| Due to the Wei Bei Plateau as China's ancient dry farming have some influences from geographical location and natural environment,plant growth depends strongly on natural rainfall,artificial rainfall based on field test and theoretical analysis,the research on soil physicochemical properties and plant growth during the year changes,to effectively improve the utilization of agricultural water resources rate,alleviate the problem of shortage of water resources,accelerate the development of precision agriculture and ecological agriculture,and provide a theoretical basis to promote balanced development between water resources and ecological environment.The main achievements are as follows:(1)In the growth period of 6 kinds of plant the plants height showed a trend of first increase rapidly after gradually slow,coverage showed fist increased gradually then tends to be stable,aboveground biomass showed slowly increased at first and then increased rapidly into a slowly increasing trend,underground biomass due to different kinds of plant types are not the same,of which 3 kinds of crop specific belowground biomass first increased and then decreased trend,ground biomass of 3 green manure crops showed a trend of rapid growth then slow growth;The traditional Logistic model can better simulate 6 kinds of plant height,coverage,aboveground biomass and underground biomass of 3 kinds of green manure crops.According to the variation of plant growth characteristics,based on the analysis of the classic Logistic curve model,modified Logistic curve model can use green manure crops in different growth stages of the plant height measured value and the growth period of the maximum amount of biomass on the ground to predict the dynamic change of aboveground biomass.(2)The bulk density of soil depth of 0-25cm showed an increasing trend under the condition of 3 kinds of crop and showed Gradually increased and then decreas trend during the growth period under the condition of 3 kinds of green manure crops;With the change of plant growth period,the soil moisture absorption coefficient increased first and then decreased gradually under 6 kinds of plant were planted;The Hydrus-1d software was used to analyze the soil water dynamic parameters in the whole growth period of 6 plants,the plant growth period of crop growth period of wheat,soybean,and hairy vetch Coronilla varia and red clover planting conditions in the soil water dynamic parameters increased at first and then gradually stabilized,but the soil water dynamic parameters showed a decreasing trend during the growing period under the condition of millet were planted,among them,the degree of soil saturated hydraulic conductivity is more severe,the change amplitude is greater than 25%,the variation range of soil suction suction is between 6%-18%and The variation range of saturated water content and retained water content of soil was not significant between 2.50%-8%.Soil organic matter content at soil different depths under 6 kinds of plants were planted have changes in the performance of specific:the content of soil organic matter showed a trend of decreasing first and then increasing of the depths of 0-5cm?5-10cm,and the content of soil organic matter showed a tend that first increased and then decreased and then increased of the soil depths of 5-10cm?10-15cm?10-15cm under 6 kinds of plants were planted.The soil ammonium nitrogen content changes tend is that first increased and then decreased under the condition of 3 kinds of crops,and a change trend of MMM type was first increased and then decreased and then increased and then decreased of the depths of 5-10cm?10-15cm,a change trend of "s" type of the depths of 10-15cm?15-20cm?20-25cm;the content of soil nitrate content showed a trend of gradually decreasing of the depths of 0-5 cm,and the content of soil nitrate content showed that first increases and then decreases,then increases and finally tends to be stable of the soil depths the soil depth of 5-10cm?10-15cm?15-20cm?20-25cm under 6 kinds of plants were planted.The content of soil available phosphorus showed a trend of decreasing firstly and then increasing of the soil depth of 0-5cm,the content of available phosphorus increased first,then decreased and then increased,and finally tended to be stable of the soil depth of 10-15cm?15-20cm?20-25cm;The coefficient of variation of organic matter content,nitrate content,nitrogen content and available phosphorus content was between 10%and 100%,belonging to moderate variation under 6 kinds of plants were planted.(3)In the plants whole growth period,the plant height and the amount of organic matter cumulative consumption,nitrate cumulative consumption,nitrogen cumulative consumption of soil were linear correlation,and soil available phosphorus cumulative consumption is logarithmic relation under 6 kinds of plants were planted;In plant growth stage(jointing/branching period maturity)plant height and soil nitrogen cumulative consumption and nitrate cumulative consumption were power function relationship under 6 kinds of plants were planted;In the whole growth period,organic matter cumulative consumption,nitrate cumulative consumption,nitrogen cumulative consumption,phosphorus cumulative consumption and biomass of 6 kinds of plants were logarithmic relation under 6 kinds of plants were planted;In the plants whole growth period,the plant underground biomass and the amount of organic matter cumulative consumption,nitrate cumulative consumption,nitrogen cumulative consumption of soil were linear correlation,and soil available phosphorus cumulative consumption is logarithmic relation under 6 kinds of plants were planted;In plant growth stage(jointing/branching period maturity)plant height and soil nitrogen cumulative consumption and nitrate cumulative consumption were power function relationship under 6 kinds of plants were planted.(4)Under the 6 kinds of plants conditions,the soil depth of 0-15cm cumulative increase of soil bulk density,moisture retention,saturated water content,soil saturated hydraulic conductivity,shape parameters and plant biomass were related to quadratic function on the 6 kinds of plants whole growth period. |
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