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Forage Yield and Quality of Phalaris as Affected by N Fertilization and Defoliation Regimes 1
Author(s) -
Saibro Joao C.,
Hoveland Carl S.,
Williams John C.
Publication year - 1978
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1978.00021962007000030033x
Subject(s) - forage , perennial plant , agronomy , phalaris arundinacea , biology , dry matter , human fertilization , growing season , phalaris minor , fodder , zoology , crop , wetland , ecology
Phalaris ( Phalaris aquatica L., also referred to as P. tuberosa L.) is a winter productive cool‐season perennial grass species having potential in the southeastern U.S. The purpose of our study was to determine the effect of N fertilization rates and defoliation on forage yield, in vitro dry matter digestibility (IVDMD), total forage N and NO 3 ‐N, and total non‐structural carbohydrates (TNC) stored in conns. The synthetic, ‘AP‐2’ phalaris, was fertilized at 100, 200, 300, and 400 kg N/ha/year and harvested at vegetative, inflorescence emergence, and seed stages of growth over a 2‐year period in the field. Forage yield, total N, and NO 3 ‐N concentration increased linearly with increasing N fertilization. Maximum dry forage yield was 10 metric tons/ha annually. Total N concentration ranged from 2.8 to 4.0%. Forage NO 3 ‐N concentration was highest in autumn but less than that considered potentially toxic to ruminants. Harvesting at more advanced plant maturity increased forage yield while reducing NO 3 ‐N and IVDMD. The IVDMD was relatively high, averaging 63% over the year. Corm reserves of TNC decreased with N fertilization but increased with plant maturity. TNC in corms remained low throughout the active growing season. Results of this study indicate that AP‐2 phalaris can utilize up to 300 kg N/ha annually either under frequent defoliation or cutting at hay stage. This grass maintains relatively high IVDMD at a fairly advanced stage of maturity.