Influence of meteorological conditions on cropping power and quality of green mass in Sudan-grass

Abstract

The decrease of spring crops productivity is a fairly common phenomenon. Sudangrass differs from other spring crops due to its drought and heat tolerance and lack of special demands to soil. Despite high tolerance to drought, Sudan grass is highly responsive to additional moisture and intensively accumulates the growing mass. The quantity of precipitations and air temperature are the main climatic factors which determine productivity of any crop, including Sudangrass. The precipitations in the period ‘sprouts (shoots) - 1 cut’ (0,89±0,22) showed the greatest effect on the productivity of green chop of Sudangrass in our trials. Under the increase of the precipitations on 1mm during the very period the yield of green chop increases on 0,14 t/ha. The productivity of green chop and absolutely dry matter possessed an average and week feedback with the sum of temperatures, the yield of digestible protein had a positively average one. While increasing the sum of air temperatures on lCPCthe green chop yield decreases on 0,06 t/ha, the yield of digestible protein increases on 0,007 t/ha. The highest yield of green chop can be obtained under a combination of the following hydrothermal conditions: 140...180 mm of precipitations and 2550...2700°C for vegetation of Sudangrass. The hydrothermal coefficient (HTC) is the main index which shows the correlation between the amount of precipitations and air temperature. The HTC increase on 0,1 results in the increase of the productivity of green chop on 3,58 t/ha, absolutely dry matter on 0,47 t/ha and digestible protein on 0,09 t/ha.