This paper introduces a set of green,high-yield and high-efficiency cultivation technique of rape for both vegetable and oilseed utilization,including selection of suitable varieties and sowing methods,seedling raisin...This paper introduces a set of green,high-yield and high-efficiency cultivation technique of rape for both vegetable and oilseed utilization,including selection of suitable varieties and sowing methods,seedling raising,timely transplanting,field management,pest and disease control,timely harvest,drying rapeseed into storage and so on.The technique not only improves the yield of rape,but also enriches the citizens’vegetable basket and farmers’pocketbook.展开更多
: Shifting cultivation is a major form of agricultural practice in most parts of tropical regions worldwide. In places where the bush fallow period is excessively shortened or the period of cultivation is extended for...: Shifting cultivation is a major form of agricultural practice in most parts of tropical regions worldwide. In places where the bush fallow period is excessively shortened or the period of cultivation is extended for too long, the rate of vegetation recovery and biodiversity on abandoned lands of shifting cultivation would decline. The recovery of the secondary plant communities could even be inhibited for a prolonged period because of grass occupancy. Because of the vital significance of the early recovery communities to secondary succession, we studied the community characteristics of early recovery vegetation on abandoned lands of shifting cultivation in Bawangling of Hainan Island. Measurements were made of the community composition and structure of early recovery vegetation. The sprouting abilities of different functional groups and different species in the same functional group, and the effect of the grass functional group on the composition and quantitative characteristics of tree and shrub functional groups were analyzed. Results indicated that only a few families, genera, or species apparently dominated in the early recovery vegetation on the abandoned lands of shifting cultivation and that deciduous species occurred with a rather high percentage in this early recovery community compared with the natural secondary or old growth forests. Small-sized individuals dominated the woody community. The abundance and basal area of sprouting stems for species in the tree functional group were greater than those of seeder stems, whereas the abundance and basal area of resprouters and seeders for species in the shrub functional group did not differ. The total abundance of stems for the community, stem abundances for species in tree or shrub functional groups, and for seeder or resprouter stems were all negatively correlated with coverage of the grass functional group. The mean sprouting ability in the tree functional group was greater than in the shrub functional group. The sprouting ability for different species in the same functional group was also significantly different.展开更多
In the present study, we investigated the effect of hillslope gradient on vegetation recovery on abandoned land of shifting cultivation In Hainan Island, south China, by measuring community composition and structure o...In the present study, we investigated the effect of hillslope gradient on vegetation recovery on abandoned land of shifting cultivation In Hainan Island, south China, by measuring community composition and structure of 25-year-old secondary forest fallows along a hillslope gradient （up-, middle-, and down-slope position）. A total of 49 733 free-standing woody plant stems higher than 10 cm and belonging to 170 species, 112 genera, and 57 families was found in the three l-hm2 investigation plots. Stem density was highest in the down-slope stand and lowest in the up-slope stand. Species richness and the Shannon-Wiener Index were both highest in the middle-slope stand, and lower In the down-slope and up-slope stands. The recovery forest fallows on different hiUslope positions were all dominated by a few species. The five most abundant species accounted for 70.1%, 58.8%, and 72.9% of total stem densities in stands in the up-, middle-, and down-slope positions, respectively. The five species with the greatest basal areas accounted for 74.5%, 84.3%, and 74.7% of total stem basal area for the up-, middle-, and down-slope positions, respectively. The number of low-density species （stem abundance less than five） Increased from the up-slope position downward. Of the nine local common species among three different functional groups, the short-lived pioneer species dominated the up-slope position, but long-lived pioneer species dominated the middle- and down-slope positions. The climax species of primary tropical lowland rain forest was found in the downslope position. Both the mean diameter at breast height （DBH） and mean height of the trees Increased with decreasing hillslope gradient. The stem density and basal area in different size classes were significantly different in stands In different slope positions. Our results indicated that the rate of secondary succession varies, even over small spatial scales caused by the hlllslope gradient, in early vegetation recovery.展开更多
基金Supported by National Rape Industry System Construction Project(CARS-12)Sichuan Provincial Innovation Team Project(SCCXTD-2022-03)+1 种基金Collaborative Science and Technology Support Project of Sichuan Academy of Agricultural Sciencesthe 13th Five-Year Plan for Crop Breeding Project of Sichuan Province(2016NYZ0031)。
文摘This paper introduces a set of green,high-yield and high-efficiency cultivation technique of rape for both vegetable and oilseed utilization,including selection of suitable varieties and sowing methods,seedling raising,timely transplanting,field management,pest and disease control,timely harvest,drying rapeseed into storage and so on.The technique not only improves the yield of rape,but also enriches the citizens’vegetable basket and farmers’pocketbook.
