INCREASE IN MINERAL N IN SOILS DURING WINTER AND LOSS OF MINERAL N DURING EARLY SPRING IN NORTH-CENTRAL ALBERTA

1986 ◽  
Vol 66 (3) ◽  
pp. 397-409 ◽  
Author(s):  
S. S. MALHI ◽  
M. NYBORG
Keyword(s):  
Field Experiments ◽  
Early Spring ◽  
Soil Samples ◽  
Frozen Soil ◽  
Late Winter ◽  
Mineral N ◽  
N Accumulation ◽  
N Content ◽  
North Central ◽  
Cultivated Soils

Ten field experiments were conducted on cultivated soils in north-central Alberta to determine any change in mineral N content of soils during winter, and during early spring after the soils had thawed. Soil samples were taken periodically from fall to spring to a depth of 120 (or 90) cm and were analyzed for NH4-N and for NO3-N. Mineral N changes occurred primarily in the top 60 cm. Between fall and late winter, there was an increase of 48 kg N ha−1 of mineral N (range of 27–83) in the 60-cm depth of eight experiments set on stubble and the value increased only to 55 kg N ha−1 when the sampling depth was extended to 120 (or 90) cm. Considering only the values from soil samples taken when soils were frozen, the increase in mineral N was 31 kg N ha−1 (range of 14–54) in the 120-cm depth, and the average net mineral N accumulation was 0.35 kg N ha−1 d−1 (range of 0.26–0.43). There was a loss of mineral N during early spring of 44 kg N ha−1 (range of 18–71). The two experiments on summerfallow had more over-winter accumulation of mineral N and more loss in early spring compared to the stubble experiments. This study showed large increases in the mineral N content when the soil was frozen and large decreases in the early spring. The mechanism of increase in mineral N in frozen soil was not determined. The cause of the decrease in early spring was most likely denitrification, and was not leaching of nitrate. The results of the investigation may have implications for the time of soil test sampling and for the loss of native N from cultivated soils. Key words: Ammonium N, frozen soil, mineral N, nitrate N, early spring loss

Enhanced accumulation of mineral-N following canola

1999 ◽  
Vol 39 (5) ◽  
pp. 587 ◽  
Author(s):  
J. A. Kirkegaard ◽  
P. M. Mele ◽  
G. N. Howe
Keyword(s):  
Field Experiments ◽  
Crop Residues ◽  
N Cycling ◽  
Microbial Populations ◽  
Free Living ◽  
Mineral N ◽  
N Accumulation ◽  
N Content ◽  
Summer Fallow ◽  
Total Bacteria

The accumulation of mineral-nitrogen (N) in the top 10 cm of soil during the summer fallow was measured in 2 replicated field experiments following a range of crops including wheat, oats, canola, peas and lupins. At the first site, mineral-N was measured following harvest and in autumn before sowing subsequent crops across 3 seasons (1994–96). Crop residues were retained on the surface with intermittent grazing by sheep throughout the summer fallow and burnt before the autumn measurements. The smallest increase in mineral-N accumulation occurred following the cereals in all 3 seasons (mean increase 31 kg/ha). The highest accumulation of mineral-N in all seasons occurred following canola (mean 94 kg/ha), 3 times as much as that following cereals, and significantly higher than that after the legumes in 2 of the 3 seasons (mean 50 kg/ha). Differences in the amount, N content, or C : N ratio of the surface-retained crop residues are unlikely explanations for the observed differences in mineral-N accumulation. At a second site, measurements of the accumulation of mineral-N following canola and wheat were accompanied by measurements of populations of selected microorganisms involved with N cycling in soil. More mineral-N accumulated after canola than after wheat, however, populations of free-living, N-fixing bacteria, potential Azospirillim species and NH4+ oxidising bacteria were significantly lower following canola than following wheat, and populations of total bacteria and NO2− oxidising bacteria did not differ. These results suggest that greater mineral-N accumulation following canola does not result from a shift in those microbial populations which favour mineral-N accumulation, however, more detailed studies are required to resolve the exact cause of the differences. A possible explanation is that biocidal compounds released by canola roots during decay may cause a general ‘biofumigation’ and thereby result in a flush of mineral-N similar to that which accompanies chemical fumigation.

