Soil Health Overview
29 May 2019
Compared to most arable crops, black-grass thrives in cold, wet soil conditions – so they have the competitive advantage from the off, both in terms of physiological development and seed survival. There are some things you can do to make the early life of black-grass a little more difficult, and at the same time consider the long term health of your soil.
Soils with a high clay content and poor structure, and soils that maintain high water content, will favour black-grass. To assist cultivation practices designed to improve black-grass control, soil physical conditions can be improved by applications of organic matter and gypsum.
Organic matters such as manures, composts and digestants stimulate biological functions that influence soil aggregate formation and move soils towards a more aerobic state. This is often associated with an increase in nitrogen and phosphorous mineralization that can encourage arable crops to establish quicker and become more competitive. Gypsum can be used to similar effect.
Cover cropping can be an effective soil improvement option that assists Black-grass control, both in the short term and over the course of the rotation. A cover crop establishing in the stubble of a previous combinable crop, will provide a degree of competition for emerging Black-grass, while driving root mass and Carbon in to the soil, to promote biological process that build and maintain soil structure.
In soils with high Black-grass densities, cover crops could be established with lower seed rates, to assist the efficacy of herbicides used to desiccate and destroy the cover crop and the Black-grass emerging within it. At high seed rates, cover crops will have more impact on soil conditions and nutrient re-cycling, but may reduce the ability of herbicides to penetrate the canopy and hit the Black-grass. The timing of cover crop destruction relative to establishing the following arable crop can have a major influence on both Black-grass control and the establishment, growth rate and yield of the arable crop.
While stale seedbeds and cover crops can be used to promote Black-grass germination and control, the timing and management of these techniques provide effective evolutionary stress on Black-grass. Given the broad germination and dormancy characteristics of Black-grass, cultural and chemical control strategies run the risk of effectively selecting against Black-grass with low dormancy and early germination, inducing a shift in Black-grass population dynamics towards higher dormancy and later germination. To combat this, cultural controls need to be considered over the entire rotation, and should be integrated with appropriate use of selective pre- and post-emergence herbicides.
- What lies beneath; how to ensure your soil is doing its part in BG control
- The science behind soils impact on black-grass
- Tipping the balance between BG control and soil health
- Farmer interview on soil (best practices)