| 摘要: |
| 将一定量的肥料KH2PO4溶于灌水,配制成速效磷(P2O5)含量为87 mg/L的溶液进行滴灌施肥试验,研究滴头流量分别为2,4,6 L/h、灌水施肥量分别为8,16,24 L时,水分和速效磷在土娄土中的运移分布规律。结果表明,灌水施肥量为8 L时,随滴头流量增大,滴头周围地表积水区半径增大,水分径向运移距离增大,纵向入渗水量减小;当滴头流量为2 L/h时,随灌水施肥量增大,水分径向和纵向运移距离均增大,径向运移距离增大幅度较纵向明显。速效磷在土壤中的迁移聚集机制为“对流主导、对流-吸附控制”型;速效磷含量随土层深度增大逐渐减小,随径向距离增大呈先逐渐减小再增大趋势,在滴头处及湿润锋附近速效磷含量相对较高;随滴头流量增大,速效磷在土壤中的纵向运移距离减小,滴头径向距离为0～30 cm时,0～2.5 cm土层速效磷含量增大,10～25 cm土层速效磷含量减小;随灌水施肥量增大,速效磷径向运移距离增加,滴头径向距离为0～30 cm、深度为0～25 cm土层速效磷含量增大。供试地区采用滴灌施肥方式补施磷肥,滴头流量以2 L/h为宜,灌水施肥量控制在8 L左右、滴头间距60 cm左右较为合理。 |
| 关键词: 滴灌施肥 水分分布 土壤速效磷分布 滴头流量 灌水施肥量 |
| DOI： |
| 分类号: |
| 基金项目:国家“863”计划项目（2001AA242101）子课题“黄土高原几种典型土壤水肥一体化研究” |
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| Distribution of soil water and available phosphorus under drip fertigation |
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| Abstract: |
| Irrigation water with 87 mg available phosphorus in each liter prepared with KH2PO4 was used for dripping fertigation.Distributions of water and available phosphorus in Lou soil were investigated under the controlled condition such as dripping end rate at 2,4,6 L/h and fertigation volume at 8,16,24 L.The results showed that as fertigation volume was 8 L,with dripping rate increased,surface catchment radius around tip increased and more water transported horizontally,while less water transported vertically.As dripping rate was 2 L/h,dripped water transporting to horizontal and vertical direction both increased with irrigation volume increased.But water increased more obviously in horizontal direction than in vertical direction.Under the condition of dripping fertilization,available phosphate distribution in soil was controlled by water convection and soil absorption.In vertical direction,available phosphate decreased with the increase of soil depth,while in horizontal direction,available phosphate got to the highest at point of drop tip,with the character of decreasing with the increase of horizontal distance firstly,and then increasing again at wetting peak;as flow rate increased,transportation distance of available phosphate to vertical layer decreased.At the range of 0 to 30 cm from drop point horizontally,available phosphate increased in the layer of 0-2.5 cm and decreased in the layer of 10-25cm vertically;as fertilization volume increased,transporting distance of available phosphate in horizontal direction increased,and at the range of 0 to 30 cm from drop point in horizontal direction,available phosphate increased in the layer of 0 to 25 cm in vertical direction.It's proved that the available phosphate for spreading irrigation and fertigation in the tested district,should be the rational flow rate of dripping end,2 L/h;irrigation and fertigation rolume,about 8 L,and the distance betweem dripping end,about 60 cm. |
| Key words: dripping fertigation,water distribution,available phosphorus distribution,flow rate of dripping end,irrigation volume |
