Autumn and spring applications of ammonium nitrate and urea to bromegrass influence total and light fraction organic C and N in a thin Black Chernozem

2002 ◽  
Vol 82 (2) ◽  
pp. 211-217 ◽  
Author(s):  
S S Malhi ◽  
J T Harapiak ◽  
M. Nyborg ◽  
K S Gill ◽  
N A Flore

An adequate level of organic matter is needed to sustain the productivity, improve the quality of soils and increase soil C. Grassland improvement is considered to be one of the best ways to achieve these goals. A field experiment, in which bromegrass (Bromus inermis Leyss) was grown for hay, was conducted from 1974 to 1996 on a thin Black Chernozemic soil near Crossfield, Alberta. Total organic C (TOC) and total N (TN), and light fraction organic C (LFOC) and light fraction N (LFN) of soil for the treatments receiving 23 annual applications of 112 kg N ha-1 as ammonium nitrate (AN) or urea in early autumn, late autumn, early spring or late spring were compared to zero-N check. Soil samples from 0- to 5- cm (layer 1), 5- to 10- cm (layer 2), 10- to 15- cm (layer 3) and 15- to 30-cm depths were taken in October 1996. Mass of TOC, TN, LFOC and LFN was calculated using equivalent mass technique. The concentration and mass of TOC and LFOC, TN and LFN in the soil were increased by N fertilization compared to the zero-N check. The majority of this increase in C and N occurred in the surface 5-cm depth and predominantly occurred in the light fraction material. In layer 1, the average increase from N fertilization was 3.1 Mg C ha-1 for TOC, 1.82 Mg C ha-1 for LFOC, 0.20 Mg N ha-1 for TN and 0.12 Mg N ha-1 for LFN. The LFOC and LFN were more responsive to N fertilization compared to the TOC and TN. Averaged across application times, more TOC, LFOC, TN and LFN were stored under AN than under urea in layer 1, by 1.50, 1.21, 0.06 and 0.08 Mg ha-1, respectively. Lower volatilization loss and higher plant uptake of surfaced-broadcast N were probable reasons from more soil C and N storage under AN source. Time of N application had no effect on the soil characteristics studied. In conclusion, most of the N-induced increase in soil C and N occurred in the 0- to 5-cm depth (layer 1) and in the light fraction material, with the increases being greater under AN than urea. Key words: Bromegrass, light fraction C and N, N source, soil, total organic C and N

2019 ◽  
Vol 17 (3) ◽  
pp. e1102
Author(s):  
Lixia Zhu ◽  
Jutian Chen ◽  
Yufang Shen ◽  
Shiqing Li

Aim of study: A field study was conducted to assess responses of soil organic C (SOC) and total N (TN) to film mulching and manure, which were important in identifying the changes of SOC and TN.Area of study: A semiarid area in northwestern China.Material and methods: The field (soil classified as CumuliUstic Isohumosol) has been planted with spring maize (Zea mays L.) for years. Three treatments were: 1) NPK fertilization and no film mulching (CK), 2) NPK fertilization and film mulching (PF) and 3) film mulching and NPK fertilization combined with cow manure (OMF).Main results: Compared with CK, OMF significantly increased SOC and TN, while no significant effect was observed under PF. The average increases of SOC storage in OMF were 39.2% in 0-10 cm layer and 34.3% in 10-20 cm layer. The average increases of TN storage were 37.6% in 0-10 cm layer and 31.3% in 10-20 cm layer, relative to CK. Compared with the initial SOC (8.86 g/kg) and TN (0.99 g/kg), CK and PF decreased 1.4% and 6.9% of SOC, and 9.1% and 17.2% of TN, whereas OMF increased SOC and TN. The SOC/TN was not affected by treatments but slight increase was observed since the beginning of experiment. Both PF and OMF significantly increased maize grain yields (on average 45.8% and 75.7%, respectively) compared with CK.Research highlights: Manure combined with film mulching significantly increased soil C and N, ameliorating harmful effects of plastic film mulching, improving soil fertility in the long term and increasing crop yields.


