Effectiveness of Biochar and Elemental Sulfur for Sustaining Maize Production in Arid soils

Sandy soils represent most of the arable lands in Egypt. These soils are infertile and therefore incorporating organic products such as biochar in their surface soil layers are recommended to improve their productivity. Yet, biochar is of alkaline nature which may diminish the availability of many soil nutrients needed for proper plant growth. Thus, the current study investigates the impacts of adding elemental sulfur together with biochar to lessen the negative consequences of normal biochar on productivity of maize plants grown on a poor fertile light-textured soil. Also, acid modified biochars with either sulfuric or phosphoric acids were used herein to attain this goal. To attain this goal, a pot experiment of a randomized block design was conducted, comprising 2- factors: (1) 3-types of biochar (non acidified (BC), acid modified biochar with sulfuric acid (SMBA) and acid modified biochar with phosphoric acid (PMBA)) mixed with a soil (loamy sand, 97% sand) at a rate of 10 g kg-1 as well as the non-amended-control. (2) elemental S applied at rates of 0, 2 and 4 g kg-1 soil. All pots received 1.6 g kg-1 compost then left to equilibrate for two weeks. Later, maize seeds were planted for 60 days. Results reveal that maize dry weights and heights were significantly enhanced owing to application of acidified-biochars; while the corresponding increases owing to application of non-acidified biochar were almost significant. Such increases were correlated significantly and positively with both Olsen-P and AB-DTPA-Zn. On the other hand, application of S recorded no direct significant impacts on maize growth parameters, nevertheless it decreased significantly soil-pH, especially with increasing the dose of application and this in turn upraised extractable-AB-DTPA-extractable-Fe and Zn. Interactions between non-acidified biochar and S recorded further positive improvements in nutrient availability and plant growth versus applying each soil; yet such increases were still below the ones recorded for acidified biochars. The environmental impacts for using these additives on global warming threats were also considered in this study via calculating C-cycle feedback and all estimated values were positive. This indicates that sequestered C was probably higher than its emissions. Future perspectives are needed to investigate the efficiencies of using these additives under field conditions for at least two successive seasons while evaluating the economic and environmental outcomes for these additives.