【作者】 戴相林；

【导师】 周建斌；

【作者基本信息】 西北农林科技大学 ， 植物营养学， 2012， 硕士

【摘要】 关中平原地区是陕西省粮棉油主产区，也是我国的大灌区之一，同时也是我国农业生产集约化程度较高的地区之一。改革开放以来，这一地区农业生产发展迅速，种植业结构中经济作物种植比例在不断增加，农田施肥水平也不断增加，一些地方不合理施肥现象严重，导致土壤养分平衡状况发生了明显的变化，引发的生态环境问题开始凸显。针对以上问题，本文以养分平衡理论为指导，采用田间试验与养分平衡调查等方法，从田块、农户及区域尺度，分析不同地区近年来农田土壤养分的平衡状况，皆在为实现关中地区作物的高产稳产、资源持续利用、环境友好的协调发展提供理论依据。得到的主要结果包括：1.以在杨凌连续进行8年的夏玉米－冬小麦轮作定位试验为研究对象，研究了不同栽培模式及施氮下氮、磷、钾的养分平衡状况。结果表明，随时间的推移，不同处理土壤氮、磷、钾的养分支出量呈下降趋势，而盈余量呈上升趋势。8年来，覆草、垄沟模式下氮素的平均盈余率为正值，分别为9.9%和0.6%；而常规、控水模式为负值；覆草、垄沟及控水模式与常规模式相比，有助于土壤磷的平衡；覆草、垄沟模式有助于钾的平衡，且覆草模式要优于垄沟模式。8年来不同施氮水平下，N0、N₁₂₀和N₂₄₀水平下的氮素平均盈余率分别为-85.4%、-1.2%和74.9%，说明施N240kg/ha处理氮素累积量高，带来的环境问题值得关注；N₁₂₀和N₂₄₀水平下土壤磷、钾平均盈余率无显著性差别，分别在-44.5%～-44.9%和-228.3%～-241.9%范围内，土壤磷、钾均长期处在亏缺状态，应适当增加磷、钾的投入量。2.以陕西省扶风县农户调查数据为研究对象，研究了这一地区16年来小麦-玉米轮作农田施肥和土壤养分平衡状况。结果表明，自1994年以来，小麦、玉米2种作物氮、磷养分投入量的年均增长率高于其产量的年均增长率，说明生产中施用氮、磷肥的利用率在不断降低；小麦、玉米农田单位面积化肥提供的养分量及其所占的比例均不断上升，而有机肥提供的养分量及其所占的比例则在下降。2种作物农田单位面积氮、磷、钾养分盈余量与其单位面积有机肥的施用量有密切关系，随着小麦和玉米单位面积有机肥施用量的下降，其单位面积农田氮、磷、钾的养分盈余量也在下降。尽管16年间，小麦-玉米种植体系内氮、磷、钾养分盈余量呈下降趋势，但氮、磷养分一直盈余，而钾素自2001年开始一直亏缺。16年间，氮、磷、钾盈余累积量分别为2268.3、4273.3和274.1kg/ha。氮、磷的大量盈余无疑会增加农业面源污染的风险，而钾素累积量可能会在近几年内出现赤字。扶风县应在小麦和玉米这2种作物上，增加有机肥和钾肥投入量，减少氮、磷肥的投入量，从而达到维持土壤养分平衡，改善生态环境，保障农业可持续发展的目的。3.以扶风县农户为研究对象，采用农户调查和养分平衡法研究了这一地区16年来的农田土壤养分平衡状况。结果表明，自1994年以来，扶风县单位面积农田化肥养分投入量呈增加趋势，其占养分总投入量的比例由1994年的60.8%，增加到了2009年的88.3%，而有机肥养分投入量所占比例，却由1994年的26.9%减少到了2009年的4.4%。单位面积农田氮、磷一直处于盈余状态，且磷的盈余量及盈余率要明显高于氮；钾一直处在亏缺状态，每年亏缺率平均为54.1%。随着扶风县农业产业结构的调整，尤其是经济作物播种面积的增加，该县应采取“减氮、控磷、增钾”的措施，避免农田土壤氮、磷盈余过量，钾长期亏缺带来的问题。4.以位于陕西秦岭北麓的周至、户县和长安3个区县为研究对象，采用养分平衡法分析这一地区1980-2009年农田土壤养分的平衡状况。结果表明，自1980年以来，研究地区农田化肥和有机肥的投入量均呈增加趋势，其中化肥投入量占养分总投入量的比例由1980年的47.2%增加到2009年的75.4%，而有机肥投入量所占比例却由1980年的34.8%减少到2009年的18.8%。农田土壤中氮一直处于盈余状态，磷则由亏缺转向明显盈余，钾一直亏缺，但亏缺率呈减小的趋势。陕西秦岭北麓地区应采取“减氮、控磷、增钾”的措施，以控制该区域农田土壤因氮、磷盈余过量而可能带来的农业面源污染问题。更多还原

