【作者】 李忠芳；

【导师】 徐明岗；

【作者基本信息】 中国农业科学院 ， 土壤学， 2009， 博士

【摘要】 作物产量是土壤肥力和所处的气候条件及人为管理措施等因素的综合表现,其中施肥是提高产量的主要人为手段。长期施肥对粮食持续生产和土壤质量的影响及其程度、趋势一直是人类关注的重要问题。玉米、小麦和水稻是目前世界上主要的粮食作物,在我国更具有重要的战略意义。因此,探明长期施肥下我国玉米、小麦和水稻在不同气候和轮作方式下长期动态演变特征具有重要的理论意义和实践价值。以中国农业科学院组织和主持的20个农田长期肥料定位试验为研究平台,具体分析不施肥(CK)、单施氮肥(N)、施氮钾肥(NK)、施氮磷肥(NP)、施磷钾肥(PK)、施氮磷钾肥(NPK)、施有机肥(M)和氮磷钾配施有机肥(NPKM)共8个处理下各产量系列的差异、变化趋势及产量可持续性指数(SYI)等用来表征产量演变特征相关参数,及综合分析施肥与产量、产量与时间空间的关系。以期为土壤肥力提升和培育提供理论依据。主要研究结果如下:(1)长期不同施肥下作物产量差异显著。与CK相比,偏施N、NK和PK处理3种作物产量无显著差异,而施NP、NPK、NPKM和M能显著提高作物产量,其中施NPK、NPKM产量最高。最优施肥(NPKM)玉米(7140 kg?hm-2)产量高于小麦(4230 kg?hm-2)和水稻(5892 kg?hm-2),与不施肥相比增产率分别为142%、229%和81%。施NP、NPK和NPKM小麦产量与纬度呈显著正相关,表明小麦在我国北方地区种植具有高产优势。低纬度地区(祁阳、进贤、徐州和武昌等)作物增施K肥(施NP基础上)和增施有机肥(施NPK基础上)作物增产显著(玉米11%～86%、小麦和水稻11%～21%);玉米、小麦和水稻产量每年一熟制分别比两熟制的高49%,34%和46%。(2)长期施肥下作物产量存在着随时间的变化趋势。玉米和小麦产量变化大,而水稻相对稳定。玉米和小麦在不施肥和化肥偏施(N、NK和PK)产量呈显著下降趋势,而配合施用化肥或化肥配施有机肥产量呈不同程度的上升趋势;水稻产量在各施肥下相对稳定。水稻产量变化率与纬度及水热因子间相关性小。小麦和玉米产量变化率与纬度及年日照时数间呈正相关关系,而与种植地年平均温度、积温及降雨量间均呈负相关,表明在北方利于其产量稳定和上升,而南方高温多雨使土壤养分矿化加速淋溶而流失,导致产量趋于逐年下降。1熟和2熟制玉米产量年增长率分别为12 kg?hm-2和-23 kg?hm-2。不施肥、偏施N、NK和PK肥的3种作物产量变化趋势与初始产量都呈显著负相关,表明不合理的施肥模式其初始产量越高越难以维持。(3)长期不同施肥下水稻SYI值比小麦和玉米高0.1～0.2。不施肥、施N和NK下作物SYI小于0.45,产量可持续性差;施NP和PK作物SYI在0.45～0.55间,可持续性居中;施NPK、NPKM和M作物SYI大于0.55,产量可持续性好。水稻SYI变异小与各因子间没有显著相关性;小麦居中;玉米不施肥SYI或偏施N肥变异最大,且与纬度及水热因子间存在显著的相关性。表明作物产量可持续指数的变化与施肥及作物种类密切相关,水稻产量可持续性高于小麦和玉米,其中施用NPK化肥配合有机肥作物产量可持续性最高。(4)不同作物基础地力贡献率不同,水稻季的(各地变化幅度42%～79%,平均值为62%)大于小麦季(各地变化幅度0.20～0.61,平均0.36)和玉米季(各地变化幅度10%～79%,平均42%)。玉米季基础地力贡献率大小与所处纬度呈极显著的正相关关系,表明纬度越高产量对基础地力的依赖就越大,而小麦和水稻季与纬度无显著相关性。在时间的变化上,水稻季基础地力贡献率相对稳定。玉米季和小麦季基础地力贡献率都随时间变化呈显著下降趋势。其中小麦季下降的速率与纬度呈显著的负相关关系,表明高纬度下其初始值较高难以维持而易下降。作物施肥产量与不施肥产量呈显著的正相关,长期施用化肥作物产量对基础地力的依赖程度高于NPKM。总之,不施肥或化肥偏施小麦和玉米产量呈下降趋势,尤其在低纬度地区下降更为严重,表明北方小麦和玉米产量较高且稳定。但是在全国水稻产量相对稳定。南方要提高产量尤其注重增施钾肥或有机肥。化肥配施有机肥是最有效高产稳产的可持续性施肥模式。更多还原

