The root system of kidney bean is developed, the main root is buried 60 ~ 70 cm, and the lateral roots can extend over1.0 m. At the initial stage of growth, the growth rate is very fast, far exceeding the above-ground parts, and root groups can be quickly formed, mainly distributed in the topsoil of 15 ~ 40 cm. The cultivation is mainly direct seeding, and attention should be paid to protecting the root system when transplanting seedlings. Rhizobia and kidney beans grow in roots. It can fix the free nitrogen in the air, synthesize nitrogen-containing substances, provide nutrition for kidney beans and increase the nitrogen content in the soil.
Kidney bean has higher requirements on soil than other beans, and is most suitable for growing on neutral to slightly acidic soil with rich humus, deep soil layer, good drainage and pH value of 6.2 ~ 7.0, which is beneficial to the growth of root system and the activities of rhizobia. Beans have poor alkali resistance, especially chlorine salts. The demand for nitrogen and potassium fertilizer in the whole growth and development stage of kidney beans is large, and the law of fertilizer demand is: the absorption of nitrogen and potassium fertilizer is large in the early growth stage; By the time it blooms and bears fruit, the demand for nitrogen and potassium fertilizers will increase rapidly. With the change of growth center, the nitrogen and potassium in seedling stems gradually transferred to pods. Because leguminous rhizobia is not as developed as other leguminous plants, it is necessary to supply appropriate amount of nitrogen fertilizer in time in production, which is beneficial to obtain high yield and improve quality. Although the absorption of phosphorus fertilizer is less than that of nitrogen and potassium fertilizer, rhizobia are particularly sensitive to phosphorus. The content of phosphorus in rhizobia is 65438 0.5 times higher than that in roots. Therefore, the application of phosphate fertilizer can achieve obvious effect of increasing production by combining phosphorus and nitrogen.
Dwarf kidney beans have a short growth period and enter a vigorous nutrient absorption period from the peak of flowering. When the tender pod began to elongate, the transfer rate of inorganic nutrients from stem and leaf to tender pod was 24 %, K2O P2O5 and 40% for K2O. When pods mature, the absorption of nitrogen gradually decreases, while the absorption of phosphorus gradually increases.
The growth and development of rattan beans are relatively slow, and the time to absorb a lot of nutrients is relatively delayed. When the tender pods begin to elongate, they enter a vigorous period of nutrient absorption, and the daily absorption is larger than that of dwarf varieties, so they still need to absorb a lot of nitrogen in the later stage of growth. At pod setting and jointing stage, the transfer of inorganic nutrients from stems and leaves to pods was also less than that of dwarf beans. The two should be treated differently in fertilizer management. Dwarf varieties have short growth period, suitable for early topdressing, promote their early development and multi-branching, and achieve the goal of early flowering, early fruiting and early maturity. Creeping kidney bean has a long growth period and a long flowering and pod setting period. Therefore, it is necessary to pay attention to topdressing in the middle and late stage, and apply multiple fertilizers such as nitrogen, phosphorus and potassium for many times to prevent plants from premature aging and prolong the fruiting period.
Different types of nitrogen fertilizer have different effects on the growth and development of kidney beans. Kidney beans like NO-3-N fertilizer, and too much NH+4-N fertilizer will affect the normal development of rhizobia.
Bean is very sensitive to magnesium fertilizer, and its demand for trace elements such as boron and molybdenum is more important than other elements, especially for rhizobia. Therefore, proper application of magnesium, boron and molybdenum fertilizers can improve its yield and quality. According to the research, per 1000 kg of fresh pods, N10.2 kg, P2O5 0.3 kg and K2O10.0 kg need to be absorbed.