Effects of pH and Water Content on the Activity and Effectiveness of Bacillus subtilis Bio-organic Fertilizer
In order to produce high-quality Bacillus subtilis bio-organic fertilizer,decomposed sheep manure was used as the main raw material,the pH value of the fertilizer was adjusted to 6.00,6.50,7.00,7.50,8.00 and 8.88 by adding furfural residue,and the optimal proportion was determined by measuring the number of live bacteria,and the optimal water content of the Bacillus subtilis bio-fertilizer was determined by different water contents.The results showed that adjusting the acidity and alkalinity of bio-organic fertilizers with rice bran aldehyde residue did not significantly affect the viable count of Bacillus subtilis in the biofertilizer.Regardless of the acidity and alkalinity,the viable count remained around 10×109 cfu/g after 180 days.The acidity significantly affected the count of filamentous fungi and miscellaneous bacteria in the biofertilizer(P<0.01).The undesirable count increased with pH until it reacheed 7.00,with a maximum of 6.17×106 cfu/g.When the pH was greater or lesst than 7.00,the undesirable count decreased.Different acidity levels of biofertilizers had a significant impact on seed germination index,showing a decreasing trend as pH increased,indicating that excessively high pH in biofertilizers could inhibit root growth.As moisture content increased,the number of Bacillus subtilis gradually decreased,while the count of filamentous fungi and miscellaneous bacteria in the fertilizer increased.When the moisture content reached 40%,the count could reach up to 3.67×107 cfu/g.When the moisture content was below 10%,the count was minimal,suggesting that low moisture levels inhibit miscellaneous bacteria growth.In conclusion,the optimal pH for producing biofertilizers with Bacillus subtilis is between 6.00 and 7.00,with a moisture content below 20% .
pHMoistureBacillus subtilisBio-organic fertilizerActive cultivable countNumber of contaminant
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