What are the methods for rational topdressing of tomatoes?
Tomato (Tomato), alias xihongshi, yangshizi. Ancient names liuyueshi, xibao sanyuan. In Peru and Mexico, it was first called “wolf peach”. The whole plant is covered with sticky glandular hairs and has a strong odor. The stem is prone to lodging. Leaves are pinnately compound or pinnately parted, with leaflets extremely irregular in size, ovate or oblong, with irregular serrations or lobes along the edges. The calyx is rotate, with lanceolate lobes that persist on the fruit; the corolla is rotate and yellow. The berry is oblate or nearly spherical, fleshy and juicy, orange-yellow or bright red, smooth; seeds are yellow. Flowering and fruiting period is summer and autumn.
Environmental requirements of tomato
1) Temperature: Tomato is a warm-loving vegetable. Under normal conditions, the optimum temperature for assimilation is 20-25°C, and the optimum soil temperature for root growth is 20-22°C. Raising the soil temperature not only promotes root development, but also significantly increases the nitrate nitrogen content in the soil, accelerating growth and development and increasing yield.
2) Light: Tomato is a light-loving crop, with a light saturation point of 70000lx, and a suitable light intensity for tomato of 30000-50000lx. Tomato is a short-day plant, basically requiring short days during the transition from vegetative growth to reproductive growth, but the requirement is not strict. Some varieties can bud and bloom earlier under short days, while most varieties bloom earlier and grow robustly under 11-13h of daylight.
3) Water: Tomato needs a fair amount of water, but it does not need frequent large irrigation. Generally, a soil moisture of 60-80% and an air humidity of 45-50% are suitable. High air humidity not only hinders normal pollination, but also leads to severe disease under high temperature and high humidity conditions.
4) Soil and nutrition: Tomato is not very strict about soil conditions, but to obtain high yield and promote good root development, deep soil with good drainage and fertile loam rich in organic matter should be selected. The suitable soil pH is pH6-7, and soil that is too acidic or too alkaline should be improved. During its growth process, tomato needs to absorb large amounts of nutrients from the soil. According to reports by E.J. Russell, for every 5000kg of fruit produced, 33kg of potassium oxide, 10kg of nitrogen, and 5kg of phosphoric acid need to be absorbed from the soil.
How to carry out rational topdressing of tomatoes?
Tomato is very sensitive to fertilizer. When topdressing, the principle of “one control, two boosts, three sprays, four taboos” should be mastered.
One control: During the period from transplanting to fruit setting, tomato should be topdressed according to the seedling condition, and the amount of topdressing should be controlled. If too much topdressing is applied and too concentrated, it is easy to cause excessive vegetative growth of the plant, and even cause flower and fruit drop. Therefore, except when the plant is severely deficient in fertilizer, the amount of topdressing should generally be controlled, and lightly applying dilute manure water or biochemical organic fertilizer liquid is sufficient.
Two boosts: During the young fruit stage and harvest stage, tomato should be heavily topdressed to promote its growth and development. When the first cluster of fruit grows to the size of a walnut, quickly apply quick-acting fertilizer 1-2 times, generally using a concentration of 30% human manure or 5% sulfur-containing compound fertilizer extract, to ensure the plant does not run out of fertilizer. After the young fruit enters the expansion stage, in order to meet the growth needs of the plant and avoid fertilizer deficiency in the later stage, the method of frequent topdressing and vigorous maintenance should be adopted, generally applying once every 10 days on sunny days at a concentration of 40% human manure or 5% sulfur-containing compound fertilizer extract.
Three sprays: Tomato not only absorbs nutrients from the soil through the roots, but can also absorb mineral nutrients through the leaves to promote the development of fruit and seeds. Therefore, during the fruit growth period, especially when continuous rain in the early stage prevents soil topdressing, foliar fertilizer should be sprayed 2-3 times. Biochemical organic liquid fertilizer can be sprayed at 300-500 times dilution, and chelated multi-element compound micro-fertilizer can also be sprayed at 500 times dilution to improve tomato quality.
Four taboos: Tomato topdressing should not be carried out when the soil is relatively wet or at noon under high temperature, and concentrated fertilization should be avoided. Concentrated fertilization easily causes excessive vegetative growth and fertilizer damage; fertilizing when the soil is relatively wet easily causes physiological diseases such as flower drop, leaf drop, and fruit drop; fertilizing under high temperature conditions causes large water evaporation from plant leaves, which affects the effectiveness of the fertilizer. In addition, the fertilization time should avoid high temperature periods, and early morning or evening is preferable.