Antecedent effects of catch crops upon the cycling of phosphorus in agro-ecosystems and scavenging of plant-fixed phosphorus by the soil microbiome

所有植物都需要磷（P）来生长。现代农业依赖于定期投入磷肥，在作物被移除后补充土壤。土壤中大部分的磷被强烈地束缚，植物无法有效利用。捕集作物-种植植物品种，以减少主要作物之间的养分损失，否则没有植被覆盖-被成功地用于减少氮（N）从土壤中浸出，“捕获”植物组织中的矿化N，这是在植被分解后释放。关于捕捞作物在限制磷损失和向主要作物提供磷方面的有效性，知之甚少。一旦被捕获，衰老的渔获作物中的P将以核酸或ATP的形式存在，但更大比例的是以植酸盐的形式存在，植酸盐是一种复杂的储存分子，一旦进入土壤，植物就无法进入。然而，植酸盐可以被真菌和细菌同化。为了使这些储存物可用于作物，需要微生物酶（各种植酸酶和磷酸酶）来水解植酸盐。一个重要的考虑因素，如果渔获作物被开发，以提高磷的利用效率是前茬作物的影响，支持和调节植酸水解的土壤微生物组成员和他们的动员磷，使其提供给主要作物。该项目将探讨目前通常用作渔获和覆盖作物的植物的这种现象，并考虑在这方面可能具有更高能力的新物种，目的是：（i）确定作为渔获作物生长时具有从土壤中积累磷的最佳特性的候选植物物种;（ii）确定这些物种支持具有增加的水解植酸盐能力的土壤微生物组的能力;（iii）确定这些物种的生长状况。（iii）探讨这些物种作为生产系统中新的渔获作物的潜力，将其作为改善土壤磷管理和供应的实用手段。

All plants require phosphorus (P) for growth. Modern agriculture depends on regular inputs of phosphate fertilizer, replenishing soil following crop removal. Large proportions of P in soils are strongly bound, effectively unavailable to plants. Catch crops - plant varieties grown to reduce nutrient losses between main crops when there is otherwise no vegetation cover - are successfully used to reduce nitrogen (N) leaching from soils, 'trapping' mineralised N in plant tissue which is released following vegetation decomposition. Much less is known regarding the effectiveness of catch crops in limiting P losses and provisioning P to main crops. Once captured, P in senescent catch crops will be present as nucleic acids or ATP, but with a greater proportion in the form of phytate, a complex storage molecule which once in soil is inaccessible to plants. However, phytate can be assimilated by fungi and bacteria. For these stores to become available to crops, microbial enzymes (various phytases and phosphatases) are required to hydrolyse phytate. An important consideration if catch crops are to be developed to increase P use efficiency is the effect antecedent crops have on supporting and conditioning the phytate-hydrolysing members of the soil microbiome and their mobilisation of P to render it available to main crops. This project will explore such phenomena in relation to plants currently commonly used as catch and cover crops, and consider novel species which may have enhanced capabilities in this respect.Aims: (i) identify candidate plant species with optimal properties to accumulate P from soils when grown as catch crops; (ii) determine the ability of such species to support soil microbiomes with increased capacities to hydrolyse phytate; (iii) explore the potential for such species to be used as a practical means to improve soil phosphorus management and supply, as novel catch crops in production systems.