Manganese sulfate is an essential trace element for crop's growth, though the content only takes up ppk or much less.
It promotes the photosynthesis. Mn is one part of chloroplast, and leaves will lose green color when lacking of manganese, and photosynthesis will restrain, carbohydrate will decrease.
It adjusts the redox reaction, Mn exists in the form of divalention to be absorbed, and exists in the form of tetravalence ion to take part in the reduction process of kinds of materials. Mn increases the plant breathe, and adjusts the redox reaction. E.g. when a crop absorb nitrate nitrogen, Mn acts and turn nitrate nitrogen to amino acid, and then combines protein. The protein combination will decrease when lack of manganese.
Mn also can adjust the transformation of ferrous and ferric iron, and then promote the redox reaction. This shows that Fe and Mn affect each other, and Mn content will cause Fe deficiency. What’s more, Mn has a very close relationship with Cu and Zn as a catalyst.
It promotes the nitrogen metabolism. N content in kernel and amylan protein content in the protein composition increased after apply some Mn fertilizer for wheat. For peanut, the root nodule quantity and volume are increased. For Leguminosae, weight of root and N content of soil will increase.
Mn affects nitrogen metabolism very much, and free amino acid will accumulate and the protein combination decrease when lacking of Mn. Hereby, N content of kernel will increase if applying some Mn fertilizer.
It benefits for seed’s germination. Mn stimulates coleoptile to extend, and strengthen the hydrolysis process of amylum and protein for seeds, makes the content of monosaccharide and amino acid higher than that of untreated. Mn can speed the assimilation materials (cane sugar in special) transfer from the leaves to roots or other parts to supply enough energy to all parts of plant. The experiment shows that applying some Mn to cotton will lighten bud drop and receive long fibre cottons with bright color.
Ability of premunition improves when apply some Mn fertilizer. It can lighten smut for barley, smut disease and covered smut for rye. It also can improve the resistance of late blight for potato, damping off for sugarbeet and tan disease. What’s more, manganese sulfate can strengthen the cold resistance of crops.