scholarly journals The strength of the biotic compartment to retain nitrogen additions prevents nitrogen losses from a Mediterranean maquis

2011 ◽  
Vol 8 (4) ◽  
pp. 8041-8065
Author(s):  
T. Dias ◽  
M. A. Martins-Loução ◽  
L. Sheppard ◽  
C. Cruz
Keyword(s):  
Initial Response ◽  
Ecosystem Functions ◽  
N Availability ◽  
Inorganic N ◽  
N Losses ◽  
Total N ◽  
Soil Inorganic N ◽  
Mediterranean Maquis ◽  
N Additions ◽  
Soil Inorganic

Abstract. Nitrogen (N) is one of the nutrients most limiting to ecosystem productivity. However, N availability is increasing globally, which may affect ecosystem functions and stability. To understand the role of each ecosystem compartment in the cycling of increased N, we studied the initial response of a nutrient-poor ecosystem, a Mediterranean maquis, to increased N. N availability (dose and forms) was modified by three N additions along the year (spring, summer and middle autumn/winter). Soil inorganic N pools (nitrate in particular) strongly reflected the N additions in autumn, almost matching the total N added along the three additions. Cistus ladanifer, the dominant plant species, responded to the increased N (cover and N concentration in leaves and litter), and given that leaf shedding occurs in the summer, the importance of this N pool returning to the soil through litter decomposition on the total soil inorganic N in autumn was investigated. Data suggest that living plants and litter have a crucial role in preventing N losses from Mediterranean maquis. This is the first integrated field study on how European Mediterranean ecosystems retain increased N of different forms and doses, however longer-term studies are needed to explore the generality of this study's observations.

scholarly journals The strength of the biotic compartment in retaining nitrogen additions prevents nitrogen losses from a Mediterranean maquis

2012 ◽  
Vol 9 (1) ◽  
pp. 193-201 ◽  
Author(s):  
T. Dias ◽  
M. A. Martins-Loução ◽  
L. Sheppard ◽  
C. Cruz
Keyword(s):  
Initial Response ◽  
Ecosystem Functions ◽  
N Availability ◽  
Inorganic N ◽  
N Losses ◽  
Total N ◽  
Soil Inorganic N ◽  
Mediterranean Maquis ◽  
N Additions ◽  
Soil Inorganic

Abstract. Nitrogen (N) is one of the nutrients most limiting to ecosystem productivity. However, N availability is increasing globally, which may affect ecosystem functions and stability. To understand the role of each ecosystem compartment in the cycling of increased N, we studied the initial response of a nutrient-poor ecosystem, a Mediterranean maquis, to increased N deposition. N availability (dose and form) was modified by three N additions over the year (middle autumn/winter, spring and summer). Soil inorganic N pools (nitrate in particular) strongly reflected the N additions in autumn, almost matching the total N added over the three additions. Cistus ladanifer, the dominant plant species, responded to the increased N (cover and N concentration in leaves and litter). Given that leaf shedding occurs in the summer, the importance of this N pool returning to the soil through litter decomposition on the total soil inorganic N in autumn was investigated. Data suggest that living plants and litter have a crucial role in preventing N losses from Mediterranean maquis. This is the first integrated field study on how European Mediterranean ecosystems retain increased N of different forms and doses, however longer-term studies are needed to explore the generality of this study's observations.

PROPAGATION AND MANAGEMENT OF GLIRICIDIA SEPIUM PLANTED FALLOWS IN SUB-HUMID EASTERN ZAMBIA

2004 ◽  
Vol 40 (3) ◽  
pp. 341-352 ◽  
Author(s):  
R. CHINTU ◽  
P. L. MAFONGOYA ◽  
T. S. CHIRWA ◽  
E. KUNTASHULA ◽  
D. PHIRI ◽  
...  
Keyword(s):  
Biomass Production ◽  
Crop Yields ◽  
Gliricidia Sepium ◽  
N Availability ◽  
Inorganic N ◽  
Soil Inorganic N ◽  
Tree Survival ◽  
Maize Yields ◽  
Bare Root ◽  
Soil Inorganic

