Using silicon fertilizers to improve soil phosphorus availability and uptake by winter wheat in high-phosphorus soils

View the project final report

• 2015 annual report
• 2016 annual report

Commodities

• Agronomic: wheat

Practices

• Crop Production: fertilizers, nutrient management

Historical application of manure to agricultural lands in areas of intensive animal production, like the Delmarva Peninsula, has led to accumulation of soil test phosphorus (P) to levels that far exceed agronomic optimum. The increased risk of P losses from these legacy P soils is linked to water quality degradation in sensitive water bodies, like the Chesapeake Bay. Farmers growing small grains on the Delmarva Peninsula often apply starter P fertilizers (despite excessive soil test P levels) to address early season P deficiencies. Fertilization of soils with silicon (Si) is promising as a best management practice (BMP) that can enhance crop P uptake, eliminate fall starter-P applications for small grains, and improve small grain yields. The purpose of this project is to evaluate the effects of Si fertilizer type and rate on soil P dynamics and winter wheat yield and P uptake. We hypothesize that Si fertilization increase soluble P in soils and enhance early season P uptake by winter wheat, which will reduce the need for starter P fertilizer and promote more rapid draw-down of soil test P during a typical grain crop rotation. This project extends previous research on the dynamics of Si and P in soils to legacy P soils. Results of this project will inform Si fertilization recommendations that can reduce the environmental risk of grain production on legacy P soils and increase small grain yields and farm profits.

The overall goal of my PhD research is to increase understanding of P dynamics in high P agricultural soils and to evaluate possible BMPs to mitigate the potential for P losses from these soils. The objective of this SARE project is to evaluate fall Si fertilization to enhance soil P availability and uptake by winter wheat from legacy (excessive soil test) P soils.

Northeast SARE funding will be used to support a pot study and a corresponding field trial. The pot study is designed to determine the effects of Si fertilizer sources and Si rate on soil P dynamics and winter wheat response (e.g., yield, P uptake). The field trial extends the pot study determine the utility of applying locally available Si sources to winter wheat under field conditions. The overall goal of the proposed Si fertilization research is to develop a novel BMP that can help farmers reduce the environmental risks associated with legacy P soils, increase crop uptake of P to speed draw down of soil test P levels, and enhance winter wheat yields.