scholarly journals Relationship between mineral N content and N mineralization rate in disturbed and undisturbed soil samples incubated under field and laboratory conditions

Soil Research ◽  
1992 ◽  
Vol 30 (4) ◽  
pp. 477 ◽  
Author(s):  
J Sierra
Keyword(s):  
N Mineralization ◽  
Negative Relationship ◽  
Feedback Mechanism ◽  
Soil Samples ◽  
Mineralization Rate ◽  
Mineral N ◽  
Undisturbed Soil ◽  
N Content ◽  
Undisturbed Samples

An investigation of in situ N mineralization, using undisturbed soil samples, indicated a negative relationship between the mineral N content [(NO3+NH4)-N] at the beginning of the experiment and the mineral N produced during it. This suggests that a maximum value of mineral N accumulation in intact soil cores could be calculated from the relationship between mineral N content and N mineralization rate. This value would be related to the size of the mineralizable N pool. If this hypothesis is true, the amount of mineralizable N could be estimated from in situ incubations and utilized in the modelling of N mineralization in the field. The aim of this work was to verify this hypothesis. The relationship between the mineral N content and the N mineralization rate was analysed for in situ and laboratory incubations of disturbed and undisturbed soil samples. A negative relationship between the two variables was only obtained for the experiments carried out with undisturbed samples (in the field and laboratory incubations) when the soil moisture content was not limiting for N mineralization. Futhermore, in undisturbed samples, a negative relationship between mineralization rates of consecutive incubation periods was observed, i.e. the soil sample producing relatively more, during a given period, produced relatively less in the following period. This relationship suggests a feedback mechanism operating in N mineralization which would be related to a mineralization-immobilization process in soil microsites. Thus, the N mineralization pattern was more complex than that described by initial hypothesis. The possible consequence of this feedback mechanism on in situ N dynamics is discussed.

Application of anhydrous ammonia or urea during the fallow period for winter cereals on the Darling Downs, Queensland .II. The recovery of 15N by wheat and sorghum in soil and plant at harvest

Soil Research ◽  
1992 ◽  
Vol 30 (5) ◽  
pp. 711 ◽  
Author(s):  
WM Strong ◽  
PG Saffigna ◽  
JE Cooper ◽  
AL Cogle
Keyword(s):  
Field Experiments ◽  
15N Recovery ◽  
Fertilizer Management ◽  
Fertilizer Placement ◽  
Mineral N ◽  
N Content ◽  
Fallow Period ◽  
Anhydrous Ammonia ◽  
Winter Cereals ◽  
Application Depth

Three field experiments were conducted on the Darling Downs (Queensland) to evaluate fertilizer management practices such as application depth and addition of nitrification inhibitor (N-serve), for nitrogen (N) applied in the February-May fallow period for winter cereals. Anhydrous ammonia or urea was applied in February, March or May at two depths (7 or 17 cm), with or without N-serve. Soil fertilized in February generally had a lower mineral-N content at sowing than soil fertilized in May. Deeper application (17 cm) in February did not increase soil mineral-N content to 0.2 m depth in May but addition of N-serve did at one site where it appeared to slow the movement of mineral N into the subsoil (0.2-0.4 m). A companion experiment was conducted at each site in which 15N-enriched urea was applied to a small (1 m2) area at the centre of a 4 m2 fertilized plot. Effects of fertilizer placement and N-serve treatment, as were used in field experiments, were evaluated in terms of crop recovery of 15N and total 15N recovery in plant and soil at harvest. Recovery of 15N by wheat, sown at two sites in June, showed that neither fertilizer management practice, application depth nor N-serve affected 15N recovery. At only one site did wheat recover less February-applied N than May-applied N. N-serve had no effect on 15N recovery by sorghum sown in October, of N applied in February or May, but 15N recovery was increased by deeper fertilizer placement. Total recovery of 15N in soil and plant after wheat harvest was lower (-74%) for February-application than for May-application (>94%). Similarly, total 15N recovery after sorghum was lower the earlier the fertilizer was applied. Unrecovered 15N was presumed lost due to denitrification during periods of temporary waterlogging of surface soil. Use of N-serve with the fertilizer application had no effect in conserving 15N applied for wheat or sorghum. However, deeper (17 cm) placement of N than normal (7 cm) promoted higher total recoveries, and therefore reduced losses, of applied 15N at the three sites.

