层则正好相反;在播种后65~96 d内,滴灌棉花根长增加速率明显低于漫灌;棉花生长发育后期（播种后125~160 d）,滴灌处理棉花根系显著衰退,且主要集中在0—40 cm深度、距滴灌带30—70 cm土体范围内,播种后160 d与125 d相比,0—10 cm土层下降了13.8%,而10—40 cm衰退幅度更大（22%）,与此同时,漫灌处理除0—10 cm土层根长有所下降外（7.7%）,10cm以下依然保持增长状态（10—40 cm及40—60 cm层分别增加了5.5%与10.2%）;播种后125 d,滴灌棉花地上部生长量明显高于漫灌,而根系正好相反,其冠根比较漫灌高,而在播种后160 d剧烈下降（地上部叶片及蕾、铃的大量脱落所致）。【结论】膜下滴灌棉花根系由于浅层分布,根系体积小,而地上部生物量过大,导致其在生长发育后期快速衰退。今后应研究适宜的水肥调控措施,以构建更早、更深的根系系统,控制生殖生长期内棉花的营养生长,实现膜下滴灌棉花的高产稳产。
【Objectives】Xinjiang is a typical arid area worldwide and cotton crops are mainly watered by drip irrigation under mulch film（DI）. Roots are in direct contact with the soil and thus are the first plant organ to be affected by the water and fertilizer application strategy. Many studies have proved that long-term use of drip irrigation technology can have negative impacts on crop root systems. Restriction of root growth under drip irrigation reduces the soil volume that can be explored by the root system and hence the availability and uptake of essential minerals, and finally affects shoot growth and yield. The main objective of the present study is to explore the growth and dynamic changes in the spatial distribution of cotton roots and aboveground growth in response to DI in a field trial.【Methods】A field experiment that included two treatments consisting of drip irrigation undermulch film（DI） and flood irrigation under mulch film（FI） was conducted. The monolith method was used to harvest roots at seven time points in the growth periods, and the root length, and shoot and root dry weight were measured.【Results】The total root length per plant in the 0–10 cm soil layer was higher under DI, whereas in the 30–60 cm soil layer roots were longer under FI. From 65 to 96 days after sowing（DAS）, the rate of increase in root length was lower under DI than FI. Total root length decreased after 125 DAS under DI, and was mainly centered in the 0–40 cm soil layer and at distances of 30–70 cm from drip-lines. The shoot： root ratio at 125 DAS was higher under DI than FI, but at 160 DAS the shoot： root ratio abruptly declined under DI. The decline in root length under DI during advanced growth stages may be attributable to the higher root density in shallow soil layers and the increase in the shoot： root ratio.【Conclusions】For the cotton cultivated in the drip irrigation under mulching system, the cotton roots are mainly distributed in 0–40 cm of soil, which is significantly shallow
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2016年第5期1384-1392,共9页
Journal of Plant Nutrition and Fertilizers
基金
新疆自治区青年科技创新人才培养工程–青年博士科技人才培养项目(2014731024)资助
关键词
棉花早衰
膜下滴灌
根系构型
cotton presenility
drip irrigation under mulch film
root architecture
