THE PHOTOSYNTHETIC PRODuCTIVITY OF MAIZE uNDER THE APPLICATION OF TROPHY 90 HERBICIDE

Abstract

In today's conditions to achieve appreciable performance increase o f agricultural crops impossible without reliable protection of their sowing from weeds. Now the really effective measure for weed control is the use of modern combined herbicides with several active ingredients and small application rules.However herbicides being physiologically active substances influence to agricultural crops which although not belonging to the target sites to action of preparations but in conditions of agrocenosis their undergo to phytotoxic effects, accompanied by multi-directional violations of physiological functions, including changes in the contents of photosynthetic pigments. This in turn has a influencethe to value of the net productivity of photosynthesis. Because from the magnitude of the above parameters in direct proportion is the level a productivity o f culture the objective of our research was to establish the value of change under the applications o f herbicide Trophy 90 content of chlorophylls and carotenoids in maize leaves and value o f photosynthesis net productivity.It is found that value the studied parameters depended both on the rules applying herbicide and weather conditions during the growth of maize, because they was differed during the research period. The most favorable for the growth of maize and thus the accumulation of pigment and formation a net productivity of photosynthesis parameter was 2011 year. However although the indicator o f chlorophyll and net productivity o f photosynthesis was different in the years o f research, but the dependent of formation their values under the herbicide application rules was maintained.Among the variants of experiment with the application of different rules of herbicide most effective in terms of increase a studied parameters was the rule of preparation of 2.5 l/ha. In this variant of experiment the content of chlorophyll sum (a+b) higher than the control I (without the use of herbicides and hand weeding) at 15-19%, and the value of net productivity of photosynthesis - by 18-22%. In other variants of the experiment, the value of studied parameters was lower. The hand weeding has a slightly better efficiency.The conducted of regression analysis revealed a close correlation between the amount of chlorophyll content (a+b) and the net productivity of photosynthesis which is described as a regression equation: y = 0,38x + 0,74 where y - the content of the sum of chlorophyll (a+b) in leaves of maize plants, mg/g of wet substances; x - the net productivity of photosynthesis g/m2 per day.Consequently the use of herbicide Trophy 90 has a positive effect to the increase of content of photosynthetic pigments and value of net productivity of photosynthesis, especially in norm 3.5 l/ha. At the same time although the variant with hand weeding was showed slightly better results, but its use in industrial scale is unlikely under present conditions and requirements, as it can not ensure prompt and timely removing of weeds from maize sowing and too costly and unproductive.