Nutrient Utilization and Effluent Clean-Up Potential of Tropical Forage Grasses. (4896)
Authors:
R.B. Valencia-Gica - University of Hawaii at Manoa, Honolulu, Hawaii V. Wilcox - University of Hawaii at Manoa, Honolulu, Hawaii
R.B. Valencia-Gica* - Univ. of Hawaii at Manoa
R.S. Yost - University of Hawaii at Manoa, Honolulu, Hawaii C.I. Evensen - University of Hawaii at Manoa, Honolulu, Hawaii
Abstract:
Land application and plant utilization are among the most viable options for animal waste disposal, but information is inadequate under tropical conditions. The
dynamics of biomass production and nutrient removal potential of various tropical pasture grasses is being studied in Waianae effluent irrigation experiment.
Suerte-Paspalum atratum, bana-Pennisetum purpureum, signal-Brachiaria
decumbens and star-Cynodon nlemfuensis) were planted in augmented completely randomized design (CRD) and subsurface drip-irrigated with dairy effluent. Grass selection was based on preliminary fertilization studies in high elevation, cool Mealani site. Initial results from sea-level, arid environment in Waianae indicated higher annual dry matter (DM) and nutrient uptake (NU) of effluent-irrigated grasses than in Mealani. Bana’s small plot annual DM (32500-40600 kg ha-1) and NU (500-800, 70-100, 900-1400 kg ha-1 of N, P, K, respectively) were highest in Mealani—results also expected in Waianae as evidenced by its robust growth in the propagation plots. In Waianae, star (1300 kg N ha-1 and 300 kg P ha-1) and signal (50 kg Na ha-1) had higher uptake of some nutrients than suerte, which had highest DM (80000 kg ha-1) based on a single harvest interval (35 days). Overall, these results suggest high potential of different tropical forage grasses for use in effluent clean-up and land treatment systems. The study will also evaluate the effect of two effluent application rates: 3 mm dy-1 and 13 mm dy-1.
Speaker Information: Rowena Valencia-Gica, Univ. of Hawaii at Manoa, 3190 Maile Way, Honolulu, HI 96822; Phone: 808-956-6821; E-mail: [email protected]
Session Information: Wednesday, November 3, 2004, 4:00 PM-6:00 PM Presentation Start: 4:00 PM (Poster Board Number: 0415)
Keywords: dairy effluent; nutrient uptake; salinity tolerance; subsurface effluent irrigation
