Since October last year, the rainfall in the south of the Yangtze River, most of South China, and southwestern my country has been 40%to 70%less than that of the same period in normal years. Less than 60%, the weather drought is more serious. As of January 29, 2021, there are moderate or above meteorological droughts in southeastern and southwestern Jiangnan, most of southern China, and southern Yunnan, and some areas of Hunan and Guangxi have severe droughts.
Generally speaking, the continued drought will have certain adverse effects on fruit tree production in Jiangnan and South China. Compared with shallow-rooted crops, fruit trees and tea trees have deeper root systems and stronger drought tolerance. In addition, the main fruits in southern China are basically mature and the tea gardens have not yet started picking, so the overall impact is limited. According to the Central Meteorological Observatory’s forecast, from the 7th to the 10th, there will be moderate to heavy rains in southern China and southern Jiangnan, heavy rains in some areas, and heavy rains locally. It is expected that the drought will be greatly alleviated. In the near future, focus on the following tasks to reduce the impact of disasters.
One is to strengthen drought monitoring. The main symptoms of drought are discoloration, scorching, shedding of leaves, dry branches and even death of the whole tree. Only part of the leaves of tea plants are discolored and scorched, and the buds and leaves on the upper branches are green, which are mildly injured; most of the leaves are scorched or fall off, but the leaves or tea buds at the top of the branches have not completely withered, which is moderate damage; The whole plant died and was severely injured. According to the degree of drought, corresponding disaster prevention and mitigation measures should be taken in time.
The second is to implement irrigation measures. For orchard tea gardens with drip irrigation conditions, irrigate early and lightly to reduce the impact of drought. The surface is hardened after continuous drought, and the wet depth of direct watering is generally only 5-10 cm, and the drought resistance effect is poor. The orchard recommends digging 3-4 loose soil pits around the canopy drip line when irrigation and drought resistance are carried out. The width and depth are 25-30 cm. Each time the position of the loose soil pit is filled, the irrigation effect can be improved. Tea gardens should be irrigated in the morning and evening through artificial watering and drip irrigation facilities and equipment to alleviate drought. Young tea trees are weak in drought resistance, so every effort should be made to irrigate and protect seedlings.
The third is to pay attention to the prevention and control of pests. Low humidity environments are prone to outbreaks of insect pests such as red spiders and yellow spiders. Pay attention to field inspections and prevent and control them in time.
The fourth is to strengthen soil management. Conditional orchard tea gardens should cover the tree trays with straw, chaff, weeds, degradable grass cloth, etc., to increase moisture and heat insulation, especially young tea gardens should be fully covered by the ground. For orchard tea gardens that are prone to water accumulation, the drainage ditch should be cleaned in time to prevent water accumulation and root rot when the rainy season arrives.
The fifth is to strengthen tree management. After the drought, the tree becomes weak, and the orchard can increase the nitrogen fertilizer once according to the soil condition, and spray 0.2%—0.4%potassium dihydrogen phosphate or 0.5%potassium nitrate to restore the tree vigor. Tea gardens should seize the opportunity of rainfall and apply germination fertilizer about 30 days before spring tea mining. For tea gardens with drip irrigation, drip fertilization can be implemented, and for those without drip irrigation, water-soluble urea fertilizer, amino acid and humic acid foliar fertilizer, medium and trace element foliar fertilizer can be sprayed manually.
Six is to seize the rainfall window period, do a good job of water storage, and prevent the sudden turn of drought and flood. Do a good job in the cleaning of reservoirs and canals, make good use of the recent strong rainfall process, and enhance the water storage capacity and sustainable drought resistance capacity around the orchard and tea garden. In case of continuous heavy rain, deep ditch should be opened in time for the orchard and tea garden to drain the soil to prevent waterlogging. The depth of the drainage ditch should be more than 60 cm.