Soil biogeochemistry during the early spring in low arctic mesic tundra and the impacts of deepened snow and enhanced nitrogen availability

2009 ◽  
Vol 99 (1-3) ◽  
pp. 127-141 ◽  
Author(s):  
Kate M. Buckeridge ◽  
Yan-Ping Cen ◽  
David B. Layzell ◽  
Paul Grogan
Keyword(s):  
Nitrogen Availability ◽  
Early Spring ◽  
Soil Biogeochemistry ◽  
Low Arctic

scholarly journals Changes in Bacterial Denitrifier Community Abundance over Time in an Agricultural Field and Their Relationship with Denitrification Activity

2008 ◽  
Vol 74 (19) ◽  
pp. 5997-6005 ◽  
Author(s):  
Catherine E. Dandie ◽  
David L. Burton ◽  
Bernie J. Zebarth ◽  
Sherri L. Henderson ◽  
Jack T. Trevors ◽  
...  
Keyword(s):  
Nitrogen Availability ◽  
Pore Space ◽  
Inorganic Nitrogen ◽  
Environmental Parameters ◽  
Spatial Location ◽  
Early Spring ◽  
Agricultural Field ◽  
Pseudomonas Mandelii ◽  
Spatial Locations ◽  
Over Time

ABSTRACT This study measured total bacterial and denitrifier community abundances over time in an agricultural soil cropped to potatoes (Solanum tuberosum L.) by using quantitative PCR. Samples were collected on 10 dates from spring to autumn and from three spatial locations: in the potato “hill” between plants (H), close to the plant (Hp), and in the “furrow” (F). The denitrification rates, N2O emissions, and environmental parameters were also measured. Changes in denitrifier abundance over time and spatial location were small (1.7- to 2.7-fold for the nirK, nosZ, and cnorB B guilds), whereas the cnorB P community (Pseudomonas mandelii and closely related spp.) showed an ∼4.6-fold change. The seasonal patterns of denitrifier gene numbers varied with the specific community: lower nosZ gene numbers in April and May than in June and July, higher cnorB P gene numbers in May and June than in March and April and September and November, higher nirK gene numbers in early spring than in late autumn, and no change in cnorB B gene numbers. Gene numbers were higher for the Hp than the H location for the nosZ and nirK communities and for the cnorB P community on individual dates, presumably indicating an effect of the plant on denitrifier abundance. Higher cnorB P gene numbers for the H location than the F location and for nosZ and cnorB B on individual dates reflect the effect of spatial location on abundance. Denitrifier abundance changes were not related to any environmental parameter, although a weak relationship exists between cnorB P gene numbers, extractable organic carbon values, and temperature. Denitrification and N2O emissions were mostly regulated by inorganic nitrogen availability and water-filled pore space but were uncoupled from denitrifier community abundances measured in this system.

Response of oats to nitrogen and defoliation

1974 ◽  
Vol 14 (68) ◽  
pp. 373 ◽  
Author(s):  
LJ Cook ◽  
JV Lovett
Keyword(s):  
Dry Matter ◽  
Nitrogen Availability ◽  
Dry Weight ◽  
Early Spring ◽  
Climatic Conditions ◽  
Growth Responses ◽  
High Nitrogen ◽  
Active Growth ◽  
Rate Of Decline ◽  
Tiller Density

Field and glasshouse trials were conducted to examine the growth responses of oats to defoliation and nitrogen fertilizer. In a field crop, nitrogen increased tillering early in the growth of the crop and slowed the rate of decline in tiller density in the spring. A dressing of nitrogen after a midwinter defoliation failed to increase the regrowth rate of the crop until early spring. The severity of the defoliation had little effect on the regrowth rate, with subsequent differences in yield being due largely to differences in residual dry matter. In glasshouse experiments, the parts of the plant responded differently to defoliation. The roots stopped growing almost immediately; did not recommence active growth for approximately two weeks, but generally maintained their dry weight during this time. The leaf sheaths declined in dry weight for seven days after defoliation, but then recovered their pre-defoliation weight after a further three days. The growth rate of the leaf laminae was apparently unaffected by the defoliation. Plants with a high nitrogen availability recovered faster after defoliation. The more severe the defoliation, the longer the plant took to recover, but once active growth recommenced, there was no difference between the growth rates of plants defoliated to different degrees. The prevailing climatic conditions also influenced the time to recommence active growth. A second defoliation imposed before the plants had replaced the weight lost by the leaf sheaths after an earlier defoliation reduced the subsequent regrowth. situation is discussed.