Gliricidia sepium features prominently as a soil replenishment tree in planted coppicing fallows in eastern Zambia. Its usual method of propagation, through nurseryseedlings, is costly and may possibly hinder wider on-farm adoption. We compared fallows propagated by potted and bare root seedlings, direct seeding and stem cuttings, in terms of tree coppice biomass production, soil inorganic N availability and post-fallow maize yields under semi-arid conditions. We hypothesized that cutting fallows initially in May (off-season) would increase subsequent seasonal coppice biomass production as opposed to cutting them in November (at cropping). The tree survival and biomass order after two years was: potted = bare root > direct > cuttings. The post-fallow maize productivity sequence was: fertilized maize = potted = bare root > direct > cuttings = no-tree unfertilized controls, across seasons. However, farmers may prefer directly seeded fallows owing to their cost effectiveness. Soil inorganic N and maize yield were significantly higher in May-cut than in November-cut fallows. Preseason topsoil inorganic N and biomass N input correlated highly with maize yields. This implies that bothparameters may be used to predict post-fallow crop yields.

Growing season nitrogen dynamics in manured soils in south coastal British Columbia: Implications for a soil nitrate test for silage corn

1997 ◽  
Vol 77 (1) ◽  
pp. 67-76 ◽  
Author(s):  
B. J. Zebarth ◽  
J. W. Paul
Keyword(s):  
British Columbia ◽  
N Uptake ◽  
Dairy Manure ◽  
N Recovery ◽  
Soil Nitrate ◽  
Inorganic N ◽  
Total N ◽  
Soil Inorganic N ◽  
Coastal British Columbia ◽  
Soil Inorganic

Spring soil nitrate and ammonium dynamics in south coastal British Columbia soils were examined with respect to the potential to develop a soil nitrate test for silage corn (Zea mays, L.). Soil nitrate and ammonium contents were measured to 90 cm depth in two soils from April to July of two growing seasons. Treatments included a control, spring application of either 300 or 600 kg total N ha−1 as liquid dairy manure, or 200 kg N ha−1 as inorganic fertilizer. Significant amounts of ammonium were present until late May following manure and until mid-June following fertilizer application, requiring simultaneous determination of both nitrate and ammonium concentrations to assess soil inorganic N contents during this period. Most of the changes in soil nitrate over time occurred in the top 30 cm, suggesting that sampling to 30 cm depth would be sufficient in most cases for a soil nitrate test in this region. Most of the increase in soil inorganic N associated with the spring application of manure occurred by 1 June. A soil nitrate test in early to mid-June when the corn is at the six leaf stage appeared to be most suitable for use in south coastal British Columbia to determine if additional fertilizer N is required. A sample taken at this time will measure soil nitrate contents just before the period of rapid corn N uptake, after most of the additional inorganic N associated with spring manure application is already present in the soil as nitrate, and after nitrification of the manure ammonium has occurred. Key words: N recovery, preplant nitrate test, pre-sidedress soil nitrate test

scholarly journals Effect of soil covering on nitrogen availability of vineyards soils in Champagne area

OENO One ◽  
2005 ◽  
Vol 39 (4) ◽  
pp. 163
Author(s):  
Pascal Thiebeau ◽  
Christian Herré ◽  
Anne-France Doledec ◽  
André Perraud ◽  
Laurent Panigai ◽  
...  
Keyword(s):  
Organic Matter ◽  
N Mineralization ◽  
Farmyard Manure ◽  
N Availability ◽  
Soil N ◽  
Inorganic N ◽  
Growing Period ◽  
Soil Inorganic N ◽  
Soil Inorganic

