Plant growth and potassium supply dynamics on a chernozem soil of a long-term fertilization and irrigation experiment with maize monoculture in Hungary
For the plant production used soil's nutrient supplying ability ideally should correspond to the needs 
of the plants. The aim of our experiment work is to study as precisely as possible, how the dynamics of 
growth and nutrient uptake of the maize plant develop during the vegetation period. For their 
determination the basis of our research work was a long-term irrigation and fertilization monoculture 
maize field experiment that has been set up in 1984 near to Debrecen, Hungary. The soil of this 
experiment is a medium-heavy, loam texture calcareous chernozem type based on loess. The deepness 
of humus soil layer is between 70 and 90 cm. Its upper layer has become leached due to the intensive 
production in the past decades, so it doesn't content any significant lime-amount. Therefore, the soil pH 
is slightly acidic in the production layer, which is favorable for nutrient-mobilization and -uptake. This 
field represents the production circumstances of the chernozem soils of Hungary with excellent 
productivity. Effects of three factors were studied: genotypes of maize (3), fertilizer dosages (6) and 
irrigation levels (2). The total number of investigated treatments (plots) was 36. Plant samples were 
collected 7 or 6 times during the vegetation period, and the above-ground dry matter and the nutrient 
uptake of plants were determined. For characterizing and describing of the plant growth and nutrient 
uptake dynamics was used the so-called “S-type” (acceleration – saturation) equation as follows: 
y=A/(1+exp(-k*(x-x0)))*(1-b*x), where “y” is the actual value of the measured (dependent) factor on the 
day “x” after plant shooting, “A” is the maximum value of “y”, “x0” is the day of maximum growth rate of 
“y” (point of inflexion) and “b” is the rate of decreasing of dependent value for one unit. According to 
our results and calculations it can be concluded, that beside the previously used soil and plant nutrientcontent 
the consideration and calculation of the plant-extracted nutrient-amount – depending on the 
applied hybrid and other agro-technological measurements – is suggested in order to characterize 
precisely the nutrient-supply of maize. This parameter informs us not only about the available nutrientamount 
at the sampling time, but about the supply level of the plants until the sampling time as well. 
We suggest for sampling times the intensive vegetative growth period, the switch between the vegetative 
and generative growth phases (silking), just as the grain-filling phase.
Changes in the quality of maize hybrids in various agricultural management systems
Changes in the chemical contents of the kernels of maize hybrids were analysed in three consecutive years (one dry, one arid and one wet) in samples originating from irrigation and fertilisation experiments. The results indicated that while irrigation and wet years had a protein-decreasing effect, the water supply did not influence the starch and oil contents. Under the influence of fertilization, the calcium and zinc contents of maize kernels decreased to varying degrees depending on the hybrid, while the sulphur contents changed parallel to the protein contents. Based on these data and on the use of more modern measuring equipment, tables giving recommendations for chemical contents should be revised.
Assessment of some agro-technological parameters of cactus pear fruit ( Opuntia ficus-indica Mill . ) in Morocco cultivars
Cactaceae had always attracted attention by their strange shapes and important adaptability supporting extreme conditions. For this reasons, Fruit traits were measured on 13 cultivars growing in different locations in Morocco. Results show significant differences between the cultivars. The source of this variation was probably genetic without excluding the geographic effects. The Tamri, Berkan, Ait Baha cultivars showed small fruit dimensions and weight. In contrast, Sidi-Ifni M, Nador, Mohammedia and Ben Guerir were greater than 100 g by fruit. Sidi-Ifni M, Hoceima, Mohammedia and Nador, although larger, contained few seeds, about 200 seeds per fruit; while Tamri, Ait Baha, Safi, Meknes and Tafraout contained over than 230 seeds per fruit. High levels of juice about 62 ml/100 g pulp were obtained with Sidi-Ifni M, Nador, Mohammedia and Ben Guerir cultivars. Total sugars of the 13 cultivars were quite similar and pH was low in Tamri and close to neutrality in the rest of cultivars. Therefore, oil extracted from Opuntia ficus-indica seeds constituted 13.6% of the whole seed. Thin-layer chromatography in conjunction with gas-liquid chromatography-mass spectrometry revealed a relatively high degree of unsaturation, 83.32% and 16% for saturated fatty acid, with a linoleic acid content of 63.66% followed by oleic 18.34%, palmitic 12.84% and stearic acid 2.81%. Based on these results, O. ficus-indica seed oil appears to be a good potential source of edible oil for human and (or) animal consumption. Our investigation describes that Tamri and Tafraout cultivars are not really a commercial viable fruit due to low total soluble solids value and highest seeds number per fruit. Against Mohammedia, Sidi Ifni M and Nador cultivars proved to have the highest fruit weight, very good total soluble solids value and low number of seeds, these cultivars can therefore be planted for both fruit production and for harvesting of cladodes for animal feed.