What are the symptoms of fertilizer burn in rice? How to prevent and control it scientifically

Fertilizing is an important part of the rice growing process, and topdressing is required many times throughout the whole growth period. Each fertilization is very important for rice, as it is the foundation of its growth and development. If improper fertilization causes fertilizer burn, how should fertilizer burn be prevented and controlled? Let's take a look together.

1. Ammonia water burning

Symptoms and causes: The leaves initially turn a uniform bright yellow, and as time goes on, the entire leaf turns yellow-brown or red-brown, and in severe cases the leaves wither and die. The main cause is the ammonia gas volatilized from the application of ammonia water, which is dispersed by the wind and burns the leaves. When ammonium bicarbonate is broadcast on the field surface during fertilization, ammonia gas is volatilized during the decomposition process, causing localized leaf burning, especially in the basal leaves, where the condition is more serious.

Prevention and control measures: When using ammonia water, pay attention to keeping shallow water in the field, and plow immediately after fertilization so that the ammonium is adsorbed by the soil. In this way, ammonia gas will not volatilize, and it also helps root absorption. Fertilization should not be carried out at noon, and for topdressing, the concentration should preferably be 1%-2%. At the same time, pay attention to the wind direction to avoid burning the leaves.

2. Ammonium sulfate burning

Symptoms and causes: Affected leaves develop irregular white spots, and sometimes they also look very much like they have turned black and rotted. The main cause is that when ammonium sulfate is applied while the dew has not dried, the fertilizer adheres to the leaves. The local concentration of fertilizer adhering to the leaves is relatively high, and rain dissolves and washes it away, causing the leaves to burn and bleaching chlorophyll so they turn white. In the later growth stage, if the field lacks water, applying too much ammonium sulfate or broadcasting it unevenly can cause the roots to turn black and rot.

Prevention and control measures: When applying ammonium sulfate, pay attention not to do so in the early morning when the dew has not dried or when there are water droplets on the leaves, so as to prevent the fertilizer from adhering to the leaves. Maintain a water layer during fertilization and plow once, which helps root absorption.

3. Lime nitrogen burning

Symptoms and causes: Affected leaves first become dark red, then burn to show many scattered red-brown or dark brown spots of varying sizes. Soon afterward, the leaf tips wither and die and become red-brown, just like they have been scorched by fire. In severe cases, the roots turn black and die. The main cause is damage from lime nitrogen spots, which makes the powder particles adhere to the leaves, leading to brown or dark green water-soaked lesions.

Prevention and control measures: When using lime nitrogen as a base fertilizer, dry-plow once after broadcasting, then irrigate and transplant rice seedlings after a week, which is relatively safe. In addition, lime nitrogen should not be used directly for topdressing. It needs to be mixed with 10 times its amount of moist soil and piled for 10-20 days, kept moist, and applied after its toxicity has disappeared.

The above is an introduction to the symptoms of fertilizer burn in rice and its prevention and control measures. We hope it can help you. To learn more related knowledge, please keep following us.