Study On Control Measures Of Potato Safe Planting In Pb And Cd Contaminated Soil

Potato is the third largest food crop in Yunnan Province,with a perennial planting area of about 600,000 hm2,mainly in the poor mountainous areas of northeast Yunnan,and has become one of the important pillar industries for consolidating the results of poverty alleviation,bridging rural industrial revitalization and ensuring food security because of its wide growth adaptability,high yield potential and comprehensive nutrition.However,the mining of mineral resources has led to increasingly serious environmental pollution problems,especially the pollution of soil heavy metals around mining areas has affected the production of potatoes and food safety,therefore.In order to understand the potato soil heavy metal pollution in Yunnan Province,to fundamentally coordinate the soil fertilization performance,improve the crop growth environment,improve the quality of crops,and develop and produce green and organic potato products,this study was conducted to determine the physical and chemical properties of the soil,the total amount of soil and the heavy metals Cd and Pb in various parts of potatoes in the surface soil of Jin Ding Town,Lanping County and Zehai Town,Huize County,the main mining areas in Yunnan Province.content of potatoes.The degree of soil heavy metal pollution in different regions was analyzed by using the single factor index method and the Nemero composite index method.In addition,we conducted low accumulation variety screening for potato production areas with heavy metal contamination to verify the effects of different levels of Pb-Cd contaminated soils on potato,and studied the effects of different fertilization measures and foliar barrier control measures on the safe cultivation of potato crops,and conducted safe utilization pattern screening for potato production areas.In order to provide technical support for soil pollution evaluation,safe utilization and safe planting of potato in arable land in Yunnan Province.The results of the study are as follows:(1)The soils in the two potato study areas were acidic overall,and the average contents of heavy metals Cd and Pb in the soils had exceeded the background values of Yunnan soils.Among them,the average content of Cd and Pb in the study area of Shihai Town,Huize County was 5.00 mg/kg and 277.11 mg/kg,respectively,and the quality of Cd in the soil exceeded the risk control value of soil pollution of agricultural land,and the quality of Pb in the soil was between the screening value and the control value,indicating that the Cd pollution in the area was more serious.The contamination of Cd in this study area is serious and the risk level is high,followed by the risk of Pb.The average content of soil heavy metals Cd and Pb in the study area of Lanping County was 1.04 mg/kg and 77.47 mg/kg,respectively,and the quality of Cd in the soil at each sampling point was between the screening value and the control value,and there may be a risk of soil contamination in the area such as edible agricultural products not meeting quality and safety,while the quality of Pb in the area was slightly lower than the screening value,indicating that there may be soil contamination of agricultural land in the area risk,and the contamination is low.(2)Through the determination of different potato varieties in the two study areas,it was concluded that there were large differences in the content of Pb and Cd in different potato varieties.The safety of potatoes in the two study areas was evaluated using the National Food Safety Standard Limits of Contaminants in Food(GB2762-2017),and only Yunnan high-yielding early-ripening yellow-skinned yellow heart tuber Cd did not exceed the safety limit in the study area of Huize County,with an exceedance rate of 88.8%.Yunnan seven-color potatoes red skin red heart,Yunnan high-yielding early yellow skin yellow heart,flowering tuber content below 0.2mg/k did not exceed the limit,the remaining six varieties of tuber Pb content exceeded the limit,the exceedance rate of 66.6%.Among the 27 potato varieties in the study area of Lanping County,the Cd content of edible parts of 13 potato varieties such as Yan11,You10,Eugene,K34,K37,Yan8,K136,K13,Xingjia2,East314,China Potato No.5,Fujin and East310 exceeded the limit value,with an exceedance rate of 48.14%;4potato varieties such as Yan11,You10,East324 and K136 4 potato varieties such as Yan11,You10,East 324,K 136 and other edible parts Pb content exceeded the limit value,the rate of exceedance is only 14.82%.We can screen out low Cd and Pb accumulation varieties: Yunnan high-yielding early yellow skin and yellow heart,Yunnan potato 104,East 317 province,Yan 13,early large white,gram 35 province.(3)Using the soil in the high background area of heavy metals as the test soil and setting different levels of Pb and Cd contamination,pot experiments were conducted on three main potato varieties,and it was found that with the increase of Cd and Pb treatment concentration,the single potato weight,plant height and stem thickness of different potato varieties showed a decreasing trend,the number of potato tubers did not change significantly,and the edible parts of potato Cd and Pb showed an increasing trend,in which,for Cd For Pb,as the soil Pb content increased,the content in potatoes was from large to small: green potato 9 > cloud potato 105 > cloud potato 104,and under heavy pollution conditions,cloud potato 105 did not exceed the limit value.(4)The effect of different fertilization measures on potatoes was compared in the study area of Huize County using Yunnan main cultivar Qingye 9 as the test variety.The treatments not only improved potato yield and quality,but also effectively reduced the content of Pb-Cd in potatoes.Treatments dedicated fertilizer,conventional fertilizer + soil conditioner,dedicated fertilizer + soil conditioner,bio-organic inorganic,bio-composite fertilizer and conventional fertilizer + passivate increased the yield by 36.15%,8.84%,12.73%,32.20%,25.98% and 15.63%,respectively,compared to CK.The highest vitamin content(13.5 mg/100g)was reached with the application of special fertilizer,which was 1.33 times higher than the treatment CK(10.08 mg/100g),the highest starch content was reached with the application of bio-compound fertilizer,which was 17.5 g/100 g,and the lowest starch content was reached with the application of special fertilizer,which was 14.9 g/100 g.The highest soluble sugar content was reached with the application of special fertilizer+ soil conditioner,which was 2.7%.The use of different fertilization measures can effectively reduce the potato flesh,potato skin and root Cd,Pb content(P<0.05),compared with CK,Cd content potato flesh content decreased by 20.73%-65.85%,including the most obvious effect of biological compound fertilizer,conventional fertilizer + passivation agent,after the application of potato flesh Cd content decreased by 65.85%,52.38%;Pb potato flesh Cd content,respectively,52.38%;Pb potato flesh decreased by 15.09%-35.85%,of which the effect of conventional fertilizer + passivator was the most obvious,and the content of green potato 9 Pb decreased by 35.85% after use.We can screen out the bio-compound fertilizer with higher yield,highest vitamin content,lowest starch content and greater reduction in Pb and Cd content for further promotion.(5)The effect of different foliar blocking agents: YZ-1,YZ-2,YZ-3,YZ-4 and Cd-lowering agent on the accumulation and enrichment coefficients of Pb and Cd in potato was compared in the research area of Huize County using Yunnan main cultivars Green Potato No.9 and Cooperative 88 as the test varieties,and the contents of Cd and Pb in the flesh of Green Potato No.9 were reduced by 68.29% and 40.38%,62.19% and 23.07%,57.32% and 21.15%,73.17% and 38.46%,56.09% and 13.46%,respectively.The contents of Cd and Pb in cooperative 88 potato flesh were reduced by 61.29% and 35.08%,46.77% and 42.10%,40.32% and 28.07%,72.58% and43.86%,66.13% and 12.28%,respectively.Among them,spraying YZ-4 was the most effective in reducing the Pb-Cd content in the edible part of potato.It was also found that YZ-4 significantly reduced the Cd enrichment coefficient of green potato 9 and cooperative 88,YZ-1 significantly reduced the Pb enrichment coefficient of green potato 9;YZ-2 significantly reduced the Pb enrichment coefficient of cooperative 88.