A Complete Analysis of Key Points of New Chestnut Planting Techniques

I. Soil, Fertilizer and Water Management for Chestnuts

(I) Soil Management After the autumn chestnut harvest and before leaf fall, deep plowing of the chestnut orchard should be carried out, with a depth of 60-80 cm being appropriate, and root damage should be minimized during deep plowing. Separate the topsoil from the subsoil, and when backfilling, mix the topsoil with organic fertilizer (turf, dead branches and fallen leaves) evenly and fill it into the bottom layer, then place the subsoil in the upper layer. The number of times of intertillage and weeding each year should be no fewer than 3 times, and the plowing depth should be 15-25 cm, with green manure plowed under during cultivation. Cover the tree disk with green grass at a thickness of 20 cm, press a little soil on top, and in autumn turn it into the tree disk and bury it underground. For drier chestnut orchards without irrigation conditions, cover with plastic film.

(II) Fertilization

① Base fertilizer: mainly farmyard manure, preferably applied from late September to early October, supplemented with an appropriate amount of inorganic fertilizer. For young trees, dig a ring-shaped ditch 30-40 cm wide and 20-30 cm deep at 20-30 cm outside the crown edge for fertilization. For large trees, radial ditch application should be used, with ditch width 30-40 cm, shallow near the trunk and deepening outward, digging 4-8 radial ditches. For farmyard manure, generally a 15-year-old chestnut tree should receive no less than 50 kg per tree, and a 25-year-old chestnut tree no less than 150 kg per tree. ② Topdressing: carried out 2 times a year. The first time is before bud break (late March to mid-April), mainly with urea, 0.5-1.5 kg per young and medium tree, and 2-5 kg per mature tree. The second time is during the fruit swelling period (July-August rainy season), applying compound fertilizer, with the same application rate as the first time.

③ Foliar fertilization: foliar fertilizer can be sprayed together with pesticides. In mid-to-late May, spray 0.25%-0.3% urea; in mid-to-late June, spray 0.3%-0.5% urea; in early July, spray 0.3%-0.5% urea. After early July, spray 0.1%-0.3% potassium dihydrogen phosphate once every 15 days until early September.

(III) Orchard Water Conservation Before the rainy season, carry out deep plowing and at the same time dig horizontal anti-erosion ditches to retain more precipitation within the chestnut orchard.

II. Techniques for Promoting Female Flower Formation

The 3 weeks before chestnut bud break are the period of female flower morphological differentiation. Watering before early spring bud break satisfies the tree's water requirements. When the basal leaves have just unfolded and are changing from yellow to green, spray 0.1% potassium dihydrogen phosphate once to increase the number of female flowers. When the male inflorescences are 1-2 cm long, except for keeping the 5 male flowers at the upper end of the new shoot, remove the rest of the male flowers. Removing male flowers can increase female flowers by more than 20%. When the new shoot grows to about 30 cm, pinch off the terminal bud, then pinch once every additional 20 cm of growth, with the last pinching possible in late August; a large bud can form below the leaf scar ring, prune back to the ring in winter, and the large bud can sprout and bear fruit the following year.

III. Techniques for Improving Fruit Set Rate

(I) Watering at flowering stage Watering at flowering stage can increase the fruit set rate.

(II) Artificial pollination Select varieties with large grains, good quality, early maturity and high compatibility as pollinating trees. Pick male flowers when the male inflorescences change from green to yellow; picking before 8:00 is better. Spread the collected male inflorescences on glossy paper and place them in a dry, ventilated, dust-free place, turning them 1-2 times a day; after 24 hours pollen will be released. Pollination can be carried out when the multi-lobed stigmas of the three female flowers in the involucre extend out, roll back and turn yellow, using a pencil with an eraser for spot pollination.

IV. Techniques for Increasing Single-Grain Weight

In summer, collect weeds from the edges of the field and cover them in the tree disk at a thickness of no less than 10 cm, pressing them down in spots with soil. From June to August, apply organic fertilizer plus chemical fertilizer; apply 3000 kg of organic fertilizer per 1 mu (667 sq m) of chestnut orchard. From late August to early September, water before harvest. Chestnut weight gain mainly occurs in the later stage, especially fastest in the 10 days before harvest, so harvest at the proper time.