Soil dynamic parameters are essential in guiding agriculture production, engineering designfor soil and water conservation and irrigation works. In this paper, RETC software is used to deduce thesoil water retention e...Soil dynamic parameters are essential in guiding agriculture production, engineering designfor soil and water conservation and irrigation works. In this paper, RETC software is used to deduce thesoil water retention equations and soil hydraulic conductivity of van Genuchten model based on soilmechanical composition and bulk density in cinnamon soil. The soil specific water capacities are obtainedform differential coefficients of the equations for soil water retention. The result is verified by fieldmeasurement using EQ15 equilibrium tensiometers and Trime-IT soil moisture sensors. It is concludedthat the relative error of soil water retention is less than 10% and that of soil hydraulic conductivity is inthe range of 18%～39%, both of them tends to decrease with the decrease of soil water potential.Therefore, it is feasible to use RETC software to derive soil hydrodynamic parameters.展开更多
Kdesorption from soils in a constant electric field(field strength:44.5Vcm-1) by means of electro-ultrafil-tration (EUF) followed second-order kinetics and could be described by the equation dd/dt = k(D-d)2. From thee...Kdesorption from soils in a constant electric field(field strength:44.5Vcm-1) by means of electro-ultrafil-tration (EUF) followed second-order kinetics and could be described by the equation dd/dt = k(D-d)2. From theequation, such kinetic parameters relating to K desorption from soils as the maximum desorbable quantity D, quantity of K desorbed within 40 minutes d40, initial desorption rate Vo, desorption rate constant k and half-time t1/2 could be calculated. An expression which describes the relationships between the kinetic parameters on the one hand and the responses of barley to fertilizer-K in the field experiments in different sites and the potassium-supplying power of soils on the other was established. Vo, D and d40 were significantly correlated with barley relative yield, K uptake by barley and the content of soil available potassium. The rate constants of K desorption varied between 4.42 × 10-4-1.80 × 10-3kg mg-1 min-1 and highly correlated with the relative yield of barley. The kinetic parameters including Vo, D, d40 and k were successfully used to estimate the K-supplying power of soils.展开更多
This study aims to estimate the hydrodynamic properties of soils under various agricultural practices in the Tougou catchment in northern Burkina Faso. The methodology adopted is based on the determination of the unsa...This study aims to estimate the hydrodynamic properties of soils under various agricultural practices in the Tougou catchment in northern Burkina Faso. The methodology adopted is based on the determination of the unsaturated hydraulic conductivity and capillary sorptivity close to saturation. This method relies on the measurement of the transient infiltration flux at the soil surface with imposed hydraulic head varying from -60 to -20 mm. These tests are carried out on control, stony line, half-moon and zai plots. The results show a difference in hydrodynamic parameters according to the agricultural practices. The unsaturated hydraulic conductivity is 33.1 cm/h, 13.1 cm/h, 20.3 cm/h and 4.0 cm/h for zai, control, stony line and half-moon plots respectively. The unsaturated hydraulic conductivity is 33.1 cm/h, 13.1 cm/h, 20.3 cm/h and 4.0 cm/h for zai, control, stony line and half-moon plots respectively. The pores participating to water transfer also differ. The mean size of drainable pores is 43.7, 56.2, 22.3 and 87.2 pm on control, stony line, half-moon and zai plots respectively.展开更多
The overall objective of the present study is to evaluate the impact of the heap fermentation of cocoa on microbial dynamics and physicochemical parameters of the soil. The methodology was to heap fermentation broad b...The overall objective of the present study is to evaluate the impact of the heap fermentation of cocoa on microbial dynamics and physicochemical parameters of the soil. The methodology was to heap fermentation broad beans 600 cocoa pods moved to a place after the soil was taken for microbiological and physicochemical analyzes considered the control sample. In addition, cocoa lixiviate and soil were subjected to analyze. Chemical analysis of cocoa lixiviate revealed the absence of heavy metals such as cadmium, chromium. It appears from the analysis of soil than clays represent on average 46.67%, 8.03% for fine silt, heavy silt 5.69%, 15.39% fine sands and heavy sands 20.02%. Microbiological analysis revealed the abundance of total coliform up to 4.6× 103 CFU/g soil. The variations of the abundance of yeasts are 0.01 × 103 CFU/g soil obtained on day 2 at 12 o＇clock to 3.5 × 103 CFU/g soil observed on day 3 to 18 pm （0-3 cm deep）. However, further study on the assessment of biodiversity after the fermentation would determine its species richness.展开更多
文摘Soil dynamic parameters are essential in guiding agriculture production, engineering designfor soil and water conservation and irrigation works. In this paper, RETC software is used to deduce thesoil water retention equations and soil hydraulic conductivity of van Genuchten model based on soilmechanical composition and bulk density in cinnamon soil. The soil specific water capacities are obtainedform differential coefficients of the equations for soil water retention. The result is verified by fieldmeasurement using EQ15 equilibrium tensiometers and Trime-IT soil moisture sensors. It is concludedthat the relative error of soil water retention is less than 10% and that of soil hydraulic conductivity is inthe range of 18%～39%, both of them tends to decrease with the decrease of soil water potential.Therefore, it is feasible to use RETC software to derive soil hydrodynamic parameters.
