Effects Of Continuous Cropping Of Maize Straw And Application Of Phosphorus On Phosphorus Absorption And Yield In The Songnen Plains Of China

Maize is an important food and feed crop.Songnen Plain is an important corn producing area in China.With the continuous development of the rural economy,the amount of corn stalks used for fuel has been rapidly reduced,while the area of straw returning has been reduced,and a large surplus of corn stalk resources has led to open burning of large areas of straw and serious pollution of the atmosphere.Straw returning can not only improve physical properties such as soil bulk density,agglomerate distribution,and water retention,but also increase the accumulation of inorganic and organic nutrients in the soil.It can also improve the soil microenvironment and promote soil fertility and promote crop growth.Phosphorus is the main nutrient element of the earth's life system and an important nutrient limitation factor in the ecosystem.Inorganic phosphorus is the main form of phosphorus absorption in crops.Its content will affect the absorption of phosphorus by crops,biological metabolism and resistance to adversity.Excessive application of phosphate fertilizer will lead to the loss of phosphorus,but the return of crop straw to the field can replace a considerable portion of phosphate fertilizer.The combination of phosphate fertilizer and straw not only has a fast effect,but also can maintain the supply of phosphorus for crops for a long time to ensure crop yield stability,but some scholars have different or even opposing views.Therefore,in view of the characteristics of maize production in the Songnen Plain,it is of great significance to study the effect of straw returning and phosphorus application on phosphorus absorption and yield of maize,and to implement scientific straw returning and reasonable application of phosphate fertilizer in the Songnen Plain.In this experiment,in 2016 and 2017,under the continuous cropping maize condition,frame planting?diameter 30cm,height 33cm?was adopted,and two maize varieties,Xinzhonglong No.1and Jiudan 48,were used as test materials.Three straws returning treatment methods were also designed and tested.The field treatment methods are straw not returning?S0?,straw direct mixing?S1?and straw incineration?S2?;In the three straw treatment methods,4 levels of phosphorus are set,according to the application.Diammonium phosphate?P₂O₅:46%?0 kg/hm²?P0?,75 kg/hm²?P1?,150 kg/hm²?P2?,225 kg/hm²?P3?,and the amount of P₂O₅ converted was 0,34.5,69.0,103.5kg/hm²,the corresponding dosage of calcium superphosphate?P₂O₅:44%?was calculated to be 0g,0.55g,1.10g,1.65g per box.The effects of straw return and application of phosphorus on dry matter accumulation,phosphorus content and accumulation,soil phosphorus and yield of three-leaf stage,jointing stage and harvest stage were systematically studied.The results show:1.The return of maize straw and application of phosphate fertilizer had effects on the dry matter accumulation in three sampling periods.The general trend was that with the increase of phosphorus application amount,the dry matter accumulation of maize increased.The accumulation of dry matter of the return of maize straw incinerationto and straw did not return to the field is higher than the direct treatment of straw.2.Phosphorus content in maize plants was similar to the jointing stage in the three-leaf stage,which was significantly higher than that in the harvesting stage.With the increase of phosphorus application rate,the phosphorus content of maize plants did not show a consistent pattern of changes.Straw incineration and direct returning could increase the above-ground part of phosphorus content in the three-leaf stage and jointing stage,and the overall performance was incineration?S2?>directly returning field?S1?>not returning field?S0?,the content of phosphorus in the root is the opposite,and the phosphorus content is less when the straw is returned to the field.At the harvesting stage,the phosphorus content of the plant does not show the same regularity as the return of the straw.3.Phosphorus accumulation in maize plants increased with the growth period,and phosphorus accumulation increased with the increase of phosphorus application.However,the phosphorus accumulation in maize plants with the change of phosphorus application rate did not show the same pattern in the two-year experiment,and showed an increasing trend overall.The accumulation of phosphorus in straw returned to the field showed an increasing trend,but it could not reach a significant level.The phosphorus accumulation in the straw incineration treatment?S2?was the highest.4.With the increase of phosphorus application rate,the content of available phosphorus in soil shows an increasing trend,especially in the three-leaf stage.Except for high-level phosphorus application,the straw incineration returning field?S2?and straw direct returning field?S1?treatment can be different.The level of available phosphorus in soil was increased in different periods,and the content of available phosphorus in soil was the highest when straw was directly returned to soil?S1?at low phosphorus level.Phosphorus application had no significant effect on the total phosphorus content.The direct straw returning?S1?and straw incineration?S2?treatment could increase the soil total phosphorus content,but the difference between straw return treatments did not reach a significant level for two consecutive years.5.With the increase of phosphorus application,the yield increased,and the straw yields were the highest in the high phosphorus application levels.Straw returning has an impact on yield and traits.The order of high-to-low crop yields in two years is straw incineration?S2?>straw not returning?S0?>straw direct return?S1?,continuous straw return treatment had no significant effect on yield.