Fertilizer Requirements for New Plantings of Tall Fescue and White Clover on Two Low-Fertility Ultisols1
- C. H. Burmester and
- Fred Adams2
The use of optimum fertilizer rates is an essential component ofmanaging pasture forages. Tall fescue (Festuca arundinacea Schreb.), the dominant cool-season pasture grass in much of the South, is often interplanted with white clover (Trifolium repen L.) for improved forage quality and as an N source for the grass. Inadequate P and K fertilizers allow weeds to invade new plantings; too much N fertilizer allows tall fescue to choke-out white clover. Since a paucity of data exists on N-P-K requirements for new plantings of fescue and fescue-clover, two on-farm experiments were established on soils that are typical of extensive pasture acreage. Three N rates (0, 67, and 134 kg ha−1), four P rates (0,15, 30, and 60 kg ha−1), and four K rates (0, 28, 56, and 112 kg ha−1) were applied to fescue and a fescue-clover mixture; tall fescue alone received an additional N rate of 201 kg ha−1. Swards were clipped when 20 to 25 cm tall. Optimum N rate for tall fescue differed for the two sites; with clover in the sward, however, it was zero for both. Soil test P was very low for both soils (2 mg kg−1), and the optimum P rate for fescue was 15 kg ha−1 on one soil and 45 kg ha−1 on the other. With clover in the sward, optimum P rates were 50 to 55 kg ha−1 on both soils. Soil-test K differed for each site (low vs. medium), but optimum K rate for fescue alone was 28 kg ha−1 for each soil; with clover in the sward, however, optimum K rate was higher on the soil with the lower soil K (110 vs. 28 kg ha−1). In fescue-clover swards, weeds became dominant in the no-P and no-K plots at one site; tall fescue became dominant at the other. White clover almost disappeared in the no-P and the highest-N plots at both sites.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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