Based on Soil Plant Analysis Development (SPAD) values, nitrogen (N) deficiency, nutrient need, and the effect of fertilizer treatments on crop conditions can be quickly estimated, but the method of SPAD measurement significantly affects the accuracy of estimation. In field experiments near Debrecen, Hungary, we measured the reliability and accuracy of SPAD measurements in maize and potato populations using a Minolta SPAD-502 meter (Minolta, Tokyo, Japan). The aim of our study was to determine which SPAD measurement methods are capable of detecting small differences in the SPAD values. During the examination of maize ear leaves, we determined the distribution of SPAD values along the leaf blade and then identified single-and multipoint measurement methods. By comparing the results of the measurement methods we established that the single-point-based measurements are less suitable for the determination of the average SPAD value of the leaf blade than the multipoint-based measurements. Also, we showed that the increase in the number of measurement points does not influence the accuracy of the measurement in the case of systematic measurement methods based on the distribution of SPAD values. Thus we recommend five-point measurements to obtain the average SPAD values of the ear leaves: the tip of the leaf blade and at one quarter and one half of the leaf blade from the base on both the right and left sides. From the measurements conducted in potato, we showed that the SPAD values change at every foliar level and that the measurements carried out on the middle foliar level provide the closest correlation with the average SPAD values of the leaf canopy. Based on these results, we recommend making measurements at different foliar levels or on the middle foliar level to determine the average SPAD value of the potato leaf canopy.
The aim of our examination was to evaluate the correlations between the normalized difference vegetation index (NDVI) and yield, as well as to examine the possibility of yield estimation basedon NDVI in a seasoning paprika population.
Significant correlations were observed during the examination of the correlation between NDVI and yield. Furthermore, it was concluded that yield can be estimated with a 6.6–8.3% mean error based on the regression equations. No significant difference was shown between the error of estimations performed with various regression types and that of the estimations performed at various dates. For this reason, the identification of the optimum estimation method and the determination of the optimum date for estimation call for further examinations.
Larger cultivated plots are heterogeneous from a pedological aspect. Heterogeneity causes problems during fertilization and harvest. The heterogeneity of cultivated areas can be compensated by fertilization which is based on soil analysis. We carried out research into the changes of the soil on three soil types, from 1966 to 2006, on the cultivated areas of Hajdúszoboszló.There were no significant changes in pH on chernozem meadow soil and meadow chernozem soil, but the pH increased in 0-30 cm layer on type meadow solonetz soil. The saline content decreased in every examined soil type. Decrease was the largest on meadow solonetz soil. Decline of humus content was the largest (0.95%) on chernozem meadow soil, and the smallest (0.39%) on meadow chernozem soil. The nitrogen content decreased with 528 ppm in the 0-30 cm layer on chernozem meadow soil, and decreased by 186 ppm on meadow solonetz soil. Phosphorus andpotassium content increased in every examined soil types. Rise of phosphorus content was 188.9 ppm in the 0-30 cm layer on meadow chernozem soil. The potassium content rose by 153.7 ppm on this soil type. Phosphorus content increased with 70.8 ppm, and potassium content increased by 57.6 ppm from 1966 to 2006.
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