[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water res...[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water resources. [Method] Three differ- ent loosening treatments for maize in ridges were performed in field trials as fol- lows： conventional ridge tillage, loosening the cm in spring （deep loosening in spring）, and depth of 30 cm in autumn （deep loosening in soils between rows to a depth of 30 oosening the soils between rows to a autumn）. Then the soil properties and the development of root system were measured to evaluate the effects of different loosening methods. [Result] Soil compactness was significantly reduced after deep loosening in spring, There were significant differences in soil compactness in 0-20 cm depth and soil bulk density in 0-40 cm depth between deep loosening in spring and deep loosening in autumn, deep loosening in spring and conventional ridge tillage. The soil water holding capacity was also significantly different between the two deep loosening treatments and conventional ridge tillage. Moreover, the root ac- tive absorption area of maize of deep loosening in spring was higher than that of conventionai ridge tillage. [Conclusion] Deep loosening can reduce soil compactness, bulk density, and improve soil water holding capacity, soil water content and the root activity of maize. Deep loosening in spring is better in soil improvement be- cause spring is closer to the growth period of crops than autumn. So, deep loosen- ing is conducive to the improvement of soil compactness and structure.展开更多
The supply of cadmium from soil to plant roots mainly depends on the diffusion process. This work was conducted tostudy the effect of some soil properties on cadmium diffusion coefficient (D) in soil. Measurements we...The supply of cadmium from soil to plant roots mainly depends on the diffusion process. This work was conducted tostudy the effect of some soil properties on cadmium diffusion coefficient (D) in soil. Measurements were made using the Shofield and Graham-Bryce's isotopic labelling method. Cadmium diffusion coefficients varied from 10￣(-7) to 10￣(-9) cm￣2s￣(-1),Higher values were observed in acid sandy soils and lower values in calcareous clay soils. Liming an acid soil resulted in a sub-stantial decrease of D. Addition of cadmium as nitrate salt generally increased D, while addition of sewage sludge and organ-ic matter resulted in a significant decrease of cadmium diffusion. The rhizospheric activity also induced a moderate reduction in D. The relationships between D 10￣(-9)cm￣2s￣(-1)) on the one hand and soil PH, moisture (Mc, g kg￣(-1)), organic matter (OM, gkg￣1 ), clay (Cy, g kg￣(-1)) and cadmium content (Cd, mg kg￣(-1)) on the other were obtained by the multigle regression:D=182. 1-29.g1 pH+0.210Mc-0.303OM+0.011Cy+1.64Cd (R￣2=0.859,n=22 ).展开更多
基金Supported by National Maize Industry Technology System(CARS-02-38)Science and Technology Development Project of Jilin Province(LFGC14308)Special Fund for Scientific Research in the Public Interest(201303125-03)
文摘[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water resources. [Method] Three differ- ent loosening treatments for maize in ridges were performed in field trials as fol- lows： conventional ridge tillage, loosening the cm in spring （deep loosening in spring）, and depth of 30 cm in autumn （deep loosening in soils between rows to a depth of 30 oosening the soils between rows to a autumn）. Then the soil properties and the development of root system were measured to evaluate the effects of different loosening methods. [Result] Soil compactness was significantly reduced after deep loosening in spring, There were significant differences in soil compactness in 0-20 cm depth and soil bulk density in 0-40 cm depth between deep loosening in spring and deep loosening in autumn, deep loosening in spring and conventional ridge tillage. The soil water holding capacity was also significantly different between the two deep loosening treatments and conventional ridge tillage. Moreover, the root ac- tive absorption area of maize of deep loosening in spring was higher than that of conventionai ridge tillage. [Conclusion] Deep loosening can reduce soil compactness, bulk density, and improve soil water holding capacity, soil water content and the root activity of maize. Deep loosening in spring is better in soil improvement be- cause spring is closer to the growth period of crops than autumn. So, deep loosen- ing is conducive to the improvement of soil compactness and structure.
文摘The supply of cadmium from soil to plant roots mainly depends on the diffusion process. This work was conducted tostudy the effect of some soil properties on cadmium diffusion coefficient (D) in soil. Measurements were made using the Shofield and Graham-Bryce's isotopic labelling method. Cadmium diffusion coefficients varied from 10￣(-7) to 10￣(-9) cm￣2s￣(-1),Higher values were observed in acid sandy soils and lower values in calcareous clay soils. Liming an acid soil resulted in a sub-stantial decrease of D. Addition of cadmium as nitrate salt generally increased D, while addition of sewage sludge and organ-ic matter resulted in a significant decrease of cadmium diffusion. The rhizospheric activity also induced a moderate reduction in D. The relationships between D 10￣(-9)cm￣2s￣(-1)) on the one hand and soil PH, moisture (Mc, g kg￣(-1)), organic matter (OM, gkg￣1 ), clay (Cy, g kg￣(-1)) and cadmium content (Cd, mg kg￣(-1)) on the other were obtained by the multigle regression:D=182. 1-29.g1 pH+0.210Mc-0.303OM+0.011Cy+1.64Cd (R￣2=0.859,n=22 ).
