适宜灌水施氮方式利于玉米根系生长提高产量

为研究不同灌水方式和施氮方式对玉米根系生长分布的影响,2011年在大田条件下采用垄植沟灌技术,设交替灌水、固定灌水、均匀灌水和交替施氮、固定施氮、均匀施氮2因素3水平的随机完全组合试验方案。分抽雄期、灌浆期和成熟期对0~100 cm土层监测植株正下方、植株正南侧和植株正北侧的根系生长状况。结果表明,灌水方式对各位置根长及根系总量影响均达显著水平,施氮方式只对植株南侧根长和根系总干质量影响显著,二者的交互作用只对植株北侧根长和总根长影响显著。交替灌水均匀施氮在监测时期内维持了较大总根长,并使得灌浆期植株不同位置根长、总根量(总根干质量除外)均较大,并最终获得较大的产量(11 524 kg/hm2)。而固定灌水固定施氮总根长最小,产量最低。各处理下0~40 cm土层根长所占整个土层根长比例均较高,该比值以交替灌水均匀施氮最大。对比发现,根系生长分布对灌水方式更加敏感,通过不同灌水与施氮调控玉米根系生长分布应集中在0~40 cm土层,交替灌水均匀施氮最有利于根系的生长和产量的提高,为垄植沟灌下较好的灌水施氮方式。该研究为通过不同灌水施氮方式调控作物根系生长并获得高产提供了一定理论依据。

Rational irrigation and nitrogen supply methods improving root growth and yield of maize

Abstract: Ridge-furrow irrigation is wildly used in crop production. Few studies focus on the interaction effect of furrow irrigation methods and nitrogen supply method on crops, especially for root distribution. In this study, the coupling effects of different furrow irrigation and nitrogen supply methods on growth and distribution of root and yield for maize were investigated. Ridge-furrow irrigation was conducted in field in 2011 with spring maize of Jinsui4. Three furrow irrigation and N-fertilizer supply methods were designed including alternate, fixed and conventional furrow irrigation, and alternate, fixed and conventional nitrogen supply. Each treatment was replicated three times and the plot was layout by complete randomized design. The root length and weight beneath the plant canopy, south and north of the plant in the soil layers of 0-100 cm were measured at the growth stages of tasseling, filling and maturity with sampling at 20 cm as an interval. Grain yield was also measured at the harvest. The results showed that only root length and the total dry weight of the plant in the south were significantly influenced by nitrogen supply methods. The total root length and root length of the plant in north was influenced by the interaction of irrigation and nitrogen supply methods. The total root length of plants under the alternate furrow irrigation was kept larger in the growth period. Meanwhile, under the alternative furrow irrigation and conventional N-supply, the root length of the plant in north, south and beneath the canopy in the soil layer of 0-100 cm, as well as total root length and total root surface area at the filling stage were larger, thereby resulted in highest yield of 11 524 kg/ hm2. In contrast, total root length as well as yield of fixed furrow irrigation with fixed nitrogen supply was smallest. The root length under the plant in the soil layer of 0-100 cm of the alternate furrow irrigation with alternate nitrogen supply was as large as the alternate furrow irrigation with conventional nitrogen supply. The root length ratio in the soil layer of 0-40 cm to 0-100 cm was larger under different treatments and the largest one was found in the treatment of alternate furrow irrigation combined with conventional nitrogen supply. The results suggested that root growth and distribution are more susceptible to irrigation methods. Regulation for root growth and distribution of maize through different irrigation and nitrogen supply methods should be mainly in the soil layer of 0-40 cm. Yield and root growth of maize can improved by alternate furrow irrigation with conventional nitrogen supply but inhibited by fixed furrow irrigation with fixed nitrogen supply. Alternate furrow irrigation with alternate nitrogen supply is only inferior to alternate furrow irrigation with conventional nitrogen supply in improving the yield and root growth of maize, but superior to the other treatments. Thus, alternate furrow irrigation combined with conventional nitrogen supply is considered an optimum coupling pattern of irrigation and nitrogen supply method under the ridge-furrow irrigation.