Relations between Optical Properties and N Status of Tomato Leaves

An efficient use of N fertilizers in intensive vegetable production systems is one of the most important keys to reduce harmful side effects on the environment and to produce yield with high quality in a competitive market. Due to the fact that the N level in the soil and in the plant can vary highly during cropping period and within a field area, the measurement of the current and site-specific N status of plants can be a rewarding effort for the cultivator. Nevertheless, sensor based systems to detect the N status in real time have been scarcely implemented for horticultural purposes. This study was conducted with the objective to evaluate the use of a non-invasive sensor technology using spectral feedback signals from tomato leaves. The results indicate that it is possible to infer the N status of tomato crops using optical sensor technologies. Accordingly, the study showed that corresponding to N fertilization the use of optical sensors can supply data to specify the N input to an accurate level.