The root system of carob is relatively developed, but its regeneration ability is relatively weak. The depth of the main root is generally between 80 and 100 cm. The group roots are mainly distributed in the ploughing layer of 15 to 18 cm. ability is relatively weak. Carob roots have wide adaptability to soil, but fertile, well-drained and air-permeable soil is better. Too sticky and low-humidity soil is not conducive to root growth and nodule activity.
Carob does not require high fertilizer. In the early stage of plant growth (pod setting stage), since the root nodules have not yet developed and the nitrogen fixation ability is weak, nitrogen fertilizer should be supplied in moderation. After flowering and pod formation, the plant's demand for phosphorus and potassium elements increases, and the nitrogen-fixing ability of rhizobia increases. During this period, due to the simultaneous development of vegetative growth and reproductive growth, the demand for various nutrient elements increases. Relevant studies have shown that: every 1000 kg of beans requires 10.2 kg of pure nitrogen, 4.4 kg of phosphorus pentoxide, and 9.7 kg of potassium oxide. However, due to the nitrogen fixation effect of rhizobium, the growth of beans requires more potassium nutrition and phosphorus nutrition. Second, nitrogen nutrients are relatively low. Therefore, in the cultivation of beans, water and fertilizer should be properly controlled, appropriate amount of nitrogen should be applied, and phosphorus and potassium fertilizers should be increased.
