Variation of soil quality in typical farmlands in China under long-term fertilization and research expedition
[Objectives] Fertilization , as the major practice in increasing crop yield , significantly affects soil quality .Researches on the relationship between long-term fertilization and soil quality have been hot spots .Duringthe last three decades , the input in agriculture has been increased and the grain yields have achieved "eleven continuous growths" since 90 s in last century in China , which has definitely produced great influence on soil quality.Investigation on the variation of soil quality after a long term different fertilization modes is critical to keep the sustainability of soil quality and maintain stable grain yield in China .[Methods] Papers related to soil quality in farmland under long-term fertilization around China were reviewed in this paper .The effects of long-term fertilization on the main physical and chemical properties were summarized , the research focuses , present situation were discussed and expedition in the future was proposed .[Results] 1 ) Thirty one papers were collected in this issue , and over 60%of them focused on the study of soil organic matter and phosphorus availability , indicating the soil organic matter and phosphorus balance are the two key indexes in the evaluation of soil quality in farmland in China .2 ) After nearly 30-years continuous application of chemical fertilizers , the soil organic matter content ( SOM) in the black soil in northeast China is decreased at rate of 1 g/kg per decade , but increased at a rate of 1.4-2.5 g/kg per decade in other areas .Long-term combined application of organic manure and straw with chemical fertilizers benefits the accumulation of SOM , the increase rated is respectively 51% and 68% in the northwestern and the north China , and 24%in dry land of the southern China and paddy field in the Yangtze River catchments . 3 ) The average carbon efficiency of organic materials is 16.3%in cropland in China , which is decreasing with the increasing gradients of precipitation and temperature .The average efficiency of carbon utilization in northwestern and northeastern China is 22%-26%, greater than those in northern (13%) and southern part of China (10%) . 4) Fertilization managements have significantly influenced soil available phosphorus ( P) contents.When the annual P application rate is 20-33 kg/hm2 , the contents of total P and available P in soil keep stable on a certain level or greatly increased depending on both the soil type and P application rate , with the highest increase of 2.1 mg/kg annually .5 ) Combined application of organic manure and chemical fertilizers will significantly activate stored P in soil , and expending the room for available P increase .The maximum increase in available P content could be as high as 9.3 mg/kg.6) Fertilizer P application could promote the accumulation of soil P in the form of active inorganic P ( Ca2-P, Ca8-P, Al-P, Fe-P) , while the combined application of fertilizer P with organic manure will greatly increase the content of active organic P pool in soil .[Prospects]Under present intensive agricultural management in China , the primary factor affecting the balance of soil organic matter is sufficient application of organic materials .More researches on soil quality should be focused on soil biological index , soil ecological and healthy function , and the evolution of soil quality .Meanwhile , more attention should be paid on the development of proper models and the optimization on the best-fitted parameters , to enhance the simulation and forecast of the change trends of soil quality in agro-productive practices in the future .
国家科技期刊平台
NSTL
万方数据
维普
