Weed vegetation in fields of post-harvest green manure crops and their use as green fertilisers

Perennial weed species predominate in the fields sown with post-harvest green manure crops, surpassing the number of annual weeds. These are mainly represented by persistent and difficult-to-eradicate rhizomatous and root-sprouting noxious weeds. This study aimed to analyse the significance of the agroclimatic potential of the central part of the Chüy Valley in Kyrgyzstan, along with the provision of uninterrupted irrigation of fields during the introduction of post-harvest green manure crops into agricultural production, under conditions where weed growth and development are stimulated on irrigated arable land. The study examined weed vegetation in fields sown with intermediate post-harvest green manure crops (white mustard, oilseed radish, white sweet clover, spring barley, and lacy phacelia) following the harvest of spring wheat. The subsequent incorporation of phytomass into the soil was carried out to serve as a green fertiliser and to analyse its effect on the phytosanitary condition of the soil. The findings confirmed that when green manure crops are incorporated as green fertiliser, weed plants are destroyed in masse; that is, the green biomass of weeds undergoes mineralisation in the arable layer and thereby serves as a source of green fertiliser. The agrotechnological approach of suppressing weed growth in agricultural crop fields through the integration of intermediate post-harvest green manure agrocenoses – white mustard, oilseed radish, white sweet clover, spring barley, and lacy phacelia – into the cropping structure, without the need for additional arable land, reflects a high level of cultivation practice in the irrigated farming systems of the Kyrgyz Republic. These green manure crops are sown after the harvest of spring wheat (the first ten-day period of July) on irrigated fields with typical sierozem soils. This practice fully meets the key principles of environmentally sustainable organic farming. The targeted use of plant phytomass (both intermediate postharvest green manure crops and weed vegetation) as green fertiliser possesses significant biological potential for reducing greenhouse gas emissions from agricultural production. It also supports carbon sequestration (CO2 capture) in the organic matter of soils and contributes to the resilience of agroecosystems in the face of climate change, thus playing a crucial role in climate change mitigation