Effects Of Different Sowing Rates On Root Growth And Soil Physical And Chemical Properties Of Wheat

There were several heavy rainfalls in October 2017,which led to the late broadcast of wheat in Shanxi.Province.The direct problem of late sowing was the uncertainty of the amount of sowing.Therefore,the sowing test was started in Taigu County,Jinzhong City.The tested variety was Zhongmai 175.Five sowing gradients of Dl,D2,D3,D4,and D5 to study the absorption layer of underground roots under different wheat yields Relationship with soil microbial activity and soil physical and chemical properties.The results are as follows:The effect of different sowing on yield:As the amount of sowing increased,the yield was inverted "V".The yield from high to low:6337.85 kg·hm-2>6214.85 kg·hm-2>4476.50 kg·hm->4482.15 kg·hm-2>4960.40 kg·hm-2,the first two higher yield treatments respectively It is D2 and D3,and the difference between the two is not significant.The effect of different sowing on the root system:the root system developed best under the treatment of D2 and D3;the wheat roots maintained the growth trend before the flowering stage,and the jointing stage was the peak of wheat root growth.At the same stage,the roots of wheat in the jointins-flowering period increased gradually,and the jointing stage was the peak period of wheat root growth.The root length,root surface area,root volume,average root diameter,and the number of root tips per plant were 214.52,respectively.235.41%,217.8420.53%,205.7519.57%,212.5022.73%,205.6817.87%.Effects of different wheat yields on soil physical properties(1)soil bulk density of Dl.D2,D3,D4 and D5 sowing-flowering period was 4.13%,1.65%,1.65%,3.31%and 3.31%,respectively;D1,D2,D3,D4 and D5 sowing-flowering soil pores The degree of decline is 3.47%,1.39%,1.39%,2.78%and 2.78%;(2)the Quantitative Ratio of 0.25 and D3 for the treatment of 0.25 mm or more was the largest,and the proportion of soil fraction at the jointing stage under different sowing rates The largest is 0.25-1 mm,the maximum proportion of flowering period is 0.25 mm or more,and the grain size of 0.25 mm above jointing stage is 95.36%in D2 and 93.54%in D3.The flowering period of D2 accounted for 97.37%,and D3 accounted for 97.28%.Effects of different sowing rates on soil biological properties:Quantitative D2 and D3 treatment of soil microbial carbon and nitrogen content and soil enzyme activities in jointing and flowering stages(catalase,sucrose The activities of enzyme,urease and alkaline phosphatase were the highest,and the soil microbial carbon and nitrogen contents and sucrase activity in the flowering stage were higher than the jointing stage,and the soil catalase,urease and alkaline phosphatase activities were opposite.The effects of different yields on soil chemical properties:(1)The soil organic carbon,alkali nitrogen,available phosphorus and available potassium were the highest in the jointing and flowering stages of wheat treated with D2 and D3.During the jointing and flowering stages of wheat,the soil organic carbon showed an inverted;LV,shape with increasing sowing amount.The soil's alkali nitrogen,available phosphorus and available potassium showed "N" type,and the peak value was D2 and D3.There was no significant difference between the two treatments in treatment.Under the same treatment,the contents of soil organic carbon,alkali nitrogen,available phosphorus and available potassium in the flowering stage were higher than the jointing stage;(2)the amount of D2 and D3 The soil total nitrogen,total phosphorus and total potassium content in the jointing and flowering stages of wheat treated with were the highest.During the jointing and flowering stages of wheat,the total nitrogen and total potassium content of the soil decreased first and then increased,showing a "V" shape,the total phosphorus was "N" type,and the valley value was D2.There was no significant difference between the two treatments and D3 treatment.Under the same treatment,the total nitrogen,total phosphorus and total potassium in the flowering stage were lower than the jointing stage.In summary,wheat root function reduces soil bulk density and provides a suitable environment for microorganisms,so that roots and microorganisms act together on soil nutrients,ultimately affecting yield.The roots and microorganisms treated with 225 kg·hm-2and 300 kg hm-2 were the highest,which led to the enhancement of soil enzyme activity and the increase of available nutrients in the corresponding stage.The content of total nitrogen,total phosphorus and total potassium was the lowest,and the yield was the highest.The amount of broadcast is the appropriate amount of late broadcast in the Jinzhong area.