A, fertilizer law

Fertilizer characteristics: lettuce is like heat and fear of cold, like water and fear of drought, like fertilizer fertilizer, to expand the underground rhizomes as the main edible products of the aquatic high-efficiency economic crops. Requirements for soil with high organic matter content, soft and loose soil, deep and permeable clay loam soil. Lettuce from sprouting to the emergence of standing leaves, the beginning of new roots, mainly by the nutrients stored in the root; the peak of the long term nutrient demand is large, is the key period of fertilizer; root and lotus synchronous development, nutrient uptake is reduced, stalk and leaf nutrients are mostly transferred to the root and lotus.

Fertilizer requirements: generally under the condition of 1800 kilograms of acres of fresh lotus root, about the absorption of pure nitrogen (N) 7.7 kilograms of pure phosphorus (P2O5) 3.0 kilograms of pure potassium (K2O) 11.4 kilograms of lettuce on nitrogen, phosphorus and potassium absorption of pure nutrients in the proportion of roughly 2:1:3. Lettuce belongs to the potash-loving crops, the absorption of potash is more, followed by nitrogen, the least amount of phosphorus. Nitrogen promotes stem and leaf growth, phosphorus promotes root growth and nutrient absorption, and potassium promotes the formation of starch and fat.

Lettuce fertilizer law and fertilization technology

Two, fertilization technology

Supply enough base fertilizer: base fertilizer can improve the soil, fertilization of the ground. It creates good soil conditions for lettuce growth and provides sufficient nutrients for a sustained period of time. Generally choose the soil organic matter content is high, the soil is soft and loose, the soil layer is deep and breathable, fertile, convenient irrigation and drainage of the field. Deep winter turning 33 ~ 40 cm, so that the soil weathering, early spring combined with the whole land per mu into the rotted organic fertilizer 2500 ~ 3000 kg, or organic and inorganic compound fertilizer 300 ~ 400 kg, 45% carbon supplement saturated composite fertilizer ﹝20-20-20 ﹞, and supplemental application of calcium, boron, zinc and other micro-fertilizers. Continuous deep turning many times, mixing soil and fertilizer, leveling the ground.

Reasonable fertilizer: lettuce throughout the reproductive period of fertilizer 3 times. The first time in 1 ~ 2 pieces of standing leaves (planting 25 ~ 30 days) when applied, combined with plowing and weeding, per acre of high nitrogen compound fertilizer 25 ~ 30 kg, organic and inorganic compound fertilizer 30 kg. The second time in 5 ~ 6 standing leaves (40 ~ 50 days after planting, that is, when the rows are closed) applied, per mu of high-nitrogen and high-potassium compound fertilizer 30 ~ 35 kg. The third fertilizer in the termination of the emergence of the leaf, when the lotus root began, that is, the pursuit of lotus root fertilizer, per mu of high potassium compound fertilizer 15 to 20 kg. Precautions: ① shallow water lotus root field, should choose sunny and windless weather fertilization, avoid the hot sun at noon, fertilization before the release of water, shallow water fertilization, fertilization after 2 days and then irrigation to restore the water layer. ② deep water lotus root field, in order to prevent the fertilizer floating, should be made into fertilizer mud group application is good.