Tea garden irrigation

Irrigation in tea gardens is an important measure to ensure increased tea production in arid conditions. The effectiveness of irrigation depends on the duration of drought. Its main functions are to increase production and improve the quality of tea. The irrigation methods for tea gardens mainly need to pay attention to the following aspects:

Timely irrigation

Timely irrigation is the first step to fully utilize the irrigation effect. The so-called timely irrigation refers to replenishing water when the soil moisture decreases to the lower limit of the suitable range before the tea trees are affected by drought. To achieve timely irrigation, scientific analysis must be conducted based on the weather, soil, and tea tree conditions to explore reasonable irrigation indicators.

1. Weather:

During the hot summer and autumn seasons, if there is no rain for 7-10 consecutive days, irrigation is necessary. In the northern tea region, there is windy weather in spring, and irrigation is necessary if there is no rain for 10-15 days.

2. Soil:

Soil moisture is divided into quantitative and strength indicators. Soil moisture content, field water holding capacity, available water, saturated water holding capacity, etc. are all expressed in terms of quantity. Soil suction is expressed in units of energy such as bars or decibars, and there is a close relationship between them.

(1) 70% of the field capacity is the lower limit for irrigation in tea gardens. The relationship between soil moisture content and tea tree growth indicates that during high temperature weather in summer and autumn, when the soil moisture content drops to 70% of the field water holding capacity, the growth of new tea tree shoots slows down, leading to the formation of a large number of leaves and easy aging. After irrigation, the tea tree quickly recovers its vitality. So, this is the lower limit of irrigation. If irrigation is not carried out at this time, it will inevitably affect the growth of tea trees.

(2) Irrigation of tea gardens is indicated by soil suction (PF). Soil suction is a strength indicator of soil moisture, which can directly reflect the effectiveness of soil moisture. Using a soil moisture meter to measure soil suction has good reproducibility. During the process of tea garden soil from wet to dry, there is a good functional relationship between soil suction and soil moisture content. The curve drawn based on this functional relationship is called the soil “water holding curve”. Soil suction can generally be measured in terms of bar value or PF (PF is the logarithm of the water column height in centimeters of tea garden soil suction). The greater the soil suction, the higher the bar value or PF, and the drier the soil, making it less likely for tea trees to absorb soil moisture. According to the measurement, during the high temperature season, when the soil suction PF is 2.7 (i.e. 50 cm), the field water holding capacity of the tea plantation cultivation layer (0-45cm) is 70%, and the tea plantation needs to be irrigated.

3. Growth status of tea trees:

The changes in the concentration of sap in tea plant bud and leaf cells and the water absorption capacity of leaf tissues are physiological responses of tea plants to environmental conditions, usually measured by the water absorption capacity of leaf tissues at 7-9 atmospheres. Because at this point, the water in the tea tree’s body is relatively tight, making it difficult for the tea tree to absorb water from the soil. Therefore, it is necessary to irrigate the tea garden. However, this type of measurement requires some equipment and technical expertise, making it difficult to apply in production. Observing the characterization reaction of tea trees is relatively simple and feasible. In the morning, there is no dew on the tea leaves. At noon, the leaves lose their luster and make a rustling sound when touched, indicating that the tea trees are severely dehydrated and urgently need to replenish their water. It should be pointed out that these symptoms occur after the appropriate irrigation period has passed, and irrigation should generally be carried out earlier.

Selection of Irrigation Methods

There are various irrigation methods for tea gardens, including irrigation, drip irrigation, sprinkler irrigation, and drip irrigation. The first two irrigation methods have long been used in tea production, while the latter two methods have developed rapidly in recent years, especially sprinkler irrigation. The selection of irrigation methods for tea gardens should be tailored to local conditions. The characteristics of various irrigation methods are described as follows:

1. Watering:

It is the most primitive and labor-intensive irrigation method, which is not suitable for large-scale use and should only be used when no other irrigation facilities have been built or temporary drought resistance measures have been implemented.

2. Flow irrigation:

The use of irrigation in tea gardens can completely alleviate drought. But there are many weaknesses, namely: high water consumption and serious leakage; The irrigation uniformity coefficient is extremely poor, and it is difficult to evenly irrigate tea gardens with undulating terrain; Requires a certain area of canal system land and high cost; Only suitable for gentle slope tea gardens with abundant water sources and minimal terrain changes.

3. Sprinkler irrigation:

Water is sprayed into the air through sprinkler irrigation equipment and falls into tea gardens, similar to natural rainfall. Main advantages: Water conservation, high efficiency, minimal footprint, low labor intensity, and no damage to the soil structure of tea gardens.

4. Drip irrigation:

Dripping irrigation, through pipes, slowly drips water from a dropper towards the roots of tea trees to maintain soil moisture within the required range for tea tree growth. Main advantages: It saves water more than sprinkler irrigation; Maintain soil structure; Good ventilation is beneficial for the reproduction of soil aerobic microorganisms, promotes fertilizer decomposition, and facilitates the absorption of tea trees; Reduce ground evaporation of water, suitable for arid areas with water scarcity. Disadvantage: Strict filtering equipment is required, otherwise the pipeline and dripper are prone to blockage; High cost.

The irrigation method for tea gardens must be tailored to local conditions and economically practical. Generally speaking, drip irrigation can be used for young tea gardens with insufficient water sources or small tree ages and low coverage; Sprinkler irrigation is suitable for mature tea gardens with high coverage, as it can not only replenish water in the tea garden, but also improve the microclimate and have a beneficial impact on the growth of tea trees.