scholarly journals Soil factors controlling mineral N uptake by Picea engelmannii seedlings: the importance of gross NH4+ production rates

2004 ◽  
Vol 165 (3) ◽  
pp. 791-800 ◽  
Author(s):  
F. Grenon ◽  
R. L. Bradley ◽  
M. D. Jones ◽  
B. Shipley ◽  
H. Peat
2019 ◽  
Vol 446 (1-2) ◽  
pp. 163-177 ◽  
Author(s):  
Arlete S. Barneze ◽  
Jeanette Whitaker ◽  
Niall P. McNamara ◽  
Nicholas J. Ostle

Abstract Aims Grasslands are important agricultural production systems, where ecosystem functioning is affected by land management practices. Grass-legume mixtures are commonly cultivated to increase grassland productivity while reducing the need for nitrogen (N) fertiliser. However, little is known about the effect of this increase in productivity on greenhouse gas (GHG) emissions in grass-legume mixtures. The aim of this study was to investigate interactions between the proportion of legumes in grass-legume mixtures and N-fertiliser addition on productivity and GHG emissions. We tested the hypotheses that an increase in the relative proportion of legumes would increase plant productivity and decrease GHG emissions, and the magnitude of these effects would be reduced by N-fertiliser addition. Methods This was tested in a controlled environment mesocosm experiment with one grass and one legume species grown in mixtures in different proportions, with or without N-fertiliser. The effects on N cycling processes were assessed by measurement of above- and below-ground biomass, shoot N uptake, soil physico-chemical properties and GHG emissions. Results Above-ground productivity and shoot N uptake were greater in legume-grass mixtures compared to grass or legume monocultures, in fertilised and unfertilised soils. However, we found no effect of legume proportion on N2O emissions, total soil N or mineral-N in fertilised or unfertilised soils. Conclusions This study shows that the inclusion of legumes in grass-legume mixtures positively affected productivity, however N cycle were in the short-term unaffected and mainly affected by nitrogen fertilisation. Legumes can be used in grassland management strategies to mitigate climate change by reducing crop demand for N-fertilisers.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1482
Author(s):  
Silvia Pampana ◽  
Alessandro Rossi ◽  
Iduna Arduini

Winter cereals are excellent candidates for biosolid application because their nitrogen (N) requirement is high, they are broadly cultivated, and their deep root system efficiently takes up mineral N. However, potential N leaching from BS application can occur in Mediterranean soils. A two-year study was conducted to determine how biosolids affect biomass and grain yield as well as N uptake and N leaching in barley (Hordeum vulgare L.), common wheat (Triticum aestivum L.), durum wheat (Triticum turgidum L. var. durum), and oat (Avena byzantina C. Koch). Cereals were fertilized at rates of 5, 10, and 15 Mg ha−1 dry weight (called B5, B10, and B15, respectively) of biosolids (BS). Mineral-fertilized (MF) and unfertilized (C) controls were included. Overall, results highlight that BS are valuable fertilizers for winter cereals as these showed higher yields with BS as compared to control. Nevertheless, whether 5 Mg ha−1 of biosolids could replace mineral fertilization still depended on the particular cereal due to the different yield physiology of the crops. Moreover, nitrate leaching from B5 was comparable to MF, and B15 increased the risk by less than 30 N-NO3 kg ha−1. We therefore concluded that with specific rate settings, biosolid application can sustain yields of winter cereals without significant additional N leaching as compared to MF.


1995 ◽  
Vol 124 (1) ◽  
pp. 1-9 ◽  
Author(s):  
G. S. Francis ◽  
R. J. Haynes ◽  
P. H. Williams