Nitrogen fertilization of grass seed crops as related to soil mineral nutrition.

1988 ◽  
Vol 36 (4) ◽  
pp. 375-385
Author(s):  
W.J.M. Meijer ◽  
S. Vreeke
Keyword(s):  
Field Experiments ◽  
Poa Pratensis ◽  
Application Rate ◽  
Early Spring ◽  
Soil Mineral ◽  
Mineral N ◽  
Yield Responses ◽  
Seed Crops ◽  
N Rates ◽  
The Relationship

The relationship between the level of soil mineral N present in early spring and the economically optimum application rate of N fertilizer was investigated in field experiments in 1978-84 at 4 locations in the Netherlands with Lolium perenne, Poa pratensis and Festuca rubra. Spring dressings, as split and single applications, of 30-210 kg N/ha and autumn dressings of 0-90 kg N/ha were used. The optimum spring rates were linearly related to mineral N in the 0-90 cm soil layers in L. perenne. No such relationship existed for the other species. The economically optimum spring N rates were 110 and 84 kg/ha, and yields were highest with autumn N dressings of 60 and 30 kg/ha for P. pratensis and F. rubra, resp. Autumn dressing had no effect on L. perenne if the spring dressing was near or above the optimum. A split spring dressing produced greater vegetative regrowth and reduced yields. Seed yield responses to fertilization were related to number of inflorescences produced rather than weight of seed per inflorescence. (Abstract retrieved from CAB Abstracts by CABI’s permission)

The winter treatment of grapevines with zinc and its interaction with time of pruning

1964 ◽  
Vol 4 (14) ◽  
pp. 241 ◽  
Author(s):  
BG Coombe
Keyword(s):  
Zinc Sulphate ◽  
Field Experiments ◽  
Early Spring ◽  
Late Winter ◽  
Early Winter ◽  
Zinc Treatment ◽  
One Year ◽  
June July

Field experiments on dormant Sultana vines showed that yields were increased by applying zinc sulphate solutions immediately after pruning. Treatment by the swabbing of pruning cuts gave similar results to a cover spray. Increasing the concentration of zinc sulphate (up to the maximum tested-35 per cent) increased yield and no bud injury was seen. A delay of a day or more between pruning and treatment drastically reduced its effectiveness. Shorter intervals were tested but the results fluctuated ; a possible reason for this is discussed. The movement of zinc along Sultana canes was gauged by analysis of sections of cane cut up at varying times after swabbing the pruned end. In one year zinc moved at least 20 inches within two days, whereas, in another, it moved only 10 inches after one month. The yield of Grenache vines was increased when pruning was delayed from early winter until late winter and early spring. Zinc treatment increased yields in vines pruned in June, July, and August, but depressed yields when applied to vines pruned in September.

EFFECTS OF SOIL ACIDITY AND LIMING ON MINERALIZATION OF SOIL NITROGEN

1978 ◽  
Vol 58 (3) ◽  
pp. 331-338 ◽  
Author(s):  
M. NYBORG ◽  
P. B. HOYT
Keyword(s):  
Soil Ph ◽  
Soil Nitrogen ◽  
N Mineralization ◽  
Soil Acidity ◽  
Field Experiments ◽  
Base Saturation ◽  
Organic N ◽  
Soil N ◽  
Mineral N ◽  
Cultivated Soils

