Dryland agriculture is critical in the High Plains but is often subject to water scarcity, weed pressure, and soil health degradation. One way to improve water storage, weed control, and soil health is by increasing the amount of crop residue left on the soil surface. Winter wheat is a major dryland crop in the High Plains, and its residue has the potential to contribute significantly to these goals. However, the extent to which winter wheat residue is affected by wheat stem sawfly (WSS) and its relation to water storage, soil health, and subsequent crop yield is not fully understood.
The goal of this project is to investigate the relationship between infested and non-infested winter wheat residue, water storage, soil health, and following crop yield in a dryland cropping system. The project aims to (1) quantify the rate and extent of infested and non-infested residue degradation over time, (2) evaluate the impact of infested and non-infested wheat residue on soil-water storage and following corn yield, (3) assess the effects of infested and non-infested residue degradation on soil health indicators, and (4) compare the residue quality of commercially available wheat varieties that differ in their stem thickness.
These experiments will be conducted at the University of Nebraska High Plains Agricultural Laboratory (HPAL) over several years (2021-2025), where some of the highest levels of WSS infestation have been observed. To measure residue degradation, composited samples of infested and un-infested wheat tissue of twelve varieties will be placed on a bare soil surface within enclosures, and the remaining residue amounts will be monitored over time. Standing and lodged residue on large plots will also be monitored until corn harvest the following year. Access tubes for use with an Am-Be neutron gauge will be used to measure soil water content at various intervals over time, and soil samples will be collected to monitor nutrient cycling and soil health.
The experiments will provide insights into the relationship between WSS infestation and winter wheat residue degradation, soil-water storage, following corn yield, and soil health in a dryland cropping system. The findings are relevant to farmers in the region who are battling WSS infestation and seeking to improve soil health and crop productivity and profitability.
This proposal outlines a robust, multi-year study that has the potential to provide valuable information to the agricultural community in order to sustainably maintain dryland winter wheat production in regions impacted by WSS.
Project objectives from proposal:
Farmers in the High Plains region will be able to (1) improve water storage and soil health by understanding and increasing winter wheat residue on the soil surface and their relationship with the major wheat pest WSS, and (2) identify the effects of WSS infestation on water storage, soil health, and subsequent crop yield. This will lead to more efficient and sustainable dryland cropping system practices, resulting in increased crop productivity and environmental benefits. Major outcomes will be shifts in the way residue is managed under WSS infestation to promote ecological benefits that translate to economic viability. Specifically, these outcomes may influence wheat variety selection, protection of residue through agronomic practices related to no-till product, and improved monitoring of residue and soil health and soil water storage. We will evaluate the success of our research and outreach endeavors by formal surveying, continued engagement with targeted farmers for feedback, and the use of resources generated by the project. Long-term outcomes could include increased or sustained wheat acreage, improved corn and subsequent crop yields as measured by local reporting and insurance claims, as well as continued engagement of growers in research efforts at the High Plains Agricultural Lab.