SUMMARYTwo field experiments at Canterbury, New Zealand during 1991–93 investigated the effect of the timing of ploughing a 4-year-old ryegrass/white clover pasture and the effect of two winter cover crops on subsequent N mineralization, nitrate leaching and growth and N uptake of the following wheat crops.Net N mineralization of organic N (of plant and soil origin) increased with increased fallow period between ploughing and leaching. The total amount of N accumulated in the profile by the start of winter ranged from 107 to 131 and from 42 to 45 kg N/ha for fallow treatments started in March and May respectively. Winter wheat (planted in May) had no effect on mineral N contents by the start of winter, whereas greenfeed (GF) oats (planted in March) significantly reduced the mineral N content in one year.Cumulative leaching losses over the first winter after ploughing-in pasture varied markedly between years in relation to rainfall amount and distribution. Leaching losses were greater from the March fallow (72–106 kg N/ha) than the May fallow treatments (8–52 kg N/ha). Winter wheat did not reduce leaching losses in either year. GF oats did not reduce losses in 1991/92, but losses in 1992/93, when major drainage events occurred late in the winter, were only c. 40% of those under fallow.Incorporation of a large amount (> 7 t/ha dry matter) of pasture or GF oat residue in spring depressed yield and total N uptake of the following spring wheat, largely due to net N immobilization which could be overcome by the application of fertilizer N.First-year treatments had very little residual effect in the second year. Leaching losses over the second winter (mean 142 kg N/ha) were largely unaffected by the extent of first year leaching losses. Second year leaching losses were greater than first year losses, probably due to the greater amount of mineral N at depth in the soil before the start of the second winter.


2008 ◽  
Vol 17 (1) ◽  
pp. 73 ◽  
Author(s):  
A. NYKÄNEN ◽  
A. GRANSTEDT ◽  
L. JAUHIAINEN

Legume-based leys form the basis for crop rotations in organic farming as they fix nitrogen (N) from the atmosphere for the succeeding crops. The age, yield, C:N, biological N fixation (BNF) and total N of red clover-grass leys were studied for their influence on yields, N uptake and N use efficiency (NUE) of the two sequential cereal crops planted after the leys. Mineral N in deeper soil (30-90 cm) was measured to determine N leaching risk. Altogether, four field experiments were carried out in 1994-1998 at two sites. The age of the ley had no significant effect on the yields and N uptake of the two subsequent cereals. Surprisingly, the residual effect of the leys was negligible, at 0–20 kg N ha-1yr-1. On the other hand, the yield and C:N of previous red clover-grass leys, as well as BNF-N and total-N incorporated into the soil influenced subsequent cereals. NUEs of cereals after ley incorporation were rather high, varying from 30% to 80%. This might indicate that other factors, such as competition from weeds, prevented maximal growth of cereals. The mineral N content deeper in the soil was mostly below 10 kg ha-1 in the sandy soil of Juva, but was 5-25 kg ha-1 in clayey soil of Mietoinen.;


1983 ◽  
Vol 63 (3) ◽  
pp. 563-578 ◽  
Author(s):  
D. W. L. READ ◽  
C. A. CAMPBELL ◽  
V. O. BIEDERBECK ◽  
G. E. WINKLEMAN

The distribution of NO3-N in the soil, and N uptake by the crop during the first 12 yr of a long-term rotation study at Swift Current, Saskatchewan were studied. A considerable amount of NO3-N appeared to be leached beyond the rooting zone of the cereal crop in years of above average precipitation and also in some relatively dry years with heavy spring rains. Thus, leaching of NO3-N seemed to occur even under continuous wheat rotations. At all times there was considerable NO3-N situated at the 60- to 120-cm depth. In wet years N uptake by the plants reduced the amount of NO3-N located in the subsoil, but in dry years the amount of NO3-N in the subsoil remained higher throughout the growing season. The latter could result in groundwater pollution, especially if such a soil was fallowed the next year. Fall rye (Secale cereale L.) made more efficient use of mineral N than spring-sown crops. In dry years more NO3-N persisted in the root zone of N-fertilized wheat than in the root zone of unfertilized wheat, but in wet and average years there was little difference due to N application. The average rate of net NO3-N production in fallow land from spring thaw to freeze-up (166 days) was 107 kg∙ha−1. Values ranged from about 60 to 175 kg∙ha−1 with the lowest values being obtained during very dry or very wet years. The quantity of N mineralized (kg∙ha−1) between spring thaw and freeze-up was related to precipitation (mm) by the equation Nmin = 29.0 + 0.20 precipitation for the 0- to 60-cm depth (R2 = 0.65*). Key words: Nitrate leaching, N uptake, crop rotations, N mineralization rate


