【作者】 王伟妮；

【导师】 鲁剑巍；

【作者基本信息】 华中农业大学 ， 植物营养学， 2014， 博士

【摘要】 水稻是全世界重要的粮食作物,水稻生产对保障全球粮食安全具有十分重要的意义。水稻的高产离不开氮、磷、钾肥的合理施用。肥料施用不足不能充分发挥水稻的产量潜力,施用过量则易引起环境污染。然而,长期以来,我国水稻生产中普遍存在施肥状况不清、施肥效果不明的问题,且由于缺乏适用于当前生产条件的土壤养分分级指标和推荐施肥方法,施肥不合理的现象常有发生。本研究通过分析湖北省2008年测土配方施肥项目获取的6530份土壤样品,以及2006-2010年在湖北省7个稻作区布置的626个水稻田间肥效试验的结果,以湖北省为例,从区域尺度系统分析了水田土壤的肥力现状及变化规律,研究了早、中、晚稻氮、磷、钾肥的施用效果及肥料利用率状况,建立了水田土壤氮、磷、钾养分供应能力的分级指标,并初步确定了水稻氮、磷、钾肥的适宜用量及推荐方法。主要研究结果如下：1.湖北省水稻土有机质、碱解氮、有效磷和速效钾含量及pH平均值分别为26.1g/kg、124.2mg/kg、13.1mg/kg、89.1mg/kg和6.3,主要分布范围分别为10-40g/kg、>90mg/kg、5-40mg/kg、50-150mg/kg和5.0-7.5。各养分元素在不同稻区的分布均存在一定的差异,从全省来看,有机质含量具有东、南高,西、北低的分布特征；碱解氮具有西、南高,东、北低的特征；速效钾和pH具有西、北高,东、南低的特征；而有效磷没有表现明显的区域分布规律。与第二次土壤普查相比,由于长期施用氮、磷肥和肥料用量不断增加以及秸秆还田面积和数量的增加,一方面促进了水稻土有机质、碱解氮和有效磷含量的提高,另一方面也加速了土壤的酸化；而钾肥用量的不足及高产水稻品种对钾素的大量吸收,也导致了土壤速效钾含量的下降。2.水稻施用氮、磷、钾肥均有显著的增产、增收效果。早、中、晚稻适量施氮后的增产量分别平均为1631、2021和1631kg/hm2,增产率分别为37.0%、35.7%和32.4%,增收值分别为2205、2965和2262元/hm2；适量施磷后的增产量分别平均为850、937和646kg/hm2,增产率分别为15.8%、14.0%和10.6%,增收值分别为1201、1423和921元/hm2；适量施钾后的增产量分别平均为648、876和750kg/hm2,增产率分别为11.4%、12.8%和13.0%,增收值分别为582、966和661元/hm2。相比于单一肥料的施肥效果,氮、磷、钾肥配施的增产、增收效果更加明显,早、中、晚稻的平均增产量分别为2128、2594和2068kg/hm2,增产率分别为57.3%、51.5%和45.6%,增加的净收益分别为2187、3071和2080元/hm2。可见,不同类型水稻的施肥效果是不同的,若以增产率为评价标准,早稻的氮肥、磷肥以及氮磷钾肥配施的增产效应均最高,而晚稻的钾肥增产效应最高。3.在适量施肥的条件下,湖北省水稻的氮肥偏生产力、农学利用率、吸收利用率和生理利用率分别平均为46.6kg/kg N、11.3kg/kg N、29.2%和36.5kg/kg N,相应的磷肥利用率指标分别平均为131.6kg/kg P2O5、14.7kg/kg P2O5、15.0%和78.6kg/kg P2O5,相应的钾肥利用率指标分别平均为92.1kg/kg K20、9.8kg/kg K20、43.0%和18.7kg/kg K2O。水稻对土壤氮、磷、钾素的依存率分别平均为65.3%、86.0%和80.1%,相应的对氮、磷、钾肥的依存率分别为34.7%、14.0%和19.9%,可见,水稻植株吸收的氮、磷、钾素主要来自于土壤,改善土壤供肥能力是提高水稻产量和节约肥料资源的有效措施。4.土壤碱解氮不能作为土壤供氮能力的有效评价指标,而无氮产量可有效评估土壤供氮能力,利用其建立的土壤供氮能力分级指标共有6个等级,所对应的相对产量分别为>90%、800%-90%、70*%-80%、60%-70%、50%-60%和≤50%。土壤有效磷和无磷产量都可作为评估土壤供磷能力的有效指标,利用它们建立的土壤供磷能力分级指标各等级所对应的相对产量相同,从等级1到等级6都是>95%、90%%-95%、85%-90%、80%-85%、75%-80%和≤75%。土壤速效钾和无钾产量均可有效评估土壤供钾能力,其中利用土壤速效钾建立的土壤供钾能力分级指标有5个等级,所对应的相对产量分别为>95%、90%-95%、85%-90%、80%-85%和≤80%；而利用无钾产量建立的土壤供钾能力分级指标有6个等级,所对应的相对产量分别为>95%、90%-95%、85%-90%、80%-85%、75%-80%和≤75%。5.湖北省早、中、晚稻利用肥料效应函数估算的最佳经济施氮量均值分别为135、149和158kg N/hm2,最佳经济施磷量均值分别为53、55和45kg P2O5/hm2,最佳经济施钾量均值分别为71、74和78kg K2O/hm2,分别比试验设定的2水平氮、磷、钾肥用量降低了6.5%-19.2%、14.1%-23.2%和15.5%-24.3%。早、中、晚稻在湖北省50%的田块上的适宜氮用量区间分别为110-180、120-180和130-200kg N/hm2,适宜磷用量区间分别为45-65、40-75和35-60kg P2O5/hm2,适宜钾用量区间分别为45-90、50-95和60-95kg K2O/hm2。早、中、晚稻的最佳经济施氮量、最佳经济施磷量和最佳经济施钾量在湖北省及不同稻区随相应土壤供肥能力的下降均呈逐渐上升的趋势,可见,在为水稻确定氮、磷、钾肥用量时应把土壤供肥能力考虑在内。另外,不同稻区氮、磷、钾肥的区域平均适宜施用量是不同的,因此应按不同区域推荐施肥量。总体来看,利用“以区域平均适宜施肥量为基础,根据土壤供肥能力进行微调”的方法推荐氮、磷、钾肥用量是可行的。更多还原

【Abstract】 Rice is an important food crop of the world, and plays an important role in ensuring global food security. Nitrogen (N), phosphorus (P), and potassium (K) are essential nutrients that require careful management in intensive rice systems, since insufficient amounts might result in yield losses, and excessive application might harm the environment. However, farmers often tend to apply a large excess of N fertilizer but insufficient P and K fertilizer, primarily because of the absence of reliable methods to estimate optimal fertilizer application rates.Through the project of soil testing and fertilizer recommendation in2005-2009, a lot of data about soil nutrients in paddy fields were acquired. Based on the data obtained in2008, status quo of the soil fertilities in seven rice producing regions of Hubei province were systematic analyzed and compared with the data obtained during the second