2020 ◽  
Vol 8 (1) ◽  
pp. 1-8
Author(s):  
Refki Aulia Wiwaha ◽  
Syahrul Kurniawan

The Kali Kungkuk micro watershed which is located in the upper area of Brantas watershed, had experienced forest conversion to horticulture during the last fourth decades. Since the physiographic of Kali Kungkuk micro watershed is hilly, forest conversion to horticulture may result in soil nutrient stock changes. The research aimed to analyze soil nutrient stock from forest to horticulture land uses (i.e. apple orchard and vegetables) in the Kali Kungkuk micro watershed. The field research was conducted on three different land uses (i.e. vegetable land (PK), apple orchard (PA), and forest (PH)) and four land slope classes (i.e. slope 0-8% (K1), 8-15% (K2), 15-25% (K3), and > 25% (K4)), with three, replicates plots of each. Soil samples were collected at three different depths (0-10, 10-30, and 30- 50 cm) from each plot. The parameters measured included soil texture, bulk density, standing litter mass, canopy cover, basal area, soil organic carbon and total nitrogen. Data analysis was conducted with Linear Mixed Effect Models with a level of 5% and a further analysis of LSD test level of 5% as well as a correlation test between observational parameters. The results showed that differences in land use and slope affected to significant differences in the content of soil organic C and total N. In general, forests had higher soil C and N stocks as compared to other land uses (i.e. apple orchard and vegetables). Furthermore, soil organic C and total N was higher in the low slopes (i.e. 0-8%) and (8-15%) as compared to the high slopes (i.e. 15-25%) and (> 25%). The study found a positive correlation between soil nutrient stocks (i.e. C and N) and clay content. In contrast, soil C and N stock was negatively correlated with soil bulk density. Soil fertility degradation that occurs in the Kali Kungkuk micro watershed (i.e. apple orchard and vegetables) requires serious attention in soil management in order to ensure the sustainability of apple and vegetable production.


2013 ◽  
Vol 37 (3) ◽  
pp. 784-795 ◽  
Author(s):  
José Augusto Amorim Silva do Sacramento ◽  
Ana Caroline de Moraes Araújo ◽  
Maria Eugenia Ortiz Escobar ◽  
Francisco Alisson da Silva Xavier ◽  
Ana Clara Rodrigues Cavalcante ◽  
...  

In the semiarid region of Brazil, inadequate management of cropping systems and low plant biomass production can contribute to reduce soil carbon (C) and nitrogen (N) stocks; therefore, management systems that preserve C and N must be adopted. This study aimed to evaluate the changes in soil C and N stocks that were promoted by agroforestry (agrosilvopastoral and silvopastoral) and traditional agricultural systems (slash-and-burn clearing and cultivation for two and three years) and to compare these systems with the natural Caatinga vegetation after 13 years of cultivation. The experiment was carried out on a typical Ortic Chromic Luvisol in the municipality of Sobral, Ceará, Brazil. Soil samples were collected (layers 0-6, 6-12, 12-20, 20-40 and 40-60 cm) with four replications. The plain, convex and concave landforms in each study situation were analyzed, and the total organic C, total N and densities of the soil samples were assessed. The silvopastoral system promoted the greatest long-term reductions in C and N stocks, while the agrosilvopastoral system promoted the smallest losses and therefore represents a sustainable alternative for soil C and N sequestration in these semiarid conditions. The traditional agricultural system produced reductions of 58.87 and 9.57 Mg ha-1 in the organic C and total N stocks, respectively, which suggests that this system is inadequate for these semiarid conditions. The organic C stocks were largest in the concave landform in the agrosilvopastoral system and in the plain landform in the silvopastoral system, while the total N values were highest in the concave landform in the native, agrosilvopastoral and silvopastoral systems.


2008 ◽  
Vol 32 (3) ◽  
pp. 1253-1260 ◽  
Author(s):  
Fabiano de Carvalho Balieiro ◽  
Marcos Gervasio Pereira ◽  
Bruno José Rodrigues Alves ◽  
Alexander Silva de Resende ◽  
Avílio Antonio Franco

