Symptom Manifestations and Identification Points of Nutrient Deficiency in Common Beans

Nitrogen deficiency: Plants grow poorly, leaf color is pale green, leaves are small, lower leaves age and turn yellow first, and even drop off, then gradually move upward and spread throughout the whole plant; few pods are set, and pod growth and development are poor.

Phosphorus deficiency: During the seedling stage, leaf color is dark green, leaves are stiff, and plants are dwarfed; during the pod-setting stage, lower leaves turn yellow, upper leaves are small and slightly upright.

Potassium deficiency: In the early growth stage of common beans, slight yellowing appears at the leaf margins, first at the leaf margins, then yellowing between the veins, in an obvious sequence; leaf margins die back, and as the leaves continue to grow, they curl outward, the leaves become somewhat hardened, and the pods are slightly short.

Calcium deficiency: Plants are short, decline before aging, and vegetative growth at the stem tip is slow; the tips of lateral roots die and form nodular protrusions; the areas between the veins of the upper leaves are pale green or yellow, young leaves curl, and after the leaf margins turn yellow and lose chlorophyll, they die inward from the leaf tip and leaf margin; the terminal bud of the plant necroses, but the old leaves remain green.

Magnesium deficiency: During the growth and development of common beans, the green color between the veins of lower leaves gradually turns yellow, and with further development, except for a little green remaining in the veins and leaf margins, the areas between the veins all become yellow-white.

Zinc deficiency: Discoloration starts from the middle leaves, and compared with healthy leaves, the veins are clearly visible; as the areas between the veins gradually fade, the leaf margins change from yellowing to brown; internodes become shorter, small leaflets cluster at the stem tip, the plant form is bushy, the leaves curl slightly outward, and the plant does not flower or set pods.

Boron deficiency: The growing points of the plant shrink, turn brown, and dry up. Newly formed leaf buds and petioles are pale, hard, and easily broken; upper leaves curl outward, parts of the leaf margins turn brown, and when the veins of upper leaves are carefully observed, there is shrinkage, and the pod surface becomes lignified.

Iron deficiency: The areas between the veins of young leaves become chlorotic, appearing yellow-white, and in severe cases the entire leaf turns yellow-white and dries up, but no necrotic spots appear, nor does death occur.

Molybdenum deficiency: Plant vigor is poor, young leaves become chlorotic, the mesophyll between the leaf margins and veins appears as yellow patches, the leaf margins curl inward, the leaf tips shrink, and the plant often flowers but does not set pods.