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
The results from comparative study of the EUF-K values of four different soils and of their varions particlefractions (<2μm, 2-10μm and 10 50μm) showed that the EUF-K values were related to the composition ofcl...The results from comparative study of the EUF-K values of four different soils and of their varions particlefractions (<2μm, 2-10μm and 10 50μm) showed that the EUF-K values were related to the composition ofclay minerals and the soil particle size. The EUF-K values (0-35 min) were closely related to the amountof rapidly available K and part of non-exchangeable K of soils. Biological experiments proved that EUFtechnique was an effective method for evaluating soil K-supplying power.展开更多
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The results from comparative study of the EUF-K values of four different soils and of their varions particlefractions (<2μm, 2-10μm and 10 50μm) showed that the EUF-K values were related to the composition ofclay minerals and the soil particle size. The EUF-K values (0-35 min) were closely related to the amountof rapidly available K and part of non-exchangeable K of soils. Biological experiments proved that EUFtechnique was an effective method for evaluating soil K-supplying power.
