Study On The Calculating Of The Soil Effective Coefficient In The Arable Land Gradation And Classification ——A Case Study In Li County Hebei Province

In order to grade and class arable land, a modular evaluation system was established which was divided into three independent and correlative modules (light-temperature productive potential model, land-use coefficient model and land economic coefficient model). The calculating of the soil effective coefficient was an important work in the light-temperature productive potential model. No effective method was put forward in the calculating of the soil effective coefficient .ln this paper, the theory and method for the calculating of the soil effective coefficient in arable land gradation was analyzed in case of Li County. Aimed at the conception of soil effective coefficient, the definition was analyzed, the characters of it were put out and the calculating methods were concluded as six kinds. The merit and defect of the methods were analyzed and a method of sliding average and double regression was put forward. Base on the conditions of the soil, terrain, physiognomy and productive features of Huabei alluvial plain, a set of factors for arable land gradation was put forward which include five main factors (soil texture, soil body configuration, relief, salt-status and contamination). Li County was divided into 902 grading unit by a method named duplex map, which include relief map, soil map and land use map. Based on the soil map, 138 standards quadrates and a number of extra quadrates were given. Applying half-orientation method, functions between soil texture and yield. organic and yield, rapidly available phosphorus and yield, rapidly available potassium and yield, soil texture and organic, soil texture and rapidly available phosphorus, rapidly available phosphorus and rapidly available phosrhorus were put forward for wheat and maize. By using the sliding average and the抎ouble regression method, the equation of the soil effective coefficient ~7or wheat and maize was put forward: Y - 4699.2+52.828x1-0.6674x12 Y 5146.4+93.738x1-l.1944x12 In the paper, the soil effective coefficient was defined by using the sequence and disperses data processing. The conception of associated land type was put forward, and the soil effective coefficient of different associated land types were work out on the base of the features of alluvial plain. The method of associated land type was a simple and easy method that can be used by administers. The conception of social fertility and social fertility yield was put forward at the discussion part. Social fertility yield of wheat and maize in different soil texture can be work out. These data were considered have a mechanism in rewords and punishment and give a method in treat of the problem of soil fertility in the arable land classification. The theory and method for the calculating of the soil effective coefficient can be popularized in the other counties in the Huabei alluvial plain and can be demonstrated in the other area in our Country.