Project

Optimizing P management strategies based on soil P dynamics and rhizosphere processes

Insight in impacts of soil properties and rhizosphere processes on P adsorption-desorption parameters and P fertilizer distribution is crucial to predict future P fertilizer needs. This project contributes to a better understanding of the effect of soil properties and plant rhizosphere processes on P adsorption-desorption processes and the distribution of added P fertilizer to different soil P pools an related plant uptake.

Introduction

High P (phosphorus) inputs in excess of plant P uptake have caused significant soil P accumulation in China. In order to reduce P fertilizer inputs, soil P processes and plant rhizosphere-based management strategies are needed. To find out these strategies, insight in impacts of soil properties and rhizosphere on P adsorption-desorption parameters and P fertilizer distribution is crucial to predict future P fertilizer needs.

Objectives

The objectives of the project are to find out the soil P sorption-desorption processes in different type of soils and to develop sustainable P management strategies based on soil P and plant rhizosphere processes.

Methods

Soil incubation experiments were used to assess the distribution of added P fertilizer to different soil P pools. Non-linear regression equations were used to estimate the distribution of the applied P over the weakly bound, strongly bound and dissolved P pools with time to predict subsequently the distribution after one year.

Adsorption-desorption and and greenhouse pot experiments were used to assess the impacts of soil properties and rhizosphere processes on P adsorption-desorption parameters and.. P adsorption parameters were obtained by using a Langmuir isotherm and P desorption parameters were obtained by a linear equation. In the greenhouse pot experiments A “root-mat” approach was applied to investigate the P dynamics in the rhizosphere.

(Expected) results

Changes in dissolved, weakly bound, strongly bound and stable phosphorus pools in response to phosphorus addition as affected by soil properties
Phosphorus adsorption-desorption characteristics of major soils in China in relation to soil properties
Effect of plant rhizosphere processes on soil phosphorus adsorption-desorption and phosphorus fractions
Heterogeneous supplies of phosphorus, sulfur and carbon enhance phosphorus availability by improving rhizosphere processes in a calcareous soil