The biodiversity of weed communities in cropland is an important element for the reliable and sustainable provision of agroecosystem services. As one of the environmental indices, seed community provides resources for higher trophic groups, supports a high diversity of insect species and birds, and promotes nutrient cycling and soil preservation. Good nutrient management practices could not only provide desirable crop production, but also preserve plant biodiversity resources.   

Based on a long-term fertilization field experiment since 1994 in Mengcheng County in the Anhui province, Prof. CHEN Fang and his research team from Wuhan Botanical Garden investigated the effects of different fertilizing patterns on cropland weed community biodiversity in agroecosystem and the adaptive mechanisms. Six fertilizer treatments with different rates of nitrogen (N), phosphorus (P) and potassium (K) were included. 

The weed community and winter wheat responded differently to fertilizing treatments with varying density, plant height, shoot biomass and nutrient uptake.  

Weed community changed sharply among different fertilization treatments. Four dominant weed species (Galium aparine, Vicia sativa, Veronica persica and Geranium carolinianum) had formed their own adaptive mechanisms. For instance, Galium aparine grew well under higher soil fertility conditions through climbing into more favorable light conditions by internode elongation. 

The PK treatment showed higher weed density, shoot biomass, Shannon-Wiener and Pielou Indices (which were used to evaluate weed species diversity) than N and P treatments.  As for the N1/2PK treatment (half the P rate), the wheat yield was 31% less than that in the NPK treatment, but its species number, the Shannon-Wiener and Pielou Indices were higher than that of the NPK treatment. The negative effects on wheat yield in the treatment could be balanced and complemented by the simultaneous positive effects of reduced herbicide usage. Therefore, the N1/2PK treatment could be considered as a recommend fertilization treatment for adjusting the interactions of wheat and weeds in agroecosystems.  

This study suggests that appropriate combinations and rates of fertilization would produce a win-win situation: keeping the derivable crop productivity and maintaining the biodiversity of weed community.  

Resash  was supported by the China Program of International Plant Nutrition Institute and the Opening Project of Hubei Key Laboratory of Wetland Evolution & Ecological Restoration. Results entitled “Impact of Fertilizing Patterns on the Biodiversity of a Weed Community and Wheat Growth” were published in Plos One.