Document Type : Research paper
Authors
Department of Water and Soil Sciences& Engineering, Nuclear Agriculture Research School, Nuclear Science and Technology Research Institute (NSTRI), Iran.
Abstract
This study applied a nuclear technique based on thermalized neutrons (TNs) to estimate maize yield losses arising from water shortage. Crop biomass consists of water, and light hydrogen (1H) existing in water slows down fast neutrons. Hence, TNs can be probably suitable predictors to determine crop losses. A greenhouse experiment was performed to evaluate the effects of various levels of water stress on crop losses and quantify relationships between crop losses and TNs. Once maize ripened, wet weights of the samples were measured, and then the samples were put around an access tube of the Hydro-probe Neutron Meter to count TNs. Thereafter, the samples were transferred to the oven for measuring dry weight and in turn, biomass water equivalent (BWE). Findings showed that the average values of TNs count ratio were positively and negatively correlated with BWE and damage (%), respectively. The regression models estimating crop losses were cross-validated based on the leave-one-out technique. An absolute mean error equal to 15% and R2 more than 0.6 were found indicating somewhat well performance of the models. This study shows a forward step in the feasibility of applying nuclear instruments to estimate crop losses. Further farm studies are recommended for practical applications.
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