文摘Kdesorption from soils in a constant electric field(field strength:44.5Vcm-1) by means of electro-ultrafil-tration (EUF) followed second-order kinetics and could be described by the equation dd/dt = k(D-d)2. From theequation, such kinetic parameters relating to K desorption from soils as the maximum desorbable quantity D, quantity of K desorbed within 40 minutes d40, initial desorption rate Vo, desorption rate constant k and half-time t1/2 could be calculated. An expression which describes the relationships between the kinetic parameters on the one hand and the responses of barley to fertilizer-K in the field experiments in different sites and the potassium-supplying power of soils on the other was established. Vo, D and d40 were significantly correlated with barley relative yield, K uptake by barley and the content of soil available potassium. The rate constants of K desorption varied between 4.42 × 10-4-1.80 × 10-3kg mg-1 min-1 and highly correlated with the relative yield of barley. The kinetic parameters including Vo, D, d40 and k were successfully used to estimate the K-supplying power of soils.
文摘This study aims to estimate the hydrodynamic properties of soils under various agricultural practices in the Tougou catchment in northern Burkina Faso. The methodology adopted is based on the determination of the unsaturated hydraulic conductivity and capillary sorptivity close to saturation. This method relies on the measurement of the transient infiltration flux at the soil surface with imposed hydraulic head varying from -60 to -20 mm. These tests are carried out on control, stony line, half-moon and zai plots. The results show a difference in hydrodynamic parameters according to the agricultural practices. The unsaturated hydraulic conductivity is 33.1 cm/h, 13.1 cm/h, 20.3 cm/h and 4.0 cm/h for zai, control, stony line and half-moon plots respectively. The unsaturated hydraulic conductivity is 33.1 cm/h, 13.1 cm/h, 20.3 cm/h and 4.0 cm/h for zai, control, stony line and half-moon plots respectively. The pores participating to water transfer also differ. The mean size of drainable pores is 43.7, 56.2, 22.3 and 87.2 pm on control, stony line, half-moon and zai plots respectively.
文摘The overall objective of the present study is to evaluate the impact of the heap fermentation of cocoa on microbial dynamics and physicochemical parameters of the soil. The methodology was to heap fermentation broad beans 600 cocoa pods moved to a place after the soil was taken for microbiological and physicochemical analyzes considered the control sample. In addition, cocoa lixiviate and soil were subjected to analyze. Chemical analysis of cocoa lixiviate revealed the absence of heavy metals such as cadmium, chromium. It appears from the analysis of soil than clays represent on average 46.67%, 8.03% for fine silt, heavy silt 5.69%, 15.39% fine sands and heavy sands 20.02%. Microbiological analysis revealed the abundance of total coliform up to 4.6× 103 CFU/g soil. The variations of the abundance of yeasts are 0.01 × 103 CFU/g soil obtained on day 2 at 12 o＇clock to 3.5 × 103 CFU/g soil observed on day 3 to 18 pm （0-3 cm deep）. However, further study on the assessment of biodiversity after the fermentation would determine its species richness.
