Impact of biochar and plastic mulch on soil properties in a maize field in Nepal

Biochar is a carbon rich product obtained from organic material by a process called pyrolysis. Similarly, plastic mulch protects soil from erosion, conserve water, suppress weed, and makes soil condition favorable for crop growth. The use of biochar and mulch has the potential to boost soil fertility by raising soil pH, increasing water and nutrient holding capacity, improving cation exchange capacity, and increasing microbial population. A field experiment was conducted to evaluate the effects of biochar application and plastic mulch on soil properties applied in maize fields with sandy loam soil at Rampur, Chitwan, Nepal from 31 March to 6 July 2018. The experiment was carried out in a split-plot design having plastic mulch as a main factor and biochar doses as a sub factor with three replications. The main plot is comprised of plastic mulch and no mulch. Similarly, the subplot consisted of four biochar doses i.e., 0 t/ha, 5 t/ha, 15 t/ha, and 25 t/ha. To know the effect of treatments the soil samples were collected at random points in the middle of each plot (to avoid edge effect) from 30 cm depth with the help of a screw auger. Dried, and grounded soil samples were analyzed in the lab. The results indicated that the Bulk density of soil relatively decreased with the plastic mulch but it was significantly higher in plots with biochar. 0 t/ha biochar showed the highest (1.22 gm/cm3) bulk density and the lowest was obtained from 25 t/ha (1.09 gm/cm3). However, soil parameters such as soil pH, Cation Exchange Capacity, Nitrogen, Phosphorus, Potassium, and Organic Carbon were relatively higher under plastic mulch over no mulch. In the same way, the potassium content of the soil was significantly influenced by biochar doses, it was the highest at 25 t/ha (741.47 Kg/ha) and the lowest at 0 t/ha (351.60 Kg/ha). However, soil pH, CEC, N, P, and OC were relatively increased with increasing rates of biochar application. Therefore, application rate of 25 t ha−1 biochar and use of plastic mulch in soil is considered as suitable because these efficiently increase soil moisture. In addition to that biochar increase Potassium content, decrease bulk density, and also improves Soil pH, Cation Exchange Capacity, Nitrogen, Phosphorus, Potassium, and Organic Carbon of soil.