| Phosphorus is one of the indispensable nutritive elements for crops and a key indicator of soil quality.Phosphorus is easily immobiled by the soil,which leads to low utilization rate in season and strong after effect.There is problem in the utilization of phosphate fertilizer in the current season and the following season,which makes the long-term test of the effectiveness of phosphorus have more scientific significance.Cinnamon soil is the most important soil type in Shanxi Province,and the study was designed to explore the temporal and spatial variation characteristics and effectiveness of phosphorus components under the long-term fertilization in cinnamon soil.Its purpose was to provide theoretical basis and technical support for the rational application of phosphate fertilizer.This study was based on the long-term positioning experiment of national dry farming in Shouyang,Shanxi.It took 25 years from the spring of 1992 to the autumn of 2016.9 treatments were selected in the experiment,namely,non-fertilization(N0P0M0),four treatments of nitrogen-phosphorate fertilizer combined(N1P1M0、N2P2M0、N3P3M0、N4P4M0),three treatments of organic and nitrogen-phosphorate fertilizer combined(N2P1M1、N3P2M3、N4P2M2),high-quantity organic fertilizer alone(N0P0M6).The content of different phosphorus components in the soil layer of 0~20 cm in 1992,1996,2001,2006,2011,2016 was tested by the improved phosphorus classification method of Hedley to analyze the dynamic variation characteristics under the long-term fertilization condition.The content of different phosphorus components in the layer of 0~20 cm,20~40 cm in 2016 was determined to analyze the spatial variation characteristics of soil phosphorus components.The different phosphorus components were divided into three parts as active,medium active and stable phosphorus to analyze the dynamic variation characteristics of different active phosphorus components of 0~20 cm soil layer in 1992-2016.And the correlation was studied among different phosphorus components,Olsen-P,total phosphorus,surplus phosphorus and spring maize yields.The research results showed that:(1)Dynamic and spatial variation characteristics of different phosphorus componentsDuring the 25 years from spring of 1992 to autumn of 2016,the content of H2O-Pi,Na HCO3-Pi,Na HCO3-Po,Na OH-Pi and Na OH-Po of 0~20 cm soil layer had a slight change in the treatment of non-fertilization,while the increasing rate was small in the early stage,but significant in the later stage in the other treatments with fertilizer,and the increase was generally greater with application of organic and nitrogen-phosphorate fertilizer combined and application of high-quantity organic fertilizer alone than the application of nitrogen-phosphorate fertilizer combined.The content of H2O-Po had an increased trend in the application of high-quantity organic fertilizer alone in the soil layer of 0~20 cm,while a reduced trend was observed in the other treatments from 1992 to 2016.Contents of HCl-Pi and Residual-P were stable with a small Interannual variation,and the difference was also mild among different fertilizer treatments.In terms of spatial distribution of 0~40 cm soil layer in 2016,both the contents and difference were obvious among the inorganic phosphorus components in the soil layer of 0~20 cm.The content of Na HCO3-Po and Na OH-Po in 0~20 cm soil layer was much higher than the content in 20~40 cm soil layer,and the content of H2O-Po and Residual-P had a little variation between the soil layer of 0~20 cm and 20~40 cm.Compared with the basic value in 1992,the content of H2O-Pi,Na HCO3-Pi,Na HCO3-Po and Na OH-Po increased significantly in the soil layer of 20~40 cm in 2016 when the quantity of nitrogen-phosphorate fertilizer reached the level of N2P2M0,and higher increasing was observed in the application of organic and nitrogen-phosphorate fertilizer combined and the application of high-quantity organic fertilizer alone.(2)The dynamic interannual variation characteristics of active,medium active and stable phosphorus componentsFrom 1992 to 2016,the proportion of active,medium active and stable phosphorus in total phosphorus showed that the variation of the different active phosphorus was slight of the 0~20 cm soil layer,and the proportion of stable phosphorus was large,which accounted for about 80% in total phosphorus in the application of non-fertilizer and the application of nitrogen-phosphorate fertilizer combined.Compared with the basic value in 1992,it demonstrated a decreased trend of the proportion of stable phosphorus in the application of organic and nitrogen-phosphorate fertilizer combined and the application of high-quantity organic fertilizer alone by 6%~30% in 2016,.The medium active phosphorus had a slight increasing by 3%~6%.The active phosphorus increased larger,which was up to 24% with the application of high-quantity organic fertilizer aloneFrom 1992 to 2016,the proportion of the organic and inorganic phosphorus in active and medium active phosphorus components showed that inorganic phosphorus accounted for a larger proportion in active phosphorus,and organic phosphorus accounted for the majority in medium active phosphorus.The proportion of inorganic phosphorus in active phosphorus could be increased by long-term fertilization.The proportion of inorganic phosphorus in active phosphorus was increased by 14%~52% in 2016 than that in 1992 with the application of nitrogen-phosphorate fertilizer combined.The proportion of inorganic phosphorus in active phosphorus was increased by 28%~45% with the application of organic and nitrogen-phosphorate fertilizer combined and the application of high-quantity organic fertilizer alone.However,the proportion of organic and inorganic phosphorus in medium active phosphorus changed slight under the long-term fertilization.(3)The correlation among the total phosphorus,available phosphorus,surplus phosphorus,spring maize yields and different active phosphorus components in the 0~20 cm soil layer under the long-term fertilization.The correlation was analyzed among the total phosphorus,available phosphorus,surplus phosphorus,spring maize yields and different active phosphorus components in the soil layer of 0~20 cm from 1992 to 2016.Results showed that active and medium active phosphorus were significantly positively correlated with total phosphorus,available phosphorus,surplus phosphorus and spring maize yields,among which active and medium active phosphorus had a stronger correlation with the available phosphorus,and the correlation coefficient was 0.915 and 0.883 respectively.The stable phosphorus was not correlated with the spring maize yields while it was positively correlated with the total phosphorus,available phosphorus and surplus phosphorus and the stable phosphorus had the greatest correlation with the surplus phosphorus,whose correlation coefficient reached to 0.742.Compared with the basic value in 1992,the content of total phosphorus decreased in N0P0M0 and N1P1M0 treatments in the soil layer of 0~20 cm in 2016,while it increased in the other fertilizer treatments.The yields of spring maize were low in the treatment of non-fertilization,while it was larger with the application of different organic and nitrogen-phosphorate fertilizer combined than that with the application of nitrogen-phosphorate fertilizer combined on the whole from 1992 to 2016.The difference was small among different treatments of nitrogen-phosphorate fertilizer combined or organic and nitrogen-phosphorus fertilizer combined.Under the condition of ensuring the spring maize yields,the surplus phosphorus was the smallest in the treatment of N2P1M1,which was a better way of fertilizing. |
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