Detailed Explanation of Boxwood Cultivation Techniques and Management Methods
Boxwood (Buxus) is not strict about soil requirements and can be planted in sandy soil, loam, or brown soil, but loam rich in organic matter is best. When preparing the land, the ground should be level. In conjunction with deep plowing, apply organic fertilizer, about 2000 kg per mu. When applying base fertilizer, note that the organic fertilizer must be fully decomposed and applied deep within the planting holes. Under the climatic conditions of the Beijing area, the planting time for seedlings is mainly in spring, generally two or three days before "Qingming" in early April. For open-field planting of boxwood, the general plant and row spacing is 0.5 x 1.5 or 0.4 x 1.2 m, with about 1000-1500 plants planted per mu.
As the trees age, seedlings can later be lifted every other plant. Boxwood seedlings in nutrient pots can be planted in holes or furrows. Before planting, set out lines and mark points according to the planned row and plant spacing, then dig holes at the marked points or open furrows according to the planting row spacing. The furrow depth should be greater than the depth of the seedling roots, about 40 cm deep. Before planting, apply base fertilizer deep; mix fully decomposed organic fertilizer with soil evenly and place it at the bottom of the holes. When planting, remove the nutrient pots from the seedlings, arrange them in the furrows according to plant spacing, make the root system contact the soil, and fill and firm the soil. When firming after covering with soil, do not step on and break the root ball; step on the gap between the root ball and the planting hole instead. The covering depth should be slightly deeper than the original soil mark, so as to prevent the soil from sinking after watering and exposing the roots, which would affect survival.
Watering
Watering is the main measure to ensure seedling survival, especially in the north where spring is dry with little rain and high evaporation; if the water supply is insufficient, the seedling survival rate will be seriously affected. After planting, ridges can be built up with soil between every 4 to 6 rows to facilitate irrigation. The first watering is required within 24 hours after planting, the second watering 3 to 5 days later, and the third watering 5 to 7 days after that. After the three waterings, decide whether to water again according to the weather and the condition of the seedlings.
The amount of water should not be too much or too little. If the amount is too much, the soil becomes soft and the seedlings are prone to lodging; if too little, survival is affected. After the planted seedlings are watered or receive relatively heavy rainfall, they are prone to lodging, tilting, or root exposure. If such phenomena occur, immediately straighten them, bank soil, and firm it; otherwise, because the seedlings are sprouting and growing, the stems will bend within a few days. When straightening seedlings, first dig away the soil near the roots, straighten the seedlings, align the direction between rows and between plants, and then put the soil back and firm it. After planting, if the seedbed soil sinks and pits appear after three consecutive irrigations, level and fill the soil promptly. This can also be combined with intertillage to rake the ground level, so that the seedlings receive a consistent amount of water and uneven drought or waterlogging is prevented. Boxwood prefers water, and in watering, the principle of "prefer wet over dry" should be followed.
In the seedling stage, the root system is relatively shallow and sensitive to moisture, so generally the surface soil should be kept moist, with frequent light irrigation. During the rapid growth period of the seedlings, growth is fast and water demand is high, so heavy irrigation should be used, alternating wet and dry, with sufficient and thorough watering. However, in the late growth period, in order to prevent excessive vegetative growth and promote lignification, irrigation should be stopped. Generally, water control should begin in late summer. Irrigation time: each watering is best done in the morning and evening, not at noon when the temperature is highest.
Intertillage and Weeding
Intertillage and weeding are routine tasks in seedling-stage management. Intertillage and weeding are two concepts, but they can be carried out together.
Generally, intertillage and weeding are best done after rain or irrigation. When the soil is moist, pull the weeds out by the roots, and the soil-loosening effect is also good. Shortly after the seedlings are newly planted, most of the soil surface is exposed to the air, so the soil dries very easily and weeds grow readily. During this period, intertillage and weeding should be carried out promptly to help promote the development of the seedling root system.
Generally, near the seedling roots, cultivation should be slightly shallow, and between plants and rows it can be appropriately deeper, usually 3 to 5 cm. Intertillage during the rainy season promotes gas exchange and the evaporation of gaseous water, which can prevent waterlogging damage to the seedlings. In northern regions, spring is generally dry, and in autumn weeds have stopped growing; during these two periods, intertillage should be the main practice, while in summer weeding should be the main practice. The rapid growth period of weeds is before and after the rainy season, and weeding should be strengthened during this period, adhering to the principle of weeding early, weeding small, and weeding completely. For perennial weeds, the underground parts must all be dug out; otherwise, they will become increasingly difficult to remove.
Topdressing
Topdressing can promptly supplement the large nutrient needs of seedlings during the period of vigorous growth and development, promote seedling growth and development, and improve quality. Boxwood needs relatively more phosphorus in the seedling stage, relatively more nitrogen during the peak growth season, and relatively more potassium in autumn when growth stops.
After the seedlings are planted, a 0.4% potassium dihydrogen phosphate solution can be sprayed on the leaves, preferably on cloudy days or in the morning and evening when the air is humid. Generally, spraying potassium dihydrogen phosphate on the leaves three to four times a month is sufficient. For newly transplanted boxwood seedlings, fertilization should be done early in the initial period, but note that the fertilizer concentration must not be too high, so as not to burn the new roots. During the rapid growth period of the seedlings, the amount and frequency of fertilization should be increased, no less than once a month. Urea can be used for nitrogen topdressing, divided into dry application and wet application.
Dry application can be broadcasting or furrow application. Broadcasting is spreading chemical fertilizer evenly onto the soil between the seedlings, followed by shallow hoeing 1-2 times to cover it with soil; furrow application is opening furrows between the seedling rows, generally 15-20 cm from the seedling roots, applying the chemical fertilizer into the furrows, and then covering with soil. When applying in furrows, note that the furrow depth should be within the root distribution layer to facilitate the seedlings' absorption of fertilizer. Wet application is dissolving the fertilizer in water and sprinkling it comprehensively on the seedbed or between rows; it is best to irrigate once after application to avoid burning damage. Nitrogen fertilizer should be applied in spring and summer, and the last nitrogen application must not be later than "Liqiu" (Start of Autumn). This is to prevent excessive vegetative growth of the seedlings and reduce the overwintering ability of boxwood seedlings. In August and September, nitrogen fertilizer must be stopped, and fertilization should focus on phosphorus and potassium fertilizers. This promotes the lignification and root growth of boxwood seedlings and improves their cold resistance.