【作者】 李银坤；

【导师】 梅旭荣； 赵秉强；

【作者基本信息】 中国农业科学院 ， 农业水土工程， 2013， 博士

【摘要】 华北平原种植模式以冬小麦—夏玉米轮作为主，这里是我国重要的粮食生产基地，关系着国家的粮食安全。水资源不足一直是制约当地农业可持续发展的主要因素，优化田间水肥管理措施、提高作物水分利用效率是解决问题的关键。有机肥在改善土壤理化特性、提高土壤保水蓄水性能方面的效果显著，同时有机肥可以协调作物需水和土壤供水之间的矛盾，可促进作物生长，提高作物产量和水分利用效率。目前，关于不同有机肥施用量以及水碳氮组合对华北平原旱作粮田土壤水分动态变化、作物耗水规律以及水分利用效率的研究鲜有报道。本研究在山东省陵县试验区（中国农业科学院德州试验站）和桓台试验区（华北集约化农业生态系统试验站）分别开展了无机肥、有机肥对比试验(2006^-2012年)和水碳氮组合的微区试验(2010^-2012年)，其中对比试验设无机肥、有机肥2个因素，各10个水平（以N计），分别为0、60、120、180、240、300、360、420、500和600kgN·hm^-2，共19个处理。水碳氮微区试验共6个处理（各处理N水平相同）：（1）常规灌水（100mm·次-1）、单施无机肥(冬小麦，200kgN·hm^-2；夏玉米，152kgN·hm^-2)（W1C0N2）；（2）常规灌水、有机肥(冬小麦，100kgN·hm^-2；夏玉米，76kgN·hm^-2)与无机肥配施(冬小麦，100kgN·hm^-2；夏玉米，76kgN·hm^-2)（W1C1N1）；（3）常规灌水、单施有机肥(冬小麦，200kgN·hm^-2；夏玉米，152kgN·hm^-2)（W1C2N0）；（4）减量灌水（50⁶0mm·次-1）、单施无机肥（W2C0N2）；（5）减量灌水、有机肥与无机肥配施（W2C1N1）；（6）减量灌水、单施有机肥（W2C2N0）。研究了单施无机肥和单施有机肥，以及有机肥与无机肥配施对冬小麦—夏玉米轮作体系内的土壤水分周年动态、作物耗水、产量以及水分利用效率的影响。旨在明确碳氮组合下土壤水分周年变化规律和水分利用效率，为进一步提高华北地区旱作农田的水分和养分管理水平、挖掘土壤供水潜力提供理论依据。本研究获得的主要结论如下：1.相同灌水和N水平下，土壤增碳能够提高农田雨季蓄墒和旱季保墒的能力，降低土壤水分在茬口的损失，土壤水分的“前贮后用”效果明显。相同N水平下，与无机氮相比，增碳后冬小麦播前的土壤贮水（0¹00cm）提高了2.44⁴5.6mm，增加幅度为0.987%¹9.3%；夏玉米播前的土壤贮水（0¹00cm）也可提高1.30³0.5mm，增加幅度有0.543%¹3.9%。与单施无机氮（C0N2）相比，碳氮配施（C1N1）处理在冬小麦和夏玉米播前的土壤贮水（0¹60cm）也分别增加了12.1³1.6mm（P＞0.05）和7.17¹4.2mm（P＞0.05），增加幅度为2.93%⁷.56%和1.73%³.94%。周年的茬口土壤水分损失量为26.8⁴1.1mm（0¹60cm），平均损失强度为1.58².42mm·d-1，土壤增碳能够降低水分在茬口的损失，与单施无机氮（C0N2）相比，损失量降低了4.73¹0.4mm，降低幅度达11.5%²6.2%。施用有机肥改善了土壤团聚体结构，增加了土壤有机碳和全氮含量（P＜0.05），利用二元二次方程可以很好地模拟土壤贮水与水稳性团聚体（＞0.25mm）、土壤容重的关系以及土壤贮水与土壤有机碳、全氮的关系，模型方程系数（R2）分别达到显著（P＜0.05）和极显著（P＜0.001）水平。2.低N条件下，增碳可显著增加作物耗水和产量。其中有机肥和无机肥的N水平分别低于阈值199.4kgN·hm^-2(碳用量5293kgC·hm^-2)和113.2kgN·hm^-2时，冬小麦耗水随着碳、氮用量的提高而增加（P＜0.05）；有机肥和无机肥的N水平分别低于阈值220.6kgN·hm^-2(碳用量5855kgC·hm^-2)和110.7kgN·hm^-2时，冬小麦产量也随着碳、氮用量的增加而增加（P＜0.05）。3.高N水平下，增碳对耗水量和作物产量的影响不明显；有机肥增产作用与无机肥处理相当，但具有更好的节水效应。当有机肥和无机肥的N水平分别超过阈值220.6kgN·hm^-2(碳用量为5855kgC·hm^-2)和113.2kgN·hm^-2时，冬小麦的耗水量和产量均无显著变化；其中N水平达到一定程度后(大于220.6kgN·hm^-2)，有机肥与等N的无机肥相比，冬小麦产量几乎没有差异（仅下降了0.812%），而耗水量却降低了21.1mm，降低幅度达4.86%。其中N水平超过372.0kgN·hm^-2时，有机肥处理(碳用量超过9874kgC·hm^-2)的水分利用效率（WUEg）高于比无机肥，最大可增加15.1%。由此说明，高N条件下达到同样的产量水平，土壤增碳具有更好的节水效果。4.本试验条件下的适宜有机肥和无机肥用量。产量无显著变化时的有机肥和无机肥用量分别为220.6kgN·hm^-2和110.7kgN·hm^-2时，而获得最高冬小麦产量和较高水分利用效率时的有机肥和无机肥用量分别为481.7kgN·hm^-2(碳用量为12786kgC·hm^-2)和367.6kgN·hm^-2。可知冬小麦的有机肥适宜用量为220.6⁴81.7kgN·hm^-2(碳用量介于5855¹2786kgC·hm^-2)，无机肥适宜用量为110.7³67.6kgN·hm^-2。其中有机肥比等N的无机肥多施86.2¹14.1kgN·hm^-2，即增碳2288³029kgC·hm^-2，不仅具有同样的增产作用，而且水分利用效率较高。5.明确了本试验条件下的最优水碳氮组合。综合考虑不同水碳氮组合下的土壤蓄水保墒作用、植株生长性状、光合性能、产量以及水分利用效率，减量灌水、碳氮配施（W2C1N1）处理不仅提高了土壤贮水和供水能力，而且植株生长形状好，产量和水分利用效率高，是本试验中的最优水碳氮组合。更多还原

【Abstract】 North China Plain is one most important area of cereal producing in China, and land use isdominantly arable with winter wheat and summer maize cropping system, which is of great significanceto national food security. Water shortage in North China Plain has been the main factor restrainingagriculture sustainable development, and optimizing management of water and fertilizer and improvingwater use efficiency are considered as two effective measures to the challenge. Organic fertilizer canimprove soil physical and chemical properties, retard water shortage, coordinate the contradiction ofcrop