Effects of N, P, and K Fertilization on Barley Grown in a Newly Cleared Subarctic Soil¹

Abstract

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 43 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: R2 = 0.929,0.937 for 1979 and 1980; and protein: R2 = 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.

Establishment, Dry Matter Yield, and Crude Protein of Fertilized Smooth Bromegrass on a Cleared Alaskan Soil1

“…These high coefficients indicate that the addition of N, P, and K fertilizers accounted for much of the variation in mean plot yields and N uptake. This was expected because of the large responses observed, especially with N and P fertilizer additions, and is consistent with the fertilizer responses reported earlier for barley (Michaelson et al, 1982).…”

“…During land clearing, the native vegetation of poplar (Populus ba/sanifera) and spruce (Picea mariana) trees was removed in the winter months, and the plot area was rototilled to a depth of 10 em in the spring. More details of the land clearing operation were reported in an earlier paper (Michaelson et al, 1982).…”

“…The development, known as the Delta Project, was located near Delta Junction in the Tanana River Valley of interior Alaska. The crop with the greatest potential for this area is barley (Hordeum vulgare L.) (Lewis and Wooding, 1978), and fertilizer responses for barley have been reported (Michaelson et al, 1982). With the rapid development of this relatively large area, a market must be found for the grain.…”

Two-way NxP fertilisation experiment on barley (Hordeum vulgare) reveals shift from additive to synergistic N-P interactions at critical phosphorus fertilisation level

“…It is however not so well understood how nutrient interactions may shape the allocation of nutrients to shoots and roots. The aboveground studies of N-P interaction on cereals in most cases have a simple experimental design with few combinations of low vs high N and P fertilisation rates ( Prystupa et al, 2003 ; Prystupa et al, 2004 ) or fewer P rates compared to N ( Michaelson et al., 1982 ; Tigre, 2014 ). Fewer studies have investigated nutrient interactions across a high number of fertilisation rates.…”