Effects of Lime and Phosphorus Treatments in Specific Horizons of Acid Soil on Growth and Chemical Content of Corn (Zea mays L.) 1

The effect of phosphorus and lime applications to the Ap and/or A2 horizon of a Norfolk loamy sand upon the growth and P and A1 content of corn were determined under greenhouse conditions. Increasing the supply of P in either horizon resulted in significant increases in top growth. This increase was of greater magnitude when P was supplied to the Ap than when supplied to the A2 horizon. The growth response of roots in each horizon to P application followed the same trends as top growth except when high levels of P were applied in both horizons the relative increases were much less than with top growth. Applications of lime to the A2 horizon resulted in increases in root growth in that horizon which were not increased further by lime application to the Ap horizon. Lime application in the A2 horizon resulted in slight increases in weight of tops and of roots from the Ap horizon. However, only when lime was applied to the Ap horizon was maximum top growth and root growth in the Ap horizon realized. Significant effects upon phosphorus concentrations in tops and in roots from the Ap horizon were not observed with the first increment of phosphorus in either horizon. A marked increase in phosphorus content was obtained from the second increment of phosphorus. Lime application resulted in a decrease in P and A1 concentration. The decrease in AI concentration was much less from the lime than from the P treatment.