Abstract
Fertilization is a key management practice for maintaining or improving soil fertility and ensuring grain yield in agro-ecosystems. Nevertheless, as a low-yield soil, how fertilization strategies impact the status of albic soil physical and chemical properties, biological activity, and crop yield are poorly understood. Through a two-year positioning experiment, the albic soil fertility characteristics (physical, chemical, and biological) and changes in maize yield under different fertilization were studied. Three treatments were established: (1) conventional fertilization (chemical fertilizer) (T1), (2) optimized fertilization 1 (low amount of organic fertilizer + chemical fertilizer) (T2), and (3) optimized fertilization 2 (high amount of organic fertilizer + chemical fertilizer) (T3). The results indicated that, compared with T1, the soil bulk density of T2 and T3 treatments decreased, the average solid phase ratio of soil decreased by 8.2%, and the average liquid and gas phase ratios increased by 7.2% and 10.2%, respectively. The soil organic matter (SOM) and soil organic carbon storage (SOCS) under treatment of optimized fertilization were significantly higher than under T1, with an average increase of 10.1% for SOM and 8.8% for SOCS, respectively. T3 significantly increased the contents of alkali-hydrolyzable nitrogen, available phosphorus, and available potassium, while different fertilizations had little effect on soil pH. T2 and T3 significantly increased activities of soil urease, sucrase, phosphatase, and catalase, with an average increase of 33.7%, 56.9%, 32.0%, and 6.7%, respectively. The numbers of soil bacteria and actinomycetes under T3 increased significantly by 30.2% and 22.0% compared to T1, while the number of fungi decreased by 6.7%. The total number of soil microorganisms increased significantly by 29.0% of T3, and the proportion of soil bacteria to the total number of microorganisms increased, while the proportion of fungi and actinomycetes decreased. The maize yield of T3 was significantly higher than under other treatments, with an increase of 2368.5 kg/ha compared to T1. Correlation analysis showed that the contents of available nutrients and organic matter, the numbers of soil bacteria and actinomycetes, and the activities of soil urease and phosphatase had the most significant impact on maize yield. The optimized fertilization, which was the organic fertilizer combined with chemical fertilizer, can improve the physical properties of albic soil, increase soil organic matter content, organic carbon storage, available nutrient content, and soil biological activity, also for maize yield. Therefore, the optimized fertilization in albic soil of Northeast China is a promising and important management option for improved soil quality and grain yield. This work provides a theoretical basis and technical reference for efficient fertilization.