The thick grass cover of dry-raised seedlings will cause the seedlings to turn yellow. Do not use urea when removing the mulch film, because the seedlings that have just been covered with the mulch are still very fragile and need to slowly transport nutrients. Using urea may cause the seedlings to turn yellow. If the dry-raised seedlings are burned to death, fertilization should be applied now and not too much. It is best to wait until the transition period to apply urea, which will be beneficial to the development of the seedlings. Therefore, thick grass cover on dry-raised seedlings will cause the seedlings to turn yellow. Do not use urea when removing the mulch film.

Rice seedling, rice seedling

Morphological characteristics

Annual aquatic herb. The stalks are upright, 0.5-1.5 meters high, depending on the variety. The leaf sheath is loose and hairless; the ligule is lanceolate, 10-25 mm long, extending from the base of both sides into the edge of the leaf sheath, with 2 sickle-shaped auricles holding the stem; the blade is linear-lanceolate, about 40 cm long, About 1 cm wide, hairless and rough.

The panicle is large and sparsely spread, about 30 cm long, with many branches, rough ribs, and bends downward when mature; the spikelet contains 1 mature flower, both sides are very flattened, oblong-ovate to Oval, about 10 mm long, 2-4 mm wide; glomus extremely small, leaving only a half-moon mark at the tip of the spikelet, 2 vestigial lemmas, cone-like, 2-4 mm long; pregnant on both sides The lemma of the sexual flower is thick, with 5 veins, and the midrib is ridged. There are small checkered papillae on the surface. It is thick and papery, covered with fine hairs and the terminal hairs are dense, with or without awns. The inner lemma is the same as the outer lemma, with 3 veins, apex pointed without beak; 6 stamens, anthers 2-3 mm long.

The caryopsis is about 5 mm long, 2 mm wide, and 1-1.5 mm thick; the embryo ratio is small, about 1/4 of the caryopse length. Chromosome 2n=24 (Shu et Qu 1985, Yao Z.1984), x=12 (Mukhergee et Debnath 1985).

Growth habits

Seedlings like high temperature, humidity, and short days. They are not strict with soil, but paddy soil is the best. The minimum temperature for seedling germination is 10-12℃, and the optimum temperature is 28-32℃. The average daily temperature during the tillering stage is above 20℃, and the suitable temperature for panicle differentiation is around 30℃; low temperature prolongs the differentiation of branches, stems and spikelets. The suitable temperature for heading is 25-35℃. The optimum temperature for flowering is around 30°C. If it is lower than 20°C or higher than 40°C, pollination will be seriously affected.

The relative humidity is 50 to 90%. The period from panicle differentiation to peak grain filling is the critical period for fruiting; a population with balanced nutritional status and high light efficiency is of great significance to improving fruiting rate and grain weight. The heading and fruiting stage requires a large amount of water and mineral nutrients; at the same time, it is necessary to enhance root vitality and extend the functional period of stems and leaves. Approximately 500 to 800 kilograms of water are needed to form 1 kilogram of rice.

Urea, also known as carbamide, is an organic compound composed of carbon, nitrogen, oxygen, and hydrogen. It is also called urea and is a white crystal. One of the simplest organic compounds. The diamide of carbonic acid has the molecular formula H2NCONH2 (CO(NH2)2) and a molecular mass of 60. The major nitrogen-containing end product of protein metabolism in mammals and some fish.

Mulch film

It is a ground covering film, usually a transparent or black PE film, and there are also green and silver films. It is used for ground covering to increase soil temperature, maintain soil moisture, and maintain soil Structure, prevents pests from attacking crops and diseases caused by certain microorganisms, etc., and promotes plant growth.

The thick grass cover of dry-raised seedlings will cause the seedlings to turn yellow. Do not use urea when removing the mulch film, because the seedlings that have just been covered with the mulch are still very fragile and need to slowly transport nutrients. Using urea may cause the seedlings to turn yellow. If the dry-raised seedlings are burned to death, it is best to apply fertilizer now but not too much. It is best to wait until the transition period to apply urea, which is beneficial to the development of the seedlings. Therefore, thick grass cover on dry-raised seedlings will cause the seedlings to turn yellow. Do not use urea when removing the mulch film.