water requirement and soil water supply and improve water use efficiency. However, theinformation of various management concerning the effects of organic fertilizer rate, carbon and nitrogencombination on soil moisture dynamic, water consumption and water use efficiency were remainlimited.Two experiments of inorganic fertilizer and organic fertilizer and water, carbon and nitrogencombination micro-plot were conducted in Lingxian county and Huantai county, respectively. In orderto check the effects of inorganic fertilizer and organic fertilizer,19treatments were designed withthree replicates, which were composed of2factors of inorganic nitrogen fertilizer and organicnitrogen fertilizer with10N levels of0,60,120,180,240,300,360,420,500,600kgN·hm^-2. Thewater, carbon and nitrogen combination micro-plot experiment was designed6treatments in a certainrate of N fertilizer, including （1） normal irrigation （each time with100mm）+inorganic N fertilizer(wheat,200kgN·hm^-2; maize,152kgN·hm^-2)（W1C0N2）;（2） normal irrigation+inorganic Nfertilizer (wheat,100kgN·hm^-2; maize,76kgN·hm^-2)+organic N fertilizer (wheat,100kgN·hm^-2;maize,76kgN·hm^-2)（W1C1N1）;（3） normal irrigation+organic N fertilizer (wheat,200kgN·hm^-2;maize,152kgN·hm^-2)（W1C2N0）;（4） decrement irrigation （each time with50⁶0mm）+inorganicN fertilizer （W2C0N2）;（5） decrement irrigation+inorganic N fertilizer+organic N fertilizer（W2C1N1）;（6） decrement irrigation+organic N fertilizer （W2C2N0）. We studied the dynamicchanges of soil annual moisture, crop water consumption, yield and water use efficiency during winterwheat and summer maize growing stage, and aimed to provide theoretical basis for improving waterand nutrient use efficiency. Our major conclusions were described as following:1. Under the same irrigation and N level, soil carbon can improve the capacity of soil waterstorage in rainy season and soil water conservation in dry season, and also decrease significantlywater losses during rotation, whilst an obvious effect was observed for soil water of storage early anduse later. Compared to the treatments with inorganic nitrogen, soil water storage （0¹00cm） beforewinter wheat and summer maize sowing were increased in the treatments with organic nitrogen underthe same nitrogen levels, increasing by0.987%¹9.3%（2.44⁴5.6mm） and0.543%¹3.9%（1.30³0.5mm）, respectively. Compared to C0N2, C1N1also increased soil water storage （0¹60cm）at the early stage of winter wheat and summer maize sowing, and the ranges were2.93%⁷.56% （12.1³1.6mm） and1.73%³.94%（7.17¹4.2mm）, respectively. Annual loss of soil water duringcrops rotation was varied from26.8to41.1mm （0¹60cm）, and the mean losses was1.58².42mm·d-1. The treatments with organic nitrogen decreased the annual loss of soil water losses duringcrops rotation compared to inorganic fertilizer, at11.5%²6.2%（4.73¹0.4mm）. The capacity of soilwater storage and soil water supply was improved in treatments with organic nitrogen, and it wassignificant correlated with soil aggregate, soil organic carbon and total nitrogen.2. Organic N fertilizer could improve water consumption and crop yield under low N levels, andinorganic N