Availability of nitrogen after fertilizer applications to cereals

2001 ◽  
Vol 136 (2) ◽  
pp. 141-157 ◽  
Author(s):  
J. A. KING ◽  
R. SYLVESTER-BRADLEY ◽  
A. D. H. ROCHFORD
Keyword(s):  
Growth Period ◽  
N Recovery ◽  
Fertilizer N ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Active Growth ◽  
Soil Microbial ◽  
Winter Cereals ◽  
Crop Uptake ◽  
Active Growth Period

An experiment was conducted over seven sites in eastern England sown to winter cereals, whereby the soil mineral nitrogen (N) and N recovery in the crop were measured frequently during the active growth period. Plots received 100 kg/ha fertilizer N on one of three dates in spring (28 March, 11 April and 25 April) on each site in each of the three years (1994 to 1996), and these were compared with controls with no applied N. At one site, uncropped plots were included, and measurements of gaseous N emission, soil respiration, soil microbial biomass and root tissue N concentration were also made. The fertilizer applications boosted yields by at least 3 t/ha at all sites, but apparent recovery of fertilizer N varied throughout the previously known range of 45–85%. Soil type and timing of application had no effect on N recovery, or on final yields. N was mineralized from soil sources throughout the growth period, but mineralization was outweighed by ‘‘immobilization’’ of large amounts of N (around 30 kg/ha) in the soil, chiefly during May when crop growth was most rapid. This occurred on all sites with a crop, but not where the crop was absent. Measured losses of N2 and N2O were very small (<70 g/ha/dayN) on the site where they were measured, and no other evidence of loss or storage of N was found. The apparent recovery of fertilizer N at each site, was almost exactly explained by the amount immobilized during May. We conclude that the poor recovery of spring-applied N was due, not to losses as previously assumed but to temporary immobilization during the period of most active crop uptake. Immobilization was caused primarily by the presence of the crop.

THE STUDY OF CLIMATE EFFECTS ON THE NUT YIELD OF COCONUT USING PARSIMONIOUS MODELS

1998 ◽  
Vol 34 (2) ◽  
pp. 189-206 ◽  
Author(s):  
T. S. G. PEIRIS ◽  
R. O. THATTIL
Keyword(s):  
Sunshine Duration ◽  
Growth Period ◽  
Climate Data ◽  
Active Growth ◽  
Dry Matter Partitioning ◽  
Air Temperatures ◽  
Nut Production ◽  
Parsimonious Models ◽  
June July ◽  
Active Growth Period

The coconut yield is harvested in six picks per year at two-monthly intervals. The yield variation between and within years is very complex and this variability has not yet been explained. The analysis of long-term nut yield and monthly climate data: rainfall (RF), pan evaporation (EV), sunshine duration (SS), wind velocity (WV), minimum and maximum air temperatures (TMIN and TMAX), and relative humidity in forenoons and afternoons (RHAM and RHPM), using multivariate methods enabled the use of the variables TMAX, RHPM and EV as significantly important determinants (parsimonious set of variables) to represent the effects of climate on coconut irrespective of picks. Parsimonious models developed using these three variables explain how the development of bunches during the active growth period responded to climate variables without physiological parameters. The models are desirable where interpretation is concerned. The yields of picks one to six were determined by the climate variability during February, June, July, September, December and February respectively. Based on the models the proper timing of the use of some agronomic practices to enhance the productivity was recommended. A common model was also fitted (R2 = 0.81; p < 0.002) to estimate the annual yield 18 months in advance using EV, RHPM and TMAX. The three variables influence the microclimate around the crown of the palm for utilizing solar radiation in dry matter partitioning and thereby nut production. The method used to screen climatic variables so as to develop parsimonious crop–weather models using multivariate and univariate techniques can be used for other tree crops.

scholarly journals Long-term standardized forest phenology in Sweden: a climate change indicator

2019 ◽  
Author(s):  
Ola Langvall ◽  
Mikaell Ottosson Löfvenius
Keyword(s):  
Climate Change ◽  
Quantitative Methods ◽  
Food Resource ◽  
Growth Period ◽  
Phase Changes ◽  
Gradual Change ◽  
Active Growth ◽  
Statistical Precision ◽  
Active Growth Period

