Root Growth and Morphology, Nutrient Uptake, and Nutrient Status of Early Growth of Soybeans as Affected by Soil P and K1
- W. B. Hallmark and
- S. A. Barber2
Little information is available on the effects of levels of soil P and K on soybean [Glycine max (L.) Merr] root growth and morphology. Soybeans were grown for 9, 16, and 21 days in Raub silt loam soil (fine-silty, mixed, mesic Aquic Argiudoll) to measure the effect of increasing soil P and K on root growth and morphology and its relation to shoot growth, nutrient status of shoots, and net nutrient influx. Increasing soil P increased shoot weight, root surface area per plant, root surface area per g of root, P, K, Ca, and Mg influx and P, K, Ca, and Mg concentration of shoots. Adding P decreased the root surface area per g of shoot and increased root surface area per g of root. Increasing soil K increased shoot weight (with high P soil), P, K, and Ca influx, and P and K concentration of shoots. Potassium decreased Mg influx and Mg concentration of shoots. Significant positive P ✕ K interactions were found for secondary root radius, P, K, and Mg influx and shoot concentration showing that P and K had their greatest effect when the other nutrient concentration in the soil was high. The effect of P and K on nutrient concentration of shoots followed the same pattern as that for nutrient influx. Since adding P or K changes root surface area per g of shoot, influx of other nutrients changes when they are added. Where influx increases, a sufficient soil level of each nutrient is then needed so that soil supply does not limit influx.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .