Research in Herbosa Succession Process Based on Soil Fertility Evolution

Weed biodiversity is one of the indicators of farmland ecological environment and greatly affected by different fertilization patterns. This research program was to study weed community under different fertilization patterns in farmlands based on long term field experiments in Hubei, Anhui and Jiangxi provinces, and to explore evolution trend of weed community structure in the fields of rice, maize and wheat.

IPNI-2009-CHN-HB34

09 Feb 2013

2012 Annual Interpretive Summary

Effect of Soil Fertility Evaluation on the Weed Succession Process, 2012

Weeds are one of the major constraints to crop production. However, as one of the primary producers within farming systems, weeds play an important role in the biological diversity of agro-ecosystems. We hypothesized that appropriate and suitable fertilization in the agro-ecosystems would not only maintain the biodiversity of weed communities but also provide desirable crop productivity. A 16-yr field experiment was conducted by Wuhan Botanical Garden, Chinese Academy of Sciences, in a winter wheat field to evaluate the effects of different fertilizer treatments on weed community biodiversity and their adaptive mechanisms. Fertilizer treatments consisted of six combinations of different rates of N, P, and K fertilizers.

Wheat and the four dominant weed species (Galium aparine, Vicia sativa, Veronica persica and Geranium carolinianum) differed in their responses to fertilization. Similar to wheat, the density, plant height, shoot biomass, and nutrient uptake of Galium aparine were higher in the NP, NPK, and N1/2PK treatments, and it's plants were taller than wheat plants through elongation of internodes, especially from the 4th to 12th internode. By halving the fertilizer P rate, the growth advantage of G. aparine decreased, and this promoted the growth of other weed species. Vicia sativa and Geranium carolinianum grew well under low soil fertility conditions, while Veronica persica grew well only in the PK treatment. The PK treatment showed higher Shannon-Wiener and Pielou Indices than those for N plus P fertilizer treatments. Each individual weed population behaved with its own adaptive mechanisms, such as morphological adaptations, for adequate light and growth advantages. Appropriate nutrient management, such as balanced N, P and K fertilization, could be a better strategy to maintain both the biodiversity of weed communities and good wheat yield on farmland, while also benefitting the ecological environment of the farmland. Hubei-34