Abstract Because climate change alters patterns of vegetative growth, long-term phenological measurements and observations can provide important data for analyzing its impact. Phenological assessments are usually made as records of calendar dates when specific phase changes occur. Such assessments have benefits and are used in Citizen Science monitoring. However, these kinds of data often have low statistical precision when describing gradual changes. Frequent monitoring of the phenological traits of forest trees and berries as they undergo gradual change is needed to acquire good temporal resolution of transitions relative to other factors, such as susceptibility to frosts, insects, and fungi, and the use of berries as a food resource. Intensive weekly monitoring of the growth of apical and branch buds and the elongation of shoots and leaves on four tree species, and the abundance of flowers and berries of bilberry and lingonberry, has been performed in Sweden since 2006. Here, we present quantitative methods for interpolating such data, which detail the gradual changes between assessments in order to describe average rates of development and amount of interannual variation. Our analysis has shown the active growth period of trees to differ with latitude. We also observed a change in the timing of the maximum numbers of ripening berries and their successive decline. Data from tree phenology assessments can be used to recommend best forestry practice and to model tree growth, while berry data can be used to estimate when food resources for animals are most available.

Effect of nitrogen fertilizer applied to winter oilseed rape (Brassica napus) on soil mineral nitrogen after harvest and on the response of a succeeding crop of winter wheat to nitrogen fertilizer

1996 ◽  
Vol 126 (1) ◽  
pp. 63-74 ◽  
Author(s):  
M. A. Shepherd ◽  
R. Sylvester-Bradley
Keyword(s):  
Organic Matter ◽  
Oilseed Rape ◽  
Nitrogen Fertilizer ◽  
Organic Matter Content ◽  
Matter Content ◽  
Mineral Nitrogen ◽  
Fertilizer N ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Optimum Amount

SUMMARYSoil mineral nitrogen (Nmin) was measured to 90 cm at a total of 12 sites in the UK in the autumn after an oilseed rape experiment, which measured responses to fertilizer N. On average, Nmin, increased by 15 kg/ha per 100 kg/ha fertilizer nitrogen (N) applied to the rape, up to the economic optimum amount of N (Nmin). There were larger increases in Nmin where fertilizer applications exceeded Nopt, thus super-optimal fertilizer applications disproportionately increased the amount of nitrate likely to leach over-winter. The small effects of sub-optimal N on Nmin were associated with large increases in N offtake by the oilseed rape, whereas the larger effects of super-optimal N on Nmin were associated with only small increases in N offtake. Over 70% of the variation in autumn Nmin was explained by the previous rape's N fertilizer rate and the topsoil organic matter content.Nitrogen applied to the rape increased grain yields of the succeeding wheat crops when no further fertilizer N was applied to the wheat. It was concluded that N applied to oilseed rape significantly affected Nmin after harvest, and these effects were not completely nullified by leaching over-winter, so soil N supply to the succeeding wheat crop was significantly increased. Responses in grain yield indicated that each 100 kg/ha N applied to the rape provided N equivalent to c. 30 kg/ha for the following cereal. Each 1% of soil organic matter further contributed N to the wheat, equivalent to 25 kg/ha.It is important to ensure that oilseed rape receives no more than the optimum amount of fertilizer N if subsequent leaching is to be minimized. Reductions below optimum amounts will have only a small effect on leaching. Substantial changes in the economic optimum N for rape production should be accompanied by adjustment in fertilizer N application to following wheat crops. Fertilizer recommendation systems for wheat should take account of the fertilizer N applied to the preceding oilseed rape and the topsoil organic matter content.

