Effect Of Oyster Shell Soil Conditioner On Acidified Soil And The Quality Of Two Crops

At present,the area of acidified soil in our country has been estimated as more than 40%of the total cultivated land.For the purpose of ensure food production and sustainable development of agriculture,it is necessary to use effective soil amendments to improve the soil.China is the largest producer of oysters in the world,while oyster shells,which account for more than 60%of its total mass,have not been utilized effectively.In this paper,waste oyster shells were used as raw materials,after high-temperature roasting,the pore structures and basic components of oyster shell soil conditioner were analyzed.Field experiments were carried out with‘Yu Gu'melon and‘Chun Tao'tomato as experimental subjects.The application effects of oyster shell soil conditioner were evaluated comprehensively by measuring soil nutrients,the yield and quality of these two crops.The research methods and results are as follows:1)The soil conditioner was made by oyster shells and roasted at 500?1000°C for 30 minutes.The p H value of the aqueous solution was 9.0?9.5,and the content of calcium oxide was?45%.It also contained trace elements such as Mg,Mn,Se,Fe,Zn,Cu and so on.The content of heavy metal elements such as Hg,As,Cd,Pb and Cr were far below the limit standard value for fertilizer and soil conditioner of the ministry of agriculture(NY 1110-2010).The inner shells of oysters after high temperature roasting formed dense porous loose structure,and the surface of outer shell formed honeycomb porous structure.The pore size was 2?10?m,and the specific surface area has been greatly increased to improve its exchange and adsorption performance.2)Taking‘Yu Gu'melon as the experimental object,each group area was 100 m².Four application amounts of 0 kg/hm²(control CK),1500 kg/hm²(T1),1875 kg/hm²(T2),2250 kg/hm²(T3)were set for field experiments.The results showed that soil acidification neutralization enhanced with the increase of the application amounts of oyster shell soil conditioner.Among them,the T3 group presented the most significant effect of neutralizing soil acidification.Compared with the initial value,the soil p H of T3 group increased by 0.29,and the exchangeable H⁺and Al³⁺contents reduced by 62.88%and 42.93%respectively.At the same time,with the increase of the application amounts of oyster shell soil conditioner,individual fruit weight,fruit hardness,crispness and the Vitamin C content increased to different degrees,and the sugar-acid ratio decreased as well.Compared with the CK group,T3 group had the highest single fruit weight with increase of 12.66%.And the T2 group showed the best fruit quality improvement,fruit hardness and crispness which increased by 47.53%and 41.30%respectively,and the Vitamin C content increased by 70.88%.3)Taking‘Chun Tao'tomato as the experimental object,each group area was 500 m².Four application amounts of 0 kg/hm²(control CK),1500 kg/hm²(T1),2250 kg/hm²(T2),3000 kg/hm²(T3)were set for field experiments.The results indicated that the soil p H value,exchangeable calcium and organic matter content demonstrated upgrade tendency,and the alkaline nitrogen content increased slightly followed the increment of application amounts of oyster shell soil conditioner through the whole growth period.Compared with the CK group,the soil p H values of the treatment groups T1,T2 and T3 all increased by 0.06,the exchangeable calcium content increased by 7.59%,9.58%and 10.45%,and the organic matter content increased by 1.95%,0.90%and 4.45%respectively.At the same time,with the increase of the application amounts of oyster shell soil conditioner,the plant height,stem thickness and individual fruit weight,juice yield of the fruit were on the rise.The Vitamin C content,total output per unit area and economic benefits were all increased to different degrees,and the incidence of umbilical fruit rot decreased as well.After thirty days of transplanting,the plant height and stem thickness values of T3 group were the highest,which were increased by 13.27%and 14.95%respectively compared with the CK group.Through the analysis of ripe fruit,T3 group had the highest single fruit weight and juice yield,which increased by 8.39%and 11.61%respectively compared with the CK group.T1 group had the highest total output per unit area and Vitamin C content.Compared with the CK group,the fruit yield increased by 26.66%per 667 m²,and the Vitamin C content increased by 24.75%.To sum up,the oyster shell soil conditioner could neutralize soil acidification and improve physical and chemical properties of soil,thus increasing the yield and quality of‘Yu Gu'melon and‘Chun Tao'tomato.The results of this study provide an important reference for the oyster shell soil conditioner used in neutralizing acidified soil and the widespread application of crops.