Response of Tifway 2 bermudagrass to fresh or composted broiler litter containing boric acid-treated paper bedding

Recycled paper treated with boric acid (BA) is gaining acceptance as bedding in broiler production houses. Applying this litter, or compost made from this litter, to turf raises an issue of boron (B) toxicity. There is also the question of nitrogen (N) availability from composts made from borated paper and broiler manure. The objective of this study was to determine if broiler house litter containing recycled BA-treated paper poses a toxicity hazard to bermudagrass turf (Cynodon dactylon L. pers X C. Transvaalensis, Burtt-Davis) when applied at agronomic N rates. The effects of five N sources at rates equivalent to 224, 448, and 896 kg N/ha in a factorial arrangement plus an unfertilized control and a high nitrogen-phosphorus-potassium (NPK) treatment with B at 22 kg B/ha on bermudagrass were determined in pot culture during the summer of 1992. The five NPKB sources were (M1) compost made from broiler manure, BA-treated paper and yard refuse; (M2) fresh broiler manure with BA paper bedding; (M3) fresh broiler manure with pine shavings bedding; (M4) inorganic NPK; and (M5) inorganic NPK and BA. The soil was Cecil sandy clay loam subsoil. Top growth was harvested four times at 4 cm height with tops, roots, and stubble harvested at the fifth and final harvest. Composted litter was higher in water content and lower in NPK and B than fresh litter. As a result, over four times the mass had to be applied to achieve the desired N inputs. Boron concentrations in M1 on a dry matter basis were 290, M2 = 390, M3 = 52 mg B/kg, respectively. The NPK gave highest yields and compost (M1) gave the lowest yields. Yield response of fresh manure + BA paper was not different from fresh manure + pine shavings. Nitrogen recovery in plant growth from composts was very low. Nitrogen recovery in compost residue at the soil surface was very high. Nitrogen recoveries for BA paper litter and pine shavings litter were similar. No visual symptoms of B toxicity were observed, although a 16% yield reduction occurred at 22.4 kg B/ha at the 896 kg N/ha rate from NPK. Boron recovery in plant growth was negligible, but considerable B remained in the residue at the soil surface. Yield response efficiency was M1 = 2.5, M2 = 4.8, M3 = 5.3, NPK = 15.5 NPKB = 14.3 mg DM/mg N, respectively. Plant top N recovery response efficiency in mg N recovered/mg N per pot was 0.07, 0.15, 0.165, 0.63, and 0.58 for M1, M2, M3, NPK, and NPKB, respectively. Adding stubble, roots, and residue to total N recovery resulted in the following recoveries: M1 = 0.97, M2 = 0.25, M3 = 0.35, NPK = 0.73, NPKB = 0.68 mg N/mg N applied. The risk of B toxicity to Tifway 2 bermudagrass from compost or manure containing BA-treated paper is minimal if N rates are in the agronomic utilization range.