| This study institute for sand control and use of test base in Liaoning province in the joint application of biochar,bentonite and organic fertilizer rates of sand soil as the research object,by adopting the combination of field test and indoor test methods,with the orthogonal experimental design,through the joint application of three factors five levels to deal with the analysis of soil physical and chemical properties,The influence of different treatments on the adsorption characteristics and desorption effect of exogenous potassium was studied,so as to find the best scheme of the combined application of biochar,bentonite and organic fertilizer on the improvement of aeolian sand soil.The test results are as follows:(1)Compared with the control soil,the physicochemical properties of the tested soil were greatly improved under the combined application of biochar,bentonite and organic fertilizer.The soil bulk density can be reduced by 1.42g/cm~3.The improved aeolian sandy soil changes from acid to weakly alkaline,and the pH value is increased to 8.09.The highest content of alkali-hydrolyzable nitrogen increased by 298%compared with the control.In terms of cation exchange,the maximum cation exchange capacity of soil was 458%higher than that of the control.The organic matter content of all the tested soils ranged from 1.2%to 1.9%,and the highest was 1.88%.(2)Compared with the control,the maximum adsorption capacity of the tested soil under different treatments of biochar,bentonite and organic fertilizer was all higher than that of the control.When the treatment scheme was A5B5C3,the soil potassium uptake was the hightest,and the difference was significant compared with other treatments.On the whole,the group with more carbon application was better than the group with less carbon application,and the potassium uptake of the tested soil with plot number 21 was better than that of other treatments.Compared with the Langmuir equation,the Freunglich equation has a better fitting effect,and the K value and MBC of the tested soil under different treatment are both greater than CK.When the treatment scheme was A5B5C3,1/n was 0.58,which was less than that of other treated soils.(3)The total desorption amount of the tested soil under the combined application of biochar,bentonite and organic fertilizer was significantly higher than that of the control soil,and the desorption amount of each treatment was the highest in the previous two treatments.With the increase of the number of desorption times,the differences among the treatments decreased and finally reached the same level.The treatment with the maximum total potassium desorption amount was consistent with the treatment with the maximum adsorption amount.The desorption rate decreased with the increase of desorption times,and the desorption rate changed from fast to slow.Compared with the control group,the differences of treatment schemes A5B5C3 and A5B1C4 were more obvious.(4)There was an extremely signicant positive correlation between available potassium and the amount of adsorption and desorption(P<0.01);soil bulk density was significantly negatively correlated with available K,maximum K uptake and total desorption(P<0.01),pH value was significantly positively correlated with available K,maximum K uptake and total desorption(P<0.01),the cation exchange capacity was significautly positively correlated with the content of available potassium,the maximum potassium uptake and the total desorption(P<0.01);There was a significant positive correlation between organic matter and available potassium(P<0.01),was significantly positively correlated with the adsorption capacity of potassium(P<0.05),but not significantly correlated with desorption amount. |
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