The balance between crop production and weed community diversity is important for agroecosystems and farmland sustainable development. Integrated weed management practices in the agroecosystems would therefore match crop production with the conservation of weed biodiversity. Understanding the response of farmland weed community assembly to fertilization is important for designing better nutrient management strategies in integrated farmland ecological systems. Many studies have focused on weed characteristics, mainly crop–weed competition responses to fertilization or weed communities alone. However, weed community assembly in association with crop growth is poorly understood in the agroecosystems, but is important for the determination of integrated weed management.

PhD student TANG Leilei at the supervision of professor CHEN Fang from Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden investigated the cumulative effects of different fertilization patterns on the floristic composition and species diversity of farmland weed communities along with wheat growth in a winter wheat–soybean rotation based on an 11- year field experiment, located in Mengcheng County in the Anhui Province of China. The field trial included five fertilization patterns with different combinations of N, P and K fertilizers. Weed investigation was based on residual weed stands that were tolerant surviving weeds or weeds emerging after herbicide usage.

The study found that the indices of species diversity (species richness, Shannon–Wiener, Pielou and Simpson indices) showed significant linear relationships with wheat yield. Moreover, competition for nutrients and solar radiation between crops and weeds was the main indirect effect of fertilization on the changes in weed community composition and species diversity, and the residual weed community assembly was influenced primarily by topsoil available nutrients in the order P > N > K. The results enlighten integrated weed management and would be helpful for the sustainable development of agroecosystems.

This research was financially supported by China Program of International Plant Nutrition Institute (IPNI-HB-34) and the Opening Project of Hubei Key Laboratory of Wetland Evolution & Ecological Restoration (2011-02). Relevant results were published in Journal of Plant Ecology entitled “Effect of fertilization patterns on the assemblage of weed communities in an upland winter wheat field”.

Article link: http://jpe.oxfordjournals.org/content/early/2013/04/05/jpe.rtt018.full?keytype=ref&ijkey=FBTCLax4a6Jfjza 

Relationship between wheat yield and species richness, Shannon−Wiener, Simpson and Pielou indices of weed communities in winter wheat field(image by CHEN’s group)