To address the low productivity of sandy farmlands, our study aimed to conduct a comparative study on the effects of different organic amendment (OA) inputs for the potential improvement of crop yield and soil quality in sandy alkaline farmlands through the selection of a suitable OA. This study set up straw (ST) returning as control and chemical fertilizer (CF) treatment as a side control, and chose three OAs returning as treatments, including pig manure (PM), biogas residue (BR), and straw biochar (BC), for improving soil fertility, with all amendments having matched doses of nitrogen (N). The experiment was conducted at the Wuqiao Experimental Station (37°41 N, 116°37 E) of China Agricultural University in Hebei Province, China, from October 2012 to September 2016. The cropping rotation was the winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system. Through a consecutive four-year field experiment, the principal results showed that three types of OA application significantly increased soil organic carbon from 1.46 g kg⁻¹ to 8.24 g kg⁻¹, soil total N from 0.21 g kg⁻¹ to 0.64 g kg⁻¹, soil available potassium from 55.85 mg kg⁻¹ to 288.76 mg kg⁻¹, and soil available phosphate from 4.86 mg kg⁻¹ to 65.00 mg kg⁻¹ in the 0–20 cm soil layer. The BR was the most effective in improving soil nutrients as compared with the ST. The PM and BR treatments were more conducive to promoting crop yield by 6–20% than ST, and the BC treatment significantly reduced the yield of winter wheat by 19% and summer maize by 8%. As the BR and PM treatments improved the soil nutrient content and significantly increased crop yield, these were the top choices for transforming the low-yield sandy farmlands.

The agricultural sustainable development for human well-being considers food security and ecological health as well as people’s socio-economic conditions. Nowadays, most of the holistic assessments of agricultural sustainability, mainly focus on food production and ecological consequences, relatively lacking analysis from the socio-economic perspective. In this context, this study constructs an agricultural social life cycle assessment model based on the guidelines of UNEP to assess the social and economic impacts on the three major staple grain crops in China, including maize, rice and wheat. The assessment model aims to analyze effects of stakeholders containing farmer, agricultural value chain actors, consumer, rural areas, society, and impact categories including high-quality growth of agriculture, a comfortable life in rural areas, the prosperity of rural people. The data is mainly from national statistical databases and representative industry databases. The impact assessment adopts social risk and social impact as quantitative characterization methods, and Analytical Hierarchical Process to obtain weights. The results show that: among the three major grain crops, farmers are the most important factors for stakeholders, and agricultural industrial development has the greatest potential negative impacts on society; maize has the most positive impacts on agricultural sustainable development in China.