What are the key management techniques for pear orchards in autumn and winter?
Autumn and winter are an important period when pear trees shed their leaves and go dormant. Strengthening field management of pear orchards in autumn and winter benefits pear tree growth and flowering and fruiting the following year.
1. Reasonable fertilization: before the end of November, apply one deep autumn fertilization to the pear orchard. The amount applied should account for more than 30% of the total annual fertilization, mainly organic fertilizers such as decomposed oil cake (rapeseed cake) fertilizer, residue fertilizer, compost, and human, livestock and poultry manure. The method is: at the drip line of the canopy of mature pear trees, dig 1-2 ring-shaped fertilization trenches about 60 cm long and 25 cm deep and 25 cm wide. Apply 30-40 kg of decomposed human, livestock and poultry manure per tree, mixed with 1-1.5 kg of decomposed oil cake (rapeseed cake) fertilizer (or 10-20 kg of decomposed residue fertilizer, compost, etc.). For young trees, apply half or 1/4 of the amount, and cover with soil after fertilization.
2. Intertillage and weeding: remove weeds in the pear orchard and bury them deeply in the fertilization trenches. Then, deep-plow the pear orchard, shallow-cultivate under the canopy, and deep-plow 20-30 cm between rows, so that the soil is loose and the soil is heated to kill overwintering insect eggs.
3. Shaping and pruning: for young pear orchards planted 1-2 years ago, on the basis of branch bending in the summer of the same year, for the 2-4 branches already cultivated, use methods such as bending, propping and hanging branches to keep them at an opening angle of 60-70 degrees, so as to moderate tree vigor and form a dwarfed canopy; for mature fruiting trees, use thinning, heading back and renewal pruning according to the tree to make the canopy well ventilated and let light through, with clear layers, achieving the goal of bearing fruit inside and out.
4. Pest and disease control: in winter after pear trees shed their leaves, take comprehensive measures to control overwintering pests and diseases. First, remove dead branches and fallen leaves near the pear orchard, prune diseased and pest-infested branches, scrape off loose bark on the trunks, and burn or bury them deeply in a centralized manner; second, before winter arrives, use rice straw or weeds to make 1-2 small grass bundles and place them at the branch forks of pear trees to lure pests to overwinter on the grass bundles. When spring begins, burn all the grass bundles in a centralized manner, which can eliminate a large number of overwintering pests; third, spray pesticides and whitewash. After pear trees shed their leaves and before they sprout, the pear orchard should generally be sprayed 1-2 times with 2-3 degrees Baume lime sulfur mixture, and the used medicinal residue should be used to whitewash the trunks; the following two formulas can also be used to prepare the whitewash: (1) 4 kg quicklime, 3 kg lime sulfur mixture, 0.5 kg diesel oil or kerosene, 50 kg hot water. Preparation method: first put quicklime lumps into warm water to dissolve into a slurry, then add lime sulfur mixture, diesel oil or kerosene, and stir thoroughly; (2) 5 kg quicklime, 0.5 kg salt, 100 g 40% asomate wettable powder, 0.5 kg diesel oil (or machine oil), 50 kg warm water at 60°C. Preparation method: first put lime lumps into warm hot water to dissolve into lime milk (slurry), then add salt, machine oil, pesticide, etc. and mix thoroughly.