Fertilizer requirement characteristics, High yield fertilization Technology and time of Castanea mollissima in China

Chinese chestnut is known as "king of dried fruit", and it is also called "ginseng fruit" abroad. So what is the requirement of fertilizer requirement, high yield fertilization technology and time of Chinese chestnut in China? Chinese chestnut needs more fertilizer, especially more nitrogen and potassium, and higher boron during flowering and fruiting period.

Characteristics of fertilizer requirement of Chinese chestnut

The absorption of nitrogen, phosphorus and potassium by Castanea mollissima varies with the growing period. Nitrogen began to be absorbed from root activity to pre-sprouting, and increased in shoot growth and flowering and fruiting stage. it was absorbed most in fruit expansion period (about July to September) and decreased rapidly after fruit picking. The absorption of phosphorus was more balanced throughout the year, slightly higher from flowering to harvest, and almost stopped before defoliation. Potassium was absorbed less before flowering (before June), increased sharply after flowering (July), and absorbed the most during the period from fruit expansion to harvest, which was very prone to potassium deficiency, and the amount of potassium uptake decreased rapidly after harvest. In recent years, it has been found that Chinese chestnut is sensitive to magnesium and has a high demand, especially in the period of fruit development, magnesium deficiency is quite common, so attention should be paid to the application of magnesium fertilizer.

Fertilization Technology of Castanea mollissima

The root system of Castanea mollissima is well developed, and the new roots generally have ectomycorrhiza. when the soil pH5.5~7.0 and site conditions are good, there are more mycorrhiza, which can improve the absorption of water, phosphorus and calcium nutrients by Castanea mollissima, which should be considered when applying fertilizer. The fertilization of Chinese chestnut is mainly based on base fertilizer, topdressing by stages and combined with foliar fertilizer.

According to the study, the mountain chestnut orchard with a yield of 400 kg to 500 kg requires 22 kg of nitrogen, 26 kg of phosphorus and 29 kg of potassium for every 667 square meters. Among them, basal fertilizer and topdressing account for 2% and 3%, respectively. The base fertilizer was combined with deep turning in late autumn and was applied in a circular trench under the canopy. Topdressing can be applied twice before germination and during the fruit expansion period, mainly in the fruit expansion stage. Topdressing combined with watering can improve the effect. According to the practice in some high-yielding chestnut orchards, the application of magnesium fertilizer and foliar fertilizer during the growing period has a good effect. Magnesium fertilizer was applied during the expansion period of fruit trees, with 0.1-0.5 kg magnesium sulfate per tree, ditched and watered. During the shoot growth period, fruit expansion and postharvest spraying 0.5% urea and 0.25% potassium dihydrogen phosphate played a good role in promoting shoot growth, fruit expansion and postharvest tree potential recovery. Spraying 0.2% borax solution at flowering stage can increase the fruit setting rate of Chinese chestnut, reduce the empty greenhouse rate, and significantly improve the yield and quality.

Variety classification

China has a vast territory and great differences in ecological conditions, which has formed a large number of chestnut variety resources. More than 300 varieties of Chinese chestnut have been named in China, but generally speaking, they can be divided into two types, namely, northern chestnut and southern chestnut.

1. Northern chestnut

It is mainly distributed in the Yanshan and Taihang Mountains and their adjacent areas in North China. Including Hebei, Beijing, northern Henan, Shandong, Shaanxi, Gansu and northern Jiangsu. It is characterized by less fruit shape, the average weight of a single grain is about 10 grams; the meat is waxy, and the sugar content is as high as 20%; the pulp contains low starch content and high protein content; the peel is dark and shiny; the fragrance is strong, and the astringent skin is easy to peel off, which is suitable for stir-frying chestnuts.

Second, southern chestnut

Mainly distributed in Jiangsu, Zhejiang, Anhui, Hubei, Hunan, southern Henan. In this area, high temperature and rainy, chestnut shape is large, the average weight of a single grain is about 15 grams, the maximum can reach 25 grams, but the sugar content is low, the starch content is high, and the meat quality is partial to japonica, so it is often used as vegetable chestnut. There are many varieties of Chinese chestnut in the north and south of China, and there are differences in the characteristics and characteristics of variety groups between the south and the north. In general, the quality of the southern variety group is not as good as that of the northern variety, and the meat is partial to japonica, which is suitable for cooking, also known as Chinese chestnut.