Purity refers to the percentage of tested seeds that meet the characteristics of the variety. In other words, the higher the percentage, the better the seed quality.
Cleanliness refers to the percentage of the weight of pure seeds to the weight of all tested seeds except inclusions.
1000-grain weight 1000 grain weight means the weight of 1000 watermelon seeds. The 1000-grain weight of different varieties is different, but the 1000-grain weight of seeds of the same variety is basically determined. Under the condition of standard water content, the 1000-grain weight of seeds reflects the variety.
The seeds with full seeds and high 1000-grain weight have good quality.
Water content Seed water content has a great influence on seed life and storage life. The water content of seeds stored at room temperature should be kept below 12%- 14%. In other words, the lower the water content, the higher the seed quality.
Germination rate Seed germination rate refers to the percentage of all normally germinated seeds in the final stage of germination test within a specified date.
Germination rate (%) = number of all germinated seeds/number of experimental seeds × 100 within the specified date, and germination rate is one of the bases for determining sowing amount. The germination rate of primary seeds is not less than 95%, and the germination rate of secondary seeds is 80%.
What should we pay attention to in watermelon field regulation?
The first is to disinfect the soil. Watermelon fields can be disinfected by spraying 3-5g 1 m2 of dijunling or 0/00kg of quicklime (both methods are ploughing after sowing, so that the medicine and soil are mixed evenly, and quicklime cannot be used year after year). In fields with more pests, soil pesticides can be sown or sprayed everywhere in the fields.
The second is to re-apply base fertilizer. The optional formula of base fertilizer is: 3000 kg of farm manure, 0/00 kg of phosphate fertilizer/kloc and 40 kg of potassium sulfate; Or 3000 kg of chicken and duck manure (used after fresh manure is fermented), 50 kg of phosphate fertilizer and 30 kg of potassium sulfate.
The third is the whole field. After the fertilizer is evenly mixed into the soil, the warehouse (ditch) is opened at 2.5-3.5 meters. If intercropping, leave1.3m and1.3m other vegetables on the melon road. In this way, the amount of base fertilizer for watermelon and melon road will be halved. If there is no potassium sulfate, it can be replaced by potassium dihydrogen phosphate per mu 10 kg, and the effect is better. Then before planting, turn the fertilized melon road flat and thin, box it, and make a ditch more than 20 cm deep (the ditch should be 30 cm until the rain stops and the ditch is dry).
The fourth is to weed with chemicals. Because of the large area of watermelon, manual weeding is very troublesome. The experiment shows that the following herbicides are effective by spraying and sealing the soil before plastic film mulching: trifluralin on Gramineae and Portulaca oleracea, diamide on Tol and Cyperus esculenta, and Dipendazole on Gramineae and Cyperus esculenta.
How does watermelon control pests and diseases?
Watermelon diseases mainly include damping-off, damping-off, Fusarium wilt, powdery mildew, anthracnose and so on. If you suffer from Rhizoctonia solani, you can disinfect the seedbed with carbendazim and Luheng 1. If you suffer from Fusarium wilt, you can use 15% watermelon continuous cropping agent 1No. to water the roots with 300-350 times of liquid. 0.5 kg each time, when planting 3-4 real leaves, the control effect is good; If it is powdery mildew and anthracnose, chlorothalonil, thiophanate, fenxiuling and other drugs can be used alternately.
The pests of watermelon mainly include bedbugs, aphids, ladybugs, root maggots and red spiders. The control agent can be avermectin, dichlorvos, diphacinone, etc. Root maggots can be irrigated with trichlorfon. Advocate the installation of insecticidal lamps and yellow boards to trap and kill, and carry out physical control.
It is worth mentioning that root-knot nematode disease is very serious now, and there are outbreaks in many areas. Root-knot nematodes mainly infect plants at seedling stage, which is very harmful. Therefore, the seedbed must choose plots without root-knot nematodes. If nematodes are found after the seedlings are planted, the roots can be irrigated with avermectin such as 1% acaricide 2000 times and 1.8% avermectin 3000 times. Pesticides such as phoxim, Mi Le, carbofuran, diazinon and chlorpyrifos can be used for field preparation.