<p style="text-align: justify;">We studied the effect of soil cover (bare soil, mulch of barks or composted organic materials, grass cover) on soil N dynamics in various experimental vineyards located in Champagne area (France). Soil cores were sampled periodically to measure water and mineral N in soil profile during autumn and winter. These measurements were used in a simple dynamic model (LIXIM) to calculate nitrate leaching and N mineralization. N mineralization potential of soils were also determined in laboratory incubations in controlled conditions. In most sites, soil inorganic N contents (0-75 cm) varied between 20 and 60 kg N ha-1, depending of the season. Soil inorganic N in plots receiving barks or composted barks or covered with grass did not differ significantly from control plots. Higher amounts of inorganic N were found in soils amended with refuse compost, peat or mixed compost (barks + farmyard manure) or composted farmyard manure. The model indicated that N leached varied from 8 to 77 kg N ha-1 and that the mean nitrate concentration in drained water was less than 50 mg NO3- L-1 except for plots receiving refuse compost or bark + farmyard manure compost. The calculated N mineralization varied from 9 to 45 kg N ha-1 over the autumn-winter period, i.e. 118 to 182 days. The N mineralization rate (Vp), expressed per 'normalised day' i.e. day at 15°C and field capacity, varied from 0.15 to 0.82 kg N ha-1 nd-1, including all sites and experimental treatments. Effect of organic matter addition on Vp was only observed for long-term experimental sites where large amounts of organic nitrogen had been added to soil using peat, refuse compost or compost mixtures with barks and farmyard manure. The Vp values measured in laboratory incubations showed the same trends and were in the same order of magnitude than those calculated with LIXIM model using in situ data. In average, the values measured in laboratory incubations underestimated the actual N mineralization in field conditions. The model was used to predict N mineralization and inorganic N in soil during the vegetative period using Vp values. It allowed to estimate the N uptake by vine: 10 ± 5 kg N ha-1 at flowering and 57 ± 5 kg N ha-1 over the whole growing period. These results show that soil N availability was sufficient to feed the vine during the whole growing period and that no inorganic N fertilisation was necessary, even in the grass covered soil. In this soil, water availability is probably the limiting factor when depressive effects are observed. On the long-term, it is necessary to manage the amount and quality of added organic matter since organic inputs may modify N availability and therefore vine behaviour, wine quality and environmental risks.</p>

Strip Intercropping of Rye–Vetch Mixtures: Effects on Weed Growth and Competition in Strip-tilled Sweet Corn

Weed Science ◽  
2019 ◽  
Vol 67 (1) ◽  
pp. 114-125 ◽  
Author(s):  
Carolyn J. Lowry ◽  
Daniel C. Brainard
Keyword(s):  
Sweet Corn ◽  
N Uptake ◽  
Corn Yield ◽  
N Availability ◽  
Hairy Vetch ◽  
Inorganic N ◽  
Cereal Rye ◽  
Soil Inorganic N ◽  
Strip Intercropping ◽  
Soil Inorganic

AbstractStrip-intercropping of functionally diverse cover crop mixtures including cereal rye (Secale cerealeL.) and hairy vetch (Vicia villosaRoth) is one mechanism by which nitrogen (N) banding can be applied to an organic, strip-tilled system to increase crop competitiveness over weeds. We hypothesized that by targeting hairy vetch, a low C:N legume, to the tilled strip directly in row with future crop establishment, and cereal rye, a high C:N grass, to the untilled strip directly between future crop rows, that N would be preferentially available to the crop. We conducted a field study between 2011 to 2013 in southwest Michigan to examine the effects of rye–vetch mixture spatial arrangement (strip intercropping vs. full-width mixture) on (1) soil inorganic N; (2) weed biomass; and (3) sweet corn (Zea maysL.) biomass, yield, and competitiveness against weeds. We found that as the proportion of vetch biomass in the crop row (in-row, IR) increased, we also saw increasing levels of IR soil inorganic N and greater early sweet corn N uptake and growth relative to weeds. However, sweet corn yield and final biomass were more responsive to vetch biomass across the whole plot (WP) and did not respond to rye and vetch segregation into strips. Increasing vetch WP biomass increased sweet corn final biomass across both years, but only increased corn competitiveness against weeds in 1 out of 2 years and decreased sweet corn competitiveness in the other year. Strip-intercropping of cereal rye and hairy vetch has potential to increase soil N availability to the crop, thereby increasing early crop competitiveness, which may lower weed management costs.

scholarly journals Abiotic versus biotic controls on soil nitrogen cycling in drylands along a 3200 km transect

2016 ◽  
Author(s):  
Dongwei Liu ◽  
Weixing Zhu ◽  
Xiaobo Wang ◽  
Yuepeng Pan ◽  
Chao Wang ◽  
...  
Keyword(s):  
Arid Zone ◽  
N Cycling ◽  
Mean Annual Precipitation ◽  
N Availability ◽  
Soil N ◽  
Inorganic N ◽  
N Transformations ◽  
Soil Inorganic N ◽  
Soil Inorganic ◽  
Biotic Controls

