The Effect of Surface‐applied Phosphate and Limestone on Soil Nutrients and pH of Permanent Pasture

I F satisfactory results can be obtained, topdressing limestone and phosphate on permanent pasture is a moredesirable practice than incorporating these materials into the soil in the South than in most other sections of the United States. The heavy rainfall, erodable slopes, and erodable soils prevailing over much of the South are deterrents to the thorough preparation of a seedbed for the purpose of incorporating lime and fertilizer into the soil. The present study is the soil phase of a more inclusive investigation of the effectiveness of topdressing limestone and varying rates of phosphorus, and other fertilizer materials, on increasing the available nutrients in the soil and pasture production. A review of the literature (6, 7, 8) on the penetration into the soil of lime and phosphorus applied as topdressings reveals contradictory results. A careful study of some investigations shows, .however, that many factors affect results. Some of these factors are rate of application of the material (i, 10), time between application, and soil sampling (i), amount of rainfall and, consequent percolation and soil moisture conditions, rate of nutrient removal by plant (3), soil type (4, 10, 2), other fertilizer materials (7, 9), source of material (6), and interrelation between lime and phosphate (3). The present study includes the effect of some of the above factors on pH and available nutrients .at various soil depths under conditions prevailing in the Piedmont section of Georgia.