In Cameroon, most farmers rely on their perceptions for fertility evaluation and choice of agricultural land units. However, because of environmental change, this knowledge is mostly disregarded. The use of farmers＇ ...In Cameroon, most farmers rely on their perceptions for fertility evaluation and choice of agricultural land units. However, because of environmental change, this knowledge is mostly disregarded. The use of farmers＇ knowledge is important for the identification of relevant information for the choice of agricultural land units. The objective of this study was to compare farmers＇ perceptions of soil fertility with a conventional scientific approach in two locations of the forest margin zone of Center Cameroon. Through interviews and soil analysis, this study spelled and weighed the relationships between farmers＇ perceptions and soil fertility status. One hundred and twenty households＇ heads were interviewed and 30 soil samples collected. Farmers＇ perceptions were used to assess the topsoil fertility status across the studied areas, while a conventional scientific approach was used to quantify soil fertility status by the means of a soil fertility index （SFI）. Results showed that farmers, for soil differentiation, used color, texture, depth, drainage and vegetation. Soil＇ names delivered key messages for their location. Although the low overall SFI approximated by the conventional approach, farmers＇ perceptions could differentiate fertility levels between soils. This knowledge is relevant for the design of technical innovations in perceived fertility niches.展开更多
Diuron is frequently detected in surface- and groundwater under the vineyards, where organic amendments are often used, in Burgundy of France. Undisturbed column experiments were conducted to study the influence of th...Diuron is frequently detected in surface- and groundwater under the vineyards, where organic amendments are often used, in Burgundy of France. Undisturbed column experiments were conducted to study the influence of three composted organic amendments on diuron leaching through columns of two vineyard soils from Vosne-Roman′ee(VR, calcareous Cambisol) and Beaujolais(Bj, sandy Leptosol), France. Bromide(used as non-reactive tracer) and diuron breakthrough curves(BTCs) were analyzed using convectivedispersive equation(CDE), two-region(mobile-immobile, MIM) and two-site models. No influence of the composts was observed on the bromide recovery rates. The CDE model described well the bromide BTCs for all columns of the Bj soil and seven of the VR soil, suggesting a homogeneous water flow. However, for five VR soil columns, the MIM model fitted better, suggesting a partition of the water flow(15%–50% of matrix flow). The texture, the coarse material content and the tillage of the VR soil could explain this heterogeneity. However, for all columns, diuron leaching was greater through the Bj soil(46%–68%) than the VR soil(28%–39%). The compost addition resulted in a contrasting effect on diuron leaching: no difference or a decrease was observed for the VR soil, probably due to an increase of adsorption sites, whereas no difference or an increase was observed for the Bj soil possibly because of interactions and/or competition of diuron with the compost water-extractable organic matter which could facilitate its transport. All the diuron BTCs were best described using the two-site model, suggesting a large proportion of time-dependent sorption sites(30%–50%). The soil type and the nature of the amendments had contrasting influences on diuron transport. Composts with a high water-soluble fraction must be avoided in sandy soils to reduce the risk of groundwater contamination.展开更多
文摘In Cameroon, most farmers rely on their perceptions for fertility evaluation and choice of agricultural land units. However, because of environmental change, this knowledge is mostly disregarded. The use of farmers＇ knowledge is important for the identification of relevant information for the choice of agricultural land units. The objective of this study was to compare farmers＇ perceptions of soil fertility with a conventional scientific approach in two locations of the forest margin zone of Center Cameroon. Through interviews and soil analysis, this study spelled and weighed the relationships between farmers＇ perceptions and soil fertility status. One hundred and twenty households＇ heads were interviewed and 30 soil samples collected. Farmers＇ perceptions were used to assess the topsoil fertility status across the studied areas, while a conventional scientific approach was used to quantify soil fertility status by the means of a soil fertility index （SFI）. Results showed that farmers, for soil differentiation, used color, texture, depth, drainage and vegetation. Soil＇ names delivered key messages for their location. Although the low overall SFI approximated by the conventional approach, farmers＇ perceptions could differentiate fertility levels between soils. This knowledge is relevant for the design of technical innovations in perceived fertility niches.
文摘Diuron is frequently detected in surface- and groundwater under the vineyards, where organic amendments are often used, in Burgundy of France. Undisturbed column experiments were conducted to study the influence of three composted organic amendments on diuron leaching through columns of two vineyard soils from Vosne-Roman′ee(VR, calcareous Cambisol) and Beaujolais(Bj, sandy Leptosol), France. Bromide(used as non-reactive tracer) and diuron breakthrough curves(BTCs) were analyzed using convectivedispersive equation(CDE), two-region(mobile-immobile, MIM) and two-site models. No influence of the composts was observed on the bromide recovery rates. The CDE model described well the bromide BTCs for all columns of the Bj soil and seven of the VR soil, suggesting a homogeneous water flow. However, for five VR soil columns, the MIM model fitted better, suggesting a partition of the water flow(15%–50% of matrix flow). The texture, the coarse material content and the tillage of the VR soil could explain this heterogeneity. However, for all columns, diuron leaching was greater through the Bj soil(46%–68%) than the VR soil(28%–39%). The compost addition resulted in a contrasting effect on diuron leaching: no difference or a decrease was observed for the VR soil, probably due to an increase of adsorption sites, whereas no difference or an increase was observed for the Bj soil possibly because of interactions and/or competition of diuron with the compost water-extractable organic matter which could facilitate its transport. All the diuron BTCs were best described using the two-site model, suggesting a large proportion of time-dependent sorption sites(30%–50%). The soil type and the nature of the amendments had contrasting influences on diuron transport. Composts with a high water-soluble fraction must be avoided in sandy soils to reduce the risk of groundwater contamination.