【Abstract】 Guangzhong plain is the main region of industry and grain in Shaanxi Province, and it isalso one of the irrigation regions and high degree intensive agriculture areas in China. SinceChina adopted the reform and opening-up policy, the agricultural production in this region hasdeveloped rapidly. The proportion of cash crop and farmland fertilization level has beengradually increasing as well. The phenomenon that unbalanced fertilization in some regionsbecomes serious, leading to the obvious changes of soil nutrient balance. All of the abovetrigger ecological environment problems.Based on the previous problems, this study took nutrirnt balance theory as the guide,using field experiment and nutrient balance investigation to analyze the balance condition ofsoil nutrient in farmland plot, farmers and regional scales. Aim to provide a theoretical basisof stable and high yield, sustainable development of resource and environment friendly. Themain results were as follows:1. Regarding the8-year maize-wheat rotation experiment in Yangling as the researchsubject, investigate the nutrient balance of N, P₂O₅and K₂O in different cultivation patternand N use. The results showed, as the times went on, the outcome of N, P₂O₅and K2Odecreased while the balance increased in different cultivation pattern and N use. In the8years,the N balance rate of mulching and furrow were respectively9.9%and0.6%, while the Nbalance rate of convention and water-controling were minus. So, mulching and furrow werehelpful for N balance; mulching, furrow and water-controling were more helpful for P₂O₅balance than convention; mulching and furrow were helpful for K₂O balance and mulchingwas better than furrow. By comparison of different N application rate treatments, the averageN balance rates of N0, N₁₂₀and N₂₄₀were respectively85.4%,-1.2%and74.9%. The averageN balance rate of N₂₄₀ was far higher than20%, so it will cause serious environmentproblem when apply240kg/ha N fertilizer into soil. There was no difference in P₂O₅and K2Oaverage balance rates between N₁₂₀and N₂₄₀treatments, which ranged respectively from－44.5%to－44.9%and from-228.3%to-241.9%. Long term deficit of P₂O₅and K₂O couldcause the degradation of soil fertility, so it should increase the application amount of P₂O₅properly considering the after-effect and increase the application amount of K2O.2. Regarding Fufeng County household survey date as the research subject, we investigated the fertilizer use and soil nutrition in the wheat-maize rotation system during16years by using the investigation and nutrient balance method. The result showed that since1994, the mean annual growth rate of the inputs of nitrogen and phosphorus fertilizer in wheatand maize was higher than that of the yields of wheat and maize, indicating that the utilizationefficiency of nitrogen and phosphorus fertilizer has been decreasing gradually. The per unitarea of wheat and maize field, the amount and concentration of nutrient provided by fertilizerhad increased, while the amount and concentration of nutrient provided by organic fertilizerhad decreased. The pre unit balance index of N, P₂O₅and K₂O in wheat and maize field had arelationship with the pre unit organic fertilizer use. The pre unit balance index of N, P₂O₅andK₂O decreased as the use of organic fertilizer decreased. In the16years, the balance index ofN, P₂O₅and K₂O has decreased, but N and P₂O₅have been in surplus while K₂O has been indeficit. In the16years, the accumulations of N, P₂O₅and K₂O were respectively2268.3,4273.3and274.1kg/ha. The over-surplus of N and P₂O₅could raise the risk of non-pointpollution and the balance of K₂O could be in deficit. Fufeng County should increase the useof organic fertilizer and K₂O fertilizer and decrease P₂O₅fertilizer properly to balance the soilnutrient, improve the soil fertility, and accomplish the sustainable development of agriculture.3. Regarding Fufeng County as the research subject, we investigated the balance offertilizer use and soil nutrition in16years by using the investigation and nutrient balancemethod. The results showed, since1994, pre unit use amount of fertilizer has increased. Itspercentage of total nutrient increased from60.8%in1994to88.3%in2009, while thepercentage of organic fertilizer decreased from26.9%in1994to4.4%in2009. The amountof pre unit N and P₂O₅has been in surplus and the surplus amount of P₂O₅was higher than N.The amount of pre unit K₂O has been in deficit and the change of deficit rate was stable andaveraged at-54.1%. As the structural adjustment for crop production was continued,especially the increase of cash crop area, Fufeng County should take the “decrease N, controlP and increase K” action to avoid the over-surplus of N and P₂O₅and the deficit of K₂O whichcould lead to the non-point pollution and decline of soil fertility.4. In this study, we analyzed the nutrient inputs and outputs in soils of the northern areasof Qinling Moutain in Shaanxi, including Zhouzhi, County Hu and Chang’an in1980－2009,with data and parameters obtained from agriculture statistical reports and references in theregion. The results indicated that since1980, both the nutrient input from chemical fertilizerand organic fertilizer had an increasing trend, especially the nutrients from chemical fertilizer.The proportion of chemical fertilizer to total nutrient input in the region increased from47.5%in1980to75.4%in2009, whereas the proportion of organic fertilizer to total nutrient inputdeclined from34.6%in1980to18.8%in2009. Nitrogen balance in soil of the region was at surplus; phosphorus balance became positive since1990, instead of deficiency in1980; andpotassium balance was still in negative, but the negative rate became less and less. To preventthe non-point pollution caused by the excessive accumulation of nitrogen and phosphorus insoil in the north region of Qinling moutain of Weihe River in Shaanxi, we suggest controlingthe application rates of nitrogen and phosphorus fertilizers and increasing potassium fertilizerin the agriculture.更多还原