Can Biochar retain water in arid climates?  

Abstract

<p>Many studies have indicated that biochar could retain water for an extended period of time. Very little has been demonstrated the behaviour of biochar in arid environments where water retention is vital. The United Arab Emirates is one of the warmest countries in the World where farmers enjoy harvesting more crops during winter, however, during summer date palm trees is one of the main sources of food.  About 44 million date palm trees produce approximately 20 Kilograms of palm frond waste per year per tree (which is around 0.88 million tons of date palm biomass annually). This waste is currently sent to landfills. In this study, we proposed that in the arid soil conditions found in the UAE, this date palm waste could be converted to biochar and used to improve the water holding capacity of UAE soils. Therefore, this study aimed to compare the water holding capacity of amendments of date palm frond (DPF) and its biochar in UAE soils in different local weather conditions (winter and summer). A mesocosm experiment was used to assess the treatments at summer and winter temperature conditions. For the mesocosm, there were 6 different biochar and DPF treatments (1%, 3%, 6%, 12%, 15% and 18% biochar or DPF in soil) along with the controls (sharp sand, DPF biochar and DPF). The experiment was divided into 3 cycles with varying modified humidity. The impact of the experimental treatments was assessed using ANOVA. Both biochar and DPF had no significant effect during the first two cycles (wet and dry) but during the third cycle, the DPF had a 1% better water holding capacity than biochar. Given the mass loss of 5.7% during the production of biochar from DPF. It would seem that the best option is simply use collected date palm fronds. Therefore, further investigations are being processed to assess water binding capacity and physiochemical properties of the biochar, DPF and soil. </p><p> </p><p> </p><p> </p><p> </p>