Effect Of Lime And Sugarcane Leaf Carbon On Acidification Improvement Of Lateritic Soil In Sugarcane Region Of North Qiongzhou

Based on the investigation of soil nutrients in Qiongbei sugarcane plantation,Hainan,it is clear that the serious acidification of latosol in sugarcane plantation is an important limiting factor for sugarcane growth.In order to solve this problem,first of all,soil culture experiments of lime improvement were carried out on acidified latosol in sugarcane area to determine the reasonable application range of lime.Then,several different amounts of lime were set in the interval,and the soil acidification improvement effect and sugarcane growth status were compared and analyzed through field experiment,and the suitable application amount of lime in the field was determined.At the same time,the sugarcane leaves discarded after sugarcane harvest were used to prepare biochar,and pot experiments were conducted to compare the effects of sugarcane leaf charcoal and lime on improving acidified soil.The specific results are as follows:1?According to the investigation of soil nutrients in Qiongbei sugarcane plantation,Hainan Province,the majority of sugarcane soils in Qiongbei sugarcane region are latosol with serious clay-heavily acidified texture,and the average pH value is only 4.43.All latosol samples are acidic or strongly acidic soils with pH value below 4.8,of which 63.6%were strongly acidic soils with pH less than 4.5.In order to increase sugarcane yield and sucrose content it is necessary to apply amendments in time to improve soil acidification.In addition,the level of soil alkali-hydrolyzed nitrogen is generally high,,and 88.4%of soil alkali-hydrolyzed nitrogen is high content level,while the available pHospHorus and available potassium varies greatly.In the later stage of fertilization,attention should be paid to reducing the amount of nitrogen fertilizer,and rational balanced application should be carried out according to the status of soil available pHospHorus and potassium.2?The application of lime can significantly improve the soil pH value,and the amount of lime application is positively correlated with the soil pH.To adjust the Latosol with pH value of 4.4 to 5.5-6.5,which is basically suitable for sugarcane growth,it is necessary to apply 1.5-3 g/kg lime,equivalent to 220-440 kg per mu.In addition,lime application can affect the availability of various nutrients in soil.The contents of available nitrogen,available pHospHorus,exchangeable calcium and magnesium in soil will increase with the increase of lime application,while the contents of trace elements such as iron,manganese,copper and zinc will decrease.At the same time,the content of exchangeable aluminium,which is toxic to sugarcane in acidic soils,will decrease dramatically with the increase of lime application.3?The field application of lime can rapidly increase the soil pH value in a short time,but the effect of soil acidification improvement will gradually weaken with the extension of time.It is necessary to apply lime continuously in order to maintain the effect of soil acidification improvement.In addition,lime application also played an active role in promoting the growth of sugarcane.The contents of nitrogen,pHospHorus and chloropHyll in leaves of some treatments were significantly higher than those of the control at tillering stage and stem elongation stage.At the same time,the application of lime also significantly increased sugarcane yield and sucrose content.When the application amount of lime was 366.7 kg/mu,the effect of increasing sugarcane yield and sugar was the best.Compared with the control,the yield increased by 20%,and the sucrose content increased by 0.73 percentage points.4?The application of sugarcane leaf charcoal can significantly increase the pH value of acidic soil and effectively reduce the content of exchangeable aluminum in soil,but its improvement effect is significantly weaker than that of lime treatment alone,and the effect of soil acidification improvement can be superimposed under the condition of mixed application of two amendments.In addition,the effect of sugarcane leaf charcoal on soil nutrient availability was better than that of lime.The application of sugarcane leaf charcoal could significantly increase the contents of soil organic matter,alkali-hydrolyzed nitrogen,available pHospHorus and available potassium.The biomass of sugarcane seedlings was significantly increased by applying lime and sugarcane leaf charcoal,and The most obvious way to increase the biomass of sugarcane seedlings was the mixed treatment of sugarcane leaf charcoal and lime,which increased by 29%compared with the control.Mixed application of two modifiers can synthesize the advantages of lime and biochar,and the effect of promoting crop growth is better than that of applying only one of the amendments.