黄土塬区麦田水分、氮素平衡及生产力的试验与模拟研究

【作者】 张益望；

【导师】 刘文兆；

【作者基本信息】 中国科学院研究生院（教育部水土保持与生态环境研究中心） ， 生态学， 2010， 博士

【摘要】 水分和养分(特别是氮素营养)一直是制约黄土高原地区作物生产力提高的主要限制性因素。探讨不同水肥条件下冬小麦水氮利用及生产力变化规律,对于本地区麦田合理施肥及作物产量提高等具有重要意义。本研究针对黄土塬区降水少且季节分配不均,土壤严重缺氮的特点,设置了雨养及补充灌溉条件下不同氮磷配施冬小麦种植试验,并依托长期定位施肥试验,结合DSSAT模型,通过田间试验及DSSAT模型模拟相结合的方法,对黄土塬区不同水肥条件下冬小麦生产力及水分、氮素平衡过程进行了试验研究与模型模拟,主要结论如下:(1)补充灌水及不同施肥均显著影响麦田水分平衡过程,不同处理土壤含水量随施肥水平提高而降低。氮磷配施及氮磷有机肥配施均显著降低了土壤含水量,土壤含水量随氮磷配施水平提高而减小。雨养条件下,降雨入渗深度随氮磷配施水平提高而降低,测定年份长期试验地CK,N,NP和NPM处理休闲期土壤水分入渗深度分别为220cm,200cm,180cm,160cm。补充灌溉及不同施肥水平对冬小麦全生育期耗水量及土壤储水变化量影响显著。不同施肥处理冬小麦耗水量及土壤储水变化量大小次序均为:NPM>NP>N>CK;与对照相比较,不同施肥处理耗水量增加13.0~40.7mm,其中,NP和NPM处理显著高于CK。补充灌溉处理冬小麦总耗水量较雨养处理增加51.7~143.5mm;耗水量随氮磷配施水平提高而增加,雨养和补充灌水条件下,不同氮磷配施处理较不施肥处理耗水量分别增加61.9~112.5mm,和112.1~183.8mm。(2)冬小麦叶绿素相对含量(SPAD值)受施氮水平影响显著,施氮不但可以提高冬小麦SPAD值,而且能维持高SPAD值持续时间。补充灌水及氮磷配施均能够增加冬小麦地上部氮素累积量及氮素利用率,冬小麦地上部氮素积累量与施氮水平间具有显著的相关性,不同氮磷配施处理氮素积累量较对照增加83.2%~204.3%,补充灌溉氮素积累量较雨养处理增加1.3%~12.1%。不同处理0~30cm土层土壤全氮含量差异明显,以不施肥处理全氮含量最低,低氮和高氮处理均较高,但二者差别不明显。(3)CK及单施氮肥处理二者产量均较低,其次为NP处理,较对照增产168.9%,而M,NM和NPM三个处理则对照增产260%以上;冬小麦籽粒产量随氮磷配施水平提高而增加,雨养和补充灌水条件下,氮磷配施处理分别较CK增产2530~3717 kg·hm-2和2528~4533 kg·hm-2,补充灌溉后籽粒产量提高2~1188 kg·hm-2,表明氮磷配施的增产效果显著高于补充灌水。方差分析表明,不同施氮水平对籽粒产量影响显著,补充灌水及施磷作用不显著。不同施肥均能提高作物水分利用效率(WUE);N,NP和NPM处理水分利用效率分别较对照提高42.5%,104.4%,109.8%,其中NP和NPM处理显著高于CK和N。WUE随氮磷配施水平提高而增加,2007-2008年,氮磷配施处理WUE较不施肥处理提高4.2~7.6 kg·mm-1·hm-2。补充灌溉对WUE的影响主要与灌水多少及试验年降水条件有关,2007-2008年,补充灌溉处理冬小麦水分利用效率较雨养处理降低0.2~2.3 kg·mm-1·hm-2,但二者差异不显著,2008-2009年补充灌溉处理WUE稍高于相应的雨养处理。不同处理冬小麦株高、叶面积和生物量等生长指标与籽粒产量有相同的变化趋势,即随施肥水平的升高,冬小麦株高、叶面积和生物量也增加。不同生育期除拔节期叶面积指数与籽粒产量间相关性不显著外,其他时期各指标与籽粒产量均显著相关。(4)组建了黄土塬区DSSAT模型气象、土壤和作物遗传参数数据库,并利用田间实测资料对模型的相关参数进行了标定和验证。结果表明DSSAT模型能够准确模拟冬小麦生育期和冬小麦产量,模型适用于本地区作物生长模拟。对不同施氮条件冬小麦土壤含水量动态、氮素吸收动态及冬小麦生产潜力进行了模拟研究。结果表明,土壤含水量模拟结果与实测值吻合度较高,能够反映不同土层土壤含水量变化规律及不同处理间的差异。冬小麦不同器官含氮量动态模拟结果以籽粒含氮量最好,而叶片含氮量的模拟结果相对较差。黄土塬区冬小麦24年光温生产潜力为5547~10920kg·hm-2,气候生产潜力在3193~6443 kg·hm-2间变化。1985~2009年间冬小麦水分满足率为0.513~0.782,表明本地区冬小麦生产力仍然有较大的提升空间。更多还原

