Effect of charcoal (biochar) amendments in Manawatu sandy-loam soil (New Zealand) on white clover growth and nodulation

New Zealand primary industries such as dairying produce significant amounts of greenhouse gases, particularly methane. Storage of carbon in agricultural soils in the form of biochar has been proposed as a means of offsetting carbon emissions. Biochar could also improve soil conditions for plant growth. This paper reports the effects of biochar as a soil amendment added to a Manawatu sandyAloam soil, on the s pH, soil carbon and nitrogen, mineralisable nitrogen and hot water extractable carbon, together with root and shoot growth for white clover ( Trifolium repens var Emerald). Biochar was added to the soil in differing proportions. The proportions were 0:100, 20:80, 40:60, 60:40, 80:20 and 100:0, biochar to soil. Each of these six treatments was replicated four times and set up in a pot trial in a glass house configured with a Randomised Complete Block Design (RCBD). The addition of biochar reduced the growth of white clover shoot and root dry matter. The increased carbon content of soil and reduced supply of plant nutrients may be the reason for the reduced growth of white clover and biochar increased the pH.