【作者】 刘威；

【导师】 鲁剑巍； 鲁明星；

【作者基本信息】 华中农业大学 ， 植物营养学， 2010， 硕士

【摘要】 紫云英是我国南方稻区的重要绿肥作物。本研究采用模拟试验与田间试验相结合的方法,研究了紫云英的养分积累规律、还田腐解特性以及还田利用后对水稻产量、经济效益及土壤肥力的影响,以期为当前种植制度下恢复和推广紫云英的生产及利用提供依据。获得以下主要结果：1.随着生育期的进程,紫云英地上部的氮含量总体呈现降低趋势,至种籽成熟期略有回升；地上部的磷含量呈现先降后升的变化趋势,以种籽成熟期的含量最高；地上部钾含量总体上呈现缓慢下降趋势；地上部碳含量时有波动,但变化相对较小。随着生长发育的推进,紫云英地上部干物质积累量和养分吸收量均呈现为前期增长缓慢、中间迅速增加、后期略有减少的趋势。花期(播种后135～170 d)是紫云英干物质积累最快的时期,干物质积累量占总积累量的55.8%-83.7%；养分吸收强度也最大,该时期氮养分吸收量占总量的30.6%-54.7%,磷养分吸收量占总量的40.6%-69.6%,钾养分吸收量占总量的53.6%-82.8%,碳积累量占总量的55.8%-83.9%。为保证紫云英最大的有机体及养分还田量,合理翻压期应选择为紫云英的盛花期。2.6个紫云英品种的生育期调查结果显示,在试验条件下,早熟品种信阳种、安徽大叶青种的生育期明显靠前,而中熟品种弋江种、浙紫5号种和晚熟品种宁波大桥种、余江大叶种生育期相差不大。从干物质积累及养分积累情况上来看,弋江种和浙紫5号种更适合作为湖北地区的稻田绿肥品种。3.采用模拟培养方法,研究了紫云英的腐解特征以及对淹水培养土壤表层溶液和土壤理化性质的影响。结果表明：紫云英在翻埋前32 d分解较快,在32 d以后物质分解几乎停滞。养分释放速度表现为：钾>磷>氮>碳。在水浸泡中紫云英的物质释放更多,养分释放更快。不同用量水平对紫云英的腐解和养分释放影响不大。试验条件下,施入紫云英后,土壤表层溶液的pH在培养前期(约两周左右)先降后升,变幅较大；表层溶液中的电导率值、全氮、铵态氮、全磷和全钾浓度都是约在培养后32 d左右时达到最大。整个培养时期土壤的肥力变化动态结果表明：紫云英翻埋后,土壤pH不断提高,96d的培养结束后土壤由原来的弱酸性(为6.08)上升到中性(7.00左右)；土壤钱态氮、速效钾、全氮和有机质含量均得到了显著性提高,尤其是在培养32 d以前的增幅较大；对土壤硝态氮及速效磷含量影响不大。4.在湖北孝昌、黄陂研究了紫云英还田后对水稻生长、产量、养分吸收、经济效益及土壤肥力的影响。结果表明,在常规化肥用量减少40%的情况下,孝昌和黄陂两试验点翻压紫云英15000～45000 kg/hm2均能获得与常规化肥持平或更高的早稻产量。各处理间比较,孝昌和黄陂两试验点均以30000 kg/hm2翻压量时效果最好,两地早稻产量分别较常规化肥处理提高了8.5%和15.4%。孝昌和黄陂两地的等氮磷钾养分试验结果表明,在等氮磷钾养分的情况下,施用紫云英后的早稻产量与单施化肥相比均没有显著性的差异。以上试验结果表明：在水稻生产中,施用紫云英具有替代化肥养分,起到减少化肥投入、提高产量和经济效益的作用。试验条件下,翻压紫云英15000～45000kg/hm2一般可替代20%-60%化肥量。更多还原