文摘: Shifting cultivation is a major form of agricultural practice in most parts of tropical regions worldwide. In places where the bush fallow period is excessively shortened or the period of cultivation is extended for too long, the rate of vegetation recovery and biodiversity on abandoned lands of shifting cultivation would decline. The recovery of the secondary plant communities could even be inhibited for a prolonged period because of grass occupancy. Because of the vital significance of the early recovery communities to secondary succession, we studied the community characteristics of early recovery vegetation on abandoned lands of shifting cultivation in Bawangling of Hainan Island. Measurements were made of the community composition and structure of early recovery vegetation. The sprouting abilities of different functional groups and different species in the same functional group, and the effect of the grass functional group on the composition and quantitative characteristics of tree and shrub functional groups were analyzed. Results indicated that only a few families, genera, or species apparently dominated in the early recovery vegetation on the abandoned lands of shifting cultivation and that deciduous species occurred with a rather high percentage in this early recovery community compared with the natural secondary or old growth forests. Small-sized individuals dominated the woody community. The abundance and basal area of sprouting stems for species in the tree functional group were greater than those of seeder stems, whereas the abundance and basal area of resprouters and seeders for species in the shrub functional group did not differ. The total abundance of stems for the community, stem abundances for species in tree or shrub functional groups, and for seeder or resprouter stems were all negatively correlated with coverage of the grass functional group. The mean sprouting ability in the tree functional group was greater than in the shrub functional group. The sprouting ability for different species in the same functional group was also significantly different.
基金Supported by the National Natural Science Foundation of China(30340047 and 30430570)
文摘In the present study, we investigated the effect of hillslope gradient on vegetation recovery on abandoned land of shifting cultivation In Hainan Island, south China, by measuring community composition and structure of 25-year-old secondary forest fallows along a hillslope gradient （up-, middle-, and down-slope position）. A total of 49 733 free-standing woody plant stems higher than 10 cm and belonging to 170 species, 112 genera, and 57 families was found in the three l-hm2 investigation plots. Stem density was highest in the down-slope stand and lowest in the up-slope stand. Species richness and the Shannon-Wiener Index were both highest in the middle-slope stand, and lower In the down-slope and up-slope stands. The recovery forest fallows on different hiUslope positions were all dominated by a few species. The five most abundant species accounted for 70.1%, 58.8%, and 72.9% of total stem densities in stands in the up-, middle-, and down-slope positions, respectively. The five species with the greatest basal areas accounted for 74.5%, 84.3%, and 74.7% of total stem basal area for the up-, middle-, and down-slope positions, respectively. The number of low-density species （stem abundance less than five） Increased from the up-slope position downward. Of the nine local common species among three different functional groups, the short-lived pioneer species dominated the up-slope position, but long-lived pioneer species dominated the middle- and down-slope positions. The climax species of primary tropical lowland rain forest was found in the downslope position. Both the mean diameter at breast height （DBH） and mean height of the trees Increased with decreasing hillslope gradient. The stem density and basal area in different size classes were significantly different in stands In different slope positions. Our results indicated that the rate of secondary succession varies, even over small spatial scales caused by the hlllslope gradient, in early vegetation recovery.
