Common weeds and weeding techniques in the cultivation of the Chinese medicinal herb galangal (Alpinia officinarum)

The common weeds in galangal (Alpinia officinarum) fields mainly include goosegrass, barnyardgrass, fireweed, and alligator weed, most of which are dicotyledonous weeds. These weeds compete with the medicinal plants for nutrients and water in the soil, affecting the yield and quality of galangal to a certain extent. Therefore, manually removing weeds from galangal fields is a routine field management task. At the same time, in the process of weed control, different methods can be used for different weeds. Choosing suitable chemical agents for weed control not only saves labor and time but is also relatively thorough and reliable, achieving good control results.

1. Weeding before planting.

Chemical weeding should focus mainly on applying chemicals to the soil before planting the medicinal herb, aiming to keep the entire growing period free from weed damage with a single application. The commonly used agents for soil treatment before planting are as follows:

(1) 48% trifluralin emulsifiable concentrate.

Trifluralin emulsifiable concentrate has a broad weed control spectrum and can effectively control annual grass weeds that reproduce by seed, such as goosegrass, foxtail, and barnyardgrass. The spraying time is mostly 5-10 days before planting and before weeds germinate. The dosage is mixed with water according to the instructions, and the soil surface of the medicinal field is evenly sprayed. Because trifluralin volatilizes and photodegrades easily, shallow tilling should be done immediately after spraying to mix the solution into the 5-7 cm soil layer in time. If conditions permit, mechanical spraying and harrowing in one pass is best, and the weed control effect can reach over 90%. It is also possible to water thoroughly immediately after spraying, but the effect is not as good as shallow tilling and mixing into the soil. After application, planting is generally done only after 5-7 days.

(2) 50% acetochlor emulsifiable concentrate. This agent is mainly absorbed by the aboveground parts of weeds, inhibiting protein synthesis, stopping the growth of buds and roots, and thereby causing weeds to die before emergence, before seedling emergence, and shortly after seedling emergence. It has a special effect on many annual grass weeds and can also control some broadleaf weeds with small seeds. The spraying time is mostly 3-5 days before planting or transplanting. Note that it must be applied before weeds emerge. Use 70-75 milliliters of this agent per mu, diluted with 40-60 liters of water, and spray evenly on the soil surface.

2. Weeding after planting

Galangal usually has more weeds germinating and growing only at the seedling stage and the early stage after planting, so manual and frequent weeding should be the first choice.

If there are many weeds, use 40 milliliters of 5% Xianchu emulsifiable concentrate per mu diluted with 30 liters of water and spray; or use 150-200 milliliters of 20% napropamide diluted with 30-50 liters of water and spray; or use 70-80 milliliters of 6% Caoxing emulsifiable concentrate per mu diluted with 30-40 liters of water and spray evenly on the stems and leaves.