Nitrogenase activity associated with Zostera marina from a North Carolina estuary

1982 ◽  
Vol 28 (4) ◽  
pp. 448-451 ◽  
Author(s):  
Garriet W. Smith ◽  
Steven S. Hayasaka
Keyword(s):  
North Carolina ◽  
Zostera Marina ◽  
Nitrogenase Activity ◽  
Growth Period ◽  
Winter Period ◽  
Late Winter ◽  
Active Growth ◽  
North Carolina Estuary ◽  
Active Growth Period

Nitrogenase activity (at in situ temperatures) associated with Zostera marina reflected the active growth periods of this plant in North Carolina coastal waters. During the plants most active growth period (late winter – spring) nitrogenase activity was primarily rhizospheric (8.47 μmol nitrogen fixed∙m−2∙day−1), while during its fall – early winter period it was primarily phyllospheric (8.03 μmol nitrogen fixed∙m−2∙day−1). No nitrogenase activity was detected during the warmer summer months when the plant is dormant. Phyllospheric nitrogenase activity (possibly the result of epiphytic heterocystic blue-green bacteria) was highest when plants were incubated aerobically in the presence of light.

Effects of long-term straw management and fertilizer nitrogen additions on soil nitrogen supply and crop yields at two sites in eastern England

2002 ◽  
Vol 139 (2) ◽  
pp. 115-127 ◽  
Author(s):  
MARTYN SILGRAM ◽  
BRIAN J. CHAMBERS
Keyword(s):  
Soil Nitrogen ◽  
Nitrogen Supply ◽  
Fertilizer N ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Mineral N ◽  
Plough Layer ◽  
N Rates ◽  
Soil Nitrogen Supply

The effects of straw incorporation (early and late cultivation) and straw burning were contrasted in a split-plot study examining the impact of long-term straw residue management, and six fertilizer nitrogen (N) rates on soil mineral nitrogen, crop fertilizer N requirements and nitrate leaching losses. The experiments ran from 1984 to 1997 on light-textured soils at ADAS Gleadthorpe (Nottinghamshire, UK) and Morley Research Centre (Norfolk, UK).Soil incorporation of the straw residues returned an estimated 633 kg N/ha at Gleadthorpe and 429 kg N/ha at Morley on the treatment receiving 150 kg/ha per year fertilizer N since 1984. Straw disposal method had no consistent effect on grain and straw yields, crop N uptake, or optimal fertilizer N rates. In every year there was a positive response (P<0·001) to fertilizer N in straw/grain yields, N contents and crop N offtakes at both sites. Nitrate leaching losses were slightly reduced by less than 10 kg N/ha where straw residues had been incorporated, while fertilizer N additions increased nitrate leached at both sites.At both sites there was a consistent effect (P<0·001) of straw disposal method on autumn soil mineral N, with values following the pattern burn>early incorporate>late plough. The incorporation of straw residues induced temporary N immobilization compared with the treatment where straw was burnt, while the earlier timing of tillage on the incorporate treatment resulted in slightly more mineral N compared with the later ploughed treatment. Fertilizer N rate increased (P<0·001) soil mineral nitrogen at both sites. At Morley, there was more organic carbon in the plough layer where straw had been incorporated (mean 1·09 g/100 g) rather than burnt (mean 0·89 g/100 g), and a strong positive relationship between organic carbon and fertilizer N rate (r2=93·2%, P<0·01). There was a detectable effect of fertilizer N on readily mineralizable N in the plough layer at both Gleadthorpe (P<0·001) and Morley (P<0·05). At Morley, there was a consistent trend (P=0·06) for readily mineralizable N to be higher where straw had been incorporated rather than burnt, indicating that ploughing-in residues may contribute to soil nitrogen supply over the longer term.

scholarly journals An analysis of the response of sugar beet and potatoes to fertilizer nitrogen and soil mineral nitrogen.

1989 ◽  
Vol 37 (2) ◽  
pp. 129-141 ◽  
Author(s):  
J.J. Neeteson ◽  
H.J.C. Zwetsloot
Keyword(s):  
Soil Type ◽  
Field Trials ◽  
Soil Mineral N ◽  
Fertilizer N ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Mineral N ◽  
Organic Manures ◽  
The Difference ◽  
Prior Application

