Balance of supply and demand of straw fodder resources and development potential of animal husbandry in the dry farming area of central Gansu: A case study in Anding District, Dingxi City

The utilization of straw feed is of strategic importance to promote the development of the grass-fed livestock industry, to store food in grass to reduce competition between humans and animals for land, and to increase food security. In this study, the grass valley ratio and energy conversion theory were used to estimate the amount of crop straw resources and the potential of straw fodder to save food in the settled area. On this basis, two scenarios of planting structure adjustment (A) and straw fodder utilization enhancement (B) were designed with eight scenarios to estimate the development potential and economic benefits of grass-fed livestock farming. From 2000 to 2018, the total amount of straw resources of the bulk crops wheat, corn, and potato in Anding District was 4.870 3 million tons; the stock of grass-fed livestock was 11.326 1 million sheep units, the demand for straw feed was 7.441 2 million tons, and the amount of straw fodder was 1.770 5 million tons. There was a huge gap between the supply and demand of straw feed. Wheat, corn, and potatoes are three major crops and they had a straw food saving potential of 288.5 thousand tons, 572.1 thousand tons, and 1.181 7 million tons, respectively. Using the actual 2018 stock of 142.8 thousand sheep units as a baseline, the combination of scenarios was compared. The straw carrying potential under the A_h + B_h scheme was as high as 286.9 thousand sheep units, with an economic benefit of 302.113 7 million CNY, which was the optimal scheme. The potential for livestock development of the worst option, A_l, was 44.2 thousand sheep units, with an economic benefit of 46.550 3 million CNY, a difference of 242.7 million sheep units, and an economic benefit of 255.563 4 million CNY compared to the optimal scheme. Overall, the livestock-carrying potential and economic benefits under the combined A and B scenarios were higher than the potential of a single scenario, and integrated grass–livestock development was an effective development model that could be promoted in dry farming areas.