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Evaluation of the correlation between SPAD readings and absolute chlorophyll content of maize under different nitrogen supply conditions
121-126Views:362Currently, one of the most important objectives of agriculture is to maintain the principles of the sustainability. The use of precision technologies in agriculture belongs to this topic. The use of precision technologies is increasingly widespread in the cultivation of various agricultural crops, including maize. Sensing is an important part of these techniques. In our experiment we compared two methods: measuring relative chlorophyll content and the method of determine the extractable chlorophylls. The experimental plant was maize (Zea mays L.) and the measurements were performed at an early development stage (V8) of three genotypes. Three levels of nitrogen (0; 80; 160 kg ha-1) were applied during the experiment. The relative chlorophyll content was measured by SPAD-502 (Minolta, Japan) and a handheld GreenSeeker (Trimble, USA) device. The extractable total chlorophyll content decreased in parallel with the increased nitrogen level. The obtained SPAD values were diversified furthermore the NDVI values have not been changed for the effect of different nitrogen fertilization. In the early stages of development of maize, these parameters need to be complemented with other measurements to provide reliable information about the crops nitrogen status.
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Results of the sensory analysis of precision maize production
59-62Views:194This research was carried out in 2018, at the Látókép Experimental Station of the University of Debrecen in a moderately warm and dry production area, on deep humus layered medium-hard calcareous chernozem soil. In the scope of the research, the chlorophyll content of maize (Zea mays L.) was examined under field circumstances by means of local sensory measurements and we were looking for correlation between the obtained values and the amount of yield. Our measurements were carried out with Minolta SPAD-502 and GreenSeeker devices at 3 measurement times (4 leaf stage, 10 leaf stage and silking). It was found that phenological phases had an effect on the obtained SPAD and NDVI values and were in a slightly significant correlation with the yield. The most significant correlation was found between the results obtained during silking and the amount of yield. This may be because the least time has passed between the measurement time and harvest. Results obtained during the 10-leaf stage show excessive values in each case, which can be due to a measurement error. It was found that the phenological phase had an effect on the correlation of SPAD and NDVI values and the amount of yield. As the phenological phase progressed, the correlation between the measured results and yield has increased.