半干旱区玉米水肥空间耦合效应Ⅱ.土壤水分和速效氮的动态分布

在灌水量为300m3/hm2、施N肥量为248.1kg/hm2的条件下,模拟大田条件研究了两种水肥空间耦合方式下的土壤水分、速效N的动态运移规律。试验表明,在半干旱地区隔沟灌溉水肥异区、隔沟灌溉水肥同区两种处理方式的灌溉水在剖面上均以垂直运动为主,同时存在水平运动。隔沟灌溉水肥同区处理的速效N在剖面上垂直运动明显,处理后15天速效N基本均匀地分布于0~100cm土层内,速效N含量在施肥区和未施肥区之间差异较小;而隔沟灌溉水肥异区处理的速效N垂直运动程度小,速效N主要分布在60cm以上土层,速效N水平运动不明显,施肥区速效N含量远高于未施肥区。水肥异区养分的淋溶深度较小,淋失的可能性小,有利于养分长期在剖面较浅层次中分布,为作物吸收创造了条件。

EFFECT OF WATER-FERTILIZER SPATIAL COUPLINGS ON CORN IN SEMIARID AREA: II. DYNAMIC DISTRIBUTION OF WATER AND AVAILABLE NITROGEN IN SOIL

Dynamic distribution of available nitrogen and soil water under different spatial couplings of irrigating water and fertilizer nitrogen was studied. The results revealed that after fertilization and irrigation the water mainly moved downward. The treatment of fertilizer application in the irrigated furrow had a deeper distribution of available nitrogen. 15 days after the treatment, the fertilizer nitrogen nearly distributed in the soil evenly from the surface to a depth of 100 cm and, however, mainly existed in the soil layer less than 60 cm deep in the treatment of fertilizer application and irrigation conducted in alternate furrows. The latter made it possible for plants to absorb more nutrition because less nitrogen would be leached.