Acid sulfate soil accounts for about half of the rice cultivation area in the Mekong Delta. Even the alluvial soil along the riverbanks contains acid sulfate materials in the deep soil layer. Therefore, after the fields dry and are flooded again, the soil is often very acidic, the pH value can be below 4, which is toxic to rice. In rice cultivation, it is necessary to detect early symptoms of rice poisoning in order to have measures to neutralize and limit its harmful effects.

Rice poisoned by acid sulfate has dark reddish brown roots, rough, with few root hairs. In fields buried with decomposed straw under flooded conditions, the rice roots are black with organic poisoning and die. When rice is poisoned, root respiration is reduced, not creating enough energy to absorb nutrients. Therefore, poisoned rice is often accompanied by symptoms of malnutrition and creates conditions for brown leaf spot disease to develop.

Rice poisoned by acid sulfate has poorly developed leaves. Narrow leaf blades cause poor photosynthesis, leaves are dark reddish brown and often associated with P deficiency symptoms. Alum poisoning causes poor rice germination and reduces disease resistance, especially leaf blast disease.

The weather in early June, alternating between sunshine and rain, is a favorable condition for the latent alum layer to become active. Therefore, you should pay attention to:

Pump new water into the field when the ground is slightly rough (be careful not to let it crack). Alum poisoning often goes hand in hand with organic poisoning, so after draining the water, let the field surface be slightly rough to let the toxic gaseous substances quickly evaporate. If possible, pump water in and drain it out again, that is very good.

In addition, it is necessary to apply products with high Carbon content to reduce the harmful effects of heavy metals Al3+, Fe2+ by adding betaine osmotic protection agents. You can refer to the specialized micronutrient fertilizer products for rice. Wokozim. Wokozim has the ability to absorb ions. and the decomposition of pyrite (FeS₂), Al ions^3+, Fe^2+, SO₄^2- . In case the soil is too heavily contaminated with alum, lime or phosphate can be combined to neutralize the acidity.

After a few days of pulling the rice, check the roots. If you see new white roots, continue to fertilize and care for the plant normally. If the roots have not grown much, you can use additional multi-component organic biological fertilizer Wokozim Liquid to spray on the leaves to regulate the opening and closing of stomata as well as balance the amount of water in the cells, thereby increasing the ability to withstand flooding in case of heavy rain with organic poisoning.

By simultaneously applying Wokozim micronutrient fertilizer through the roots and multi-component organic biological fertilizer Wokozim Liquid through the leaves, the rice plant will increase the biomass of the root system, increasing the plant’s ability to absorb nutrients. Increasing the photosynthesis process thereby helping to increase crop yield.