Cd Enrichment Transport And Influencing Factors Of Calcium Magnesium Phosphate Fertilizer Supplementation Between Rice And Ludwigia Prostrata Roxb

With the gradual increase of Cd-contaminated soil,the Cd-contaminated agricultural products also increase.The main grain crop in China is rice,and rice is the main source of human Cd intake.Therefore,the problems of Cd pollution and Cd accumulation in brown rice need to be solved urgently.The yellow field paddy soil,planted early rice and late rice,and studied the influence of plant absorption transport Cd and Cd,and provided data reference for field soil fertilizer and weed management of heavy metal Cd pollution.The main study results are presented as follows:（1）When planting early rice and late rice,the addition of calcium,magnesium and phosphorus fertilizer can significantly improve the soil pH and CEC,effectively improve the content of total phosphorus and effective phosphorus in the soil,and reduce the effective cadmium content in the soil.In the early rice period,compared with CK,the CEC of single and intercropping soil was 2.0P(P is normal P2O50.1g kg^-1),increasing by39.71%（p<0.05）and 36.94%（p<0.05）,respectively.Total P increased by 34.44%（p<0.05）and 26.56%（p<0.05）,respectively,and by 1.5P by 68.14%（p>0.05）and 95.09%（p<0.05）,respectively.The effective cadmium content was 2.0P and 1.5P by 9.73%（p<0.05）and 15.02%（p<0.05）,respectively,and during the late rice period,the CEC of 1.5P and 2.0P increased by 37.25%（p<0.05）and 51.34%（p<0.05）,respectively.Soil OP increased by 71.90%（p<0.05）and 68.48%（p<0.05）,respectively,and soil effective P was increased by 2.0P and 1.5P,1 9 2.23%（p<0.05）and 112.2%（p<0.05）,respectively.The effective cadmium content in the soil was most reduced by 0.5P and 2.0P,which decreased by 9.06%（p>0.05）and 18.69%（p<0.05）,respectively;（2）In planting early and late rice,the addition of calcium magnesium phosphate fertilizer reduced the Cd content of rice and polygonum,which was reduced by 2.0P treatment.For polygonum clove,the addition of calcium and magnesium phosphate fertilizer increased the dry weight of each part.（3）When planting early rice,the correlation analysis showed that the effective Cd content of soil was significantly negative correlation with pH and CEC（-0.601**and-0.462**respectively）.Cd content in brown rice was significantly negatively associated with pH（-0.626**）,with CEC（-0.367*）,with effective Cd（0.374*）,and with total phosphorus（-0.359*）.（4）When planting late rice,the correlation analysis showed that the effective Cd content of soil was significantly negative correlation with pH（-0.491**）and with total phosphorus（-0.387*）.Cd content in brown rice showed a significant negative correlation with pH and whole phosphorus（-0.527**and-0.537**,respectively）,with CEC（-0.377*）and with effective Cd（0.579**）.（5）It was less effective in assisting phosphorus and Cd absorption when planting early and late rice.The mode of rice intercropping polygonum is beneficial to the absorption and transport of heavy metal Cd in rice.It is suggested to remove weeds in the field such as polygonum as possible in the field management process to avoid aggravating the harm of heavy metal pollution.Meanwhile,it can be considered to repair heavy metal Cd pollution in the late rice period.