Fertilizer Effects on Crop Removal of P and K in ‘Coastal’ Bermudagrass Forage¹

Abstract

In 1959, an N‐P‐K ratio of 9.1‐1‐3.8 (4‐1‐2 N‐P2O5‐K2O ratio) was proposed as the proper nutrient balance for fertilizing ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] for forage, but nutrient removal in forage was not taken into consideration with this ratio. The purpose of the study was to determine fertilizer effects on removal of P and K in ‘Coastal’ bermudagrass forage using increments of a fixed N‐P‐K ratio and high rates of P and K over a range of N rates. An established sod which had not received fertilizer for at least 5 years was selected for the 3‐year study. The soil was a Fuquay loamy sand (loamy, siliceous, thermic arenic Plinthic Paleudult) which was medium in P and low in K. Annual treatments for the first 2 years were 84,168,336, and 672 kg N ha−1 applied with P and K in a 9.1‐1‐5.7 N‐P‐K ratio (4‐1‐3 N‐P2O5‐K2O ratio). In the 3rd year 73.6 kg P ha−1 and 420 kg K ha−1 were applied uniformly at all N rates. The 9.1‐1‐5.7 N‐P‐K ratio supplied inadequate amounts of P and K to compensate for crop removal at the lower fertilizer rates but were excessive at the higher fertilizer rates. The N‐P‐K ratio required the 3rd year to supply P and K equivalent to that removed in the forage ranged from 6.4‐1‐6.5 for the 84 kg N ha−1 treatment to 14.4‐1‐7.9 for the 672 kg N ha−1 treatment. This study indicates that the use of regression equations for determining P and K needs for Coastal bermudagrass is a more suitable method than the N‐P‐K ratio method.

Effects of Dairy Manure Compost and Supplemental Inorganic Fertilizer on Coastal Bermudagrass

“…Data are presented by harvest for the 2004 growing season because DM yields were not affected in 2002 or 2003 by supplemental inorganic P fertilizer (Table 3). The optimal tissue‐P concentration for Coastal bermudagrass was 2.4 g kg −1 (Day and Parker, 1985; Kelling and Matocha, 1990) and a field study by Brink et al (2004) reported tissue‐P concentration ranging from 1.5 to 2.3 g kg −1 , which is similar to values reported in this study. In 2002 and 2003, average tissue‐P ranged from 1.8 g kg −1 to 2.8 g kg −1 in the compost treatments receiving supplemental inorganic P (data not shown).…”

“…In 2004, the third season after application, all C2, C3, and M treatments had greater tissue‐P concentrations compared with UC for all four harvests (Table 6). Compost and manure treatments receiving supplemental inorganic N had lower tissue‐P concentrations than plots not receiving supplemental N. This is attributed to greater DM and consequent nutrient removal from plots receiving supplemental inorganic N. In 2004, average tissue‐P concentrations fell to 2.0 g kg −1 in the C2 and M treatments in the third and fourth harvests, which is below the critical level of 2.4 g kg −1 (Day and Parker, 1985) and explains why supplemental inorganic P increased Coastal bermudagrass DM yields in the third season following application of the low rate of compost. Supplemental inorganic P did not affect tissue‐P concentration in the C3 treatment, indicating that higher rates of compost can provide sufficient P for up to three growing seasons and supports the observed DM yield data.…”

Dairy Manure Compost Application Rate and Timing Influence Bermudagrass Yield and Nutrient Concentration

“…Year × treatment and harvest date × treatment interactions were signifi cant for P concentrations, so means are reported by year and harvest. The optimal tissue-P concentration for Coastal bermudagrass growth is 2.4 g kg -1 (Day and Parker, 1985;Kelling and Matocha, 1990), and a fi eld study by Brink et al (2004) reported tissue-P concentrations ranging from 1.5 to 2.3 g kg -1 , which is similar to the 1.3 to 3.2 g kg -1 range reported in this study. In 2003, earlyseason (H1) P concentrations (Table 4) were low compared with potential 3.2 g P kg -1 Coastal bermudagrass herbage reported elsewhere in the literature (Pierzynski and Logan, 1993).…”

“…The optimal tissue-P concentration for Coastal bermudagrass growth is 2.4 g kg -1 (Day and Parker, 1985;Kelling and Matocha, 1990), and a fi eld study by Brink et al (2004) reported tissue-P concentrations ranging from 1.5 to 2.3 g kg -1 , which is similar to the 1.3 to 3.2 g kg -1 range reported in this study. The optimal tissue-P concentration for Coastal bermudagrass growth is 2.4 g kg -1 (Day and Parker, 1985;Kelling and Matocha, 1990), and a fi eld study by Brink et al (2004) reported tissue-P concentrations ranging from 1.5 to 2.3 g kg -1 , which is similar to the 1.3 to 3.2 g kg -1 range reported in this study.…”

Impacts of Thirty‐Seven Years of Stocking on Soil Phosphorus Distribution in Bermudagrass Pastures

“…Coastal Plain soils of the southern United States are usually sandy, acidic, low in organic matter, and have a low buffering capacity. Nitrogen, P, and K are often the major nutrients limiting forage production on these soils (Wilkinson and Langdale, 1974; Day and Parker, 1985). Liming is necessary to maintain an adequate pH for production of improved forages, particularly in pastures receiving commercial N fertilizer (Cripps et al, 1988; Haby et al, 1999).…”