【作者】 李文西；

【导师】 鲁剑巍；

【作者基本信息】 华中农业大学 ， 植物营养学， 2010， 博士

【摘要】 提高作物产量、改善土壤肥力是农业可持续发展的重要内容,而土壤肥力的维持或改善是作物高产优质的重要保障。土壤肥力是土壤的基本属性,也是土壤物理、化学、生物性质的综合反映。苏丹草(Sorghum sudanense)-黑麦草(Lolium L.)轮作是我国南方的一种新型、高强度的作物种植制度,且种植面积不断扩大。该轮作体系中两个牧草收获频率高、强度大,研究如何维持较高强度、频度的种植系统中作物产量、土壤肥力、系统养分平衡以及土地生产力可持续发展等问题有着重要的意义。本论文在5年大田定位试验、盆栽试验基础上采用苏丹草-黑麦草轮作种植研究长期施肥对饲草生长、产量与品质、土壤肥力的影响。试验设CK(不施肥)、NP(氮、磷肥)、NK(氮、钾肥)、PK(磷、钾肥)、NPK(氮、磷、钾肥配施)以及3个氮(N0、N1、N2)、磷(P0、P1、P2)、钾(K0、K1、K2)水平。主要研究结果如下：1)饲草生长、生理氮磷钾肥配施能够促进饲草生长,改善饲草生理状况。大田、盆栽NPK处理的饲草株高、单株叶片数、叶长与叶宽均高于其他处理,其中氮肥的作用最大,磷肥次之,钾肥最小。武汉大田试验NPK处理的黑麦草叶绿素总量、净光和速率、过氧化物酶明显高于CK, PK处理,而蒸腾速率、丙二醛低于CK、PK处理。OM, NP、NK处理与NPK处理差异较小。2)产量、品质氮磷钾肥配施能够提高饲草产量,改善饲草品质。洪湖大田试验NPK处理的饲草鲜草总产量为110.7 t/hm2-162.7 t/hm2,平均为131.9 t/hm2,分别比不施氮(PK处理)、不施磷(NK处理)、不施钾(NP处理)增加234.6%、26.2%、21.1%,且增产效果显著。武汉大田试验NPK处理的饲草鲜草总产量为100.7 t/hm2-122.4 t/hm2,平均为110.6t/hm2,分别比不施氮、不施磷、不施钾增加429.3%、47.3%、24.4%。盆栽试验NPK处理的饲草鲜草总产量为1387.2 g/pot-2091.3 g/pot,平均为1673.4 g/pot,分别比不施氮、不施磷、不施钾增加935.2%、684.8%、14.8%。在该轮作系统中,氮肥的增产作用最大,磷肥次之,钾肥最小。结果还表明,洪湖大田试验氮肥处理的饲草粗蛋白均高于不施氮处理,而无氮浸出物显著低于不施氮处理。各施肥处理饲草粗纤维、粗脂肪高于不施肥处理,而各处理间粗灰分差异较小。3)饲草养分吸收与平衡氮磷钾肥配施能够促进饲草养分吸收,改善轮作系统养分平衡。5个年度大田、盆栽试验NPK处理的饲草N吸收量总计为2128 kg/hm2、31.95 g/pot, P吸收量总计为184kg/hm2、3.85 g/pot, K吸收量总计为2796kg/hm2、34.04 g/pot,均高于其他处理。轮作系统中,氮肥对饲草N、P、K养分吸收的促进作用最大,磷肥次之,钾肥最小。大田、盆栽轮作系统中,氮肥、磷肥的施用能够维持该轮作系统的氮素、磷素平衡,而钾素平衡处于亏缺状态。氮磷钾肥配施也能够减少氮素、磷素在土壤中大量积累,改善养分平衡,同时缓解钾素亏缺所引起的土壤钾素耗竭。4)杂草调查轮作系统中田间杂草主要出现在苏丹草试验期,禾本科千金子(Leptochloa chinensis (L.)Nees)、水稗(Beckmannia szigachne (Steud.) Fern.)为试验区优势杂草。氮磷钾肥配施能够促进杂草生长、增加杂草总鲜重,分别比PK、NK、NP处理的杂草总鲜重增加273.6%、32.8%、5.4%。施肥后杂草与牧草存在养分竞争。5)养分、水分利用率氮磷钾肥配施能够提高轮作系统养分、水分的利用效率。5个年度大田轮作系统中氮、磷、钾肥平均利用率分别为48.1%、20.9%、47.4%,盆栽轮作系统平均利用率分别为60.9%、35.7%、70.5%。5个年度NPK处理轮作系统水分生产率为15.6 kg/m3-18.8 kg/m3,平均为16.4kg/m3,分别比不施氮、不施磷、不施钾处理增加457.2%、259.7%、17.8%。6)土壤肥力大田、盆栽试验结果表明,随着种植时间的延长,氮磷钾肥配施处理的土壤有机质、全氮、全磷、速效磷升高,而pH、全钾、缓效钾、速效钾变化较小。氮磷钾肥配施能够改善土壤有机质活性组分,提高土壤肥力。氮肥施用能够提高土壤全氮、硝态氮、铵态氮含量。磷肥施用也可以增加土壤全磷、有效磷以及土壤无机磷形态Al-P、Fe-P、O-P(闭蓄态)含量,而对Ca-P含量影响较小。钾肥施用能够提高土壤缓效钾、速效钾含量,而对土壤全钾影响较小。氮肥施用可以降低AWCD、Simpson指数、McIntosh指数,对Shannon指数影响较小。经主成分分析,轮作中各处理间土壤微生物群落碳源利用类型存在差异。氮肥施用后土壤土壤微生物生物量、土壤蔗糖酶、脲酶均高于不施氮处理。大田氮肥处理的碱性磷酸酶活性低于不施氮处理,而盆栽试验结果相反。大田试验氮磷钾肥配施能够降低土壤容重,增加土壤孔隙度。更多还原

【Abstract】 High crop yield and soil fertility are all important parts of sustainable agricultural development, while maintaining or improving soil fertility assures higher yield and better quality of crop. Soil fertility is the basic property of soil, and also reflects soil physical, chemical and biological properties. The sudangrass(Sorghum sudanense) and ryegrass(Lolium multiflorum L.) rotation was a new type and more intensive cropping system in the south of China, which developed very fast in recent years, and growth areas increased gradually. In this roration, harvest frequency and intensity for two forage are high. As a more intensive cropping system, it was important to take proper nutrients