Research On Soil Fertility For Different Land Use In Xinyang City

In the past few years,the role of organic fertilizer in agronomic practices has long been replaced by chemical fertilizer.It has also brought about some unfavorable results. Besides the impairment of soil environmental and vegetable quality in protected field,this practice also caused a decline in soil productivity through excessive soil erosion,nutrient runoff,imbalanced nutrient,and deteriorated soil chemical properties.Since the human activities vary greatly with the different land use type,it is important to assess the soil nutrient quality under the different land use types.Xinyang,a city in south of Henan province,is suffering the huge changes in land use.Unfortunately,the effects of such changes on the soil nutrient still remain unknown.Through the investigation on 4 land-use types,which include the vegetable field,paddy field,tea garden,greenbelt,280 soil samples for organic matter,available nitrogen,available phosphorus and available potassium were obtained.The results are summarized as follows:1.Soil organic matter content is low in different land-use types.So it is necessary to increase the application rate of organic fertilizer,which increases the organic matter content in soil of Xinyang City.The average content in green belt,vegetable field,paddy soils and tea garden soils were 9.9,14.8,17.6和16.3mg/kg.2.The difference of soil available nitrogen content in 4 different land-use types is obvious.The average content in green belt,vegetable field,paddy soils and tea garden soils were 33.4,90.6,104.6 and 169.7mg/kg.88.1%of the soil in greenbelt is deficient in soil available nitrogen content,which in vegetable field is 31.3%,but available nitrogen content of most soil in vegetable field and paddy field is moderate,which in percent is 64.0%and 62.5%,over 94%of the soil in tea garden is high in soil available nitrogen content.Therefore,we should consider the difference of available nitrogen content in different land-use types to use nitrogen fertilizer.3.The difference of soil available phosphorus content in 4 different land-use types is obvious.The average content in green belt,vegetable field,paddy soils and tea garden soils were 18.6,35.8,42.3 and 46.5mg/kg.Much soil deficient in available phosphorus content,which in greenbelt is 51.5%,in tea garden is 51.6%,in vegetable field is 37.5%, paddy field is 44.0%,but 38.7%in tea garden,56.3%in vegetable field and 29.0%in paddy field is rich in available phosphorus content. 4.The content in available potassium in Xinyang soil is in moderate and high level, most soil sample is not deficient in K.The average content in green belt,vegetable field, paddy soils and tea garden soils were 136.9,90.6,104.8 and 119.5mg/kg...