In order to better understand the spring weed community diversity change and correlation with soil nutrients under these long-term different fertilization models, a field-investigation was conducted in winter fallow paddy field in yellow soil area under single-rice cropping system on these different treatments of the unbalanced fertilization (NP, PK, NK), constant fertilizer (NPK), single organic fertilizer (M), 1/2 organic fertilizer instead of chemical fertilizer (1/2 MNP) and not fertilization (CK) in Guizhou province, based on a continuous 24 years of long-term fertilization test. The results showed that weed density, biomass and community diversity in spring all happened to chang under the condition of long-term different fertilization modes. Such as single application of organic fertilizer (M), the soil nutrients were all higher, the total density of weed community and total biomass both were the highest, 1208.44 plants·m-2 and 1071.24 g·m-2 respectively. Compared with no fertilization (CK), the total density of weeds increased by 37.74% and the total biomass increased by 179.58%. Which indicated that single application of organic fertilizer (M) is beneficial to improving soil nutrients and increasing weed density and biomass in spring. Effects on the weed community among treatments existed difference. Under the long-term single application of organic fertilizer (M), Polypogon fugax Nees ex Steud did not occur (0 plants·m-2). Under the condition of long-term use of inorganic fertilizer, the density of Poa annua was the lowest, among 0~4.89 plants·m-2, and on the deficiency of phosphorus, Alopecurus japonicus could be suppressed, which density was the lowest (36.00 plants·m-2). These indicated that long-term different fertilization could inhibit the occurrence of different weeds. In terms of weeds biodiversity, the weed community diversity index increased, the dominance index decreased, and the weeds community structure was relatively complex under the condition of the nitrogen deficiency. On the contrary, the diversity index decreased, the dominance index increased, and the community structure was relatively simple in phosphorus deficiency. Our results indicated that total nitrogen, alkaline nitrogen and total phosphorus were the key factors affecting weed density. So, reasonable fertilization can control the harm of weeds in the field, stabilize soil fertility and species diversity, Moreover could promote the agricultural ecosystem to play the maximum ecological effect. |