Study On The Effect Of Different Fertilization Measures On Salinized Farmland Improvement In Hetao Irrigation Area

In order to study the improvement effect of different fertilization measures on salinized farmland,the salinized soil in Hetao irrigated area of Inner Mongolia was taken as the research object,and the effects of different fertilization measures on soil salt transport,nutrient,microbial change characteristics and crop yield of salinized farmland were studied by combining field experiment and laboratory analysis.In the experiment,8 treatments of fertilizer(T1),organic fertilizer(T2),straw mulching(T3),organic fertilizer+fertilizer(T4),organic fertilizer+straw mulching(T5),straw mulching+fertilizer(T6),organic fertilizer+fertilizer+straw mulching(T7)and CK were set under the condition of equal nitrogen.The results show that:(1)different fertilization measures can reduce soil pH,salinity and alkalinity of 0-20cm soil to different degrees.The pH of soil decreased by 0.08?0.25 units.Except for the single application of fertilizer,the total salt content of soil was significantly lower than that of the control group,with a decrease of 19.01%?27.21%.Soil salt-based ions Cl-,SO42-,Ca2+,Mg2+and Na+ decreased by 38.46%,29.76%,19.80%,28.33%and 13.43%,respectively.The soil alkalinity was reduced by 0.30?2.70 percentage points,among which the organic fertilizer+straw mulching had the most significant effect on reducing soil alkalinity.At the same time,the effects of different fertilizer cultivation measures on the soil desalination rate are also relatively large,straw returning to the field,straw returning to the field+organic fertilizer,straw returning to the field+ organic fertilizer+fertilizer combination on promoting salt leaching and inhibiting anti-salt effect is better,the desalination rate is 23.45%,27.79%,25.38%,respectively,but the control and single application of fertilizer treatment soil desalination effect is not good.(2)different fertilizer measures can improve the 0?20 cm of soil nutrient content and soil with organic fertilizer+fertilizer+straw counters-field processing to improve the soil organic matter,total nitrogen,phosphorus,available potassium is the most significant,respectively increased by 27.25%,57.14%,93.29%,20.85%than control,organic fertilizer+fertilizer processing to improve the most significant soil alkaline hydrolysis n,increased by 62.48%than control.(3)the effects of different fertilization measures on the total number of soil microorganisms,bacteria and actinomycetes in the 0-20cm soil layer were significantly different,while the effects on the number of fungi were not significant.The total number of soil microorganisms in each treatment was between 3.18 X 106?5.56 ×106 ·g-1 dry soils,which increased by 14.47%?74.84%compared with the control.Among them,organic fertilizer+fertilizer+straw returning to the field,organic fertilizer+straw returning to the field,and organic fertilizer treatment had a significant impact on the total number of soil microorganisms.The number of soil bacteria was between 3.00 ×106?5.35×106·9-1 dry soil,which was 15.00%?78.33%higher than the control.(4)principal component analysis(pca)was used to evaluate soil fertility in 11 indexes,such as soil saline-alkali index,nutrient index and microbial index,among which the comprehensive score of organic fertilizer+fertilizer+straw mulching treatment was the highest,followed by organic fertilizer+fertilizer treatment,indicating that these two fertilizer cultivation measures had the most significant improvement effect.Among all the soil indexes,soil organic matter,total nitrogen,available phosphorus and alkali-hydrolyzed nitrogen have a greater weight in the common factor variance and a greater contribution to soil fertility.(5)the yield of sunflower under different fertilization measures was as follows:organic fertilizer+fertilizer+straw returning to the field>organic fertilizer+fertilizer>organic fertilizer+ straw returning to the field>straw returning to the field+fertilizer>straw returning to the field>organic fertilizer>chemical fertilizer>control treatment(CK).The yield of each treatment was increased by 9.81%?48.38%,among which the organic fertilizer+fertilizer+straw mulching treatment had the most significant effect,followed by the organic fertilizer+fertilizer treatment.