Central Guizhou Yellow Soil Vegetable Soil Nitrogen Variability Of Environmental Effects

This paper studied regional variability of vegetables soil nitrogen nature about the mantle soil, the subsoil layer,the rhizospHere and non-rhizospHere soil in the yellow soil in Guiyang city.It analyzed the relationship of nitrogen contents of them in soil,leaf vegetables and irrigation water, evaluated the quality of vegetable field and vegetables,discussed the main reasons for the regional variations of the soil properties and their effects on the enviromnent.The main conclusions was as follows:(1)The character of surface soil in different vegetable field in Guiyang are as follows:PH urban area＞suburb,rural area.The tend of soil organic matter and total N is urban area＞suburb＞rural area,and the trend of alkali-hydrolyzable nitrogen,ammonium nitrogen,nitrate nitrogen is suburb＞urban area＞rural area.The content of amino acid nitrogen in urban area soil is highest,the second is suburb,the third is rural area.The difference of ammoniacal nitrogen in different areas is not obvious.The contents of amino sugar nitrogen and unknown acidolysis nitrogen in different areas are reached to significant difference.(2)The PH of the mantle soil is lower than subsoil layer in most soil samples compared with the longitudina section,but the content of soil organic matter,total N,alkali-hydrolyzable nitrogen,ammonium nitrogen and nitrate nitrogen in mantle soil are higher than which are in subsoil laver.Most organonitrogen of different form in mantle soil are higher than which are in subsoil laver,and the amino acid nitrogen and ammoniacal nitrogen in the longitudina section are reached to significant difference.(3)The PH,soil organic matter and total N in rhizospHere were more than non-rhizospHere, and the alkali-hydrolyzable nitrogen,ammonium nitrogen and nitrate nitrogen in rhizospHere and non-rhizospHere soil haven't show significant difference.The acid hydrolysis nitrogen shows significant difference in rhizospHere and non-rhizospHere soil,and the amino acid nitrogen and ammoniacal nitrogen are accumulated obvious in rhizospHere.(4)Generally speaking,the trend of property of soil in different woodland is urban area＞suburb,but the difference is not obvious.The content of different form nitrogen in vegetable field is higher than wood soil.But the proportion of ammoniacal nitrogen and no acidolysis nitrogen in woodland are higher than vegetable field.(5)The nitrogen have correlations among vegetable field,vegetable and irrigating water.The PH and ammonium nitrogen contents in irrigating water can effects the vegetable's ammonium nitrogen contents and the soil's PH and soil organic matter contents.The nitrate nitrogen has obvious influence to the soil organic matter.(6)The highest content of ammonium nitrogen and trite nitrogen is in urban area,which is lower in suburb and rural area.The trend of nitrate nitrogen is urban area＞suburb＞rural area.The content of nitrate nitrogen in irrigating water has reached drinking water primary standard (NO₃^--N＜10mg/L) no matter in high water period and low water period in rural area.The numerical value is lower than 2mg/L,which is belonged to good state.(7) Leaching through the indoor simulated experiments,we can conclude that with the increase of fertilizer,the content of nitrogen into the soil is increasing,and the content of ammonium nitrogen and nitrate nitrogen in the leaching from the soil solution are increasing too. Fertilize with organic fertilizer can reduce the nitrate and ammonium nitrogen to be leached from the soil,and chicken manure has better effects on holding the nitrate nitrogen in the soil.At the same time.maize straw has better effects on holding the ammonium nitrogen in the soil.