Spring-Planted Cover Crop Impact on Weed Suppression, Productivity, and Feed Quality of Forage Crops in Northern Kazakhstan

Abstract

Integrating cover crops into crop rotation could provide options for herbicide-resistant weed control in farming systems. To evaluate the potential effectiveness of spring-planted cover crop oats (Avena sativa L.) on weed suppression, productivity, and feed quality of annual forage crops as sole crops and intercrops in order to determine the best agroecological technique, two-year experiments were laid out under arid conditions in the Akmolinsk region in northern Kazakhstan. Three annual forage crops, namely, (Piper) Stapf.-Sudan grass (Sorghum sudanense) (control), common millet (Panicum miliaceum L.), and Japanese millet (Echinochloa frumentacea L.), and three annual intercropping systems, i.e., 50% pea (Pisum sativum L.) + 50% barley (Hordeum vulgare L.); 40% pea (Pisum sativum L.) + 30% (Piper) Stapf.-Sudan grass (Sorghum Sudanense) + 30% barley (Hordeum vulgare L.); and 50% pea (Pisum sativum L.) + 50% (Piper) Stapf.-sudan grass (Sorghum Sudanense), as well as the six mentioned treatments with the sole crops and intercrops plus cover crop oats (Avena sativa L.) were used. Japanese millet is a promising newly introduced crop in northern Kazakhstan. It was revealed that the cover crop significantly reduced weed density in the forage sole crops and their intercrops. In all cases, integrating the cover crop with annual forage crops showed higher quality and productivity than non-covered treatments. A highly productive annual crop grown with and without cover intercrop was Sudan grass. The highest yield among the three intercropping systems was recorded with the intercrop constituting 40% pea + 30% Sudan grass + 30% barley. The crude protein content was higher in biomass from sole crops and intercrops constituting cover crops. The overall view was that the use of oats as a cover crop on sole annual forage crops and their intercrops including methods that could be integrated with chemical and non-chemical methods in the field could be a valuable way to reduce weed pressure and improve quality and productivity during the vegetation period.