Effects of Two Biochar-based Organic Amendments on Soil Chemical Properties and Productivity of Selected Vegetables

Blending biochar with non-pyrolysed low-cost wastes and or compost has been mooted as a feasible replacement to pure biochars, that are either costly or don't give the desired yield increases when used alone. We, therefore, evaluated the effects of two organic amendments containing small quantities of biochar on the soil chemical properties, and productivity of lettuce and Chinese cabbage. These amendments included; (I) Pellets (made from 30% biochar and 70% non-pyrolysed wastes) and the B-C organic amendment/B-C (made by adding 20% biochar to 80% of livestock compost). The study was conducted through a pot experiment with five soil amendments including; pellets, B-C, NPK+ pellets, NPK+ B-C, NPK and the control. Chinese cabbage and lettuce were each grown separately on the amended soils. Soil chemical properties were determined both before and at the end of the growing season whereas growth and agronomic attributes of the vegetables were taken at the end of the experiment. Both B-C and pellets ameliorated soil chemical properties whilst NPK and the control either had detrimental or no effect in the soil. Regarding vegetable productivity, however, NPK and B-C treatments produced better results than the pellets. From the observations, biochar blended organic amendments are capable of replacing pure biochars in agriculture but more studies are required to clearly discern the extent of their effects on a long-term basis and under field conditions.