The Changes Of Soil Fertility Of Cane Fields And Its Improvement Countermeasures In Zhanjiang State Farms

Low sugar cane yield and sugar content had seriously hinderedthe development of cane industry of Zhanjiang State Farms for a long time, where average yield of cane was only about75t per hectare, and the sugar content was ranged from10%tol1%. It’s well known that the yield and sugar content of cane were closely related to the nutrient status and pH of soil, and the fertilizer application.The present study were conducted to collect and analysis data from previous records and survey field experiment,to investigate the main situation of soil fertility of cane fields in Zhanjiang State Farms,and pointed out the main problems andputted forward the corresponding countermeasures and suggestions of soil improvement, to provide scientific basis for the development of the sugar cane industry in Zhanjiang State Farms. The main results were following.The main problems of soil fertility of sugarcane fields in Zhanjiang State Farms included that:first, fertilizer application was unreasonable, and the soil nutrients were unbalanced, the trace elements of exchangeable calcium and magnesium were very low. Compared with the second soil surveyed, organic matter content decreased by1.50g/kg-2.50g/kg on different sugarcane fields. But available potassium content increased by44mg/kg to91mg/kg and available phosphorus content increased by2.9mg/kg to77.52mg/kg. The level of exchangeable Ca and Mg contents were under five level by soil nutrients classification table, which the contents of them were only66mg/kg and27.6mg/kg on Jinxing sugarcane fields and only112mg/kg and16.8mg/kg on Huahai sugarcane fields. Second, the soil acidity is very strong, almost all of the soil of pH value was under5.5in Reclamation Region, even under4.5. And compared with the second soil surveyed, the value of pH decreased by0.1-0.7units. Soil acidification was very serious.The results of field tests showed that1500kg lime sprinkled to sugarcane field in per hectare increased the yield over10t/ha, and pH increased by0.6.Lime sprinkled combining with sugarcane leaves chopped to field, the yield increased by more than7.6t/ha. Sugar yield was also been improved. Using FCMP, sugarcane yield increased by2.26t/ha.15000kg organic fertilizer used in per hectare cane field, sugarcane yield increased by5.95%, and soil organic matter content was also been improved.According to the effects of soil improvement tests, and to solve the above problems, proposing the following soil improvement measures:1.Additions of compost could imporve soil nutrients and cane production. Bio-organic fertilizer was commodity fertilizer, the application amount was generally2250kg-3000kg/ha, which was far less than compost. Its effect on soil nutrients and sugar cane production was not obvious, so suggesting to apply compost. More than15000kg compost could be use in per hectare cane field, and all were used as basal fertilizer, combined with chemical fertilizer was better.2.Recommendation of returning sugar cane leaves to field could improve soil nutrients and cane production. Sugarcane leaves crushed to field could be use by the farms which promoted mechanized production. Sugarcane leaves crushed by pulverizer aftersugarcane harvested. It was better to combine with sprinkling lime, and then replowing.Through high-temperature composting and sterilizing, the kind of sugarcane leaves heaped steep to field could make nutrients more quickly integrate into the soil.3.Changing the kind of phosphate fertilizer,using FCMP.The suitable amount was1500kg-2250kg/ha. And phosphate fertilizer mixed with compost heap steep10-15d before applicated may be better.4.Applicaiton of the limecould improve soil acidity. In the sugarcane areas where pH was lower than5.0,1500kg-2250kg quicklime powder were recommeded to apply in per hectare sugarcane field,and on the sugarcane areas where the pH was5.0-6.0,750kg-1125kg/ha quicklime powder were recommeded to apply in sugarcane field. Sprinkling the lime before plowing,and then re-plowing.Used combining with sugarcane leaves chopped to field,the effect of sugarcane yield increasing could be more obvious.