Effect of biochar and phosphorus fertilizer application on soil fertility: soil physical and chemical properties

This study evaluated the effect of biochar and phosphorus fertilizer application on selected soil physical and chemical properties in two contrasting soil types: Rhodic Ferralsols (clay) in Thohoyandou and Leptic Cambisols (loamy sand) in Nelspruit, South Africa. Field experiments were conducted in summer and winter. Treatments consisted of a factorial combination of four biochar levels (0, 5, 10 and 20 t ha^?1) and two phosphorus fertilizer levels (0 and 90 kg ha^?1) arranged in a randomized complete block design with three replicates. Chickpea was the test crop. Soil bulk density, aggregate stability, porosity, total C, total N, C:N ratio, K and Mg were determined. Biochar (10 t ha^?1) and phosphorus increased bulk density and decreased porosity at 0–5 and 15–20 cm soil depth on a loamy sand soil in both seasons. The interaction between biochar and phosphorus increased total C and total N on a clay soil in the summer sowing. However, in the loamy sand soil, biochar (10 t ha^?1) increased total C, C:N ratio, K and Mg in the summer sowing. The effect of biochar was more evident in the loamy sand soil than the clay soil suggesting that the influence of biochar may be soil-specific.     

Economic Valuation of a Tamarind (Tamarindus indica L.) Production System: Green Money from Drylands of Eastern Uganda

Tamarind (Tamarindus indica) is a valuable tree species Uganda and elsewhere in semi-arid Africa—for fruit, timber, leaves and shade—but like other indigenous species has been subject to decline in recent years. The success of steps to assist natural regeneration and rehabilitation will depend on the net financial benefits to the rural households, hence there is a need for improved financial information on the costs and returns of growing tamarind trees. This paper compares the financial performance of T. indica production in the open woodland and cropland areas in Uganda. Household surveys were carried out in Kamuli and Kaliro districts in eastern Uganda from July 2004 to February 2005. The estimated mean production of T. indica was 127 and 84 kg/ha/year from open woodland and cropland areas, respectively, a statistically significant difference. The net present value from T. indica products was US$ 893/ha in woodland and US$ 684/ha in cropland. In terms of foreign export earnings, T. indica juice from woodland and cropland was estimated to generate US$ 0.03/ha and US$ 0.02/ha, respectively. Returns from alternative land-use activities of agricultural cropping were highest for maize and lowest for finger millet in both open woodland and cropland sites. Sensitivity analysis revealed that an increase in the real discount rate from 9.86% (base case) to 15% decreases the financial NPVs of both the open woodland and cropland areas by 24%.     

Growth,yield and water use efficiency of chickpea (Cicer arietinum): response to biochar and phosphorus fertilizer application

Field experiments were conducted during summer (2013/2014) and winter (2014) in two different soil types to evaluate the effect of biochar and P fertilizer application on growth, yield, and water use efficiency of chickpea. Soil types include Rhodic Ferralsols (clay) in Thohoyandou and Leptic Cambisols (loamy sand) in Nelspruit, South Africa. Treatments consisted of a factorial combination of four biochar levels (0, 5, 10 and 20 t ha^?1) and two phosphorus fertilizer levels (0 and 90 kg ha^?1) arranged in a randomized complete block design and replicated three times. Biochar application at 5 t ha^?1 significantly increased biomass, grain yield and water use efficiency of biomass production (WUE_b) in the clay soil compared to 10 and 20 t ha^?1. However, the increase was attributed to the addition of P fertilizer. Biochar application had no effect on yield components in the loamy sand soil, but P fertilizer addition increased number of seeds/pod in the loamy sand soil and number of pods/plant in the clay soil. Biochar and P fertilizer application on growth and yield of chickpea varied in soil types and seasons, as the effect was more prominent in the clay soil than the loamy sand soil during the summer sowing.