不同灌水方式下春玉米的根系生长分布

Root growth and distribution of spring maize under different irrigation methods

为了研究不同灌水方式对春玉米根系分布的影响,在大田条件下对玉米进行垄植沟灌,设计常规沟灌(CI)、交替隔沟灌溉(AI)和固定隔沟灌溉(FI)3种灌水方式.结果表明,(0,40]cm土层中,根长密度以AI较大,FI较小;(60,100]cm土层中,CI下根长密度较小;FI下的植株两侧根长密度差异明显,CI和AI与之相反.(0,100]cm土层中,监测时期内,AI下的玉米总根长和总根干质量都较大.相较FI,AI下的籽粒产量、生物产量和灌溉水利用率分别提高17.37%,18.42%和17.45%.CI表现介于AI与FI之间.抽雄期、植株两侧和(0,40]cm土层根系生长分布受土壤含水率影响较大.可见,局部灌溉对深层根系生长有利,抽雄期植株两侧(0,40]cm土层根系生长分布受灌水方式影响最大;CI与AI下的根系分布相对均匀;与FI和CI相比,AI方式既能促进根系生长,也有利于产量和灌溉水利用率的提高.

Irrigation methods may have important influences on spring maize root growth. To investi- gate the effects of ridge-furrow irrigation method on the root growth and distribution of spring maize, three methods, namely conventional furrow irrigation （irrigated both sides equally, CI） , alternate furrow irrigation （ alternatively irrigated between north and south sides, AI）, fixed furrow irrigation （ irrigated one side only, FI） are attempted under field condition. The root system growth states in 0 - 100 cm thick soil （five layers, each 20 cm thick） located at the north and south sides of the plants are measured at tasselling, filling and maturity growth stages. The results show that the root length density of the maize irrigated with AI is larger than that with FI in 0 -40 cm thick soil layer; but the density by CI is smaller in 60 - 100 cm soil layer. The root length density of the maize irrigated with FI in the south side is significantly different from that in the north side, however those of the maize irrigated with CI and AI don＇t show such an effect. Also, the root total length and dry mass of the maize plant irrigated with AI are larger in 0 - 100 cm thick soil layer in the monitoring periods. Compared with FI, the grain yield, biomass yield and irrigation water use efficiency with AI are improved by 17. 37%, 18.42% and 17.45% , respectively. The performance of CI is in between AI and FI. The root growth and distribution in 0 - 40 cm thick soil layer at both sides of the plants are more greatly affected by soil water eontent at taselling stage. Obviously, a loeal irrigation is useful for root to grow in the deep soil layer, and the root growth and distribution at both sides of the plants are mostly influenced by irrigation method at tasselling stage. The root distribution is relatively uniform for the maize irrigated with CI and Al. Compared with FI and CI, AI not only can promote root growth but also increase maize yield and improve irrigation water use effieiency.