Research in Herbosa Succession Process Based on Soil Fertility Evolution

Weed biodiversity is one indicator of farmland ecology and it is greatly affected by fertilization practices. This research in Hubei and Jiangxi was aimed at studying the weed community under different fertilization patterns, and to investigate the evolution of weed community structure of late rice fields. The author studied the weed community structure and biodiversity within five long-term fertilization treatments for late rice by using the method of community ecology.

Our results displayed significant differences of soil nutrients and light transmittance amongst fertilization patterns. Rice yields under combined organic manure and fertilizer were higher than under fertilizer alone. Heleocharis plantagineiformis, Rotala indica, Cyperus difformis and Monochoria vaginalis were the dominant weed species for the zero fertilizer treatment. Paspalum paspaloides was dominant in NPK treatments. The 15 weed communities were divided into three groups within the following treatments: 1) zero fertilization; 2) NPK3/7 (30% fertilizer+ 70% manure); 3) NPK, NPK5/5, and NPK7/3 fertilization.

The result of canonical correspondence analysis indicated that: Heleocharis plantagineiformis, Rotala indica and Heleocharis yokoscensis were adapted to zero fertilizer application; Paspalum paspaloides was adapted to NPK7/3; Monochoria vaginalis, Lindernia procumbens and Marsilea quadrifolia were adapted to NPK3/7. Treatments that combined manure and fertilizer maintained the number of dominant species and biodiversity between the zero fertilizer and NPK treatments, and there was a trend that biodiversity increased with higher manure use. The biodiversity indices of the weed community were significantly correlated with available N and P, while negatively correlated with available K, and significantly positively correlated with light transmittance.

These results showed that weed community could be regulated by adjusting application rates and proportions of manure plus fertilizer to realize integrated weed management. For better potential yield of late rice, and biodiversity of the weed community, we recommend a NPK (30% manure + 70% fertilizer) treatment for late rice as it not only produced high yield, but also maintained farmland weed biodiversity.