Key technology for bagless high-quality cultivation of pear fruit
_ Ma Wenliang, etc
First, the basic situation
Pear juice is succulent and crisp, sweet and delicious, suitable for all ages, and has always been loved by consumers. Due to the hot weather and concentrated rainfall in the growing season of pears and fruits, its growth is large, and it is easy to form a high temperature and high humidity environment in the pear orchard, and the occurrence of diseases and insect pests is serious, and fruit bagging is an important measure in the prevention and control of diseases and insect pests. The advantage of pear fruit bagging is that it can effectively prevent fruit diseases and insect pests, improve the appearance quality, reduce pesticide residues, and increase economic output. The disadvantages are: manpower and material investment is larger, long-term use of non-insect bag can induce the occurrence of pests into the bag; after bagging, it will reduce the exposure of sunlight to the fruit surface, affect the formation of fruit single fruit weight and contents, and the soluble solids, soluble sugars, vitamin C content of pear fruit are significantly reduced.
In order to avoid the homogenization of the edible quality of pears and fruits on the market and create a new selling point for pears, in recent years, relevant personnel have been organized to conduct a series of technical research on the high-quality cultivation of pear fruits without bags in some pear orchards, and have achieved preliminary results for peer reference and learning.
Second, bagless high-quality cultivation technology
(1) Control of the closure of the pear garden
When the closure of orchards exceeds 0.8, the probability of large occurrence of pests and diseases increases significantly, and the difficulty of prevention and control also increases, mainly in the amount of medication and labor, the control effect is relatively reduced, and the control of pests and diseases is not complete. The control of depression closure is mainly achieved by using reasonable plant spacing and scientific plastic pruning.
1. Plant line spacing selection. Reasonable plant row spacing is the basic work to achieve bagless cultivation in pear orchards. The number of plants planted in pear orchards with bagless cultivation should be controlled at 1200 to 1800 plants per hectare, and too dense will increase the amount of labor used for plastic pruning and reduce the efficiency ratio; too thin will increase the difficulty of control of the tree body, which is not conducive to plastic pruning, spraying, harvesting, etc. In production, 2m×3m or 3m × 3m planting density can be taken. The distance between adjacent branches of rows is controlled at more than 0.8m.
2. Reasonable shape and trimming. Plastic pruning adopts free spindle shape, so that the fruiting branches are evenly distributed in a spiral on the tree body, and the principle of mutual non-interaction between the fruiting branches is maintained; each tree fruiting branch is maintained at more than 15, and the number is insufficient, and measures such as carving buds and eye injuries can be taken to promote the emergence of branches and cultivate fruit branches. The height of the tree is controlled below 3.5m, and the trunk is below 0.8m without branches, and the resulting part is too low to form an economic yield, and it is easy to infect diseases and insect pests. When pruning, the length of a single fruit branch is controlled within 1.2m; a channel of not less than 0.8m wide is left between rows to facilitate the implementation of various technical measures and fruit transportation.
(2) Fertility regulation
The fertilizer supply is reasonable, and the tree grows strong and strong. If the fertilizer supply is not scientific, it will cause many problems such as the growth or weakening of the tree body, inducing diseases and insect pests. When the pear orchard is clay land, the base fertilizer should be re-applied to improve the soil structure, and the appropriate topdressing should be appropriate during the key growth period; when loam soil, the base fertilizer and topdressing should be equally emphasized; and the sandy land should be re-applied with organic fertilizer and repeated topdressing. When the tree is strong, it is necessary to reduce the amount of fertilizer or not to fertilize; when the tree is weak, it is necessary to appropriately increase the amount of fertilizer or the number of fertilizers. When the yield is high, the amount of fertilizer should be appropriately increased; when the yield is low, the amount of fertilizer should be reduced. The specific method is to apply decomposing organic fertilizer in the ditch in late autumn and early winter, with chemical fertilizer, and timely topdressing or foliar spraying depending on the growth trend of the tree during the growth period. Taking the late autumn pineapple with a yield of 30 to 40t/hm2 as an example, 45t of organic fertilizer, 0.15t of urea, 0.3t of phosphate fertilizer, and an appropriate amount of micro-fertilizers such as iron, boron and zinc were applied per hectare.
