| Fertilization is an important measure to improve crop yield,but in recent years,China's agricultural production rely much more on fertilizer,the phenomenon of ignoring organic fertilizer is very serious.Agricultural production is more dependent on fertilizer,leading to soil compaction and decline of soil fertility.This study is based on typical red soil paddy soils in Changsha,Hunan Province.Use field positioning test set the contrast(CK,no fertilizing)?recommend fertilizing(RF)?decrement fertilizing(DF,provide RF 3/4's N)?rape straw plus low fertilizer(RS+LF,provide DF 1/2's N)?manure plus low fertilizer(M+LF,provide DF 1/2's N)?manure plus 1/2 low fertilizer(M+1/2LF provide RF 3/4's N)that six different nitrogen treatments.Based on field experiment and indoor analysis measured on rice yield,soil organic carbon,soil total nitrogen,soil active organic carbon,soil organic nitrogen components,microbial biomass carbon and nitrogen determination analysis,I analyze the effect which organic fertilizer instead of nitrogen fertilizer has on paddy soil fertility and rice yield in the condition of nitrogen reduction.The main results were as follows:(1)Different fertilizer treatments were increased on different ways in double cropping rice yield.From the early rice yield,RF and DF yields were than CK increase of 66%,64%.RS+LF?M+LF?M+1/2LF combined application of organic and inorganic manure than CK only increased by about 25%.From the late rice yield,RS+LF?M+LF?M+1/2LF combined application of organic and inorganic manure is not only 47%,30%,25% higher than CK,and 36%,20%,15% higher than RF,than DF increased by 24%?8%?5%.RF and DF yields were than CK increase of 8%?19%.From the point of production throughout the year,chemical fertilizer RF and DF hasn't significant difference,RS+LF?M+LF?M+1/2LF combined application of organic and inorganic manure yield higher than chemical fertilizer RF and DF,also have significant difference.From the annual nitrogen use efficiency(NUE),the basic and annual production trends are consistent.Thus it can be seen that the amount of fertilizer applied in subtropical regions can be reduced,on the basis of reducing fertilizer use organic fertilizer to partially replace fertilizer.It‘s not only further enhance rice yield,but also further reduce the nitrogen fertilizer application.Chemical fertilizer and combined application of organic and inorganic manure impact on the yield of early rice is also different,combined application of organic and inorganic manure on the late rice yield to enhance the effect is more obvious,but chemical fertilizer on the early rice yield to enhance the effect is more obvious.(2)Under different fertilizer treatments,soil organic carbon and its components were significantly different.RS+LF?M+LF?M+1/2LF combined application of organic and inorganic manure soil organic carbon(SOC)content is higher,than CK enhance by 27%?18%?12%.RF?DF chemical fertilizer although lower than the treatment of combined application of organic and inorganic manure,but also than CK increased by 9%,8%.There was no significant difference between chemical fertilizer RF and DF,and there was a significant difference between the other methods,it have reached significant and extremely significant levels.From the particulate organic carbon(POC),chemical fertilizer RF and DF is the lowest organic carbon content and lower than CK treatment.Combined application of organic and inorganic manure POC content is higher,compared with chemical fertilizer increased by about 30%,compared with CK increased by about 20%.From a microbial biomass carbon(MBC),RS+LF?M+1/2LF combined application of organic and inorganic manure increased significantly compared with CK,an increase of 96%,76%.Chemical fertilizer RF and DF also than CK increased by 69%,40%.This proves Soil SOC,MBC content than CK has increased in chemical fertilizer,but it caused the loss of soil POC.Soil SOC,MBC,POC have increased in combined application of organic and inorganic manure and the growth rate is faster than chemical fertilizer.Therefore,the combined application of organic and inorganic manure measures are more conducive to the accumulation of soil organic carbon and its components in paddy soil.(3)Under different fertilizer treatments,soil total nitrogen and its components did not change significantly.The combined application of organic and inorganic manure measures total nitrogen(TN)content is higher,than CK increased by only about 6%,than chemical fertilizer increased by about 3%.There was no significant difference between the other treatments except that there was a significant difference between CK and DF,M + 1 / 2LF.From the ammonium nitrogen content,chemical fertilizer is higher,than CK increased by 58%?23%.While the combined application of organic and inorganic manure than CK increased by about 25%.From microbial biomass nitrogen(MBN),all of which are faster than CK.In RS+LF?M+1/2LF combined application of organic and inorganic manure MBN content increased significantly compared with CK,increased by 74%?115%.Chemical fertilizer also increased by about 50% compared to CK.Whether it is chemical fertilizer or combined application of organic and inorganic manure,soil nitrogen content and content components are more CK has increased,especially in the combined application of organic and inorganic manure mode MBN content than CK grow faster.But in chemical fertilizer ammonium nitrogen content than CK grow faster.Comprehensive analysis shows whether chemical fertilizer or combined application of organic and inorganic manure.It could be significantly increased production,stable at a higher level of production,can significantly improve soil physical and chemical properties and improve soil fertility.Therefore it can be seen that the amount of fertilizer applied in subtropical regions can be reduced,on the basis of reducing fertilizer use organic fertilizer to partially replace fertilizer can promote soil fertility and yield increase.It's the best fertilization model for paddy fields in red soil. |
PDF Full Text Request