This paper analyzed the difference of soil nutrient and the dynamics of available nutrient in soil solution of the forest and grass composite pattern and the farmlands on site.The result showed that the content of soi...This paper analyzed the difference of soil nutrient and the dynamics of available nutrient in soil solution of the forest and grass composite pattern and the farmlands on site.The result showed that the content of soil total N,hydrolysable N,organic matter in forest and grass composite pattern was higher than in farmland.The content of total P,available P,total K and slowly K was lower than that in farmland.The seasonal change of NH-4+-N,NO-3--N,PO-4 3-and K+ was influenced by the growing of plant,precipitation and temperature.展开更多
Public welfare forest is the most important model of vegetation restoration in the Conversion of farmland to forests in Sichuan Province. It can well represent and reflect the characteristics and laws of vegetation re...Public welfare forest is the most important model of vegetation restoration in the Conversion of farmland to forests in Sichuan Province. It can well represent and reflect the characteristics and laws of vegetation restoration in hillside fields. Therefore an Alnus cremastogyne forest community developed via converting hillside fields to forest, was investigated by contrast with a weed community on abandoned hillside fields. The results indicated that: 1) In Sichuan Basin and surrounding regions of it, vegetations restored so rapid that the average DBH (diameter at breast height), tree height of A.cremastogyne tree crown density, ground vegetation coverage respectively reached 5.2 cm, 6.1 m, 0.7 and 100 percent for 3 years and after converting hillside fields to forest. 2) With vegetation restoring, community gradually developed mosaic spatial pattern and vertical stratification, simultaneously distribution of plant population changed from regular to clumped, and spatial heterogeneity of community increased. 3) Community biodiversity remarkably increased in the process of vegetation restoration in hillside fields. During the period, species richness of both commnuities changed from 20 to 39, Shannon-Wiener diversity index was 4.205 and 5.021 respectively, while Pielou equitability index dropped little. 4) Plant species frequently and dramatically altered, which mainly showed that therophytes declined rapidly from 16 to 10, while perennial ones dramatically increased from 2 to 26, and 8 of them are phanerophytes. 5) The pathway of community development approximately was from annual herbs to shrubs + perennial herbs to trees + shrubs and herbs + perennial herbs, finally to natural mixed forests, such driving force was mainly from interspecific competition.展开更多
文摘This paper analyzed the difference of soil nutrient and the dynamics of available nutrient in soil solution of the forest and grass composite pattern and the farmlands on site.The result showed that the content of soil total N,hydrolysable N,organic matter in forest and grass composite pattern was higher than in farmland.The content of total P,available P,total K and slowly K was lower than that in farmland.The seasonal change of NH-4+-N,NO-3--N,PO-4 3-and K+ was influenced by the growing of plant,precipitation and temperature.
文摘Public welfare forest is the most important model of vegetation restoration in the Conversion of farmland to forests in Sichuan Province. It can well represent and reflect the characteristics and laws of vegetation restoration in hillside fields. Therefore an Alnus cremastogyne forest community developed via converting hillside fields to forest, was investigated by contrast with a weed community on abandoned hillside fields. The results indicated that: 1) In Sichuan Basin and surrounding regions of it, vegetations restored so rapid that the average DBH (diameter at breast height), tree height of A.cremastogyne tree crown density, ground vegetation coverage respectively reached 5.2 cm, 6.1 m, 0.7 and 100 percent for 3 years and after converting hillside fields to forest. 2) With vegetation restoring, community gradually developed mosaic spatial pattern and vertical stratification, simultaneously distribution of plant population changed from regular to clumped, and spatial heterogeneity of community increased. 3) Community biodiversity remarkably increased in the process of vegetation restoration in hillside fields. During the period, species richness of both commnuities changed from 20 to 39, Shannon-Wiener diversity index was 4.205 and 5.021 respectively, while Pielou equitability index dropped little. 4) Plant species frequently and dramatically altered, which mainly showed that therophytes declined rapidly from 16 to 10, while perennial ones dramatically increased from 2 to 26, and 8 of them are phanerophytes. 5) The pathway of community development approximately was from annual herbs to shrubs + perennial herbs to trees + shrubs and herbs + perennial herbs, finally to natural mixed forests, such driving force was mainly from interspecific competition.