In spite of the normally low content of organic matter found in sandy soils, it is responsible for almost the totality of cation exchange capacity (CEC), water storage and availability of plant nutrients. It is therefore important to evaluate the impact of alternative forest exploitation on the improvement of soil C and N accumulation on these soils. This study compared pure and mixed plantations of Eucalyptus grandis and Pseudosamanea guachapele, a N2-fixing leguminous tree, in relation to their effects on soil C and N stocks. The studied Planosol area had formerly been covered by Panicum maximum pasture for at least ten years without any fertilizer addition. To estimate C and N contents, the soil was sampled (at depths of 0-2.5; 2.5-5.0; 5.0-7.5; 7.5-10.0; 10.0-20.0 and 20.0-40.0 cm), in pure and mixed five-year-old tree plantations, as well as on adjacent pasture. The natural abundance 13C technique was used to estimate the contribution of the soil organic C originated from the trees in the 0-10 cm soil layer. Soil C and N stocks under mixed plantation were 23.83 and 1.74 Mg ha-1, respectively. Under guachapele, eucalyptus and pasture areas C stocks were 14.20, 17.19 and 24.24 Mg ha-1, respectively. For these same treatments, total N contents were 0.83; 0.99 and 1.71 Mg ha-1, respectively. Up to 40 % of the soil organic C in the mixed plantation was estimated to be derived from trees, while in pure eucalyptus and guachapele plantations these same estimates were only 19 and 27 %, respectively. Our results revealed the benefits of intercropped leguminous trees in eucalyptus plantations on soil C and N stocks.


1998 ◽  
Vol 78 (1) ◽  
pp. 155-162 ◽  
Author(s):  
C. A. Campbell ◽  
F. Selles ◽  
G. P. Lafond ◽  
B. G. McConkey ◽  
D. Hahn

Society is interested in increasing C storage in soil to reduce CO2 concentration in the atmosphere, because the latter may contribute to global warming. Further, there is considerable interest in the use of straw for industrial purposes. Using soil samples taken from the 0- to 7.5-cm and 7.5- to 15-cm depths in May 1987 and September 1996, we determined organic C and total N in five crop rotations (nine treatments) using automated Carlo Erba combustion analyzer. The experiment was managed using conventional mechanical tillage from 1957 to 1989; it was changed to no-tillage management in 1990. Our objective was to determine: (a) if change to no-tillage management had changed soil C and N storage, and (b) if method of calculating organic C and N change would influence interpretation of the results. All three methods of calculation confirmed the efficacy of employing best management practices (e.g., fertilization based on soil tests, reducing summerfallow, including legumes in rotations) for increasing or maintaining soil organic matter, and showed that the latter was directly associated with the amount of crop residues returned to the soil. Where bulk density was significantly different between sampling times, the often used mass per fixed depth (MFD) (i.e., volume basis) calculation can lead to erroneous conclusions. When the recently recommended mass per equal depth (MED) method of calculation was used, it showed that 6 yr of no-tillage did not increase soil organic C or total N. However, in unfertilized systems, where crop yields are gradually decreasing since the change, there is an accompanying decrease in organic matter, while fertilized, or high-fertility systems that include legume hay crops, in which wheat yields have been maintained have tended to maintain the organic matter level over time. When the MFD calculation was used, there was no change in C over time when straw was harvested in the F–W–W system; however, the MED calculation and concentrations tend to show a decrease in soil C and N. This suggests that in time, industrial use of straw may have negative consequences for soil conservation. We concluded that concentrations may be as effective as MED for assessing changes in organic matter, provided "amounts" are not required. Key words: Straw removal, fertilizers, legumes, cropping frequency, C mass calculation


2001 ◽  
Vol 81 (2) ◽  
pp. 139-148 ◽  
Author(s):  
C A Campbell ◽  
F. Selles ◽  
G P Lafond ◽  
R P Zentner

