S and N synergistic effect
Synergistic effect is an effect arising between two or more agents, entities, factors, or substances that produce an effect greater than the sum of their individual effects. It is opposite of antagonism (Business dictionary).
By Libih’s law the lack of one of the nutrients in the soil becomes a limiting factor and leads to a yield decrease in both quantity and quality. Missing sulphur (S) and nitrogen (N) stops protein forming process in the plant, therefore diminishing seeds quality, negatively affects plant development. Because of the central role of S and N in the protein synthesis the supplies of these nutrients in plants are highly interrelated. S addition is necessary to improve efficiency of applied N fertilizer. A shortage in the S application reduces N uptake from the soil by plants, thereby increasing nitrate leaching. On the other hand, large amounts of N create a deficiency of S. Synergistic effect of N and S in major crops was considered as positive in a number of scientific studies. Optimum N:S ratio is ranged between 5:1 and 7:1.