INTEGRATED EFFECTS OF BIOCHAR AND DEFICIT IRRIGATION SUBJECTED AT VARIOUS GROWTH STAGES ON TOMATO YIELD AND WATER USE EFFICIENCY
L. Keabetswe1*, G. C. Shao1, J. Cui1, J. Lu1 and T. Stimela2
1Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil-Water Environment in Southern China, Ministry of Education, College of Agricultural Sciences and Engineering, Hohai University, Nanjing 210098, P. R. China
2Department of Crops and soil Science, Botswana University of Agriculture and Natural Resources, Gaborone, Botswana
*Corresponding author’s email: latiekebs@yahoo.com
ABSTRACT
In recent years, irrigation water resources have been diminishing leading to an exponential growth in agriculture water demand; hence the adoption of water saving techniques is inevitable. This study focused on the assessment of deficit irrigation and biochar amendment on maximizing water use efficiency of tomato with less compromise on yield.The experimental setup was a two-factorial, completely random block system, with three replications.The first factor was irrigation regime (a) full irrigation at all stages as treatments T1 and T2 (b) deficit irrigation at various stages as treatments T3, T4, T5 and T6. The second factor was biochar amendment, where by all treatment had biochar amendment except for treatment T1. The results indicated that biochar enhanced soil water status hence fruit yield and water use efficiency were improved with regard to treatment T2 over T1. Deficit irrigation applied at vegetative stage (T3) had minimal negative effect on yield while water use efficiency was improved. Yield reduction was pronounced when deficit irrigation was applied at flowering and fruit development stage followed by fruit ripening stage. A combination of biochar amendment and deficit irrigation can be a positive approach to save water while maintaining acceptable yields when applied at vegetative stage.
Keywords: Irrigation regimes, Soil water storage conservation, Water stress, Yield reduction.
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