A statistical analysis was performed to investigate if, and to what extent, the response of sugarbeet and potatoes to fertilizer N depended on the amount of mineral N already present in the soil, soil type, and prior application of organic manures. For this purpose the results of 150 field trials with sugarbeet and 98 with potatoes were used. The analysis was focussed on the within-block stratum of variation in yield, where regression models were fitted to describe the response to N. For both sugarbeet and potatoes the best fit was obtained when not only fertilizer N was taken into account, but also soil mineral N, soil type and prior application of organic manures. The response to fertilizer N was weaker as the amount of soil mineral N was larger. The optimum amount of fertilizer N plus soil mineral N required was larger on sandy soils than on loam and clay soils. The difference was about 20 kg N/ha for sugarbeet and 100 kg N/ha for potatoes. When organic manures were applied prior to the application of fertilizer N, the optimum for both sugarbeet and potatoes was 15-50 N/ha lower than without application of organic manures. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Seasonal variation in response of winter cereals to nitrogen fertilizer and apparent recovery of fertilizer nitrogen on chalk soils in southern England

1997 ◽  
Vol 128 (3) ◽  
pp. 251-262 ◽  
Author(s):  
J. P. GRYLLS ◽  
J. WEBB ◽  
C. J. DYER
Keyword(s):  
Seasonal Variation ◽  
Growing Season ◽  
Net N Mineralization ◽  
Soil N ◽  
Soil Mineral N ◽  
Fertilizer N ◽  
Soil Mineral ◽  
Mineral N ◽  
Winter Cereals

From 1985 to 1987, 20 experiments were carried out on shallow chalk soils, in which soil N reserves were expected to be small, to assess seasonal variations in the response of winter cereals to applied fertilizer N, and to relate these responses to measurements of soil mineral N (SMN), temperature and soil moisture deficits (SMD).Soil mineral N measured in autumn varied from 21 kg/ha (1986) to 73 kg/ha (1985), while SMN in spring ranged from 19 kg/ha (1987) to 91 kg/ha (1985), these values were typical of soils in long-term arable rotations. Estimates of apparent net N mineralization (AM) during the growing season were small at c. 26 kg/ha and suggested large seasonal variation. The small AM is considered to be due to the shallow topsoil drying out during the growing season. Whole crop N offtake without fertilizer N was only c. 40kg/ha. Crop N offtake, grain yield without fertilizer N and AFR (apparent recovery of fertilizer N) could not be reliably predicted by regression on SMN in autumn, SMN in spring or AM. Little or none of the variation in crop yield could be accounted for by regression on accumulated temperature over winter, maximum SMD in April to July or mean temperature in April to July.Despite optimum grain yields being only moderate at 6·59 t/ha for winter wheat and 6·78 t/ha for winter barley, response to applied fertilizer N was large, between 3·77 and 5·38 t/ha. In consequence the requirement for fertilizer N (c. 240–250 kg/ha) was also large, but differed little between seasons. This large requirement is concluded to be a result of limited fertilizer recovery and mineralization of soil N during the growing season.

EXTRACELLULAR POLYSACCHARIDES OF SERRATIA MARCESCENS

1964 ◽  
Vol 42 (10) ◽  
pp. 1403-1413 ◽  
Author(s):  
G. A. Adams ◽  
S. M. Martin
Keyword(s):  
Serratia Marcescens ◽  
Culture Filtrate ◽  
Glucuronic Acid ◽  
Carbon Sources ◽  
Growth Period ◽  
The Other ◽  
Extracellular Polysaccharides ◽  
Active Growth ◽  
Electrophoretic Behavior ◽  
Active Growth Period

Growth of Serratia marcescens on sucrose, D-glucose, D-galactose, and D-xylose as carbon sources did not affect the composition of the extracellular polysaccharides significantly. D-Glucose was the major component with lesser amounts of D-mannose, heptose, L-fucose, and L-rhamnose. Rhamnose did not appear until near the end of the active growth period and increased proportionately more than the other sugars thereafter. From the culture filtrate after 20 hours growth on sucrose, two acidic polysaccharides were isolated. They were markedly different in composition and electrophoretic behavior although both contained glucose as their major component. One was characterized by a relatively high content of rhamnose and heptose, the other by the presence of mannose; both contained glucuronic acid. Other impure polysaccharides were isolated from the culture filtrate. It seems likely that S. marcescens produced a spectrum of rather similar extracellular polysaccharides of which the two isolated ones comprise the main types.

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