national soil survey to explore laws and causes of the variation of soil nutrients in paddy field. Besides, we conducted a large-scale study comprising626fields in seven rice regions of Hubei province. The overall goals were to assess yield and profit responses of rice to N, P and K fertilizer, investigate N, P and K fertilizer use efficiency, establish indigenous soil N, P and K supply classification systems, and provide recommendations for N, P and K fertilizer application rates in this large-scale region, thereby helping farmers perform reasonable fertilizer management. The main results are summarized below.1. At present, the paddy soils in Hubei Province were10-40g/kg or26.1g/kg on average in organic matter,>90mg/kg or124.2mg/kg on average in alkalystic N,5-40mg/kg or13.1mg/kg on average in available P, and50-150mg/kg or89.1mg/kg on average in available K, and5.0-7.5in pH or6.3on average. The soil nutrients varied to a varying extent from region to region. In view of the province as a whole, the distribution of organic matter was characterized by being high in the east and south and low in the west and north, that of alkalystic N being high in the west and south and low in the east and north, and that of available K and pH both being high in the west and north and low in the east and south, while that of available P did not show any apparent rule. Compared with the findings of the second soil survey, the contents of organic matter, alkalystic N and available P increased while pH decreased as a result of long-term application of N and P fertilizers at an increasing rate and increased area and rate of straw incorporation. However, inadequate application rate of K fertilizer and the adoption of high K-demanding rice cultivar led to decrease in available K in the soil. 2. The application of N, P and K fertilizer increased the yield and profit of rice significantly. Compared with PK (without N) treatment of early, mid and late rice, yields of NPK treatment increased1631,2021and1631kg/hm2, and profits of NPK treatment increased2205,2965and2262Yuan/hm2, respectively. Compared withNK (without P) treatment of early, mid and late rice, yields of NPK treatment increased850,937and646kg/hm2, and profits of NPK treatment increased1201,1423and921Yuan/hm2, respectively. Compared with NP (without K) treatment of early, mid and late rice, yields of NPK treatment increased648,876and750kg/hm2, and profits of NPK treatment increased582,966and661Yuan/hm2, respectively. The average yield of NPK treatment of early, mid and late rice was2128,2594and2068kg/hm2higher than that of CK (without N, P and K) treatment, respectively. Compared with CK treatment, profits of NPK treatment of early, mid and late rice increased2187,3071and2080Yuan/hm2, respectively. These results showed that the combined application of N, P and K fertilizer significantly increased both rice yield and profit. The responses of different rices to fertilizer were different. The response to N and P fertilizer application for early rice was strongest, whereas the response to K fertilizer application for late rice was strongest.3. At present production conditions, nitrogen, phosphorus and potassium use efficiency of rice were partial factor productivity of applied fertilizer (PFP) of46.6kg/kg N,131.6kg/kg P2O5and92.1kg/kg K2O, agronomic efficiency (AE) of11.3kg/kg N,14.7kg/kg P2O5and9.8kg/kg K2O, recovery efficiency (RE) of29.2%,15.0%and43.0%, and physiological efficiency (PE) of36.5kg/kg N,78.6kg/kg P2O5and18.7kg/kg K2O in Hubei province, respectively. The average dependent rate of rice to soil N, P and K was65.3%,86.0%and80.1%, respectively. As a whole, the fertilizer use efficiency of early, mid and late rice was different, however N, P and K absorbed by three kinds of rice primarily came from soil but not fertilizer. As a result, sustaining and increasing soil fertility is an effective measure to increase rice yield and save fertilizer resources.4. The grain yield of no-N, rather than soil alkaline hydrolyzable-N and total N, is a better predictor of indigenous N supply (INS) in paddy fields. The classification of INS for early, mid and late rice was determined based on the relationship between relative yield and grain yield of no-N. Compared to the complete treatment, the relative yields of50%,60%,70%,80%and90%obtained from the no-N treatment were selected to establish the classification indices of the grain yield without N for rice. Both soil available P and grain yield of no-P are feasible predictor of indigenous P supply (IPS) in paddy fields. The classification of IPS for early, mid and late rice was determined based on the relationship between relative yield and soil available P or grain yield of no-P. Compared to the complete treatment, the relative yields of75%,80%,85%,90%and95%obtained from the no-P treatment were selected to establish the classification indices of soil available P and grain yield without P for rice. Both soil available K and grain yield of no-K are feasible predictor of indigenous K supply (IKS) in paddy fields as well. Compared to the complete treatment, the relative yields of80%,85%,90%and95%(or75%,80%,85%,90%and95%) obtained from the no-K treatment were selected to establish the classification indices of soil available K (or the grain yield without K) for5. The average economic optimum fertilizer rate of early, mid and late rice, which was determined according to fertilizer response models, was135,149and158kg/hm2for N,53,55and45kg/hm2for P2O5,71,74and78kg/hm2for K2O in Hubei province. Compared with the N, P2O5and K2O rate of the medium application level, average economic optimum N rate (EONR), economic optimum P rate (EOPR) and economic optimum K rate (EOKR) decreased by6.5%-19.2%,14.1%-23.2%and15.5%-24.3%, respectively. The50%confidence interval of optimum fertilizer rate of early, mid and late rice was110-180,120-180and130-200kg/hm2for N,45-65,40-75and35-60kg/hm2for P2O5,45-90,50-95and60-95kg/hm2for K2O in Hubei province. The obvious increasing trend, which was shown by the average EONR with decreasing INS, the average EOPR with decreasing IPS, and the average EOKR with decreasing IKS in Hubei province, proved the importance of indigenous nutrient supply for recommending fertilizer application rates of rice. With decreasing INS, IPS and IKS, an increasing trend of EONR, EOPR and EOKR was also shown for most rice regions. The economic optimum fertilizer rate differed among the seven rice regions in Hubei province. In conclusion, the recommended fertilizer application, based on regional mean optimal fertilizer rates in combination with indigenous nutrient supply, is feasible for regional rice production in China and other countries that have large numbers of small farmland areas and where agricultural testing equipment is absent or less modern.更多还原