【Abstract】 Water and nutrient, especially nitrogen nutrition, are the two key restriction factors in improving crop productivity in the Loess Plateau. Therefore, study the law of the water use, nitrogen accumulation and productivity of winter wheat under different water and fertilizer treatments are important to rational fertilization and yield improvement of winter wheat.According to the characteristics of less and uneven seasonal distribution of precipitation and soil nitrogen shortage in the Loess Tableland, the experiment of supplemental irrigation and different nitrogen and phosphorus rates treated winter wheat was designed and simultaneously the long-term fertilization experiments were carried out. The combined method of field experiment and simulation of DSSAT model (Decision Support System for Agrotechnology Transfer) was applied to the field experiment and model simulation of crop productivity and water and nitrogen balance process of winter wheat. The main conclusions were drawn as follows:(1) Supplemental irrigation and different fertilization had significant effects on the process of soil water balance of winter wheat, soil water content of different treatment decreased with the increasing of fertilization level. The treatment of mixed use of nitrogen and phosphorus fertilizer (NP), and mixed use of nitrogen, phosphorus and manure treatment (NPM) significantly decreased soil water content, soil water content decreased with the increasing of fertilization level. The depth of rainfall infiltration decreased with the increasing of nitrogen and phosphorus rates. Infiltration depths of CK, N, NP and NPM treatments were 220cm,200cm,180cm,160cm respectively.Supplemental irrigation and different fertilization had significant effects on water consumption and water supply amount of soil. Water consumption and water supply amount of soil of different treatment were in the order of NPM>NP>N>CK. Different fertilization increased water consumption from 13.0 to 40.7mm than CK, NP and NPM treatment had significant difference than CK. Supplemental irrigation increased water consumption from 51.7 to143.5mm. Water consumption increased with the increasing of nitrogen and phosphorus rates, water consumption of the treatment of rain-fed and supplemental irrigation increased from 61.9 to 112.5mm and 112.1 to 183.8mm respectively.(2)Nitrogen rates had significant influence on chlorophyll relative value (leaf SPAD values), which can increase leaf SPAD values as well as high leaf SPAD values duration. Nitrogen accumulation and nitrogen use efficiency increased with increased level of nitrogen rates and supplemental irrigation and supplemental irrigation, nitrogen rates had significant correlation between nitrogen accumulation, and nitrogen accumulation of different nitrogen rates treated wheat increased from 83.2% to 204.3% than CK, nitrogen accumulation of supplemental irrigation treatment increased 1.3% to 12.1% than rain-fed treatment.(3) CK and N treatments both had lower crop yields, crop yields of mixed use of nitrogen and phosphorus fertilizer treatment was 168.9% higher than CK, and M,NM and NPM increase crop production more than 260%.Crop yields increased with the increasing of nitrogen and phosphorus rates, crop yields of the treatment of rain-fed and supplemental irrigation increased from 2530 to 3717 kg·hm-2 and from 2528 to 4533 kg·hm-2 respectively, however, supplemental irrigation increased crop yields from 2 to 1188 kg·hm-2 than CK. Variance analysis showed that nitrogen rates had significant effect on crop yields, however, supplemental irrigation and phosphorus rates didn’t have significant effect.Water use efficiency (WUE) of winter wheat increased with increased level of fertilization. Water use efficiency of N, NP and NPM treatment were 42.5%,104.4% and 109.8% higher than CK respectively, NP and NPM treatment were significantly higher than CK and N treatment. Water use efficiency of winter wheat increased with increased level of nitrogen and phosphorus fertilization, from 2007 to 2008, WUE of different nitrogen and phosphorus rates were 4.2 to 7.6 kg·mm-1·hm-2 higher than CK, supplemental irrigation treatment decreased WUE from 0.2 to 2.3kg·mm-1·hm-2 than the rain-fed treatments from 2007 to 2008, which were higher than the rain-fed treatments from 2008 to 2009. Plant height, leaf area and biomass of different treatment had the same change tendency with crop yields, which increased with the increased level of fertilization level. LAI had no significant correlation with crop yields during jointing stage, during the other growth stages, plant height, leaf area and biomass had significant correlation with crop yields.(4) The databases of weather, soil and crop growth parameter of DSSAT model in the Loess Tableland were created and used to calibrate and validate the DSSAT model. The results showed that DSSAT model was reliable in predicting wheat growth stages and crop yields.Soil water content, nitrogen uptake dynamic and wheat production potential were simulated with DSSAT model. The results showed that soil water content, simulation results had the high degree of coincidence with measured results. The result can reflect soil water content dynamic at different soil depths and the differences between the different treatments. The seed’s nitrogen content had the best simulation result of different wheat organs, whereas the leaf nitrogen content was relatively poor. Photo-temperature productivity and climatic potential productivity were 5547~10920 kg·hm-2 and 3193~6443 kg·hm-2, respectively, and the water requirement ratio was 0.513~0.782 from 1985 to 2009, which indicates that the productivity of wheat has more promotion space on Loss Tableland.更多还原