Investigation And Evolution On Utilization Of Potash Resources From Organic Materials In Southwest China

Crop straw and animal manure are important resources in agriculture,which contains a wealth of nutrients and organic carbon.Straw and livestock manure return to field can reduce the amount of chemical fertilizer,especially potassium,which can relieve nitrogen,phosphorus and potassium fertilizer imbalance and increase soil organic matter, improve soil structure,It also can solve the environmental pollution caused by these resources. Thus,the utilization of straw and manure are the major issues related to resources,environment and sustainable development of agriculture.Recent studies are rarely reported on the utilization of straw and animal manure in Southwest China.Therefore, this study use the statistics of the potassium resources from organic materials in southwest region(2002to2012),meantime,the distribution of straw and manure potassium nutrient resources were analyzed and discussed by sample test and field investigation, then a pot experiment was designed to demonstrate the bio-availability of potassium from organic materials.The main results are as follows:(1) The average resource of straw in Southwest China was60376000tons from2001to2011,and the maximum amount of straw resource was Sichuan province,Guizhou province,Chongqing city and Yunnan province followed,and with the amount30581000tons,10622000tons,9983000tons,9189000tons, respectively. The content of potassium from tabacpo straw was the maximum(1.795%), followed by rice straw(1.637%),rape straw(1.505%), wheat straw(1.145%),and corn straw was the minimum(1.038%).The average potassium resource of straw in Southwest China was1077880tons,and the maximum amount of potassium from straw resource was Sichuan province(584430tons), followed by Guizhou(208080tons),Yunnan (156490tons),and Chongqing was the maximum(128880tons).(2) The average resource from excrement in Southwest China was494469000tons,and the maximum amount of manure resource was Sichuan province,Yunnan province, Guizhou province and Chongqing city followed,and with the amount223540000tons,126846000tons,92840000tons,51243000tons, respectively. The content of potassium from poultry excrement was the maximum(0.594%), followed by sheep(0.530%),cattle(0.421%), and pig was the minimum(0.171%). The maximum amount of potassium from manure resource was Sichuan province(878340tons),followed by Yunnan(542480tons),Gunnan(412480tons),and Chongqing was the maximum(185280tons). (3) According the survey, potassium from organic materials in Southwest China had little changes with an average of3096460tons in the past11years ranged from2872790tons(2007) to3376990tons(2005). The average potassium resource of straw in Southwest China was1077880tons, and potassium resource from excrement in Southwest China was2018580tons.The maximum amount of organic fertilizer potash resources in southwest was Sichuan province, followed by Yunnan, Guizhou and Chongqing reached1462770tons,698970tons,620560tons and314160tons,each accounted for47.2%,22.6%,20.0%,10.2%of total.(4) We investigate the application of potassium fertilizer in Southwest China, and found that potassium fertilizer consumption was upward trend overall in the past eleven years, with an average of757000tons. The maximum Potash fertilizer consumption in the southwest region was Sichuan province, the average reached292000tons,followed by248000tons of Yunnan,Guizhou127000tons,Chongqing was the minimum with amount of8.9million tons.each accounted for38.6%,32.8%,16.8%andll.8%of the total.(5) The main crop straws return to field was investigated in Southwest region through fieldwork,the results showed that rice straw can provide548,810tons potassium by returnning to the soil, accounting for59.9percent potassium of total.The total amount of crops straw to field achieve an average of85.0%of the total, but only28.7percent of the total was directly to field, direct to field and field burning of straw was the amount of57.3%of total potassium. Return to field directly, plus burned and directly to field, the total amount of straw to field potassium were309,500tons,617,230tons and915950tons respectively,each accounting for40.9%,81.5%and121.0%of chemical potash fertilizer.(6) A pot experiment was set up to study the bio-availability of straw potassium in2013,and found that potassium fertilizer could increase the biomass of ryegrass significantly, potassium from straw had the ability to replace chemical fertilizer, because crops biomass can be guaranteed.The application of potash fertilizer can significantly improve the absorption of potassium.In the application of potash treatments, the treatments conclude straw and chemical potash fertilizer treatment reached more than94%of the full application of chemical fertilizers treatment in the absorption of potassium,even more than the full application of chemical fertilizers treatment,which can be seen that potassium from straw could reach the cumulative effect of the chemical effects of potash in ryegrass plant,then we can use the potassium from organic materials instead of chemical potash fertilizer partily.(7) The pot experiment showed that potassium from straw replace70%chemical fertilizer had better affection,the amount of potassium from straw in Southwest China was1077880tons,thus,crop could absorb750000tons potassium from straw diretly,28.7percent of the total potassium from straw was directly to field,then straw could supply220000tons potassium by returnning to field diretly.