The parasitic weed Striga poses a serious threat to cereal production in sub-Saharan Africa. For many years, technological packages for the control of this weed were proposed and implemented on farmers＇ fields. A sur...The parasitic weed Striga poses a serious threat to cereal production in sub-Saharan Africa. For many years, technological packages for the control of this weed were proposed and implemented on farmers＇ fields. A survey was carried out in farmers＇ fields in 2010/201l cropping season in selected dryland areas of Tanzania to： （a） determine the Striga plant counts, number of capsules/Striga plant and agronomic practices used by farmers to control Striga; and （b） evaluate the relationship between Striga reproduction, soil chemical characteristics and agronomic practices. Soil samples at 0-20 cm depth were collected from 20 different farmers＇ fields. The soil samples were analyzed for pH, organic carbon, N, P and K. Results showed that there was low adoption of recommended Striga control methods. Regression analysis of agronomic practices and soil chemical characteristics revealed a positive improvement of soil N and organic carbon and reduction of soil P and K content as one shifted from sole planting to intercropping. The results showed that potassium was highly positively related to number of capsules/Striga plant. There was a reduction in the number of capsules/plant as one moved from sole planting to intercropping. Based on these findings, K in the Striga infested in soils positively influenced Striga reproduction and seed bank replenishment, hence high soil K levels may lead to high Striga incidence.展开更多
Paulownia is a fast-growing tree species that is mainly found in the central part of China. Three main cultivation areas of Paulownia are the Yellow-Huai-Hai Plain, south of the Yangtze River, and arid and semi-arid a...Paulownia is a fast-growing tree species that is mainly found in the central part of China. Three main cultivation areas of Paulownia are the Yellow-Huai-Hai Plain, south of the Yangtze River, and arid and semi-arid areas of Northwestern China. There are 9 species, 4 varieties and 4 forms used in the production in China. Study achievements were obtained in the fields of species/variety introduction, selection and breeding, afforestation techniques as well as the control of diseases and pests. The main problems existing in the current production include lack of improved varieties, mix-up of different varieties and variety degeneration due to the long course of a sexual reproduction. The author put forward countermeasures for the problems.展开更多
文摘The parasitic weed Striga poses a serious threat to cereal production in sub-Saharan Africa. For many years, technological packages for the control of this weed were proposed and implemented on farmers＇ fields. A survey was carried out in farmers＇ fields in 2010/201l cropping season in selected dryland areas of Tanzania to： （a） determine the Striga plant counts, number of capsules/Striga plant and agronomic practices used by farmers to control Striga; and （b） evaluate the relationship between Striga reproduction, soil chemical characteristics and agronomic practices. Soil samples at 0-20 cm depth were collected from 20 different farmers＇ fields. The soil samples were analyzed for pH, organic carbon, N, P and K. Results showed that there was low adoption of recommended Striga control methods. Regression analysis of agronomic practices and soil chemical characteristics revealed a positive improvement of soil N and organic carbon and reduction of soil P and K content as one shifted from sole planting to intercropping. The results showed that potassium was highly positively related to number of capsules/Striga plant. There was a reduction in the number of capsules/plant as one moved from sole planting to intercropping. Based on these findings, K in the Striga infested in soils positively influenced Striga reproduction and seed bank replenishment, hence high soil K levels may lead to high Striga incidence.
文摘Paulownia is a fast-growing tree species that is mainly found in the central part of China. Three main cultivation areas of Paulownia are the Yellow-Huai-Hai Plain, south of the Yangtze River, and arid and semi-arid areas of Northwestern China. There are 9 species, 4 varieties and 4 forms used in the production in China. Study achievements were obtained in the fields of species/variety introduction, selection and breeding, afforestation techniques as well as the control of diseases and pests. The main problems existing in the current production include lack of improved varieties, mix-up of different varieties and variety degeneration due to the long course of a sexual reproduction. The author put forward countermeasures for the problems.
