Abstract:

Revealing the land bearing capacity (LBC) state of livestock and poultry manures (LPMs) in Dezhou City, Shandong Province, can provide theoretical references for adjusting and optimizing regional livestock and poultry breeding (LPB) pattern, promoting planting-breeding combination and green development of agriculture. Based on the nutrient supply from LPM and the nutrient demand of crops, this study used the recommended method of the Technical Guide for Calculating The Land Bearing Capacity of Livestock and Poultry Manure, to calculate and analyze the spatial and temporal distribution characteristics of LBC state of LPMs from the perspective of nitrogen and phosphorus nutrients in Dezhou City in the past ten years (from 2012 to 2021). The results indicated that: (1) in terms of time distribution, the total input and supply of nitrogen nutrients from LPMs in 2021 were 15.55×10⁴ tons and 9.51×10⁴ tons, and those of phosphorus nutrients were 2.33×10⁴ tons and 1.7×10⁴ tons, the total amount of LPB was 1412.59×10⁴ (pig equivalent), and the LBC of LPMs was 1937.72×10⁴ (pig equivalent) (based on nitrogen supply and demand), the land bearing capacity index was 0.73.These overall trends was decreasing compared with 2012. The increase of the amount of LPB was 525.14×10⁴ (pig equivalent), an increase of 74.89% compared with that in 2012. (2) In terms of spatial distribution, the planting and breeding in the central and southern counties (cities and districts) were more developed, the nitrogen and phosphorus nutrients supply and demand from LPMs were higher. The results in 2021 showed that the lands were overloaded with manures in Qingyun County and Pingyuan County, and that was not overloaded in Xiajin County, but the land bore great pressure. The lands were not overloaded with manures in Yucheng City, Lingcheng District, Decheng District, Qihe County, Ningjin County, Laoling City, Linyi County and Wucheng County, but the bearing pressures of lands varied greatly among different regions. In general, the land was not overloaded with manures in Dezhou city, and there was still a certain growth space for the scale of LPB. However, there were obvious differences in the capacity of lands to absorb manures in different districts, and the development potentials of breeding scale were different. Therefore, it was necessary to optimize the pattern of LPB, promote the combination of planting and breeding, and implement inter-regional collaborative management.

Key words: Dezhou City, livestock and poultry breeding, nitrogen and phosphorus balance, land bearing capacity, planting-breeding combination