Mn is an activating agent of kinds of enzyme, and is an important part of photosynthesis, it can promote the chlorophyllous form and carbohydrate assimilation. So plants will decrease output obviously if manganese sulfate deficiency occurs.
Some crops are sensitive to manganese, such as wheat, potato, onion, spinach, apple, strawberry and so on, some other crops like maize, rye are not very sensitive to manganese.
Maize’s leaves will be soft and droop, and vein will lose green color when lacking of manganese sulfate, what’s worst, it will decrease the output even no any grain.
When maize lacks of manganese sulfate, the blade will occur yellow striation, and then wither gradually.
Rice’s plant will be short and with less tillers, the leaves will be thin and narrow, color will turn yellow and green when lacking of manganese sulfate, and then die gradually.
Other crops will occur similar symptoms when lacking of manganese, and effects will be good if applying some manganese fertilizer.
Generally, active manganese is treated as the leading indicator for soil’s supplying of manganese sulfate. It’s on extreme low level when below 5050mg/kg, 50mg/kg-100mg/kg is on low level, 100mg/kg-200mg/kg is on middle level, 200mg/kg-300mg/k is abundant. Applying some man-ganese sulfate will receive very good effects.
Manganese sulfate is the most common Mn fertilizer, and is used in top application. Soaking seeds, seed dressing, soil seed manure and slightly soluble Mn fertilizer is used as base fertilizer. Thick-ness for top application is 0.05-0.1%, 0.3-0.4% for fruit trees, 0.03% for Leguminosae crops, and 0.1% for rice. When used in seeding dressing, 4g-16g manganese sulfate for every 1kg seeds are used for different crops. So does the soil seed manure.