scholarly journals Reduction of Nitrate Content in Baby-Leaf Lettuce and Cichorium endivia Through the Soilless Cultivation System, Electrical Conductivity and Management of Nutrient Solution

2021 ◽  
Vol 12 ◽  
Author(s):  
Giulia Conversa ◽  
Anna Bonasia ◽  
Corrado Lazzizera ◽  
Paolo La Rotonda ◽  
Antonio Elia
Keyword(s):  
Product Quality ◽  
Nutrient Solution ◽  
Nitrogen Availability ◽  
Early Spring ◽  
Late Spring ◽  
Nitrate Content ◽  
Nitrogen Deprivation ◽  
Nitrate Level ◽  
Cichorium Endivia ◽  
Soilless Cultivation

Soilless cultivation systems are efficient tools to control nitrates by managing nutrient solution (NS) salinity and nitrogen availability, however, these nitrate-lowering strategies require appropriate calibration based on species/genotype-specific responses interacting with climate and growing conditions. Three experiments were carried out on lettuce and Cichorium endivia grown in ebb-and-flow (EF) and floating (FL) systems at two levels of NS salinity (EC = 2.5 and 3.5 dS m−1) (EC2.5, EC3.5, respectively) under autumn and early-spring (lettuce) and winter and late-spring conditions (C. endivia). Nitrogen deprivation (NS withdrawal a few days before the harvest) was tested at EC2.5, in the autumn and winter cycles. The EF-system caused an increase in salinity in the substrate where roots mainly develop so it mimicked the effect of the EC3.5 treatment. In the winter-grown lettuce, the EF-system or EC3.5 treatment was effective in reducing the nitrate level without effects on yield, with the EF baby-leaf showing an improved quality (color, dry matter, chlorophylls, carotenoid, vitamin C, phenol). In both seasons, the EF/EC3.5 treatment resulted in a decline in productivity, despite a further reduction in nitrate content and a rise in product quality occurring. This response was strictly linked to the increasing salt-stress loaded by the EC3.5/EF as highlighted by the concurrent Cl− accumulation. In early-spring, the FL/EC3.5 combination may represent a trade-off between yield, nitrate content and product quality. In contrast, in winter-grown endive/escarole the EC3.5, EF and EC3.5/EF reduced the nitrate level with no effect on yield, product quality or Cl− uptake, thus proving them to be more salt-tolerant than lettuce. High temperatures during the late-spring cycle promoted nitrate and Cl− uptake, overcoming the nitrate-controlling effect of salinity charged by the EF system or EC3.5. The nitrate level decreased after 3 day-long (lettuce) or 6 day-long (C. endivia) NS withdrawal. In C. endivia and EF-grown lettuce, it provoked a decrease in yield, but a concurrent improvement in baby-leaf appearance and nutritional quality. More insights are needed to fine-tune the duration of the NS removal taking into account the soilless system used and species-specific characteristics.

Early spring mycobiota of pine litter needles.

