A summary of placement and fall versus spring application of nitrogen fertilizers

Non-Peer ReviewedIn 52 field experiments since 1973-74, the yield of barley grain without N averaged 1570 kg/ha, but the yield was increased by fall and spring application of incorporated urea (56 kg N/ha) to 2540 and 3470 kg/ha, respectively. Early fall application was only half as efficient as late fall application. In five field experiments with 15N, the recovery in the spring of fall applied nitrate was low (13 to 60 %) while recovery of late fall banded ammonium was much higher (82 to 99 %). These losses came about through denitrification and not by leaching. Variable amounts of applied nitrate and ammonium were immobilized in the soil. Fall banding (45 cm spacing) and fall nesting (45 × 45 cm spacing) of urea (or aqua ammonia) gave larger yield increases than fall incorporation. In five experiments before 1978-79, yield increases of barley grain from fall application of urea by incorporation, banding and nesting were 960, 1240, and 1560 kg/ha, respectively. In the same order, yield increases were 740, 1100, and 1510 kg/ha in ten more recent experiments. However, the size of yield increases from fall banding were variable from experiment to experiment, ranging from being similar to fall incorporation to being similar to the high-yielding fall nests. With spring application of urea, banding produced slightly higher yields than incorporation, while nesting tended to produce lower yields. Retaining rather than removing the straw of the previous crop depressed the yield of barley grain by 650 kg/ha in six field experiments, and the retention of straw halved the uptake of fertilizer N by the crop. Preliminary results suggest that placement of fertilizer N in large pellets may overcome the immobilization of fertilizer N by the straw

Methods of application of nitrogen fertilizer for conservation tillage

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Methods of reducing the soil acidification caused by nitrogen fertilizers

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Influence of formulation of elemental S fertilizer on yield, quality, and S uptake of canola seed

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Influence of long-term applications of N and S fertilizers (1980-2005) on dry matter yield of grass and soil properties in a Dark Gray Chernozem in north-central Saskatchewan

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Unconventional methods of fertilizer placement to reduce losses of fall applied nitrogen

Non-Peer ReviewedIn two field experiments conducted in 1978-79, fall application of incorporated urea, or banded aqua ammonia, produced much less increase in yield and N-uptake than did spring application for barley grain. However, when the fall-applied fertilizers were placed in constricted nests (one nest per each 45 x 45 cm area) the yield and N-uptake were nearly as great as with spring application. The mechanism by which nests avert losses from fall-applied N is through slowing of nitrification, and possibly through lessening of immobilization of fertilizer N by straw. Indirect evidence suggests that placement in nests is more effective than inhibitors of nitrification in reducing losses from fall-applied N fertilizers. The two field experiments in 1978-79, and three experiments in 1977-78 with fall-applied . urea showed that band placement improved yield in comparison to incorporation, but the banding was inferior to nesting. More specifically, yields with incorporation, banding, nesting, and spring incorporation were 960, 1240, 1560, and 1830 kg/ha, respectively. In the same order, values for % uptake of fertilizer N, were 31, 38, 53, and 66 %. Taking all of the eight experiments which have been conducted with nesting during the past four years, average yield increases were 1030, 1750, and 1980 kg/ha for fall incorporation, fall nesting, and spring incorporation, respectively. This work has been restricted to northern Alberta and northern Saskatchewan, and the feasibility of practical field-scale techniques of nesting, or application of large pellets, has not yet been investigated, but nevertheless the benefit of fall nesting is large enough to suggest work on this topic by other researchers in other areas of the prairie provinces

Long-term tillage, straw, and N rate effects on quantity and quality of organic C and N in a Gray Luvisol soil

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Long-term tillage, straw, and N rate effects on quantity and quality of organic C and N in a Black Chernozem soil

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Long-term tillage, straw management, and N fertilizer rate effects on crop yield, N uptake, and N balance sheet in a Gray Luvisol

Non-Peer ReviewedA field experiment (established in autumn 1979, with monoculture barley [1980-1990] and barley/wheat-canola-triticale-pea rotation [1991-2008] was conducted on a Gray Luvisol [Typic Haplocryalf] loam soil at Breton, Alberta, to determine the influence of tillage (zero tillage [ZT] and conventional tillage [CT]), straw management (straw removed [SRem] and straw retained [SRet]) and N fertilizer rate (0, 50 and 100 kg N ha-1 in SRet, and only 0 kg N ha-1 in SRem plots) on seed yield, straw yield, total N uptake in seed + straw (1991-2008), and N balance sheet (1980- 2008). The N fertilizer urea was midrow-banded under both tillage systems in the 1991-2008 period. There was a considerable increase in yield and total N uptake up to 100 kg N ha-1 under both tillage systems. On the average, CT produced greater seed yield (by 223 kg ha-1), straw yield (by 177 kg ha-1) and total N uptake (by 5.6 kg N ha-1) than ZT. Compared to SRem treatment, seed yield, straw yield and total N uptake tended to be greater with SRet at the zero-N rate used in the study. The amounts of applied N unaccounted for over the 1980-2008 period ranged from 845 to 1665 kg N ha-1, suggesting a great potential for N loss from the soil-plant system through denitrification, and N immobilization from the soil mineral N pool. In conclusion, crop yield and N uptake were lower under ZT than CT, and long-term retention of straw suggests some gradual improvement in soil productivity