Chlorosis of soybean [Glycine max (L.) Merr.] and its relation with the content of chlorophyll, phosphorus, phosphorus/iron and pH vegetative tissues

Abstract

In the calcimorphic soils of México, interveinai chlorosis of young leaves affects soybean [Glycine max (L.) Merr.] most commonly during the early developmental stages. This often restricts normal growth and in severe circumstances may reduce seed yield drastically. From 1983 to 1986, soybean cultivars were grown in the northwest state of Sonora, México. Planting was done in soils rich in calcium carbonate (CaCO₃), but of poor drainage, and at different dates of seeding and plant densities. To analyze the contents of chlorophyll, phosphorus (P), and iron (Fe) and the pH level in vegetative tissues, samples were collected at different developmental stages. The highest content of chlorophyll in soybean plants with low ratings of chlorosis was related to low levels of P, a low P/Fe rates, and low pH of vegetative tissues. The succes of preventive and/or control measures requiers a closers attention at the water‐soil‐plant‐atmospheric relationship.

Key words:

• Phosphorus: iron relationship
• Chlorosis scores
• Dates of seeding by plant densities interaction