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Effects of N, P, and K Fertilization on Barley Grown in a Newly Cleared Subarctic Soil 1
Author(s) -
Michaelson G. J.,
Loynachan T. E.,
Wooding F. J.,
Mitchell G. A.
Publication year - 1982
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/agronj1982.00021962007400040024x
Subject(s) - agronomy , human fertilization , phosphorus , fertilizer , hordeum vulgare , nutrient , nitrogen , straw , chemistry , zoology , environmental science , mathematics , biology , poaceae , organic chemistry
Alaska has vast areas of undeveloped land with the potential for agricultural expansion. To develop renewable resources from oil royalty monies, the state has initiated a 24,000 ha agricultural demonstration project near Delta Junction, Alaska. Little is currently known, however, concerning the natural fertility of these virgin soils. A 4 3 factorial experiment was established, with barley ( Hordeum vulgare L. var. ‘Otra’) as the test crop, to determine responses to fertilization the first 2 years after clearing on a Typic Cryopsamment soil. Fertilizer was applied before seeding each year at 0, 45, 90, and 135 kg N/ha; 0, 34, 68, and 102 kg P/ha; and 0, 34, 68, and 102 kg K/ha. Grain yields, protein contents, and subsequent soil‐test levels were measured. Nitrogen increased grain yields from 2 quintal/ha with no applied N in 1979 to 25 quintal/ha with 135 kg N/ha and from 4 quintal/ha with no applied N in 1980 to 31 quintal/ha with 135 kg N/ha. The yield response to N was linear throughout the 0 to 135 kg N/ha range in 1979, and both the linear and quadratic regression terms were significant in 1980. Cooler initial soil temperatures, lack of native residual nutrients, or N immobilization may have contributed to lower overall yields in 1979. Grain protein increased linearly with added N both years. Phosphorus increased yield up to 34 kg P/ha, with little response beyond that in either year. In 1979, both P and K were significant in increasing the yield response to N. In 1980, only K increased the yield response to N. Neither P nor K fertilization significantly increased grain protein contents. Multiple‐regression equations were developed to predict grain yields and protein contents with rates of fertilizer applied. When considering only N, P, and K fertilizer additions, equations with relatively high coefficients of determination were obtained for the first 2 years of production (Yield: R 2 = 0.929,0.937 for 1979 and 1980; and protein: R 2 = 0.684, 0.842 for 1979 and 1980, respectively). Thus, the application of fertilizer accounted for much of the variation in yield and protein contents.