Tea gardens are characterized by a diverse range of weeds, complex Weed communities, and strong stability. According to incomplete surveys and statistics, there are as many as 202 common weed species found in domestic tea gardens, belonging to 49 families and 163 genera. Weeds can impact the growth of tea plants, causing symptoms such as stunted growth, yellowing leaves, leaf drop, and delayed development. They may also carry diseases or pests that affect tea plants directly or act as intermediate hosts, indirectly impacting the growth and development of tea plants.
“Grass to suppress grass” is an integral part of the green and efficient prevention and control technology system for Guizhou tea gardens, embodying the concept of “ecology at its Root, agriculture at its core, and biological control first.” Planting white clover in tea gardens can effectively suppress weeds and resist tea plant diseases and pests. Below are key technical points for reference.
White clover in tea gardens and pollinating insects – bees
Intercropping white clover in tea gardens
Effective “grass to suppress grass”
In recent years, research teams from Guizhou University, the Provincial Plant Protection and Inspection Station, the Provincial Academy of Agricultural Sciences, and the Provincial Soil and Fertilizer General Station have conducted a series of studies and demonstration projects on “grass to suppress grass” in tea gardens. These studies targeted the weed problems in Guizhou tea gardens, screened suitable Green manure plants for intercropping, and evaluated them based on weed control effectiveness, ecosystem assessment, tea yield measurement, quality evaluation, and cost-effectiveness.
Research led by Academician Song Bobao's team from Guizhou University in Shiqian showed that intercropping white clover in tea gardens could effectively control weeds through mechanisms such as “root allelopathic substances suppressing weeds,” “root and stem physiological positioning controlling weeds,” and “stolon physical positioning controlling weeds.”
Mechanisms of weed control with white clover in tea gardens
The results indicated that compared with clear cultivation treatment, the number of weed species, density, and weed biomass were significantly reduced in the white clover treatment group. For example, after surveys conducted from May to October 2017, the Longtang tea area had 35 weed species in the white clover treatment group and 58 species in the clear cultivation treatment group; the weed biomass was 16.71 g/m² in the white clover treatment group and 146.88 g/m² in the clear cultivation treatment group.
Weed survey in the Longtang tea area of Shiqian County
Insect surveys in tea gardens revealed that the diversity and abundance of natural enemies significantly increased in the white clover treatment group, while the number of pests such as tea green leafhoppers and tea thrips significantly decreased, reducing pest damage by 20-35%. Field surveys also showed that white clover has a long flowering period and abundant nectar, providing a source of food for natural enemy insects and pollinators like bees in tea gardens. This significantly increases the bee population in tea gardens, extends the lifespan of parasitic or predatory natural enemies, increases their field population, enhances their parasitism or predation abilities, regulates the ratio of beneficial to harmful organisms, and helps to establish a favorable ecosystem in tea gardens.
Insect survey in the Longtang tea area of Shiqian County
Compared with clear cultivation weeding or manual weeding treatments, the annual labor cost for weeding can be saved 4-6 times. Calculated at 120 yuan per labor day, the cost savings for weeding labor per mu (about 0.067 hectares) is approximately 480-720 yuan. Based on previous research, this scientific team believes that intercropping white clover in young tea gardens is a safe, simple, and economical green prevention measure for tea gardens. In the next step, the team will conduct research on the weed control mechanism of white clover, the ecological regulation effects of intercropping white clover in tea gardens, and the relationship between planting white clover and bee colony indices.
Weed quantity before planting white clover
One month after planting white clover
Three months after planting white clover
One year after planting white clover
Intercropping white clover in tea gardens
Technical measures
Sowing period:
The suitable sowing periods for white clover seeds are spring and autumn sowing. Due to high temperatures, summer sowing is not recommended. Spring sowing can take place from late March to late April; autumn sowing can occur from late September to early October. Considering tea garden operations such as tea picking, it is recommended to sow white clover in autumn.
Soil preparation:
White clover seeds are small, and the seedlings are delicate with weak emergence force and slow growth during the seedling stage. Before sowing, deep plowing and clearing of weeds in the tea garden are required, removing the weeds from the garden. The ground should be leveled, and clumps of soil should be broken up to ensure loose and permeable soil layers.
Sowing method:
Before sowing, soak the seeds in a solution containing 1 gram of ammonium molybdate and 1.5 kilograms of water for 12 hours. Drain the seeds and mix them with fine soil, sand, or substrate soil before broadcasting. The sowing depth should be 1-2 centimeters, and after sowing, cover with a 1-centimeter layer of fine soil or substrate soil. The theoretical sowing rate for white clover is 10 grams per square meter, with each gram containing 1,400-2,000 seeds, and one Seed per square centimeter is sufficient. However, in production, the actual sowing rate is often higher than the theoretical rate due to factors such as germination rate and sowing effect. Depending on the actual conditions of the soil, the sowing rate per mu can be controlled at 2-3 kilograms.
Growth management:
During the seedling stage, white clover requires supplementary nitrogen fertilization to promote robust growth. If there are no rhizobia in the tea garden soil before sowing, appropriate rhizobial inoculants or fertilizers can be added to facilitate nitrogen fixation in the white clover roots. After two years of growth, the soil layer becomes compact and less permeable. In the spring and autumn seasons before the return to green, loosen the soil and apply top-dressing fertilizer. Diseases and pests affecting white clover are relatively rare, but occasionally brown spot disease and powdery mildew