Prevention and Control of Spirits in Paddy Field

The water floss group in the paddy field wraps the seedlings, making the seedlings late, dead seedlings or single plants without tillers; lowering the water temperature, when the sponges cover area reaches 30%, it can reduce the water temperature by 2-3 ℃; when a large number of sponges occur in the paddy fields, the fertilizers applied can not fall into the roots of rice, and compete with rice for water, fertilizer and growth space. In serious paddy fields, the plant height of rice decreases, the leaves turn yellow, and the yield is reduced by about 30%.

Characteristics of sponges

Elaeagnus angustifolia belongs to the annual aquatic green algae of the family Stargaceae, which regenerates by filamentous fracture or reproduces in rows, germinates from spores into new individuals and spreads with the water. Water cotton has strong vitality and fecundity, and likes fertilizer, especially under the condition of large amount of phosphate fertilizer, the growth is exuberant and the reproduction speed is accelerated. The salt-alkali stable water surface with soil pH value of about 7.5 is the most suitable for the growth of water sponges. Generally, it began to occur in the middle of May after irrigation in spring, and propagated and harmed rapidly with the increase of air temperature and the effect of phosphate and organic fertilizer in the field in the first ten days of June.

Occurrence regularity

Drought and lack of rain, lack of water resources, irrigation often use circulating water or fields that only irrigate without drainage are prone to water damage. The sponges and filaments in irrigation and drainage canals will propagate with the water flowing into the paddy field. A large number of sponges remain in the fields with high incidence of sponges last year, and there will be a large number of recurrence after irrigation in the coming year. The deterioration of water quality, the application of high amount of phosphate fertilizer, the formation of fertilizer and water can promote the occurrence of sponges. The situations that lead to the occurrence of water sponges are: low-lying still water paddy fields with long-term stagnant water in ⑴, paddy fields with poor drainage and deteriorating water quality. ⑵ applied a large amount of phosphorus-containing fertilizer to form a fertile and watery rice field. ⑶ paddy fields where Shuimian Gao occurred last year.

Prevention and cure method

⑴ scientific fertilization, reasonable formula of nitrogen, phosphorus and potassium. ⑵ irrigation and drainage is reasonable, using shallow, dry and wet irrigation methods. ⑶ manual salvage, when the sponges form a small amount of flakes in the field, they are first fished out manually. Although the remaining filaments have been broken, they have a strong ability to absorb fertilizer and quickly reproduce to form a new population, but the broken filaments will be poisoned and killed quickly when they come into contact with the liquid, so the prevention and treatment should be applied in time after waterlogging. For chemical control of ⑷, 65 grams of 26% Spirogyra net wettable powder per mu was applied 15 days after transplanting rice seedlings, and 100g per mu was used in the "quilt stage" after July, fertilized or sprinkled with fine soil, dry soil must not be used, and the water layer should be kept in the field for 5-7 days after application. Diseased and weak seedlings or leaking paddy fields are prohibited.