作 者 ：李新乐 穆怀彬 侯向阳 李西良
期 刊 ：植物营养与肥料学报 2014年 20卷 5期 页码：1161-1167
Keywords:alfalfa, irrigation, phosphorus fertilizer, yield, water and fertilizer use efficiency,
摘 要 ：【目的】紫花苜蓿作为畜牧业生产中最主要的优质绿色饲料，是发展草食畜牧业的物质基础，同时它也是一种需水需肥较多的作物。如何从技术方面提高单位面积苜蓿产量，实现苜蓿高产栽培是科学研究人员及生产者研究的重点。北京市东南部接壤的蓟县、宝坻及南部接壤的廊坊、武清等地区，是北京市在生态和环境优先发展原则下畜牧养殖业外移的重要承接区域，苜蓿在当地种植缺乏科学指导，年干重产量仅为7500~10000 kg/hm2，盐碱地年产量更低，为4500~6000 kg/hm2。本研究通过苜蓿水肥试验确立紫花苜蓿达到高产的最佳磷肥施用水平和灌水量，为京南地区苜蓿高产及水肥的高效利用提供可借鉴的水肥管理技术。【方法】实验在低磷砂壤土条件下进行，选用紫花苜蓿中苜2号品种，设置全生育期不灌水（W0）、以及返青后及第1、2茬刈割后灌水且每次灌水25 mm （W1）、50 mm （W2）、75 mm （W3）4个灌水处理；每个灌水处理下设置不施磷（F0）、施P2O5 105 kg/hm2（F1）、210 kg/hm2（F2）3个施磷量处理，研究了灌水和施磷对紫花苜蓿产量、水分和磷肥利用效率的影响。【结果】1）灌水对1、2茬苜蓿产量的影响有显著差异，对3、4茬及全年产量的影响无显著差异；施磷肥对第3茬苜蓿产量没有显著影响，但对第1、2、4茬及全年苜蓿产量的影响均存在显著差异。2）灌水和施磷肥对紫花苜蓿的水分和肥料利用效率均有显著影响，随着施磷量的增加，苜蓿的水分利用率逐渐增大，说明施磷可以提高水分利用效率；随着灌水量的增加，苜蓿的磷肥利用效率呈先增加后降低的趋势，说明适当的增加灌水量可以提高苜蓿的磷肥利用效率。【结论】综合考虑紫花苜蓿产量、水分和肥料利用效率等指标，最优试验处理为每次灌水量50 mm，施P2O5 210 kg/hm2，其次为每次灌水量25 mm, 施P2O5 210 kg/hm2。
Abstract:【Objectives】Alfalfa (Medicago satiua L.),a very important forage crop in animal husbandry, consumes large quantity of water for growth. One of the important limit factors for alfalfa production is water deficit in the region of south Beijing including Jixian County and Baodi District, Langfang City and Wuqing District. The alfalfa yield in this region is only 7500-10000 kg/ha, and even as low as 4500-6000 kg/ha in saline soils. Therefore, suitable drip irrigation technology and phosphorous fertilization in alfalfa production was studied.【Methods】A field experiment was conducted in a loamy sand soil. The alfalfa yield and water and fertilizer use efficiencies were investigated. Four irrigation treatments include: no irrigation (W0),watering 25 mm (W1), 50 mm (W2) and 75 mm (W3) each time, and three irrigations totally in a year period. P fertilizer were applied twice after alfalfa turning green and second cut, respectively. The application rate treatments include: 0 (F0), 105 (F1) and 210 (F2) kg/ha P2O5. 【Results】Irrigation significantly impacts the dry matter yield of first and second cuts of alfalfa, not increase those of 3rd and the fourth cuts and the total annual yield of alfalfa. P application significantly affects the dry matter yield of the first, second and fourth cuts of alfalfa, as a result, significantly increase the annual yield. The highest yield (16589.4 kg/ha) is obtained with the treatment of 50 mm each irrigation plus 210 kg/ha of P fertilizer. Both water and P fertilizer use efficiency depend significantly on the watering amounts and P fertilizer levels. Alfalfa has high water use efficiency under the high amount of P fertilizer, indicating the positive effect of P fertilizer on alfalfa’s water use efficiency. Meanwhile, appropriate watering amount can improve P fertilizer use efficiency. The alfalfa yield, water and fertilizer use efficiency with treatment of W2F2 are higher than all the other treatments. 【Conclusions】The optimal watering amount is 50 mm each time and three irrigations in total, the suitable P fertilizer rate is 210 kg/ha for alfalfa in the south region of Beijing.
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