Whole-season grass response to and recovery of nitrogen applied at various rates and distributions in a high rainfall environment

Abstract

Whole-season grass response to and recovery of nitrogen applied at various rates and distributions in a high rainfall environment. Can. J. Plant Sci. 78: 445-451. High rates of nitrogen (N) fertilizer are often used on perennial grass in the coastal region of British Columbia and the Pacific Northwest, but there is little information on optimum rates for abundant high-quality yields and on their environmental implications. A field trial was conducted in each of 3 yr to determine the effect of rates and distributions of N on whole-season herbage yield and quality, and pre-and post-season extractable inorganic N in the soil. Yearly rates were 100, 200 and 400 kg N ha -1 applied to each of four cuts in the following distributions: 1.00/0/0/0, 0.50/0.25/0.25/0 and 0.25/0.25/0.25/0.25. Whole-season yield was increased by increasing rates of N in all three trials, but the increase varied from 17% (Trial 1) to 127% (Trial 3). Distributing the N uniformly through the season resulted in only a 5% increase in yield compared with applying all of the N at the beginning of the season. Rate of N had a substantial effect on average herbage crude protein and nitrate concentrations, but the distribution effect was greater on herbage N constituents than on yield. Increasing rates of N consistently increased average herbage nitrate concentrations, and crude protein in two of three trials. Applying all of the N at the beginning of the season increased average herbage crude protein and nitrate concentrations more than distributing it evenly through the season. Extractable inorganic N in the soil at the end of the season increased only at 400 kg N ha -1 rate and was not affected by distribution. Although distribution pattern influenced herbage yield and nitrogen concentrations, distribution did not influence total herbage N uptake or recovery in herbage plus soil. Rates and distributions of N on grass influenced herbage yield and quality, and soil extractable inorganic N in different ways; therefore, compromises in N management are required to optimize forage yield and quality, and soil nitrate concentrations. Autumn soil inorganic N testing may be useful as feedback information for fertilizer recommendations in the subsequent season. Spring soil inorganic N testing was a poor predictor of crop response to fertilizer in the high rainfall environment of the study. années, l'accroissement allant de 17 % la première année à 127 % dans la troisième. La répartition uniforme de la fumure N tout au long de la saison de croissance n'a apporté qu'un gain de rendement de 5 % par rapport à l'épandage en une seule fois en début de saison. La dose de N manifestait un effet substantiel sur les concentrations moyennes de protéine brute et de nitrates dans l'herbage, mais l'effet du mode de fractionnement de la fumure était plus prononcé sur les composantes azotées de l'herbe que sur le rendement. L'accroissement de la dose de N provoquait une augmentation constante des concentrations moyennes de nitrates dans l'herbe aux trois emplacements et de pr...

Yield response of forage grasses to N fertilizer as related to spring soil nitrate sorbed on anionic exchange membranes

“…This explains the large increase in forage NO 3 -concentration at the highest N rates (Table 3) and the significant quadratic component for NO 3 -concentration (Table 2). The significant linear increase in forage N uptake with fertilizer N application is consistent with others studies (Kline and Broersma 1983;Whitehead 1995;Bittman and Kowalenko 1998). The average N uptake from the N0 treatment was 80, 71, and 53 kg N ha -1 in 1994, 1995 and 1996, respectively, indicating a progressive depletion of the soil mineralizable N pool.…”

“…Close relationships between soil NO 3 -in spring and the response to N fertilizers of crops have been reported in many studies (Magdoff et al 1984;Dahnke and Johnson 1990;Holford et al 1997). Other studies, however, found that this approach is not satisfactory under cool and humid environments (Neeteson 1995;Bélanger et al 1998;Bittman and Kowalenko 1998). (Colwell 1994).…”

“…Many studies have been conducted on the effect of N on yield and quality of forage grasses (MacLeod 1965;Hunt et al 1979;Bélanger et al 1989;Bélanger and Richards 1997). Most of these studies, however, did not include soil N measurements (Bittman and Kowalenko 1998). The objectives of this study were (i): to determine the effects of N fertilizer on yield, N uptake, and NO 3 -N concentration of forage grasses produced in Western Quebec; and (ii) to compare the use of spring soil nitrate measured by anionic exchange membranes (NO 3AEMs ) to water (NO 3w ) as a criterion to predict fertilizer N requirements of forage grasses.…”

Within-season grass herbage crude-protein- and nitrate-N concentrations as affected by rates and seasonal distribution of fertilizer nitrogen in a high yearly rainfall climate

“…We previously showed that large differences in seasonal distribution of fertilizer N caused only small differences (5%) in annual yield of orchardgrass over four cuts within a growing season in southwestern British Columbia. However, the rate of fertilizer application (up to 400 kg N ha -1 yr -1 ) increased yields by 17 to 127% (Bittman and Kowalenko 1998). Fertilizer treatments in this study had a greater effect on season-average herbage crude-protein-N and nitrate-N concentrations than on total season yield.…”

Nitrogen fertilization and row spacing effects on Digitaria eriantha

“…Gargano et al (2003) also reported that dry matter yields were greater in D. eriantha under a split than bulk application of N fertilizer. Bittman and Kowalenko (1998) concluded that split applications could have practical advantages, even with no yield increases, by evening out the yield and crude-protein concentration over the season.…”