The planting of zucchini seeds is a difficult problem in production. The melon refers to the zucchini female flowers open after 3-4 days, the young fruit apex receding green yellowing, thinning and softening, the fruit is not inflated or inflated very little, the surface loss of luster, the apex shrinkage, can not form a commodity melon, and eventually rot or fall off the phenomenon. At present, zucchini seed planting melon has become a headache for vegetable farmers, now the author will be the cause of occurrence and preventive measures to give a brief introduction.
First, the cause of the melon
The main reasons for the planting of melon seeds are the discomfort of environmental conditions or the imbalance of nutrient supply. Specific can be divided into internal and external factors two aspects.
1. Due to poor pollination or no pollination at all, the ovary can not produce plant growth hormone, resulting in embryos and endosperm can not grow normally, coupled with nutritional growth and competitive nutrients, when the supply of nutrients to female flowers is insufficient, the plant growth hormone content of ovary is reduced, can not be strong and melon.
2. External causes
(1) variety of varieties, the number of melon is not the same, the general sensitivity to temperature-light is not high, there is a certain single strong ability, seedling stage endogenous hormone production of many varieties, less melon, on the contrary, more melon.
(2) temperature temperature is too high, more than 35 ℃ during the day, more than 20 ℃ at night, resulting in reduced photosynthesis, increased respiration, a large number of carbohydrates to the stem and leaf transport, long seedlings, malnutrition and melon. Temperature is too low, less than 20 ℃ during the day, less than 10 ℃ at night, the root absorption capacity is weakened, photosynthesis will also be reduced, resulting in nutritional hunger and the cause of melon.
(3) light zucchini into the flowering stage, this time if encountered continuous cloudy or rainy, day and night temperature difference is small, coupled with photosynthesis is affected, nutrient consumption is more than manufacturing, will cause malnutrition and melon.
(4) Planting density density is also one of the factors affecting the melon, density, the root of the soil in the competition of nutrients, and the upper part of the stem and leaf competition space, when the leaf area index reached more than 4, the transmittance of light permeability is reduced, photosynthetic efficiency is not high, consumption increased. When each 667m2 density up to 3000 strains, the leaves are "embedded" with each other and the shading is serious, and the rate of melon is increased.
(5) CO2 in general zucchini plants around the CO2 concentration is lower than 300mg/l, or higher than 1800mg/l, plant photosynthesis will be affected. The accumulation of carbohydrates in plants will be reduced, female flowers stunted, causing melons.
(6) The SO2 gas produced by factories in the suburbs of SO2 city drifts with the wind and can float to the zucchini fields, the protection fields are heated with coal fires, and the SO2 gas is produced after burning, and the free organic fertilizers such as rotting poultry manure and bean cake can also release a large amount of SO2 gas in the process of decomposition, which produces sulfuric acid in water, Can directly destroy the chloroplast and make the plant victimized. At the same time affect the conduct of photosynthesis, some have been tested, when the amount of SO2 in the air reached 0.2mg/l or so, after 3-4 days of zucchini on the symptoms of victimization and melon, to reach 1mg/l or so, after the 4~5h will be made of melon.
(7) NH3 in open or protected fields, ammonia is mainly derived from the decomposition of organic fertilizers and the gasification of ammonia nitrogen fertilizer at high temperature. In general, ammonia can be absorbed by soil moisture, and by the crop absorption and utilization, but high temperature so that ammonia escape into the air, when the content reached 8mg/l, zucchini can be a certain harm; When the content reaches 50mg/l, zucchini seeds will be melon, and even death.