Spatial variation of soil nutrients and evaluation of cultivated land quality based on field scale

The current cultivated land quality (CLQ) evaluation method fails to consider the determination of soil nutrients, resulting in the low efficiency of soil nutrient message extraction. In an effort to effectively solve the above problems, combined with the spatial variation of soil nutrients (SVSN) at the field scale, a CLQ evaluation method is proposed. The soil nutrients were determined according to the soil spatial variation analysis, and the soil color was standardized. The characteristic bands were determined by soil fertility and nutrients such as nitrogen, phosphorus, and potassium, and the soil nutrient message was preprocessed. On this basis, the soil nutrient message extraction model was constructed. According to the damage principle of subsoiling shovel, the limit value of the membership function of the CLQ exponent is determined, and the weighted sum method is used to calculate the CLQ exponent, so as to realize the SVSN and the evaluation of CLQ at the field scale. The experimental results show that the dimensional autocorrelation of soil bulk density and soil water content in different soil layers is high and that of capillary porosity, non-capillary porosity, and total porosity in different soil layers is strong.