Experience in achieving high yield and high quality by covering greenhouse peaches with old film
Peach trees are light-loving fruit trees and are sensitive to light; when light is insufficient, the photosynthesis of the leaves cannot proceed normally. In places with sufficient light, flower buds are numerous and plump, and fruit quality is good; in shaded places, flower buds are shriveled and fruit quality is poor.
Covering greenhouse peach trees with old film will cause insufficient light in the shed. Scientific experiments show that water droplets, grass debris, dust, and the like on the shed film will reduce the light transmittance of the shed film by about 30%; after new film has been used for 2, 10, and 15 days, the light in the shed weakens by 14%, 25%, and 28% in sequence. Old film has been used for a longer time, and the more grass debris and dust adhere to the film, and the more water droplets adhere to the inner surface of the shed because of film aging, the weaker the light in the shed becomes. Someone conducted a comparative experiment on covering greenhouse peach trees with new film and with old film (both being polyvinyl chloride drip-free greenhouse film). The former had a yield of 3160 kg per mu, with large fruit, deep coloration, high firmness, high sweetness, and good taste; the latter had a yield of 2528 kg per mu, a reduction of 20'%, with small fruit, light coloration, low firmness, low sweetness, and poor taste. Through the comparative experiment, it was found that although covering with old film saved 1200 yuan per mu in film purchase funds, it reduced income by 3600 yuan per mu compared with covering with new film. This can be described as picking up sesame seeds but losing the watermelon, where the loss outweighs the gain.
In order to increase the yield of greenhouse peach trees covered with old film and produce high-quality fruit, after several years of practice, we have worked out four lessons.
1. Extend the lighting time. On the premise that the temperature in the shed is not lower than the temperature required for peach tree growth, uncover the curtain as early as possible and cover the curtain as late as possible.
2. Keep the shed film clean. Frequently clean dust and grass debris from the greenhouse film, remove water droplets from the inner surface of the shed, and promptly sweep away snow on snowy days, so as to enhance the transparency of the shed film.
3. Remove shading leaves. During the fruit enlargement and coloring period, remove the shading leaves above the fruit. If the planting density of peach trees is high and the shed is shaded, more leaves can also be removed. The principle is: generally, for early-maturing varieties with small fruit, leave 20-25 leaves per fruit; for medium-maturing varieties (medium-sized fruit), leave 25-30 leaves per fruit; for late-maturing varieties (large fruit), leave 30-35 leaves per fruit, with a maximum of 40 leaves.
4. The whole shed needs large ventilation. During the fruit enlargement and coloring period, when the daily average temperature is stable at 13°C-20°C and the temperature in the shed exceeds 25°C, the whole shed should be ventilated greatly, lifting the upper sheet of the shed film up to the shed ridge, and lowering the front bottom skirt to ground level, so that sunlight shines directly into every corner of the greenhouse. The result of doing this is that in the greenhouse, sunlight is sufficient and the temperature is relatively high; hot air continuously rises and flows out of the shed, while cold air continuously flows in from the lower front part of the shed as replenishment, speeding up air convection. Coupled with sufficient sunlight, peach tree leaves strengthen photosynthesis, thereby producing more organic matter, making the fruit flesh substantial, firmness high, coloration good, and sweetness high.