不同灌溉策略下冬小麦根系的分布与水分养分的空间有效性  

WINTER WHEAT ROOT DISTRIBUTION AND SOIL WATER AND NUTRIENT AVAILABILITY

作　　者：刘坤[1] 陈新平[1] 张福锁[1] 

机构地区：[1]中国农业大学植物营养系,北京100094

出　　处：《土壤学报》2003年第5期697-703,共7页Acta Pedologica Sinica

基　　金：国家自然科学基金项目 ( 3 0 0 0 70 45 1 );北京市自然科学基金重大项目 ( 6980 0 0 1 )资助

摘　　要：通过田间试验研究了少量多次和少次多量的灌溉方式下冬小麦根系的分布与水分养分的空间有效性。结果表明 :少量多次的灌溉方式降低了冬小麦返青后表层根系的生长 ,减少了拔节后该层根系的衰退。在少次多量的灌溉方式下返青期不灌水促进了表层根系的生长 ,然而拔节后该层根系衰退较多 ,但中层 ( 3 0～ 60cm)根系生长高于少量多次的灌溉方式。不同灌溉策略下根系分布的差异并不影响冬小麦对土壤水分和养分的吸收 ,由于播前土体内蓄水不足 ,三种灌溉方式下 0～ 90cm土壤可用水在收获后均消耗殆尽。灌溉促进了表层硝态氮的吸收和向下迁移 ,但两种灌溉方式下硝态氮在土体内的迁移均未超出 60cm土体 ,仍在根层之内。而不同的灌溉方式对冬小麦全生育期内土体速效磷钾的分布没有影响。扬花前两种灌溉方式下冬小麦的生长发育和养分的吸收并无差异 ,扬花后少次多量的灌溉方式由于水分供应不足 ,影响了灌浆 ,降低了千粒重 ,进而影响了产量 ,同时土壤水分缺乏也减少了该时期养分的吸收。而在少量多次的灌溉方式下 ,扬花后灌水不仅可以促进冬小麦灌浆 ,提高千粒重 ,而且增加了对养分的吸收。Field experiment was conducted to investigate root distribution of winter wheat and the spatial availability of soil water and nutrients under different irrigation strategies: High frequency with low amounts (HL) and low frequency with high amounts (LH). The results showed: HL decreased root growth in topsoil after regreening, but reduced root decline after shooting, while LH increased root growth in topsoil but root decline was higher after shooting. Furthermore, in subsoil layer (30～60 cm) root biomass and root length density of LH were higher than those of HL. Change of soil moisture was solely resulted from irrigation. Also irrigation caused nitrate-N to move down, in the three treatments, not out of 0～60 cm root zone. However irrigation had no effects on available P and K distribution in soil profile during wheat growth. The difference of root distribution in soil did not affect water uptake. Due to insufficient water stored in soil before sowing, available water of soil (0～90 cm) was depleted after harvest. Furthermore different root length density in upper and middle layer did not affect nutrient uptake in those layers. It was dry in the topsoil after flowering that affected nutrient uptake. Due to irrigation after flowering HL increased not only grain milking but also nutrient accumulation of grain. Winter wheat growth, development and nutrient uptake among three treatments had no difference before flowering. After flowering insufficient water supply of LH and LW affected grain milking, which cause decrease in kernel weight and yield.

关 键 词：灌溉策略 冬小麦 根系 区域分布 水分 养分 空间有效性 

分 类 号：S512.1[农业科学—作物学]