Effect of Nitrogen and Shading on Yield and Quality of Grasses Grown under Young Slash Pines
1970
Hart, Richard H. | Hughes, Ralph H. | Lewis, Clifford E. | Monson, Warren G.
Tifhi-1 bahiagrass, Coastal bermudagrass, and prostrate dallisgrass were planted in 1962, under a stand of 5-year-old slash pines, spaced 3 m apart and averaging 5.2 m high. We applied N at 56, 112, 224, 336, and 448 kg/ha, and enough P and K to give a 2:1:1 ratio of N:P₂O₅:K₂O. Grass yields were taken every 6 weeks. In 1963, all grasses responded to N; maximum yields of bahia-, bermuda-, and dallisgrass were produced at 224, 336, and 112 kg/ha of N, respectively. N response was the same in 1964, except that bermudagrass produced maximum yields at only 222 kg/ha. No N response was seen in 1965; bahia- outyielded bermuda- and dallisgrass. In 1966, there were no differences among grasses, and no N response. In 1963, grass yields under the trees were as high as yields in the open, but in 1964, when the trees intercepted 84% of the light, they were somewhat lower. In 1965 and 1966, grass yields under trees were much lower than yields in the open. Yield decreased linearly as tree basal area increased. Crude protein content and dry matter digestibility increased with increased N rates; differences among grasses were small. Grass yields were higher than native range yields previously reported, however, the range yields were taken under different conditions of shading and fertilization. Quality of native range herbage and the grasses in this study was about the same, but quality of the unproved grasses was depressed by infrequent cutting.
显示更多 [+] 显示较少 [-]