4(81), 2014

UNC 631.6:635.25:631.8(477.72)

Relevance of the topic. One of the main elements of cultivation technology of different corn hybrids under drip irrigation is a stand density of plants and background of mineral nutrition, which allows optimization the most efficient use of natural and climatic potential of the Southern Steppes of Ukraine to obtain high yields and quality of grain, the best economic and energy indicators were discussed in the article. The establishment of features of formation of leaf surface of plants and photosynthetic activity of crops are equally important, as these parameters have a direct impact on yield formation of investigated culture.

The main results. Leaf surface area significantly varied depending on the phase of plant development, and for the hybrid structure, stand density and pattern of plant nitrogen nutrition. On hybrid Mass 44.A this indicator was the highest — 44.900. m²/ha, but on the hybrids Sangria and Tibor this figure decreased on 9,7–21,9%. The thickening to 90–100 thousand plant/ha provided growth leaf surface of all hybrids on 10,1–14,5%. Nitrogen fertilizers are also provided growth assimilation surface area to 12,3–24,7%.

The net productivity of photosynthesis slightly changed at the beginning of the growing season, but from phase of fifteen leaves was marked increase this figure to 6,9–8,4 g/m² per day. The smallest photosynthetic potential for hybrid crops was discovered with Tibor with minimal plant stand density and without making nitrogen fertilizers. This indicator gained the highest level — 4.10 million m² days/ha in the form of hybrid Mass 44.A, which grew with stand density 90 thousand plant/ha and the use of fertilizers dose N₁₈₀Р₉₀.

Conclusions. Nitrogen fertilizers significantly contribute to the growth of leaf area and indicator photosynthetic activity of crops. The highest values of the studied parameters were on hybrids Sangria and Mass 44.A in stand density of plants at 80–100 thousand/ha and application of fertilizer dose N₁₈₀Р₉₀.

Keywords
drip irrigation, maize hybrids, stand density of plants, fertilizers, leaf area, photosynthetic activity of crops. (more…)