Effects of Co-application of Biochars and Composts on Lettuce Growth

Abstract

The effect of biochar and organic resource applications on lettuce cultivation was investigated. Treatment conditions of pot experiment were designed with CN (control), IF (inorganic fertilizer), BC400-1 (Rice husk biochar 400°C 1%), BC400-1+CP (Rice husk biochar 400°C 1%+compost), BC400-4 (Rice husk biochar 400°C 4%), BC400-4+CP (Rice husk biochar 400°C 4%+compost), BC600-1 (Rice husk biochar 600°C 1%), BC600-1+CP (Rice husk biochar 600°C 1%+compost), BC600-4 (Rice husk biochar 600°C 4%) and BC600-4+CP (Rice husk biochar 600°C 4%+compost). The lettuce fresh weight in IF, BC400, and BC600 treatments increased 185, 101-219, and 83-138%, respectively, over that in CN treatment. Total amount of nutrient uptake in lettuce increased in the order BC400-4+CP > IF ≒ BC600-4+CP ≧ BC400-4 ≧ BC400-1+ CP ≧ BC600-1+CP ≧ BC600-4 ≒ BC600-1 ≧ BC400-1 ≒ CN treatments. Considering the results of fresh weight, number of leaves, and nutrients of lettuce, the growth of lettuce was most effective in BC400-4+CP treatment, over that in the IF treatment. Application of combined biochar and compost significantly affected the chemical characteristics of field soil after lettuce harvest. In addition, the positive effects of biochar and compost in soil were related to improved nutrient availability-related parameters such pH and CEC. Therefore, proper application of biochar with compost is effective at improving lettuce cultivation and can benefit the soil environment.