Cultivated Land Balance Policy (CLBP) has led to the “better land occupied and worse land supplemented” program. At the same time, the current field-scale cultivated land quality (CLQ) evaluation cannot meet the work requirements of the CLBP. To this end, this study selected 24 newly added farmland in Fuping County and performed eight different high quality farming layer construction experiments to improve the CLQ. A new comprehensive model was constructed on a field scale to evaluate the CLQ using different tests from multi-dimensional perspectives of soil fertility, engineering, environment, and ecology, and to determine the best test mode. The results showed that after the test, around 62% of the cultivated land improved by one level, and the average cultivated land quality level and quality index of the test area increased by 0.63 and 30.63, respectively. The treatment of “woody peat + rotten crop straw + biostimulation regulator II + conventional fertilization” had the best effect on the improvement of organic matter, soil aggregates, and soil microbial activity, and was the best treatment method. In general, application of soil amendments, such as woody peat when constructing high quality farmland, could quickly improve CLQ, and field-scale CLQ evaluation model constructed from a multi-dimensional perspective could accurately assess the true quality of farmland and allow managers to improve and manage arable land resources under CLBP.

Cultivated land production capacity (PC) is the basis for national food security. Health condition (HC) is an important parameter to indicate the ecological safety of arable land. The policy of “the trinity protection of quantity, quality, and ecology of cultivated land” is one of the important protection directions currently being implemented in China. However, the existing evaluation systems are diverse and overlapping, which mainly focus on the quality and production potential of cultivated land, with less attention paid to the health status and the relationship between them in China. In this study, a comprehensive PC evaluation system including factors such as climate, landform, soil, and utilization was constructed, and an HC evaluation system including internal and external factors was established to support the requirements of the trinity pattern protection policy. These new evaluation systems were applied in Gaoping city, China. The results showed that the average PC index was 1617.35 and ranged between 98.40 and 4321.53, with the largest area of the higher-grade accounting for 36.37% of the total cultivated land. The spatial distribution of PC showed a gradual decrease from the southwest to northeast regions. The average score of the HC of arable land in Gaoping was 79.86 and showed an increasing trend of low in the middle areas and high in the edge regions, which revealed the opposed spatial characteristics between human activity and health status. Approximately 2637.86 ha of the cultivated land was at the imbalance stage, indicating that this is where managers needed to focus. In general, the study offered a reference and a scientific basis for evaluating PC and HC and provided support information for sustainable cultivated land management.

To implement the balance system of cultivated land in occupation and supplement and to adhere to the principle of “supplement the occupied cultivated land of high quality with the one bearing same quality”, in the thesis, a field experiment was conducted to study the effects of woody peat on soil physical, chemical, and biological properties of the plough layer and its crop yield. Furthermore, the correlation between soil indexes and crop yield under the best fertilization mode through the addition of the natural material of woody peat instead of lengthy cultivation of the plough layer to rapidly construct a high-quality plough layer and solve the practical problem that the natural endowment of newly reclaimed cultivated land is far less than the occupied high-quality cultivated land was explored. The land remediation project of Fuping County, Hebei Province, was taken as the experimental area, and the five most representative and effective datasets were selected and studied. The results demonstrated that the addition of woody peat and rotten straw could reduce soil particle size and bulk density and alleviate soil viscosity and acidification. An increase in soil organic matter, soil microbial biomass carbon (MBC), alkali-hydrolyzable nitrogen, available phosphorus, and available potassium and a decrease in the heavy metal content were also observed. The results indicated that the application of woody peat achieved the expected effect of the rapid construction of a high-quality plough layer. The best mode of fertilization was A2, which provided a good reference for the rapid construction of a high-quality plough layer in the future. The analysis of the correlation between soil indexes and crop yield illustrated that the organic matter content, soil available nutrients, and crop yield had a significant positive correlation; the organic matter content and soil available nutrients showed the same tendency, which suggests that soil organic matter content and soil fertility level are closely related and that soil fertility plays a decisive role in crop yield under the same external conditions. Woody peat exerted an eminent influence on the organic matter content and soil available nutrients to determine the change in crop yield, which provides a reliable basis for future research on land improvement projects to increase crop yield.

Soil biodiversity drives soil-based ecosystem services and is an important indicator of soil health. To understand the responses of important soil biological indicators to different farmland use contexts, 72 fields in three agricultural regions of China were used as research objects. The distribution characteristics and the factors influencing six indicators (carbon and nitrogen contents of soil microbial biomass (MBC, MBN, respectively), soil respiration (SR), soil catalase activity (CAT), soil acid phosphomonoesterase activity (APA), and soil earthworms) were investigated using field monitoring and indoor analysis. The MBC, SR, CAT, and APA indicators showed significant differences among the regions (p < 0.05). Correlation and redundancy analyses indicated that the important factors affecting MBC, MBN, and soil respiration were cation exchange capacity, total N, organic matter, hydrolytic N, and soil bulk density, whereas the important factors affecting APA and earthworms were total phosphorus, available phosphorus, and available potassium. None of these factors had a significant effect on CAT. Climatic conditions, soil types, and farmland practices all have complex impacts on soil biodiversity. The results showed that attention should be paid to improving the physical conditions of the soil and to increasing soil fertility levels when establishing sustainable farm management patterns.