| Corn is an important grain-feeding crop in China,its yield and quality are essential to ensure food security.Songnun Plain is the main production area of spring corn in China,located in Heilongjiang and Jilin provinces.The soil organic matter level in Songnen Plain is high,soil organic matter level and fertilization have significant effects on the yield and quality of corn.The effective nutrient content and supply characteristics of soils with different organic matter content differed significantly,which have significant effect on corn yield and the agronomic efficiency of N,P and K fertilizers.Therefore,it is important to study the effects of soil organic matter and nitrogen,phosphorus and potassium fertilizers on corn yield and soil available nutrients in the corn production area of the Songnen Plain,analyze the contribution of soil organic matter and NPK fertilizers to corn yield,which have important implications for the implementation of black soil protection and"double reduction"strategy.The experiment was conducted in 2019-2020,two-factor split-plot design was conducted,the main-plot was organic matter levels including high organic matter soil(SOMH),medium organic matter soil(SOMM),and low organic matter soil(SOML);the sub-plot was different combination of NPK fertilizer including nitrogen,phosphorus,and potassium(NPK),nitrogen and phosphorus(NP),nitrogen and potassium(NK),phosphorus and potassium(PK),and no fertilizer(F0).Through the measuring and analysis of corn yield,corn plant NPK content and soil available NPK content under different organic matter conditions,the effects of soil organic matter level and NPK fertilizer application on NPK uptake,utilization,and yield of corn,and soil available nutrients were systematically investigated.The results showed that:There was a significant positive correlation between corn yield and soil organic matter content.Under the conditions of soil organic matter and nitrogen,phosphorus and potassium(NPK)fertilizer,the liner regression equation of corn yield and soil organic matter level was:y=70.58x+8550.70(R~2=0.9193),corn yield increased by 70.58kg/hm~2for every 1g/kg increase in soil organic matter.Under the high(SOMH),medium(SOMM)and low(SOML)soil organic matter,the average production contribution of N fertilizer was 3072.3 kg/hm~2,5595.9 kg/hm~2and 6087.2 kg/hm~2,the average production contribution of P fertilizer was 2444.3kg/hm~2,3923.2kg/hm~2,and4388.9kg/hm~2,the average production contribution of K fertilizer was 2287.2kg/hm~2,2696.3kg/hm~2,3752.4kg/hm~2,the average production contribution of NPK fertilizer was4697.4kg/hm~2,5995.0kg/hm~2,7141.4kg/hm~2.Therefore,the yield contribution of NPK fertilizer was as follows:N>P>K,and the production contribution of fertilizer was higher with low organic matter.The combination of higher organic matter level and NPK fertilizer application significantly increased the NPK content of corn plant at harvest time.At harvest time,the N content of corn plant was:seed>stalk>root>cob;the phosphorus content of corn plant was:seed>root>stalk>cob;the potassium content of corn plant was:cob>stalk>root>seed.The agronomic efficiency of N,P and K fertilizer under the condition of high,medium and low soil organic matter were:SOML>SOMM>SOMH,and the agronomic efficiency of fertilizers under different N,P and K fertilizer application were K>P>N.The soil available N,P and K contents were SOMH>SOMM>SOML after corn harvest.while the contents of quick-acting N,P and K in the soil without N,P or K fertilizers decreased significantly;the application of N,P and K combination increased the contents of available N,P and K in the soil;the application of P fertilizer increased the contents of available N the soil more than that of K fertilizer;the application of K fertilizer increased the contents of available P in the soil more than that of N fertilizer;the application of P fertilizer increased the contents of available P in the soil more than that of N fertilizer.The increase of soil available P content was greater with K fertilizer than that with N fertilizer.The increase of soil available K content was greater with P fertilizer than that with N fertilizer. |