(3) Water supply technology
Unified planning of the water supply system during the construction of the park. The perfect water supply system is convenient for the water control of the pear garden, and realizes the on-demand water supply and irrigation and drainage of the pear garden. In the park, the tree nutrient belt and the working belt are divided between the rows and rows of the pear trees, and the nutrient bandwidth of the tree body is 1~1.5m, and the soil mound is separated from the working belt to facilitate the control of water and nutrients. Drip irrigation belts are laid in the nutrient belt, drip irrigation and watering are implemented, and large water flood irrigation is carried out after the application of base fertilizer and in the two periods before flowering. The vegetative belt of the tree body is moistened and the working belt is managed by drought. Through the differentiated supply of water, the demand for water for pear tree growth is achieved, and the expansion of weeds and diseases and insect pests is suppressed.
(4) Raising chickens under the pear garden
Raising chickens in pear orchards can not only inhibit the growth of weeds and reduce the density of insect populations, but also improve soil fertility, mature soil, save the cost of insect control and weed control, effectively reduce the residue and enrichment of pesticides, and is of great significance to ensuring the ecological safety of pear orchards and maintaining the ecological diversity of pear orchards. The main techniques for raising chickens under the pear garden are as follows.
1. Divide the breeding community. In general, every 1 hectare and below is divided into a breeding community, and the breeding community should be separated by a separation net, and there should be a 3 to 5m isolation zone between the two adjacent communities. The corresponding position of the isolation belt of the two breeding communities should be left with a door or passage, which is usually closed, and it is conducive to rotating with each other when spraying.
2. Chicken coop construction. Each breeding community should build a simple chicken coop in the leeward sun, the chicken coop can be built 3 to 4 floors, and the upper part is set up with a rain shelter, and it is advisable for the chickens not to rain when it rains.
3. Breeding density and stocking time. Each hectare should be controlled at about 500 chickens, and the chicken seedlings should be more than 20 days. If the density of culture is too large, the risk of disease and influenza is increased; too little is difficult to achieve the purpose of curbing weeds and insect pests. The stocking time is preferably when the temperature is basically stable at 20 °C, and the area is stocked in mid-April, and each region can be advanced or delayed according to the specific conditions such as the temperature in the region.
(5) Regulation and control of flowers and fruits and supporting measures
Flower and fruit control technology is one of the core technologies of pear and fruit bagless cultivation, on the basis of the traditional flower and fruit thinning technology, the following points should be achieved.
1. To produce fruit. The amount of fruit retained is determined according to the target yield and the weight of the single fruit. Take the late autumn pineapple with a planting density of 30t/hm2 commercial pears with a planting density of 3m×3m as an example: according to the single fruit weight of the pear 0.4kg, the fruit demand per hectare is 75 000 to 80 000; 1200 pear trees per hectare, each pear tree needs to bear 70 fruits, considering some losses in production, in fact, the amount of fruit left per pear tree should not be less than 75. Other varieties can be adjusted accordingly according to their single fruit weight.
2. Fix the flowers with fruit. The amount of flowers left is determined according to the amount of fruit retained. Still taking the late autumn pineapple as an example, if the amount of fruit left per pear tree is 75, considering the influence of fruit set rate and other related factors, the amount of flowers retained is not less than 3 times the amount of fruit retention, and the effective amount of flowers left by each pear tree should be 200 to 250 flowers. Other varieties can be adjusted accordingly according to the weight of the single fruit and the fruit set rate.
3, the flower part should be reasonable. Ideally, the flowers are evenly distributed in the branches and trees. In actual production, it is often more outside and less inside, and the distribution is uneven. Through the corresponding flower thinning measures, the outside side is more sparse, the inside side is appropriately more retained, and the control is gradually reduced from the outside to the inside, so that the distribution is relatively balanced.
4. Fruit thinning technology. There are some differences between fruit thinning technology and ordinary cultivation, and the standard is that the distance between fruits and fruits should be at least 3 cm. Only 1 fruit is left for each inflorescence, and no more should be left. On the same fruit branch, there should also be a gap between the fruit and the fruit; the fruit between the different fruit branches cannot affect each other.
(6) Keep the surface of the fruit clean
The key factor in the bagless cultivation of pear fruit is whether the protective layer of the fruit surface is intact. The protective layer of the fruit surface is intact, the protection effect on diseases and insects is better, and the fruit is less harmful to diseases and insects; on the contrary, the protection effect of diseases and insects is poor, and the fruit is heavily harmed by diseases and insects. The leaves are the most important source of fruit surface attachments, and the parts of the fruit surface with leaf adhesion are susceptible to the invasion of diseases and insects. The phenomenon of leaf sticky fruit should be cleaned up in time, and too many leaves near the fruit should be properly removed, especially the leaves close to the fruit surface. Bird droppings and various secretions are also important sources of pollution on the fruit surface, and should also be cleaned up in time.
