Phosphorus Leaching Alleviated by Organic Carbon in Greenhouse Vegetable Production System

Phosphorus (P) is an essential element for crop growth; however, the continued application of P at a rate exceeding crop requirements can increase soil P concentration and the potential for P loss to surface waters. How to reduce continuous accumulation and leaching of phosphorus (P) by organic materials in high-P soils of greenhouse vegetable production systems is not well understood. This study evaluated the influence of different various organic materials on cocozelle P uptake and the soil P migration in Shandong province, China. Three high-carbon organic materials were selected to substitute for continuous application of duck manure, mushroom residue (MR), peat soil (PS), and wheat straw (WS), and duck manure (DM) was a customary control treatment. Duck manure was chosen because it is more common, easy to extract, and cheap. During a long term of winter-spring season of cocozelle, application of high-carbon organic materials increased soil pH and increased the soil C:P ratio in a 0–20-cm soil layer at the seedling stage (SS) and full fruiting stage (FFS) of cocozelle, but the peaks of microbial biomass P (MBP) and microbial biomass C (MBC) were at FFS and seedling pulling stage (SPS), respectively. However, the input of MR increased soil P content, with 334 mg kg−1 in the 0–20-cm soil layer and 192 mg kg−1 in the 20–40-cm soil layer, which were significantly higher than other treatments. The amount and available form of soil carbon will affect the transformation and utilization of soil P by soil microorganisms. Soil MBC plays a key role in the accumulation and migration of soil P in the rich-P soil, and the application of MR with high carbon content can significantly reduce the risk of P leaching in the 0–20-cm soil layer.