Effects of Integrated Application of Plant- or Animal-Derived Organic Fertilizers in Tea Garden Ecosystem

Abstract

Fertilizer integration is key for sustainable tea gardens, but the impacts of different plant- or animal-derived organic fertilizers on soil pH, nutrients, and carbon composition remain unclear. This study evaluated five fertilizer treatments: 50% chemical fertilizer combined with 50% of either compound fertilizer (CF), rapeseed cake (RC), soybean cake (SC), chicken manure (CD), or sheep manure (SD). Results indicate that both plant- and animal-derived organic fertilizers effectively increased soil pH and soil organic matter content. However, animal-derived fertilizers showed a more pronounced capacity to buffer soil acidity, albeit with the potential risk of exceeding the optimal pH range for tea cultivation. In terms of soil fertility, RC performed best, achieving the highest total nitrogen and phosphorus contents. Compared to CF, RC increased nitrogen by 27.98% and phosphorus by 89.04% in the first year, and by 51.21% (N) and 61.35% (P) in the second year. The CD demonstrated superior performance in available potassium, with increases of 52.01% in the first year and 86.09% in the second year compared to CF. Regarding soil organic carbon composition, including total organic carbon (TOC), particulate organic carbon (POC), and mineral-associated organic carbon (MAOC), both types of organic fertilizers enhanced TOC levels compared to CF. Animal-derived fertilizers were more effective in rapidly increasing TOC and POC, whereas plant-derived fertilizers promoted a more stable accumulation of POC, contributing to long-term soil fertility through sustained nutrient release. Dynamics of MAOC revealed initial enhancements under animal-derived fertilizers, but stability declined over time. In contrast, plant-derived treatments showed a steadier increase in MAOC. Ratios of POC/TOC and MAOC/TOC further indicated that RC favored a higher proportion of particulate organic carbon, which is crucial for sustained nutrient availability. In conclusion, this study highlights the importance of tailored fertilization strategies to optimize soil productivity and enhance carbon sequestration in tea gardens. Adapting fertilizer application to specific soil conditions is therefore critical for the effective management of modern sustainable tea garden systems.