Stevia sweeteners are derived from the leaves of the Stevia rebaudiana (Bertoni) plant, an herbal shrub native to South America. The stevia plant has been used for food and medicinal purposes for hundreds of years, and its leaves and crude extracts have been sold as dietary supplements. Purified extracts of the sweet substances found in the stevia leaf, called steviol glycosides, are considered to be generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA). However, whole stevia leaves and crude leaf extracts are not permitted to be sold as sweeteners in the U.S. because there is not enough toxicological information on these products, according to the FDA. Stevia sweeteners are made by extracting steviol glycosides from the leaves of the stevia plant and purifying them to remove some of the bitter attributes found in the crude extract. Stevia Stevia JINING USP INTERNATIONAL CO.,LTD. , https://www.uspintl.com
1. Effects of seed internal factors, such as decline in physiological function, metabolic disorders, and transport system disorders in the body.
2. Inappropriate cultivation and management, such as dense planting, insufficient supply of nutrients, drought or excessive rain during the jointing stage of jointing.
3. Being harmed by pests.
Second, preventive measures
1. Use corn hybrid seed varieties in line with local conditions If corn seed has inherent problems, after sowing, it will be impossible to control empty stalks, which will inevitably cause losses. Therefore, we must make sure that we have a good selection. At present, there are many good varieties of corn that are suitable for planting in various places. They should be selected by Liangzhong and selected by the reputable seed department. They should not be greedy for cheap, buy inferior species or even fake varieties.
2. Adhere to the rational density of corn planting density, should be due to land, due to fat, due to species may not be too thin, not too dense. To ensure that corn plants have good ventilation and light conditions, to meet the three-leaf corn on the light requirements. It is best to use wide and narrow rows for planting.
3. Practically strengthen the management of corn during the growth period, such as time seedlings, seedlings, and retain seedlings; maintain good cultivator and weed control; seriously prevent and treat pests and diseases; increase fertilization materials, especially in fields with low soil fertility, should reuse base fertilizer and top-dressing Should be light before and after, nitrogen, phosphorus, potassium, should also be appropriate application of micro-fertilizer, applied per acre of zinc sulfate 0.5-1 kg; reasonable irrigation, control of watering seedlings, timely irrigation and other appropriate amount of water after jointing.
4. Artificially-assisted pollination can be carried out before flowering. The long leaves of the loquat leaves can be cut 3-7 centimeters at the top to make the filaments early and increase the chance of pollination.
5. Topdressing of spikelet differentiation and panicle growth time in the plant growth and development into the ear seat and heading 5-7 days before the ear to raise a good ear.
The Cause and Prevention of Corn Empty Stalk
One, empty stem causes