Effects of biochar application rate on sandy desert soil properties and sorghum growth

The addition of biochar (BC) has been suggested to increase the soil fertility and crop productivity of agricultural lands. This study evaluated the effect of different levels of BC on properties of sandy desert soils and its ultimate impact on plant growth. The samples of desert sand were taken from the Kubuqi of Inner Mongolia, China and the Thar Desert, Pakistan. The sands were treated with a BC made from the fast pyrolysis of pine sawdust at 400 degrees C. Four BC application rates i.e. 0, 15,22 and 45 t ha(-1) were used in this study. Effects of BC addition on the water consumption and plant growth of sorghum were monitored for eight weeks in a pot experiment. The hydraulic and chemical properties of soil were analyzed to discern the effect of BC on the fertility of sandy desert soils. The results showed that BC amendment significantly improved soil hydraulic and chemical properties. The BC applied at the rate of 22 t ha(-1) provided the best results as compared to all other treatments. Compared with the control group, the soil water-holding capacity (WHC) increased by 11% and 14%, water-retention capacity (WRC) increased by 28% and 32% and hydraulic conductivity decreased by 32% and 7% under the Kubuqi and the Thar Desert soils, respectively when BC was applied at 22 t ha(-1). Similarly, total C increased by 11% and 7%, total K increased by 37% and 42%, total P increased by 70% and 68% and total Ca increased by 69% and 75% while soil pH significantly reduced by 0.67 and 0.79 units, in the Kubuqi and the Thar Desert soils, respectively. The sorghum dry matter yield (DMY) was also significantly improved by 18% and 22% under the Kubuqi and the That Desert soils, respectively. The higher sorghum DMY consequently improved water-use efficiency (WUE) by 40% and 41% under the Kubuqi and the Thar Desert soils, respectively. In contrast, the plant growth and DMY declined at higher application rate (45 t ha(-1)) of BC. The BC made from fast pyrolysis of pine sawdust at a temperature of 400 degrees C showed great potential in improving the quality of sandy desert soils. Hence, it can be used for sandy desert soil management. (C) 2015 Elsevier B.V. All rights reserved.