Search Results (4)

Microbial necromass carbon (MNC) is crucial for soil carbon sequestration in bamboo (Phyllostachys edulis) forests. However, the response of MNC to bamboo-sourced organic fertilizers (BSOF) prepared by composting bamboo plant growth-promoting microorganisms and bamboo residues remains unclear. This study examined MNC and its contribution to soil organic carbon (SOC) in Moso bamboo plantations under four BSOF treatments: control (CK, 0 t·hm⁻²), low fertilizer application (LF, 7.5 t·hm⁻²), medium fertilizer application (MF, 15 t·hm⁻²), and high fertilizer application (HF, 30 t·hm⁻²) across 0–20 cm and 20–40 cm soil layers. In these two layers, HF and MF significantly (p < 0.05) increased the total MNC, fungal necromass carbon (FNC), and their contributions to SOC compared to CK, and HF led to higher (p < 0.05) bacterial necromass carbon (BNC) levels and SOC contributions than LF and CK. Soil depth and BSOF treatment were found to interact significantly. A random forest model showed that in the 0–20 cm layer, SOC was the best predictor of total MNC and FNC, whereas available potassium was optimal for BNC. Nitrate-nitrogen (NO₃⁻-N) was the top predictor for total MNC, BNC, and FNC in the 20–40 cm layer. Partial least squares path modeling indicated that available soil nutrients directly influenced BNC and FNC, affecting SOC accumulation. These findings suggest a new method for enhancing soil carbon sequestration in bamboo forests. Full article

Effective nitrogen (N) management and the development of novel N fertilizers are essential for enhancing maize growth in tropical soils. One strategy to increase N use efficiency is the use of organic matrices as a source of N or their combination with the application of mineral N sources. Among these organic matrices, biochar emerges as a highly promising option for optimizing N use efficiency. Thus, the aim of this study was to evaluate the effects of different feedstocks, their respective biochars, and their combination with N on the dynamics and uptake of N by maize plants in two contrasting Oxisols. A 30-day greenhouse experiment was conducted using maize grown under treatments with four feedstocks (bamboo, sunflower cake, chicken manure, and shrimp carcass) and their respective biochars. The biochars were applied with or without ammonium nitrate (AN), alongside negative (no N) and positive (AN-only) controls. Ammonium and nitrate levels were analyzed in the soil solution at 1 and 15 days and in the whole soil before and after cultivation. Maize biomass production and shoot N accumulation were also evaluated at the end of the experiment. Among the main results, it was observed that soil type played a key role in available N, maize nutrition, and growth. In the medium-textured Oxisol studied, native soil organic matter partially met maize N requirements due to high content of available N observed. Biochars influenced N availability by increasing nitrate-N prevalence in the soil solution. Although whole-soil N levels were sufficient for robust maize growth, post-cultivation residual N remained low (<75 mg kg⁻¹), indicating the need for supplemental N fertilization for plants grown in pots. In the medium-textured Oxisol, bamboo or sunflower cake biochar combined with AN increased biomass production by ~12% compared with AN alone. Similarly, in the clayey Oxisol, maize fertilized with sunflower cake or shrimp carcass biochar—regardless of AN addition—outperformed AN-fertilized plants by 19–30%. Thus, this study highlights the potential of integrating biochar with N fertilization to improve soil and solution N availability and increase N use efficiency by maize plants. Full article

Bamboo shoot processing wastewater (BBPW) is rich in organic matter and organic acids and can be used as a nutrient source for microbial growth and biofertilization. In this study, Pseudomonas K22-D and Terribacillus goriness CS3 were isolated from bamboo forest soil with plant growth-promoting properties. Biofertilizers were prepared by inoculating bacteria into BBPW, and the effects of their application in a bamboo forest were evaluated. The chemical oxygen demand, TOC, TN, and NH₄-N contents decreased after inoculation, indicating that the bacteria were able to degrade macromolecules in BBPW. The BBPW biofertilizer produced by mixed bacteria (CS3 + K22-D) significantly improved the soil organic carbon and mineral-associated organic carbon content and reduced the pH, alkali-hydrolysable nitrogen, available phosphorus, and available potassium content of the soils in the bamboo forest, which might be attributed to the high C:N ratio and microbial synergism in the biofertilizer and the fast growth period of bamboo shoots. Notably, the CS3 biofertilizer significantly increased soil-available phosphorus (90.25%), and the K22-D biofertilizer significantly decreased soil-available phosphorus (70.33%) compared with CK, suggesting that the presence of inorganic phosphorus-solubilizing bacteria can promote soil P. We believe that the return of inoculated bamboo shoot processing wastewater to bamboo plantations can be an eco-friendly, sustainable practice for bamboo forest management. Full article

The rising cost of inorganic fertilizers, coupled with their adverse effects on soil conditions, has resulted in increasing interest in organic amendments. The objective of the present study was to evaluate the effect of organic amendments (OAs) with different C/N ratios on nitrogen use efficiency (NUE) and recovery rate, as well as on the growth and yield of Zea mays and soil properties. A precise pot experiment was conducted on a low-fertile, sandy-loam soil, and the dynamics of nitrogen (N) were also analyzed by the A-value method, using ¹⁵N tracer. The plant height of the treatment groups decreased in the following order: inorganic fertilizer (IF) = rapeseed waste (RW) > chicken manure (CnM) > bamboo tealeaf (BTL) > cow manure (CwM) > bamboo compost (BC). Furthermore, the maize fertilized with RW only took up half of the N in IF, despite producing the same yield, which indicates that the physiological nitrogen efficiency (PUE) of RW was twice as high as that of IF. RW and CnM were regarded as valuable fertilizers that could be used to replace inorganic fertilizers. A linear relationship between the N mineralization of the OAs was obtained by an incubation test and the pot experiments, estimating the effect of OA application on the maize. Maize plants mainly absorbed N derived from fertilizers; however, for the both sources of N (fertilizer and soil), N was mainly accumulated in grains followed by the leaves, stem, and root, suggesting that studies should be conducted to improve soil N use efficiency. Full article