【Abstract】 Astragalus sinicus L. is one of the main green manures in paddy field of southern China. The nutrient accumulation and nutrient decomposition character of Astragalus sinicus L. and effect of its applying in paddy soil was investigated in this study using the simulation experiment and field experiment, for the purpose of providing some theory basis for the restoration and popularization of the Astragalus sinicus L. applying in paddy soil under the current cropping system.The main results were showed as follows:1.A field experiment was conducted to study the dry matter accumulation and nutrient absorption with 6 varieties of Astragalus sinicus L.. The results showed that, the N contents in the aerial part of Astragalus sinicus L. kept on decreasing before seed mature period as the growth period goes on, and showed a rise trend in the seed mature period time. The P contents in the aerial part increased first and decreased afterwards, with the highest in the mature period. But the K content slowly declined in the whole growth period, while the C content changed a little. The dynamics study of dry matter accumulation and nutrient absorption showed that the flowering period (135～170 days after seedling) was the most rapid accumulation period, had the accumulation of 55.8%-83.7% of the total dry material.The amounts of N, P2O5, K2O and C nutrient accumulation were also the most during this period, in which N,P2O5, K2O and C accumulation were 30.6%-54.7%,40.6%-69.6%,53.6%-82.8% and 55.8%-83.9% of the whole respectively. In summary, the best returning time of Astragalus sinicus L. to the field was the blooming period, when the amount of organisms and nutrient absorption were the most.2.The growth periods of six varieties Astragalus sinicus L. were showed as follows.The growth periods of Xinyang Astragalus sinicus L. and Anhui Dayeqing Astragalus sinicus L. were obviously earlier than the rest four varieties, while the later four varieties had no big different. Judging from the dry matter accumulation and nutrient absorption conditions of six varieties, varieties of Yijiang Astragalus sinicus L. and Zhezi No.5 Astragalus sinicus L. were the better varieties applied in paddy soil of Hubei province.3.The objective of the simulation experiment was to determine the decomposition character of Astragalus sinicus L. and its effect on properties of soil surface solution and soil fertility. The results showed that the decomposition of Astragalus sinicus L. in the first 32 days was much faster and then almost stagnated. The rate of nutrient releasing was characterized as K>P>N>C, and the amount of nutrition released was much higher when Astragalus sinicus L. was in the water. The results also showed that applications of different amounts of Astragalus sinicus L. had no obvious effect on the decomposition rate and nutrient release rate of Astragalus sinicus L.. The dynamic change of EC, pH, and concentration of TN, NH4+-N, NO3--N, TP and TK in the surface solution were measured during the 96 d experiment. The result showed pH changed greatly at the first 2 weeks. The application of Astragalus sinicus L. to soil increased EC, concentration of TN, NH4+-N, TP, TK obviously,and reached the maximum in about 32 days after cultivation. The study of the dynamic change of soil fertility during the whole training period showed that the soil pH was rising after the Astragalus sinicus L. was mixed into soil,and the range was from pH 6.08 up to pH 7.00 when the 96 days cultivation was over. The content of soil NH4+-N, soil available K, total N and organic matter was significantly increased, especially in the first 32 days of cultivation. But the application of Astragalus sinicus L. had little influence on soil NO3-N and soil available P content.4.Effect of Astragalus sinicus L. application on the growth, nutrients absorption, yield of rice, economic benefits and soil fertility were studied by field experiments in Xiaochang and Huangpi city of Hubei province. The results showed that on the premise of 40% reduction in conventional fertilizer situation, application of mixed Astragalus sinicus L.(15000～45000 kg/hm2) and mineral fertilizers both in Huangpi and Xiaochang could have a better or the same effects on rice yields.Both field experiments in Huangpi and Xiaochang showed that the best quantity of Astragalus sinicus L. were 30000 kg/hm2, as the yield of early rice increased by 8.5% and 15.4% respectively compared to common fertilizers. Field experiments in Xiaochang and Huangpi which have the same N, P and K application showed that the treatment applied of only Astragalus sinicus L. and the treatment applied of mixed Astragalus sinicus L.(15000～45000 kg/hm2) and mineral fertilizers had not significant differences on the yield of early rice. In conclusion, application of Astragalus sinicus L. could partly replaced the use of mineral fertilizers, thus increasing the rice yields and the economic benefits from rice growings. In general,20% to 60% of mineral fertilizers application amount could be better substituted by application of Astragalus sinicus L.(15000～45000 kg/hm2).更多还原