| In order to explore the improvement effect on the combined application of organic and inorganic fertilizers on saline-alkali soil,through 2 years of field trials,the typical saline-alkali soil of Tumochuan Plain is taken as the research object in this study,to discuss the effect on combined application of organic and inorganic fertilizers for soil Saline-alkali properties,soil nutrient and sunflower yield.The optimal application ratio of organic-inorganic compounding is explored,so as to make reasonable development and utilization of saline-alkali soil in this area.The main findings are as shown as following:(1)The effects on the combined application of organic and inorganic fertilizers on soil pH,total salinity,and alkalinity were different.With the organic fertilizer application amount as 54t/hm2 and the chemical fertilizer application amount as 0.39t/hm2,the effects of soil pH,total salinity,and alkalinity were the most significant,which were 9.28%,33.07%,and 36.83%lower than the control(CK),respectively.The single application of chemical fertilizer,organic fertilizer,and organic-inorganic combination all affected the salinity changes of the soil profile in different degrees.The 0 to 60 cm soil layer was basically showed obvious desalination.The effect of desalination was obvious when the organic fertilizer application amount was 54t/hm2.and the soil desalination is the most significant with the fertilizer application amount of 54t/hm2 in organic fertilizers and 0.39t/hm2 in inorganic fertilizers,with the desalination rate reaching as 28.01%.The salt isolate was most significant under the treatment of organic fertilizer 54t/hm2+and chemical fertilizer 0.39t/hm2,which were 41.59%,44.90%,44.90%,and 20.44%and 64.09%,Ca2+and Mg2+in soil increased by 136.44%and 40.16%.(2)Single application of chemical fertilizers can significantly increase soil total nitrogen,and alkali-hydrolyzable nitrogen contents,and increase with the increase of the application amount,but the effect on available phosphorus and available potassium is not significantly different;single application of organic fertilizer can be different The degree of soil nutrient content increased.Organic matter,total nitrogen,and available phosphorus increased with the increase in application rate,while alkali-hydrolyzed nitrogen and available potassium increased at first and then decreased.Organic-inorganic combined application can increase soil nutrients to varying degrees.Among them,organic-inorganic combined application had the highest content of soil organic matter at 72t/hm2+0.39t/hm2,which was 56.56%higher than the control(CK).The soil total nitrogen,alkaline nitrogen,available phosphorus,and available potassium content were higher under the condition of organic fertilizer application amount of 54/hm2,and the content was highest under the application of chemical fertilizer application amount as 0.39t/hm2,which were increased 136,63%,98.82%,161.06%,172.18%respectively,while compared with the control(CK).(3)The largest soil fertility index under different fertilization treatments was applied as 54t/hm2 organic fertilizer+0.39t/hm2 chemical fertilizer;the followed one was applied as 72t/hm2 organic fertilizer+0.39t/hm2 chemical fertilizer.(4)Single application of chemical fertilizer,organic fertilizer,and combination of organic and inorganic fertilizers can affect the yield of sunflower in varying degrees.Compared with the control(CK),single fertilizer application increased yield by 21.35%?23.27%;single application of organic fertilizer increased production by 33.91%?101.72%compared with control(CK).Under the condition of chemical fertilizer,the sunflower yield increased with the increase of the amount of organic fertilizer application;under the condition of 18-36t/hm2 organic fertilizer application,the sunflower yield increased with the increase of chemical fertilizer application,while under the condition of fertilizer application as 54-72t/hm2,the yield of sunflower increased first and then decreased with the increase of chemical fertilizer application.Among them,the sunflower yield was the largest under the condition of organic fertilizer application rate of 54t/hm2 and chemical fertilizer application rate of 0.39t/hm2,which increased by 151.2%compared with the control(CK).In conclusion,based on the comprehensive consideration of indicators such as soil Saline-alkali properties,soil nutrient and crop yield,nutrient absorption and utilization,the suitable fertilizer application amount is recommended as 0.39t/hm2 in the research area,and organic fertilizer is recommended as between 54t/hm2 and 72t/hm2,which is suitable for popularization and application in saline-alkali soils of Tumochuan Plain. |
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