Abstract. Nitrogen (N) cycling of drylands under changing climate is not well understood. Our understanding about N cycling over larger scales to date relies heavily on the measurement of bulk soil N, and the information about soil internal N transformations remains limited. The 15N natural abundance (δ15N) of ammonium and nitrate can serve as a proxy record for the N processes in soils. To better understand the patterns and mechanisms of water availability on soil N cycling in drylands, we collected soils along a 3200 km dryland transect at about 100 km intervals in northern China, with mean annual precipitation (MAP) from 36 mm to 436 mm. We analysed N pools and δ15N of ammonium, dual isotopes (15N and 18O) of nitrate, and the microbial gene abundance associated with soil N transformations. We found that the N status and their driven factors were different on the two sides of MAP = 100 mm. In the arid zone with MAP below 100 mm, soil inorganic N accumulated, with a large fraction being of atmospheric origin. Ammonia volatilization was strong because of the higher soil pH. The abundance of microbial genes associated with soil N transformations was also significantly low. In the semiarid zone with MAP above 100 mm, soil inorganic N concentrations were low and controlled mainly by biological processes, e.g., plant uptake and denitrification. The preference of soil ammonium to nitrate by the dominant plant species may enhance the possibility of soil nitrate loss via denitrification. Overall, our study suggest that the shifting from abiotic to biotic controls on soil N biogeochemistry under global climate changes would greatly affect N losses, soil N availability, and other N transformation processes in these drylands in China.

Green manure as a nitrogen source for wheat in the southeastern United States

1996 ◽  
Vol 11 (4) ◽  
pp. 182-189 ◽  
Author(s):  
Julia B. Nelson ◽  
Larry D. King
Keyword(s):  
Green Manure ◽  
Cropping Systems ◽  
Wheat Yield ◽  
Red Clover ◽  
N Leaching ◽  
Fertilizer N ◽  
Inorganic N ◽  
Total N ◽  
Soil Inorganic N ◽  
Soil Inorganic

AbstractInterest in developing more sustainable cropping systems has led to renewed interest in legumes as N sources for crops. We conducted a 2-year study to compare the effects of green manure, green manure plus fertilizer, and fertilizer on wheat yield and N leaching potential. In 1991–92, wheat following corn and receiving 0, 45, or 90 kg N/ha was compared with wheat planted after plowing the autumn regrowth of red clover/johnsongrass hay (supplemented with alfalfa) that supplied 107 kg total N/ha. In 1992–93, wheat following corn and receiving 90 kg N/ha was compared with wheat following hay regrowth that either received fertilizer N at 45 kg/ha or 90 kg N/ha or was supplemented with alfalfa (total of 123 kg N/ha). Yield with only green manure averaged 65% of yield with 90 kg N/ha. Yields with green manure plus 45 or 90 kg N/ha were not different from yield with 90 kg N only. The first year, soil to a depth of 30 cm declined from as high as 40 kg/ha in the fall to less than 10 kg/ha as wheat growth increased in the spring. In contrast, concentration averaged 20 kg/ha throughout the growing season. Trends in soil inorganic N were similar the second year. Profile nitrate distribution indicated a greater potential for N leaching with fertilizer than with green manure. Soil from the site was used in a laboratory incubation study to determine the rate of N mineralization from white clover at 10°C. An average of 80% of the clover N was recovered as soil inorganic N; however, in the field study, recovery (soil inorganic N in the 0 to 30-cm zone + Nin above-ground wheat biomass) was only 21%. Supplementing green manures with spring applications of fertilizer N could decrease the leaching loss without decreasing wheat yield.