measures to increase crop yield, maintain soil fertility, nutrients balance, including the change of soil productivity, sudangrass(Sorghum sudanense cv. Yanchi) in summer and ryegrass(Lolium multiflorum cv. Abundant) in winter was conducted based on located field experiment and pot experiment. The experimental design was consisted of 5 treatments in a randomized block design with four replicates, including control (CK), fertilizer phosphorus and potassium (PK), fertilizer nitrogen and potassium (NK), fertilizer nitrogen and phosphorus (NP) and fertilizer nitrogen, phosphorus and potassium combination (NPK), including three levels of N (N0, N1, N2), P (P0, P1, P2), K (K0, K1, K2). The objectives of this study were that effects of NPK fertilizers on forage growth, yield and quality, soil fertility. The major results as follows:1) Forage growth and physiological indexThe Combination of NPK fertilizer could increase forage growth and improve physiological index. The height, leaves, leaf length and width of forage in NPK treatment were higher than that in other treatments both field and pot experiment. Fertilizer N obtained the highest response, following by fertilizer P and K.In the field experiment in Wuhan, chlorophyll, net photosynthetic rates, POD of ryegrass in NPK treatment were higher than that of CK and PK treatments, and transpiration rate, MDA of ryegrass in NPK treatment were lower than that in CK and PK treatments, while OM, NP and NK treatments were similar to NPK treatments.2) Yield and qualityNPK combination also increased yield and quality of forage. In the field experiment in Honghu, total yield of NPK treatment were 110.7 t/hm2-162.7 t/hm2, and average yield were 131.9 t/hm2, and were 234.6%,26.2%,21.1% higher than that of PK, NK and NP treatments. In the field experiment in Wuhan, total yield of NPK treatment were 100.7 t/hm2-122.4 t/hm2, and average yield were 110.6 t/hm2, and were 429.3%、47.30%、24.4% higher than that of PK, NK and NP treatments. In the pot experiment, total yield in NPK treatment were 1387.2 g/pot-2091.3 g/pot with the average yield of 1673.4 g/pot, and were 234.6%,26.2%,21.1% higher than that in PK, NK and NP treatments, respectively. In the rotation, the increasing effect of fertilizer N was the higher than that of fertilizer P and K, and the increasing effect of fertilizer N was the lowest.In the field experiment in Honghu, crude protein in NP, NK and NPK treatments was higher than that in CK and PK treatments, but nitrogen free extract was lower. Crude fiber and ether extract in all treatments with fertilizers in soil was higher than that in CK treatment, while there was not different for crude ash between treatments.3) Nutrients uptake and balanceNPK combination also promoted nutrients uptake of forage grasses, and improved nutrients balance in the rotation. Total N