What Can Be Grown in Low-Iron Soil?

Alfalfa

• R.H. Follett and D.G. Westfall of Colorado State University consider alfalfa as one of the plants most tolerant of low iron soil. Alfalfa prefers alkaline to acidic soil, and thus copes better with the low levels of iron that accompany alkaline soil. The long root system of the alfalfa plant transports iron and other minerals into the leaves, where it indirectly contributes to the dark green of the leafy plant. Many recipes call for alfalfa sprouts, and the plant finds heavy use in the agricultural industry as a forage plant for cattle.

Barley

• Barley's tolerance of low-iron soils attracted a team of Japanese scientists. Led by Michiko Takahashi, the University of Tokyo team took the genes responsible for barley's low-iron tolerance and spliced them into a new strain of transgenic rice. The resulting transgenic rice tolerated low-iron soil and produced yields of four times that of non-genetically-altered rice. Barley offers humans an iron-rich food, but requires special preparation for the body to fully absorb the mineral.

Corn

• Corn does not tolerate low iron soil as well as other small grains, nonetheless its tolerance exceeds that of many ornamental and fruit plants because it requires very little iron to thrive. When corn plants suffer from iron deficiency they present with interveinal chlorosis, or pronounced stripes of yellow against dark green veins on leaves. Corn plants suffer from iron deficiency most in moist, cool weather of spring. Foods made from corn potentially provide iron-rich meals for people, but phytic acid prevents the body from absorbing iron.

Improving Low Iron Soil

• Most soils contain between 1 to 5 percent iron, plenty for the needs of most plants. This iron often comes in the form of silicate minerals, iron oxides, and hydroxides - all forms that make it difficult for plants to absorb. Aerating the soil after a flood can improve the iron content, as can any general increase in microbial activity. Gardeners can increase the iron in soil by mixing manure or compost into the topsoil.