2011 ◽  
Vol 63 (2) ◽  
pp. 153-161 ◽  
Author(s):  
Ondřej Koukol
Keyword(s):  
Early Spring

EVALUATION OF CLOVERS ON SANDY COASTAL SOIL

1977 ◽  
pp. 130-138 ◽  
Author(s):  
W.M. Williams ◽  
L.B. Anderson ◽  
B.M. Cooper
Keyword(s):  
New Zealand ◽  
Drought Stress ◽  
Sandy Soil ◽  
White Clover ◽  
Plant Material ◽  
Red Clover ◽  
Early Spring ◽  
Commercial Cultivars ◽  
Mediterranean Origin ◽  
Winter Annual

In evaluations of clover performances on summer-dry Himatangi sandy soil, it was found that none could match lucerne over summer. Emphasis was therefore placed on production in autumn-winter- early spring when lucerne growth was slow. Evaluations of some winter annual clover species suggested that Trifolium spumosum, T. pallidum, T. resupinatum, and T. vesiculosum would justify further investigation, along with T. subterraneum which is already used in pastures on this soil type. Among the perennial clover species, Kenya white clover (7'. semipilosum) showed outstanding recovery from drought and was the only species to produce significantly in autumn. However, it failed to grow in winter-early spring. Within red clover, materials of New Zealand x Moroccan origin substantially outproduced the commercial cultivars. Within white clover, material from Israel, Italy and Lebanon, as well as progeny of a selected New Zealand plant, showed more rapid recovery from drought stress and subsequently better winter growth than New Zealand commercial material ('Grasslands Huia'). The wider use of plant material of Mediterranean origin and of plants collected in New Zealand dryland pastures is advocated in development of clover cultivars for New Zealand dryland situations.

Influence of mineral elements on the yield and quality of grain of the prospective line in winter tritikale

2020 ◽  
Author(s):  
I.N. Voronchikhina ◽  
◽  
A.G. Marenkova ◽  
V. S. Rubets ◽  
V. V. Pylnev
Keyword(s):  
Cost Effective ◽  
Mineral Elements ◽  
Early Spring ◽  
High Potential ◽  
Winter Triticale ◽  
Yield And Quality ◽  
Fertilizer System

The results of elements development of varietal agrotechnics of a new high-potential line 238h of winter triticale presented. It was identified that under the conditions of 2020 the most cost effective fertilizer system is an early spring application of NPK (S) (15-15-15 (10)) at a dose of 200kg/ha. The profitability level of this fertilizer was 88,9%.

Flat-cutting loosening in the system of fallow cultivation of chernozem soil and weediness of crops

2017 ◽  
Vol 1 (92) ◽  
pp. 78-84
Author(s):  
G. Koval ◽  
M. Kaliyevskiy ◽  
V. Yeshchenko ◽  
I. Martyniuk ◽  
N. Martyniuk
Keyword(s):  
Species Composition ◽  
Crop Rotation ◽  
Field Experiments ◽  
Early Spring ◽  
Weed Species ◽  
Wild Mustard ◽  
Spring Crop ◽  
White Campion ◽  
Investigation Methods ◽  
Top Soil

The article presents the results of field experiments, where on the basis of podsolized heavy loamy chernozem the influence of replacement of mouldboard ploughing with nonmouldboard cultivation over top soil weediness, weediness at the beginning and end of spring crop vegetation and weed species composition before harve sting were studied. Investigation methods of main fall ploughing under spring crops of five-course rotation: soybeans–rape–wheat–flax–barley at the depths of 15-17, 20-22, 25-27 cm were conducted after post-harvest field tillage. Analysis of data on contamination of the top soil with weed seeds have shown that with the replacement of fall main mouldboard ploughing gwith nonmouldboard cultivation the figure before sowing of all crops withdifferent tillage depthat crop rotation average increased by 131-132%. It caused the increase of actual weed infestation of all crops and at the beginning and end of spring crop vegetationafter different depths of fall nonmouldboard cultivation compared with ploughing at crop rotation average it was 120–132 and 123-138%respectively. Species composition of weeds afterthe replacement of main fall mouldboard ploughing with nonmouldboard cultivation remained mainlyunchanged; although in rape plantings the proportion of white campion and early spring weed sincreased, in wheat plantings– wild mustard andscentless mayweed, insoybean plantings– late spring weeds, in flax plantings– white campion, and in barley plantings– scarlet pimpernel.

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