Characterization Of Nutrient Changes In Major Farmland Soil Types During 1980-2010 In Bazhou

The changes of soil nutrients have great influence on the quality of farmland. Especially, the changes in the total nutrients, available nutrients and the trace elements in the soil affect the growth of crops all the time. In the last few decades, the damages caused by irregular planting and fertilization on soil are more and more serious, which leads to the decline of soil fertility.In this study, the main types of farmland in Bayinguoleng Mongol Autonomous Prefecture(Bazhou) as the research objects, compared with soil nutrients content in 1980 and 2010, the nutrient characteristics of eight soil subtypes were analyzed. Those soil subtypes blong to four main soil types: fluvo-aquic soil, irrigated desert soil,anthropogenic-alluvial soil, irrigated brown desert soil. The present situation and the change tendency of the nutrients in Bazhou were expounded, which provided scientific basis for the management offarmland and balanced fertilization.Through the comparison, the nutrient contents of different soil types had different degrees of change after 30 years of cultivation. The main results are as follows:(1) The changes of soil organic matter and total nitrogen. The organic matter contents of cumulated irrigated fluvo-aquic soil and typical anthropogenic-alluvial soil were increased only, organic matter contents of other soil types were decreased. The total nitrogen content of typical anthropogenic-alluvial soil was rise, but soil total nitrogen contents of others were decreased.(2) The changes of available nutrients. The available nitrogen contents of calcareous alluvial soil and typical irrigated desert were decreased. The available phosphorus content of calcareous alluvial soil was decreased only. The available phosphorus contents of others were increased. The available potassium contents of typical fluvo-aquic soil,calcareous alluvial soil, salinization fluvo-aquic soil, typical irrigated desert soil and irrigated brown desert soil were decreased, that of other types were increased.(3) The changes of soil trace elements. The available copper contents of saline anthropogenic-alluvial soil and typical anthropogenic-alluvial soil were increased, but the available copper contents of other types were decreased.Eexcept in the typical irrigated desert soil, the available iron contents of other soil types were increased. The available zinc and manganese contents were increased in the study area. The available boron contents of typical irrigated desert soil and irrigated brown desert were increased, but the available boron contents of other soil types were decreased.