Soil inorganic N availability: Effect on maize residue decomposition

1995 ◽  
Vol 27 (12) ◽  
pp. 1529-1538 ◽  
Author(s):  
S. Recous ◽  
D. Robin ◽  
D. Darwis ◽  
B. Mary
Keyword(s):  
N Availability ◽  
Inorganic N ◽  
Residue Decomposition ◽  
Soil Inorganic N ◽  
Soil Inorganic

scholarly journals Abiotic versus biotic controls on soil nitrogen cycling in drylands along a 3200 km transect

2017 ◽  
Vol 14 (4) ◽  
pp. 989-1001 ◽  
Author(s):  
Dongwei Liu ◽  
Weixing Zhu ◽  
Xiaobo Wang ◽  
Yuepeng Pan ◽  
Chao Wang ◽  
...  
Keyword(s):  
Arid Zone ◽  
N Cycling ◽  
Mean Annual Precipitation ◽  
N Availability ◽  
Soil N ◽  
Inorganic N ◽  
N Transformations ◽  
Soil Inorganic N ◽  
Soil Inorganic ◽  
Biotic Controls

Abstract. Nitrogen (N) cycling in drylands under changing climate is not well understood. Our understanding of N cycling over larger scales to date relies heavily on the measurement of bulk soil N, and the information about internal soil N transformations remains limited. The 15N natural abundance (δ15N) of ammonium and nitrate can serve as a proxy record for the N processes in soils. To better understand the patterns and mechanisms of N cycling in drylands, we collected soils along a 3200 km transect at about 100 km intervals in northern China, with mean annual precipitation (MAP) ranging from 36 to 436 mm. We analyzed N pools and δ15N of ammonium, dual isotopes (15N and 18O) of nitrate, and the microbial gene abundance associated with soil N transformations. We found that N status and its driving factors were different above and below a MAP threshold of 100 mm. In the arid zone with MAP below 100 mm, soil inorganic N accumulated, with a large fraction being of atmospheric origin, and ammonia volatilization was strong in soils with high pH. In addition, the abundance of microbial genes associated with soil N transformations was low. In the semiarid zone with MAP above 100 mm, soil inorganic N concentrations were low and were controlled mainly by biological processes (e.g., plant uptake and denitrification). The preference for soil ammonium over nitrate by the dominant plant species may enhance the possibility of soil nitrate losses via denitrification. Overall, our study suggests that a shift from abiotic to biotic controls on soil N biogeochemistry under global climate changes would greatly affect N losses, soil N availability, and other N transformation processes in these drylands in China.

Tillage, crop residue and crop sequence effects on nitrogen availability in a legume-based cropping system

2004 ◽  
Vol 84 (4) ◽  
pp. 421-430 ◽  
Author(s):  
Y. K. Soon ◽  
M. A. Arshad
Keyword(s):  
Crop Yield ◽  
Crop Residue ◽  
N Uptake ◽  
Microbial Biomass N ◽  
Fertilizer N ◽  
Inorganic N ◽  
Soil Inorganic N ◽  
Crop Sequence ◽  
Extractable Soil ◽  
Soil Inorganic

A field study was conducted to determine the effects and interactions of crop sequence, tillage and residue management on labile N pools and their availability because such information is sparse. Experimental treatments were no-till (NT) vs. conventional tillage (CT), and removal vs. retention of straw, imposed on a barley (Hordeum vulgare L.)-canola (Brassica rapa L.)-field pea (Pisum sativum L.) rotation. 15N-labelling was used to quantify N uptake from straw, below-ground N (BGN), and fertilizer N. Straw retention increased soil microbial biomass N (MBN) in 2 of 3 yr at the four-leaf growth stage of barley, consistent with observed decreases in extractable soil inorganic N at seeding. However, crop yield and N uptake at maturity were not different between straw treatments. No tillage increased soil MBN, crop yield and N uptake compared to CT, but had no effect on extractable soil inorganic N. The greater availability of N under NT was probably related to soil moisture conservation. Tillage effects on soil and plant N were mostly independent of straw treatment. Straw and tillage treatments did not influence the uptake of N from its various sources. However, barley following pea (legume/non-legume sequence) derived a greater proportion of its N from BGN (13 to 23% or 9 to 23 kg N ha-1) than canola following barley (nonlegumes) (6 to 16% or 3 to 9 kg N ha-1). Fertilizer N constituted 8 to 11% of barley N uptake and 23 to 32% of canola N uptake. Straw N contributed only 1 to 3% of plant N uptake. This study showed the dominant influence of tillage on N availability, and of the preceding crop or cropping sequence on N uptake partitioning among available N sources. Key words: Crop residue, crop sequence, labile nitrogen, nitrogen uptake, pea, tillage

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