OVERCOME THE PHENOMENON OF POISONED RICE WITH ALUM, ORGANIC POISONING 01/06/2022

I. THE PHENOMENON OF POISONED RICE WITH ALUM:

1. Season: Entering the annual Summer-Autumn crop, alum poisoning is very common in all provinces and cities in the country.

2. Causes: Due to the low rainfall and uneven distribution at the beginning of the Summer-Autumn crop, the prolonged drought does not actively source additional water for irrigation, making the soil layers containing alum-producing materials easily oxidized, leading to oxidation. The phenomenon of alum leakage through cracks and capillary vessels in the soil. At this time, the soil has a very acidic pH, and the mobile Fe²⁺ and Al³⁺ concentrations in the soil solution are also very high, which is the main cause of rice roots and rice plants to be poisoned

3. Symptoms:

a. Symptoms of alum phytotoxicity due to iron (Fe²⁺ ):

When the rice plant is poisoned with iron alum (also known as hot alum), the common symptom is that the rice plant is yellowish in color, small brown spots appear on the old leaves, spreading gradually from the tip of the leaf downwards. Leaves become brown, bruised, yellow or orange.

In severe iron poisoning, all leaves turn brown and older leaves die prematurely. Rice plants are dwarfed and less blooming. If you up the rice bush to check, you will see that the roots are thin, short, dark brown and curled.

Due to the underdevelopment of the roots, the ability to absorb water and nutrients to the plant is limited, causing the rice plant to become malnourished , if this situation lasts for a long time, the rice plants will be gradually depleted, dying scatteredly or in clusters..

b. Symptoms of alum poisoning (Al ³⁺):

Aluminum alum (also known as cold alum) in high concentrations causes toxicity to rice plants, affecting the growth and development of plants.

Aluminum toxicity in rice usually manifests in older leaves first. Characteristically manifested as greenish-yellow or greenish-white streaks on the leaf veins.

The rice plant is stunted.

Root growth is slow and deformed resulting in poor absorption of water and nutrients.

Aluminum is the most toxic ion in acid sulfate soil.

II. THE PHENOMENON OF ORGANICALLY-POISONED RICE (choked roots):

1. Cause:

The main cause is the lack of oxygen in the soil, causing anaerobic conditions that inhibit the respiration of rice roots.

Usually because farmers produce continuously on a field, the rice stubble straw and of the previous crop is buried in the soil decomposing under anaerobic conditions to release toxic substances harmful to the rice of the following crop (organic toxins that are phenolic , hydrogen sulfide, methane gas, organic acids increase soil acidity).

This phenomenon also often occurs when applying a lot of organic fertilizer that has not yet decayed, the field soil has a heavy mechanical composition, the soil is not dried, the soil is flooded regularly, the soil is mixed with undissolved stubble straw ...

2. Symptoms:

When the new disease arises, the top of the rice leaves turn yellow and red, dry from the tip of the leaf spreads downward, the rice leaves tend to stand upright.

If the disease is severe, many upper leaves will be yellow and red up to 1/3 of the leaves, the rice plant will stop growing, less tillering, black rotten roots with a fishy smell, new roots will not arise.

This phenomenon usually occurs when the rice is 15-30 days old after sowing.

III. DAMAGE BY ALUM POISONING: – ORGANIC POISONING:

In addition to the area that had to be sown or replanted due to the high mortality rate of rice, most of the rice area was poisoned with alum or organic poisoning, leading to poor growth, sparse growth and low yield, causing damage. harmful to the income of people who live by farming rice.                                                      

IV. HOW TO FIX:

When seeing that rice plants have alum poisoning, organic poisoning, farmers need to stop fertilizing with urea, DAP or NPK immediately, because at this time, the rice roots have been damaged, and the ability to absorb nutrients in the soil is poor. To overcome the situation of rice plants with alum or organic poisoning and help rice recover the function of the roots, it is necessary to perform the following steps:

Step 1:

For alum poisoning:

Add clean water to the field to dilute the toxicity of Fe and Al in the soil, and at the same time prevent the soil from being oxidized, leading to alum leaking phenomenon. If possible, remove the old water and replace it with new water, which will have better alum washing effect, changing the water as many times as possible.

For organic poisoning:

In 10-20 days after sowing, if the tips of the leaves are yellow or red, pull out the rice to observe the roots. If you see black rotten roots, you must drain the water in the field, dig furrows to drain all the water in the hollow to remove toxic gases and toxins in the water. Put new water in the canal into the field.

Step 2:

Apply 50kg of Calcium Nitrate fertilizer /ha to quickly raise the pH of the soil, neutralize organic acids, Fe ^2+...helping the rice roots get rid of poisoning and stimulate cell growth. After applying Calcium Nitrate about 5 days, it is recommended to change the water to remove alum and toxins remaining in the water.

Apply Calcium Nitrate-based fertilizer contains 15.5% Nitrogen and 26.5% Calcium in the form of quick dissolution (CaO), so it has a faster and better alum detoxification effect than the conventional liming method.

Step 3:

In order to help the roots recover quickly, as well as provide the necessary nutrients for rice plants to grow while the roots have not recovered, farmers need to promptly spray more high-grade foliar fertilizers of SPC according to 2 way as follows:

Option 1: Spray foliar fertilizer MKP and Multi-K 2 times 5-7 days apart with a dose of 120g of MKP fertilizer plus 120g of Multi-K for a 25-liter water tank, spray 1.5 tanks for 1,000m2 at cool weather.

Foliar fertilizer MKP with full name is Mono Potassium Phosphate containing 52% phosphorus and 34% potassium. Due to its very high phosphorus content, MKP fertilizer has the effect of stimulating rice plants to grow new roots to replace old damaged roots.

Multi-K foliar fertilizer has a formula of 13 - 0 - 46, contains 13% nitrogen and 46% potassium, also known as KNO3 or Potassium Nitrate, works together with MKP fertilizer to quickly provide nitrogen and nutrients Phosphorus and potassium are easily digestible for plants through the leaves, in order to maintain the growth of rice while the roots have not yet recovered.

Option 2: Spray foliar fertilizer Poly-feed 19-19-19 twice 5-7 days apart with a dosage of 60-80g for a 25-liter water tank. Spray 1.5 tanks for 1,000m2 in cool weather.

Poly-feed 19-19-19 fertilizer is a very advanced foliar fertilizer because it contains all 3 macronutrients (N=19%, P₂O₅=19%, K₂O=19%) and 6 micronutrients. are mainly Cu, Fe, Zn, Mn, B and Mo.

After spraying foliar fertilizer 5-7 days, pull up rice bush to observe, if white roots appear, it means that the rice roots have recovered, the rice plants have overcome the status of alum poisoning or organic poisoning. At this time, it is necessary to add DAP fertilizer or NPK compound fertilizer to fully provide essential nutrients according to the needs of rice plants.

Four fertilizer products Calcium Nitrate, Poly-feed 19-19-19, MKP and Multi-K produced by Israeli Haifa company, distributed by SPC in recent years have been used by many farmers. In addition to bringing practical effectiveness in limiting damage when rice plants are poisoned with alum and organic poisoning in particular, the above fertilizers are also widely applied in agricultural production in general, helping to improve yield and quality for many crops.

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