Modelling rice yield from biochar-inorganic fertilizer amended fields

Abstract

Rice yield is vulnerable to climatic changes. High concentrations of atmospheric CO 2 is noted to increase yield by improving upon nutrient uptake and water use efficiency of plants. Temperature variations also affect plant growth and eventually crop yield as it has an effect on respiration and photosynthesis. Soil fertility is an important parameter affecting the production of most crops and rice is not an exception. The cost as well as the environmental consequences of using inorganic fertilizers makes it necessary to use other soil amendments such as biochar. Field experiments are often time consuming and involves a lot of drudgery. This research was therefore conducted to model the quantities of biochar-inorganic fertilizer combinations that give optimum yields of rice and assess the effect of changes in climatic parameters on the yield of rice. CERES-Rice model was used to simulate the yield of rice using different combinations of biochar-inorganic fertilizer as soil amendments. Effects of changes in climatic parameters on the yield of rice were also simulated. The yield of rice from the simulations were sensitive to the soil amendments especially the biochar. Treatments with no biochar had relatively low rice yields compared with those with biochar. The average simulated yields were 1.5 t/ha, 5.6 t/ha and 5.5 t/ha for treatments with 0 t/ha, 20 t/ha and 30 t/ha of biochar respectively. Increasing or decreasing rainfall resulted in reduction in the yield of rice. Increasing carbon dioxide concentrations generally led to an increase in the simulated yields of rice. On the other hand, decreasing the carbon dioxide concentrations resulted in decreased simulated rice yields. It was observed that increasing temperature resulted in a reduction in rice yield for the various treatments. The reduction in the yield of rice ranged from 7.64% to 34 .67%. • Biochar-inorganic fertilizer improve upon simulated rice yield. • Increase in temperature results in a decrease in simulated rice yield. • Increase in carbon dioxide results in an increase in simulated rice yield. • An increase in solar radiation results in an increase in rice yield.