【Abstract】 Crop grain yield is comprehensive performance of factors from soil fertility, climate conditions and management practices and so on. The fertilization application is one of the main management practices to increase crop yields. At present, more and more people pay attention to the problems that degrees and trends of the effects of long-term fertilizer application on sustainability of food production and soil quality. Maize, wheat and rice are main food crops in the world, especially in China. Grain yields of maize, wheat and rice were collected from 20 long-term experiment sites under a wide range of soil types, climatic conditions and crop management practice in China. Most of experiments had eight treatments: non-fertilization (CK), nitrogen fertilization (N), nitrogen-potassium fertilization (NK), nitrogen-phosphorus fertilization (NP), phosphorus-potassium fertilization (PK), nitrogen-phosphorus-potassium fertilization (NPK), manure with NPK fertilization (NPKM) and manure (M) with single or double cropping systems. The main results and conclusions are given as following:(1)Grain yields were significantly higher in the NP, NPK, M and NPKM treatments than those in the CK treatments across all the sites. The highest grain yields were found in the NPK and NPKM treatments. The maize, wheat and rice yields in NPKM treatments were 7140 kg?hm-2, 4230 kg?hm-2 and 5892 kg?hm-2, respectively. Compared to the CK, the grain yields in the NPKM treatments increased by 142%, 229% and 81%, respectively. Wheat grain yields in the NP, NPK and NPKM treatments showed a significantly positive relationship with the latitude, i.e higher wheat yield in the northern China. For the sites in the southern China (Qiyang, Jinxian, Xuzhou and Wuchang), grain yields were significantly higher in the NPK (NPKM) treatments than that in the NP (NPK) treatments, showing increases of 11%～86% and 11%~21% for maize, and wheat/rice, respetively. The grain yield of maize, wheat and rice were decreased under double cropping than single cropping by 49%, 34% and 46%, respectively.(2)The interannual fluctuations in grain yields of wheat and maize were greater than that of rice. The maize and wheat yields in the CK, N, NK and PK treatments showed a significant declining trend. There was an increasing trend for the NPK and NPKM treatments although the trend was not statistically significant. The annual change rates of maize yield were 12 kg?hm-2 and -23 kg?hm-2 under the single and double cropping systems, respectively. Overall, the locations or the climate conditions had little effect on the annual change rates of rice grain yield, but considerable effect on those of maize and wheat yield. The annual change rate of maize and wheat yields showed generally positive relationships with the latitude and annual sums of sunshine hours, but negative relationships with annual mean temperature and effective accumulated temperature. These results indicate that the northern China has potential for continuous increase in maize and wheat yield.(3)The sustainable yield index (SYI) of crop varied with fertilization, crop types, effective accumulated temperature and the sunshine hours. Generally, the SYI of rice was higher than that of both maize and wheat by 0.1~0.2 regardless of fertilization. As a general rule, a good sustainable yield was obtained under NPK, NPKM and M treatments when the SYI value was more than 0.55, while a worse sustainable yield under control, N and NK treatments when the SYI was less than 0.45. The crop SYI was also affected by the longitude, altitude and climate condition, especially for maize, followed by wheat. The variation of SYI for maize, which was affected by effective accumulated temperature and the sunshine hours significantly, is biggest among the three major crops in China. It indicated that the rice yield sustainability was higer than that of maize and wheat. The sustainable of grain yield in NPKM treatment was the highest among all the treatments.(4)On average, the soil basic fertilities of rice (42%~79% across sites, average 62%) were higher than that of wheat (20%~61% across sites, average 36%) and maize ( 10%~79% across sites, average 42%). The significantly positive correlation between the fertilized and unfertilized grain yields. When the yields of unfertilized crops increased one unit, the magnitude of yields increased in NPKM treatments decreased by 0.12-0.31 compared with that in NPK treatments. The grain yields under long-term NPK fertilization were more dependent on soil basic fertility than that of NPKM fertilization.In a word, the decline trends of yields were observed for wheat and maize with no fertilizer or unbalanced fertilizers of chemical applied, especially in the Southern China. It showed that maize and wheat yields in the Northern China were high and stable. However, rice yield was little response to spaces and different fertilizer application across all sites. In order to increase the crop yield, the potassium fertilizer and manure should be applied in Southern China. Chemical fertilizer in combination with manure is more effective way to improve and maintain the grain yield, and it is strongly recommended for sustainable agriculture.更多还原