中国农业科学 ›› 2016, Vol. 49 ›› Issue (4): 695-704.doi: 10.3864/j.issn.0578-1752.2016.04.009

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

节水减氮对温室土壤硝态氮与氮素平衡的影响

李若楠1,2,武雪萍1,张彦才2,王丽英2,陈丽莉2,翟凤芝2   

  1. 1中国农业科学院农业资源与农业区划研究所/耕地培育技术国家工程实验室,北京 100081
    2河北省农林科学院农业资源环境研究所,石家庄 050051
  • 收稿日期:2015-09-16 出版日期:2016-02-16 发布日期:2016-02-16
  • 通讯作者: 武雪萍,E-mail:wuxueping@caas.cn
  • 作者简介:李若楠,E-mail:liruonan2004@163.com。张彦才,E-mail:13833101598@163.com。张彦才和李若楠为同等贡献作者。
  • 基金资助:
    国家“十二五”科技支撑计划(2015BAD22B03)、国家“863”计划(2013AA102901)、国家公益性行业(农业)科研专项(201203077)、河北省农林科学院科学技术研究与发展计划(A2015130101)

Effects of Reduced Application of Nitrogen and Irrigation on Soil Nitrate Nitrogen Content and Nitrogen Balance in Greenhouse Production

LI Ruo-nan1,2, WU Xue-ping1, ZHANG Yan-cai2, WANG Li-ying2, CHEN Li-li2, ZHAI Feng-zhi2   

  1. 1 Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences/National Engineering Laboratory for Improving Quality of Arable Land, Beijing 100081
    2Institute of Agricultural Resources and Environment, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang 050051
  • Received:2015-09-16 Online:2016-02-16 Published:2016-02-16

摘要: 【目的】针对日光温室蔬菜生产中肥水超量施用问题,以提高氮肥利用率和实现温室菜田可持续利用为目标,研究节水减氮在温室蔬菜生产中的增效潜力,推荐适宜水氮用量。【方法】采用当地典型种植茬口冬春茬黄瓜-秋冬茬番茄,在沟灌方式下设计农民习惯灌溉(W1,>100%田间持水量)和减量灌溉(W2,75%—95%田间持水量)2个灌水水平;农民习惯施氮(N1)、较农民习惯减氮25%(N2)、减氮50%(N3)和无氮(N0)4个氮肥水平,对应黄瓜季施氮1 200、900、600和0 kg·hm-2,番茄季施氮 900、675、450和0 kg·hm-2,共W1N1、W2N2、W2N3、W1N0和W2N0 5个水氮用量组合处理,3年6季定位研究蔬菜关键生育期0—100 cm土体硝态氮动态变化,分析氮素平衡和经济效益,推荐合理水氮用量。【结果】农民习惯水氮管理W1N1处理土壤硝态氮积累明显,并向土壤深层迁移。节水减氮W2N3处理3年0—60 cm土层硝态氮供应保持在相对适宜水平,平均硝态氮含量为53.3—80.9 mg·kg-1;0—100 cm土体硝态氮未出现明显积累,平均含量较W1N1处理下降13.9%—31.1%;氮素表观损失下降56%,氮肥利用率提高2.4—3.3个百分点,并保持较高的经济效益。依据0—20 cm土层硝态氮含量与产量之间的显著回归关系,获得最佳产量土壤硝态氮含量黄瓜为37.4—72.9 mg·kg-1,番茄应低于90 mg·kg-1。根据蔬菜氮素需求量和关键生长期适宜的土壤硝态氮含量,结合根区土壤水分监测,推荐与供试条件相近的温室,沟灌冬春茬黄瓜产量160—180 t·hm-2下灌水450—550 mm配合施氮600 kg·hm-2较适宜,秋冬茬番茄产量70—80 t·hm-2时灌水170—200 mm配合施氮250 kg·hm-2较适宜。分析水氮减施增效原因为:节水20%—30%使土壤硝态氮趋近根区分布,节氮50%降低土壤剖面硝态氮积累,节水20%—30%配合减氮50%将根区硝态氮供应维持在适宜水平的同时,降低进入损失途径的氮素,从而实现增效。【结论】华北平原沟灌温室黄瓜-番茄农民生产现状节水减氮潜力较大。优化水分管理是实现氮肥减施增效的关键,在合理灌水量下,推荐适宜的施氮量是水氮减施增效的有效措施。较农民习惯管理节水20%—30%配合减氮50%,能有效降低氮素损失,提高氮肥利用率,保持较高经济效益。

关键词: 温室蔬菜, 水氮用量, 土壤硝态氮含量, 氮肥平衡, 经济效益

Abstract: 【Objective】Excessive applications of nitrogen and irrigation water in greenhouse vegetable production lead to lower nitrogen (N) use efficiency and unsustainable use of land. The aim of this study was to investigate the potential of a saving on N and water in vegetable production and the best combination of N and irrigation rates.【Method】An experiment was conducted in a 4-year cultivated greenhouse with winter-spring cucumber and autumn-winter tomato double cropping system. Two irrigation levels as conventional irrigation (W1, >100% field capacity) and reduced irrigation (W2, 75% field capacity) and 4 N levels as conventional N rate (N1), saving 25% N compared to conventional management (N2), saving 50% N compared to conventional management (N3) and no nitrogen control (N0) was designed. The corresponding N rates were 1200, 900, 600 and 0 kg·hm-2 for cucumber season and 900, 675, 450 and 0 kg·hm-2 for tomato season. Five combination treatments were designed as W1N1, W2N2, W2N3, W1N0, and W2N0 in this experiment.【Result】(1) Severe accumulation of NO3--N was observed in the conventional management, and the NO3--N was leached away from the surface soil layer. No significant NO3--N accumulation was observed in W2N3 treatment. The average NO3--N content in W2N3 treatment at 0-60 cm depth was at the proper level, and the average NO3--N content at 0-100 cm depth decreased by 13.9%-31.1% compared to W1N1 treatment. Moreover, the apparent N loss decreased by 56% and the N use efficiency increased by 2.4-3.3 percentage point in W2N3 with relatively higher economic benefit. (2) Based on the significant correlations between the NO3--N content and the yield, the optimal NO3--N contents were 37.4-72.9 mg·kg-1 for cucumber growing, and the corresponding values were lower than 90 mg kg-1 for tomato growing. (3) In order to keep the proper NO3--N value for uptaking by plants at 0-20 cm depth, 600 kg·hm-2of N with 450-550 mm of irrigation were recommended for cucumber with the yield level of 160-180 t hm-2, and 250 kg·hm-2 of N with 170-200 mm of irrigation were recommended for tomato of the yield level of 70-80 t·hm-2. (4) The mechanism for improving N use efficiency by reducing N and irrigation applications is as follows: more NO3--N could distribute around rootzone as saving 20%-30% of water, and less NO3--N could be accumulated in the soil profile as saving 50% of N supply. 20%-30% of water saving combined with 50% of N reducing could keep the NO3--N supply at a proper level at rootzone and decrease the loss amount of N, which become an effective way to improve N use efficiency.【Conclusion】The potential of a saving on water and nitrogen fertilizer is huge in North China Plain. Reasonable irrigation amount is the base to reduce N application and improve N use. Recommending reasonable N rate under the proper irrigation amount is an effective way to improve N use efficiency. Saving 20%-30% irrigation water combined with reducing 50% N fertilizer could effectively decrease the NO3--N accumulation in the soil and the apparent N loss and improve the N use efficiency.

Key words: greenhouse vegetable, water and irrigation rates, soil NO3--N content, N balance, economic benefit