Effects Of Organic Amendments On The Quality Of Greenhouse Soil

In order to discover a rapid,simple and cheap method to improve soil,the experiment researched the effects of organic amendments(biological organic fertilizer,microbial fertilizer and humic acid fertilizer)on the physicochemical property of soil,content of effecitive microelements and heavy metal,enzymatic activity and the quality of crop in greenhouse,which provide theoretical foundation for soil amendment in greenhouse and production of organic vegetables.The main results are as follows:1)The pH value of soil was always above 7.0 during the crop growth period,and no acidification problem.The best treatment to improve pH value of the soil growed tomato was the low level humic acid fertilizer,while the soil growed eggplant was the microbial fertilizer.There was no significant effect on the reduction of EC in the soil growed eggplant with each treament,and microbial fertilizer had significant effect on the reduction of EC in the soil growed tomato.2)The effects of different treatments on the content of microelements were different in varied depth soil and different growth periods.The biological organic fertilizer treatment could reduce the content of available Zn and Fe,but did not reach a significant level,while had no significant effect on the available Mn.Microbial fertilizer treatment could significantly reduce the available Mn,Zn and Fe content during the early fruiting stage in tomato,but had no effect during the Full fruiting stage and after harvest.Microbial fertilizer treatment could significantly reduce the available Mn,Zn and Fe content during the early fruiting stage and full fruiting stage in tomato.For the soil growed tomato,with the increase of application amount,the content of available Mn,Zn and Fe in three humic acid organic fertilizer treatment were gradually reduced in 0-20 cm soil layer,while increase first and then decreased in 20-40 cm siol.The three treatments could reduce the available Fe content.For the soil growed eggplant,with the increase of application amount,the content of available Mn,Zn and Fe in three humic acid organic fertilizer treatment decreased first and then increased.The middle level humic acid fertilizer reduced highly significantly the content of available Mn,Zn and Fe in the sooil during the early and peak stage of flowering and fruiting.3)The content of organic matter,total nitrogen,available P and available K in layer of 0-20 cm soil was higher than that in 20-40 cm during plant growth and development.The microbial fertilizer and middle level humic acid fertilizer improved the content of total nitrogen,organic matter,available K in layer 0-20 cm soil and available P in layer 20-40 cm soil during the early fruiting stage of tamato.Each treatment can improve the content of total nitrogen and reduce the content of available K in 0-20 cm soil layer during the early fruiting stage of eggplant.The content of organic matter of each treatment was less than the control in the full fruiting stage of eggplant.After harvesting of eggplant,each treatment improved the content of total nitrogen in 0-20 cm soil layer.In addition humic acid fertilizer and biological organic fertilizer can also increase the content of organic matter,available P and available K.4)The content of heavy metals including arsenic(As),nickel(Ni),chromium(Cr),lead(Pb),copper(Cu)and zinc(Zn)do not exceed the national soil environment quality standard(GB15618-1995)but that of Cu,Zn and Cr exceed the background value of local soil.In the research of tomatos,the biological organic fertilizer and humic acid fertilizer reduced the content of Ni,Cr,Cu and Zn,while the microbial fertilizer increased the content of As,Ni,Cr,Pb and Cu in soil,so it should be used cautiously in vegetable production.In the research of eggplant,each treatment improved the content of Ni,Cr,Pb,Cu and Zn in the soil besides the microbial fertilizer in 0-20 cm soil layer.5)The activity of urease and sucrase was increased during the reproductive cycle of the crop after all treatment.The biological organic fertilizer was best for improving urease activity,while the humic acid fertilizer was the best for increasing sucrase with significant levels.As for alkaline phosphatase activities in the soil,the effects of all kinds fertilizer was little,but for that of the soil growed eggplant,all treatments increased the enzymatic activity and biological organic fertilizer was the best.All treatments did affect the activity of acid phosphatase in soil growed eggplant,but for the soil grown tamato,microbial fertilizer increased obviously the activity.For hydrogen peroxide,microbial fertilizer improved its activity in the soil grown tomato and eggplant.6)All treatments increased the contents of soluble solid,soluble sugar,titratable acid and vitamin C in tamato.The content of soluble solid,soluble sugar and vitamin C after humic acid fertilizer treatment was the highest and reached the significant levels,while the content of titratable acid was the highest after treatment with microbial fertilazer and reached the significant levels too.Only the middle level humic acid fertilizer improved the sugar-acid ratio among treatments.All treatments increased the height and stem diameter of eggplant and the effects of biological organic fertilizer and humic acid fertilizer were larger than the control significantly.Comparing the effects of all treatments on the growth of eggplant,middle level humic acid fertilizer was the largest,and followed by biological organic fertilizer,microbial fertilizer,high level humic acid fertilizer and low level humic acid fertilizer,the control treatment was the smallest.