Lentils lentils are annual or perennial herbs in Leguminosae. Also known as bean, corn bean. A crop with both grain and green manure. Chromosome number 2n= 14. Originated in southwest Asia and eastern Mediterranean. It was cultivated in the Neolithic Age. It spread to the Mediterranean, Asia and Europe in the Bronze Age. There are about 40 countries in the world that cultivate lentils, and Asia produces the most. There are two subspecies: large-grained and small-grained. The large-grained subspecies are mainly cultivated in southern Europe, northern Africa and North and South America, and the small-grained subspecies are mainly cultivated in southern Asia and eastern Europe. China is mainly produced in Shanxi, Shaanxi, Gansu, Hebei, Henan and Yunnan provinces. Plant height10 ~ 75cm. There are dwarf, erect and semi-creeping types. Pinnate compound leaves with 8 ~14 leaflets, oval; There is a leaf pillow at the base of the compound leaf, which can be closed to reduce water evaporation when there is water shortage. Racemes with white or purple flowers; Diploid stamens (9+ 1). The pod contains1~ 2 seeds, which are flat and thin, convex lens-shaped, with smooth surface, light red, yellow, black, green, grayish brown and other colors, or with spots and stripes. Some large seeds have wrinkles on their surfaces and small umbilicus. Lentils are long-day crops and are also neutral. I like warm and dry climate. Drought-tolerant but not wet-tolerant. The lowest temperature for seed germination is 15℃, the optimum temperature is18 ~ 21℃, and the optimum temperature for pod setting is about 24℃. The growth period is 90 ~120 days. The dormancy period of seeds is short, and cotyledons are not unearthed. Suitable for sandy loam but not for acidic soil. During unicast, the yield is affected by creeping stems, and it is often mixed with barley or wheat. Generally, the pods are harvested and threshed when about two-thirds of them are yellow-brown. The main diseases are wilt, root rot and rust. The main pests are aphids, bean weevil, pod borer and so on. The lack of effective rhizobia and the invasion of nodules by weevil larvae are one of the reasons for the low yield of lentils.