Forty acid surface soils of pH 4.0–5.6 were incubated with and without lime, and the amounts of N that were mineralized or nitrified were statistically compared with several soil acidity characteristics. In addition, three field experiments were used to find the effect of liming on N mineralization. There was no relation between the amounts of mineral N released per unit of organic N in 120 days of incubation and soil pH, base saturation or soluble Fe, Al or Mn. Despite this, liming the soils to about pH 6.7 approximately doubled the amounts of N mineralized during incubation. In the field experiments, lime increased uptake of soil N by 15–42 kg/ha in the 1st yr but only 7–10 kg/ha in the 3rd yr. Thus these laboratory and field experiments indicate that soil acidity does not restrict mineralization of organic N and although liming increases mineralization of N, it is generally a temporary effect. Nitrification in the 40 incubated soils occurred much more rapidly in cultivated soils than in virgin soils. For both the virgin and cultivated soils, nitrification decreased with decreasing soil pH. However, nitrification was not statistically related to base saturation or soluble Fe, Al or Mn. Liming established good nitrification in most of the soils and this effect did not diminish with time.

scholarly journals Deterring non-target birds from toxic bait sites for wild pigs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nathan P. Snow ◽  
Joseph M. Halseth ◽  
Justin A. Foster ◽  
Michael J. Lavelle ◽  
Justin W. Fischer ◽  
...  
Keyword(s):  
Population Control ◽  
Field Trials ◽  
Early Spring ◽  
Late Winter ◽  
North Central ◽  
Wild Pigs ◽  
The Us ◽  
Central Texas ◽  
Migrating Birds ◽  
Bait Stations

AbstractToxic baiting of wild pigs (Sus scrofa) is a potential new tool for population control and damage reduction in the US. Field trials testing a prototype toxic bait (HOGGONE 2 containing 5% sodium nitrite [SN]), though, revealed that wild pigs spilled small particles of toxic bait outside of bait stations which subsequently created hazards for non-target species that consumed those particles, primarily passerine birds. To deter non-target birds from consuming particles of spilled bait, we tested four deterrents at mock bait sites (i.e., baited with bird seed) in north-central Colorado, USA during April–May 2020. We found a programable, inflatable deterrent device (scare dancer) reduced bird visitation by an average of 96%. Then, we evaluated the deterrent devices at SN-toxic bait sites in north-central Texas, USA during July 2020, where the devices were activated the morning following deployment of SN-toxic bait. Overall, we found 139 dead wild pigs at 10 bait sites following one night of toxic baiting, which represented an average of 91% reduction in wild pigs visiting bait sites. We found that deterrent devices were 100% effective at deterring birds from toxic bait sites. We found two dead non-target mice at bait sites without deterrent devices. We noted that deploying toxic bait in mid-summer rather than late-winter/early-spring reduced hazards to migrating birds because they were not present in our study area during July. We recommend using deterrent devices (i.e., novel, programmable, battery operated, continuous and erratic movement, and snapping sounds) to reduce hazards to non-target birds at SN-toxic bait sites. We further recommend deploying SN-toxic bait during seasons when migrating birds are not as abundant until further research demonstrates minimal risks to migrating birds.

scholarly journals Nitrate-N in the Soil Profiles of Long-term Field Experiments

2002 ◽  
Vol 51 (1-2) ◽  
pp. 139-146 ◽  
Author(s):  
É. Bircsák ◽  
Tamás Németh
Keyword(s):  
Crop Production ◽  
Field Experiments ◽  
N Fertilization ◽  
Point Of View ◽  
Soil Profiles ◽  
Mineral N ◽  
N Content ◽  
Farm Scale ◽  
Additional Costs

Long-term N fertilization experiments were established with identical treatments at two different growing areas in Hungary: one on a calcareous sandy soil (Őrbottyán) and the other on a calcareous chernozem soil (Nagyhörcsök). The aim was to create differences in mineral-N content in the soil profiles in order to determine their N supplying capacity and to establish whether the accumulated nitrate may be regarded as a supply index for crop production. The results showed that under certain environmental conditions N may accumulate in the soil profile in the form of nitrate, resulting from N fertilization in previous years, to such an extent that it must be taken into consideration when determining the fertilizer rates to be applied. This is important not only from the point of view of economical management and environment protection, but also for reaching better yield quality. The calculations can be reliably performed if they are based on the measurement and calibration of the soil's mineral-N content. The environmental importance of such calibration experiments is that by estimating the utilization of N from the mineral-N pool, the additional costs incurred due to over-fertilization can be eliminated, and at the same time the potential danger of NO 3 leaching to the groundwater can be reduced. Extrapolation of the experimental results to farm scale can lead to both economical and environmental achievements.