(7) Comprehensive prevention and control of diseases and insect pests
Implement the principle of giving priority to prevention and comprehensive prevention and control. Efforts should be made to cultivate robust trees, reduce the base of diseases and insects, seize the critical period, and carry out key prevention and control. In terms of prevention and control, physical control is the mainstay, with mineral-derived pesticides and biologically derived pesticides for ecological control, and highly selective low-toxicity pesticides are used for key prevention and control during critical periods. Specific measures are as follows.
1. Tie the grass handle in autumn. Autumn tying grass handle is a method of controlling various insect pests such as pear small heartworms and peach small heartworms. Before the fall of leaves in autumn, a 10 cm long straw handle is tied to the trunk 50 cm from the ground, and the next year before the sting is untied, the beneficial insects are picked out, and the pests are concentrated.
2. Remove dead branches and leaves. Removal of dead branches and leaves is an important measure to reduce the base of diseases and insects, which can be carried out simultaneously in conjunction with winter shearing. The dead branches and leaves and the branches and disease residues left by the winter shears are cleaned up together, and the harmless treatment is concentrated, so as to eliminate a variety of diseases and insect eggs that overwinter, and reduce the pressure of disease and pest control in the following year.
3. Whiteen the trunk and apply the cut. After the winter shear, the trunk whitening and shearing work are carried out in time, and the whitening of the trunk has the effect of eliminating the eggs of pathogens and insects and protecting the tree body. Applying the cut in time after winter shearing can prevent pests from invading from the shear. The whitening agent formula can be prepared by using the ratio of stone sulfur compound: salt: quicklime: water = 1:1:6:20, and can be used after stirring evenly.
4. Spray stone sulfur compound at the embryonic stage. Spraying 5 baumedo stone sulfur compounds before germination can control a variety of diseases and insect pests, such as red spiders, aphids, pear web aphids, black star disease, etc.
5. Apply the trunk oil ring or tie plastic film. In mid-March, apply a 10 cm wide oil ring or tie plastic film to the trunk 50 cm from the ground to prevent overwintering mature larvae and nymphs from overwintering the tree; during the snail stage, stick sticky shellac on the plastic film and apply salt liquid or salt liquid in the oil ring to prevent snail hazards.
6. Hang a yellow armyworm board. Hanging yellow armyworm board can control adult insects of aphids, pear stem bees and a variety of pests, and hanging can effectively eliminate adult insects during the adult occurrence period, reduce the amount of eggs laid by adults, reduce the number of larvae and harm. In early May, the area hangs 1.5 m above the ground, with 150 to 200 armyworm boards per hectare, which are replaced every 7 days.
7: Place the sweet and sour solution. Sweet and sour solution can induce pear small heartworms, pear large heartworms, scarab beetles, leaf curl moths and other pests that are sensitive to the smell of sweet and sour wine, which have less environmental impact and are commonly used measures to control insect pests in pear orchards.
Sweet and sour liquid can be prepared with sugar: vinegar: wine: water = 1:5:1:15 formula, the sweet and sour solution is mixed and placed in a yellow open bottle, the amount of placement is 1/2 to 2/3 of the bottle; hanging at about 1.5m from the ground, hanging about 150 to 200 per hectare; when the wind is strong, it should be hung at the upper air outlet, and adjusted with the wind direction, cleaned once a day.
8. Timely spraying. In the occurrence of diseases and insect pests should be sprayed in time to control diseases and insects, can be used 50% carbendazim wettable powder 600 times liquid or 80% daisen manganese zinc 1200 ~ 1500 times liquid to control pear black star disease, black spot disease and rotisis and other diseases; with 1.8% avermectin emulsion 3000 times liquid to control pear lice, aphids, red spiders and other pests. Spraying on the back of the leaf is the mainstay, taking into account the front of the leaf, which can effectively improve the prevention and control effect. Spraying is prohibited for one month before fruit picking.
9. Prevention and control of bird pests. Bird pest control is relatively difficult. The erection of anti-bird nets in pear orchards is a relatively economical and feasible measure, and the erection period is appropriate in late July, and the mesh can be selected from 2cm × 2cm. The erection method is the whole garden cover, generally 1 hectare and below is an area, and the single pear orchard area of less than 1 hectare is not recommended to erect a defensive bird net.
(8) Timely harvesting
Timely harvesting is an important task to ensure revenue, generally speaking, when the fruit has the characteristics of this variety, it can be harvested, and it can be determined early or delayed according to market conditions.