fertilizer showed similarly. The water consumption of winter wheat showed increasinglywith the carbon increase below a threshold value of199.4kgN·hm^-2(5293kgC·hm^-2), and similartrend was observed in inorganic N fertilizer with a threshold value of113.2kgN·hm^-2. Carbonapplication could improve winter wheat yield with the rate increasing below a threshold value of220.6kgN·hm^-2(5855kgC·hm^-2), and similar trend was found in inorganic N fertilizer with athreshold value of110.7kgN·hm^-2. Overall, the treatments of inorganic N fertilizer affected the waterconsumption and winter wheat yield more obviously than organic N treatments under low N levels.3. Under high N levels, crop yield and water consumption affected by increasing carbon but notobviously; organic N treatments obtained equal levels of crop yield and showed a better water-savingeffect compared to inorganic N treatments. No significant difference was observed for waterconsumption and yield when the organic N was over the rate of220.6kgN·hm^-2(5855kgC·hm^-2) orthe inorganic N was over the rate of113.2kgN·hm^-2. Compared to inorganic N treatments, organic Ntreatments showed an equal impact on winter wheat yield when the N rate was over220.6kgN·hm^-2,but water consumption was reduced by4.86%（21.1mm）; water use efficiency （WUE） was increasedby15.1%in organic N treatments when the N rate was over the value of372.0kgN·hm^-2(over thevalue of9874kgC·hm^-2). Overall, organic N treatments showed better water-saving effects underhigher N level.4. The optimum rates of organic N and inorganic N fertilizer were obtained from our results. Nosignificant difference was observed at the rates of110.7kgN·hm^-2and220.6kgN·hm^-2for organic Nand inorganic N fertilizer, respectively; and higher winter wheat yield and water use efficiency couldbe achieved at the rates of481.7kgN·hm^-2(12786kgC·hm^-2) and220.6kgN·hm^-2for organic N andinorganic N fertilizer. Therefore, organic N fertilizer rate of220.6⁴81.7kgN·hm^-2(5855¹2786kgC·hm^-2) and inorganic N fertilizer rate of110.7³67.6kgN·hm^-2were considered as the optimumfertilizer range. Compared to inorganic N fertilizer, the rate of organic N fertilizer increased by86.2¹14.1kgN·hm^-2(2288³029kgC·hm^-2), not only can obtain the equal crop yield, but alsoimprove water use efficiency.5. An optimal combination of water, carbon and nitrogen was ascertained based on our results.As a result, the treatment of W2C1N1was regarded as the most optimal management due to its bettercapacity of soil water conservation, crop growth characteristics, photosynthetic performance, and cropyield and water use efficiency.In conclusion, Organic N fertilizer application affected obviously on conserving water, reducing soil water losses, increasing yield and improving water use efficiency. However, the rate of yieldincreasing showed no significant difference at the over-high rate of organic fertilizer. Therefore, theoptimum range of organic fertilize is220.6⁴81.7kgN·hm^-2. Overall, W2C1N1was the most optimalin our designed experiment, because of its better growth characteristics, photosynthetic performance,and yield and water use efficiency.更多还原