The effect of winter and early spring grazing by sheep on subsequent sward production

1978 ◽  
Vol 90 (3) ◽  
pp. 471-477 ◽  
Author(s):  
D. Wilman ◽  
P. D. Griffiths
Keyword(s):  
Field Experiments ◽  
Early Spring ◽  
Late Winter ◽  
Botanical Composition ◽  
Nitrogenous Fertilizer ◽  
Herbage Yield ◽  
Hidden Cost ◽  
Botanical Analysis

SummaryThe effect on sward production of grazing by sheep during different periods of the winter and the effect of different dates of ceasing grazing in late winter-early spring were measured in field experiments by cuts during the spring and summer and by botanical analysis.Winter and early spring grazing reduced herbage yield in April, May and June, but not subsequently. Nitrogenous fertilizer applied when grazing ceased approximately counterbalanced the reduction in yield due to grazing. The grazing treatments had little or no effect on botanical composition. The size of the reduction in yield due to grazing was such that it might reasonably be explained in terms of the date on which grazing ceased and the amount of photosynthetic tissue left at that date. The amount of yield added during a given period in the spring appeared to be very greatly affected by the amount of photosynthetic tissue present at the beginning of that period and it is suggested that this is a partially hidden cost of winter and early spring grazing which should be more fully researched.

Growth and nitrogen dynamics of spring chickpea genotypes in a Mediterranean-type climate

2009 ◽  
Vol 147 (4) ◽  
pp. 445-458 ◽  
Author(s):  
S. D. KOUTROUBAS ◽  
M. PAPAGEORGIOU ◽  
S. FOTIADIS
Keyword(s):  
Seed Yield ◽  
Field Experiments ◽  
Utilization Efficiency ◽  
Silty Clay ◽  
N Accumulation ◽  
N Content ◽  
Total N ◽  
Vegetative Period ◽  
Seed Filling ◽  
Rainfed Farming

SUMMARYChickpea (Cicer arietinum L.) is an important legume of rainfed farming systems, contributing to the sustainability of production and reducing the need for nitrogen (N) fertilization through fixing atmospheric N2. The relative importance of factors causing variations in growth, seed yield, N accumulation and N utilization efficiency among spring chickpea varieties grown in a Mediterranean-type climate was investigated in field experiments conducted in 2003 and 2004. Five chickpea varieties were grown in a silty clay soil in the farm of the Democritus University of Thrace in Orestiada, Greece. Yearly differences in plant growth and productivity were observed and were mainly associated with the variations in the weather parameters between the growing seasons. Nitrogen utilization efficiency (NUE) for biomass production during the seed-filling period was higher compared with that during the vegetative period. NUE for seed yield (SY) ranged from 18·3 to 24·5 g dry matter (DM)/g N and was positively correlated with seed yield, suggesting that high SY was associated with more efficient exploitation of N. When the environmental conditions favoured high early N accumulation, the differences among varieties in NUE were mainly due to the differences in N partitioning at maturity, e.g. the nitrogen harvest index (NHI). The amount and the efficiency of N content at the beginning of seed growth (growth stage (GS) R5) that was translocated to the seed differed among varieties and ranged from 7·0 to 16·6 g N/m2 and from 68·2 to 86·8 g DM/g N, respectively. Most of the variation (0·96) between varieties in N translocation could be accounted for by the differences in total N content at GS R5. N losses from the plant foliage between 0·61 and 9·92 g N/m2 were detected during the seed-filling period when SY was low and N content at GS R5 was high.

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