uptake for NPK treatment in the field and pot experiment was 2128 kg/hm2,31.95 g/pot for five years, and total P uptake was 184 kg/hm2, 3.85 g/pot, and total K uptake was 2796 kg/hm2,34.04 g/pot, and were higher than that of other treatments. In the rotation, fertilizer N played the highest role in improving N, P and K uptake, compared to fertilizer P and K.Fertilizer N and P could maintain N and P balance in the rotation in the field and pot experiment, but K balance was deficient. NPK combination also decreased N and P surplus in soil, maintain nutrients balance, and degraded the K depletion in soil.4) Weed investigationMore weeds occurred in the sudangrass season in the rotation. Chinese Sprangletop (Leptochloa chinensis (L.) Nees), American Sloughgrass (Beckmannia szigachne (Steud.) Fern.) were preponderance weeds. NPK increased weed growth and yield, total yield in NPK treatment were 273.6%,32.8%,5.4% higher than PK, NK and NP treatments, respectively. There were nutrient competitions between forage and weed after fertilization in the rotation.5) Fertilizer and water use efficiencyNPK combination improved fertilizer use efficiency and water productivity. Average N, P and K fertilizer use efficiency were 48.1%,20.9% and 47.4% for five years in the field experiment, and were 60.9%,35.7% and 70.5% for five years in the pot experiment, respectively.Water productivity of forage in NPK treatment was 15.6 kg/m3-18.8 kg/m3 with the average of 16.4 kg/m3, and were 457.2%,259.7%,17.8% higher than that of PK, NK and NP treatments.6) Soil fertilityThe result in both field and pot experiment indicated, with increasing time in the ration, soil organic matter, total N and P, extractable P in NPK treatment increased, but pH, total K, slow release K, available K changed less. NPK combination could increase active organic matter, and improve soil fertility. Fertilizer N could increase the content of total N, and NH4+-N. Fertilizer P also increased the content of Al-P, Fe-P, O-P in soil, but influenced less the content of Ca-P. Fertilizer K also increased the content of slow release K, available K, but affected less total K.Fertilizer N degraded AWCD, Simpson index, McIntosh index, but there were no differences between Shannon indexes in all treatments. Throughout principal component analysis (PCA), there were differences between C sources utilization by microbial communities. MBC, MBN, activities of sucrase and urease in soil following the application of fertilizer N were higher than that of other treatments. In the field experiment, alkaline phosphatase activities in soil following the application of fertilizer N were lower than that in other treatments, while alkaline phosphatase activities in the pot experiment were converse.In the field experiment, NPK combination decreased bulk density and increased porosity in soil.更多还原