1987 ◽  
Vol 109 (1) ◽  
pp. 141-157 ◽  
Author(s):  
T. M. Addiscott ◽  
A. P. Whitmore

summaryThe computer model described simulates changes in soil mineral nitrogen and crop uptake of nitrogen by computing on a daily basis the amounts of N leached, mineralized, nitrified and taken up by the crop. Denitrification is not included at present. The leaching submodel divides the soil into layers, each of which contains mobile and immobile water. It needs points from the soil moisture characteristic, measured directly or derived from soil survey data; it also needs daily rainfall and evaporation. The mineralization and nitrification submodel assumes pseudo-zero order kinetics and depends on the net mineralization rate in the topsoil and the daily soil temperature and moisture content, the latter being computed in the leaching submodel. The crop N uptake and dry-matter production submodel is a simple function driven by degree days of soil temperature and needs in addition only the sowing date and the date the soil returns to field capacity, the latter again being computed in the leaching submodel. A sensitivity analysis was made, showing the effects of 30% changes in the input variables on the simulated amounts of soil mineral N and crop N present in spring when decisions on N fertilizer rates have to be made. Soil mineral N was influenced most by changes in rainfall, soil water content, mineralization rate and soil temperature, whilst crop N was affected most by changes in soil temperature, rainfall and sowing date. The model has so far been applied only to winter wheat growing through autumn, winter and spring but it should be adaptable to other crops and to a full season.The model was validated by comparing its simulations with measurements of soil mineral N, dry matter and the amounts of N taken up by winter wheat in experiments made at seven sites during 5 years. The simulations were assessed graphically and with the aid of several statistical summaries of the goodness of fit. The agreement was generally very good; over all years 72% of all simulations of soil mineral N to 90 cm depth were within 20 kg N/ha of the soil measurements; also 78% of the simulations of crop nitrogen uptake were within 15 kg N/ha and 63% of the simulated yields of dry matter were within 25 g/m2 of the amounts measured. All correlation coefficients were large, positive, and highly significant, and on average no statistically significant differences were found between simulation and measurement either for soil mineral N or for crop N uptake.


Soil Research ◽  
2004 ◽  
Vol 42 (7) ◽  
pp. 737 ◽  
Author(s):  
D. Curtin ◽  
F. M. McCallum

Nitrogen (N) mineralised from soil organic matter can be an important source of N for crop uptake, particularly following cultivation of pastures. Difficulty in predicting the contribution of mineralisation continues to be a serious obstacle to implementating best management practices for fertiliser N. We evaluated biological tests (i.e. net N mineralised in a 28-day aerobic incubation and anaerobically mineralisable N, AMN) and chemical tests (ammonium-N hydrolysis in hot 2 m KCl) as predictors of N supply to a glasshouse-grown oat (Avena sativa L.) crop. The oat plants were grown to maturity without added N on 30 soils representing a range of management histories, including soils collected from long-term pastures and intensive arable cropping sites. The majority (average 83%) of the N accumulated in grain and straw was mineralised N. Plant N derived from mineralisation (PNDM), estimated by subtracting soil mineral N at sowing from N uptake, was generally higher for long-term pasture soils (mean 82 mg/kg, n = 9) than for long-term arable soils (mean 48 mg/kg, n = 9). The 2 measures of N mineralisation were not closely related [R2 = 0.11 (0.37*** when one outlying observation was omitted)], indicating that aerobic and anaerobic assays can give quite different N fertility rankings. Aerobically mineralisable N was the best predictor of PNDM (R2 = 0.79***). The ratio of CO2-C evolved to net N mineralised in the aerobic incubation was highly variable (e.g. mean of 13.6 for pasture soils v. 7.5 for long-term arable soils), likely due to differences in N immobilisation. The correlations of AMN (R2 = 0.32**) and hot KCl N (R2 = 0.24**) with PNDM were not much better than that between total soil N and PNDM (R2 = 0.16*), suggesting that these tests would not provide reliable estimates of N mineralisation potential in soils with diverse management histories.


1995 ◽  
Vol 125 (1) ◽  
pp. 61-68 ◽  
Author(s):  
M. F. Allison ◽  
H. M. Hetschkun

SUMMARYIn 1990–92, field experiments were performed at Broom's Barn Experimental Station to study the effect of 5 years' repeated straw incorporation on sugarbeet. Straw incorporation had no effect on plant population density. Processing quality was reduced by incorporated straw but N had a much larger effect. The effect of incorporated straw on the mineral N content of the soils and N uptake by beet was inconsistent, and this may be related to the amount of soil mineral N present when the straw was incorporated. The efficiency of fertilizer use was unaffected by straw incorporation. On Broom's Barn soils when straw was incorporated, the optimal economic N dressing was c. 120 kg N/ha, and in unincorporated plots it was c. 100 kg N/ha. At the optimal economic N rate, incorporated straw increased beet yields.


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