Society’s desire to sequester C in soils, thereby reducing the net loss of CO2 (a greenhouse gas) to the atmosphere, is well known. It is also accepted that the choice of appropriate agricultural management practices adopted by producers will affect this goal. However, quantification of the extent and rate at which it can be achieved is uncertain. A crop rotation experiment that was initiated in 1957 on a thin Black chernozemic clay soil at Indian Head, Saskatchewan, was managed using conventional tillage until changed to zero tillage in 1990. Soil was sampled (0- to 7.5- and 7.5- to 15-cm depths) in May 1987 and 1997 to determine the effects of treatments on soil organic C (SOC) and total N. The rotations were: fallow-wheat (Triticum aestivum L.) (F-W), F-W-W, continuous wheat (Cont W), legume green manure (GM)-W-W, and F-W-W-hay (legume-grass)-hay-hay (F-W-W-H-H-H). The monoculture cereal rotations were either fertilized with N and P based on soil tests or unfertilized, while the legume systems were both unfertilized. There was also a F-W-W (N+P) treatment in which the straw was baled and removed. When the experiment was changed to zero tillage management in 1990, the fertilizer protocol was changed to satisfy the “moist soil” criteria. Consequently, higher rates of N and P were added thereafter to the fallow crop, resulting in a positive yield response of wheat grown on fallow, where before there was no response to fertilizer. Over the 10-yr period (1987-1997) fertilized soil gained C and N, but unfertilized soil did not. For example fertilized F-W, F-W-W and Cont W gained about 4, 5 and 2 Mg C ha–1 in the 10-yr period. During this period, C emissions from manufacture and transportation of N fertilizer was 0.28, 0.53 and 0.90. Mg ha–1 for these three rotations, respectively. These results suggest that without adequate fertility, conversion to zero tillage may not always result in an increase in soil C or N. By 1997, fertilizer increased soil C and N in F-W-W and Cont W, and soil C and N were greater in F-W-W-H-H-H than in GM-W-W and lowest in F-W-W (all unfertilized). Straw removal had no significant effect on C or N. The analysis showed that C inputs from crop residues was the main factor influencing SOC changes. Key words: C sequestration, crop rotation, fertilizer, grain yields, total N, tillage


2020 ◽  
Vol 66 (No. 5) ◽  
pp. 222-233 ◽  
Author(s):  
Giuseppe Badagliacca ◽  
Robert Martin Rees ◽  
Dario Giambalvo ◽  
Sergio Saia

In sustainable agriculture crop residues management should consider the interactions between soil and residue properties, which can affect the decomposition and global greenhouse gases (GHGs) emission. Through a laboratory experiment, we investigated the effect of the management (incorporation and surface placement) of wheat and faba bean residues on their decomposition and CO<sub>2</sub>, CH<sub>4</sub> and N<sub>2</sub>O emissions from two soils, a Chromic Vertisol and an Eutric Cambisol. In the Vertisol, wheat residues increased the CO<sub>2</sub> emission more than faba bean when left on the surface whereas no differences among residues were observed when incorporated. In the Cambisol, faba bean emitted more than wheat when left in the surface and less when incorporated. Total CH<sub>4</sub> emissions were higher in faba bean in Cambisol for both management and only when applied in the surface in Vertisol. Total N<sub>2</sub>O emission in the Vertisol was higher when faba bean was incorporated, and wheat was left on the surface. In the Cambisol, wheat addition increased total N<sub>2</sub>O emissions by 20% compared to faba bean, with no differences between managements. Our study confirmed that contrasting properties among tested soils resulted in significant interactions with residues own degradability and their placement affecting residue decomposition, soil C and N dynamics, and GHGs emission.


1999 ◽  
Vol 79 (1) ◽  
pp. 73-84 ◽  
Author(s):  
C. A. Campbell ◽  
V. O. Biederbeck ◽  
G. Wen ◽  
R. P. Zentner ◽  
J. Schoenau ◽  
...  

Measurements of seasonal changes in soil biochemical attributes can provide valuable information on how crop management and weather variables influence soil quality. We sampled soil from the 0- to 7.5-cm depth of two long-term crop rotations [continuous wheat (Cont W) and both phases of fallow-wheat (F–W)] at Swift Current, Saskatchewan, from early May to mid-October, 11 times in 1995 and 9 times in 1996. The soil is a silt loam, Orthic Brown Chernozem with pH 6.0, in dilute CaCl2. We monitored changes in organic C (OC) and total N (TN), microbial biomass C (MBC), light fraction C and N (LFC and LFN), mineralizable C (Cmin) and N (Nmin), and water-soluble organic C (WSOC). All biochemical attributes, except MBC, showed higher values for Cont W than for F–W, reflecting the historically higher crop residue inputs, less frequent tillage, and drier conditions of Cont W. Based on the seasonal mean values for 1996, we concluded that, after 29 yr, F–W has degraded soil organic C and total N by about 15% compared to Cont W. In the same period it has degraded the labile attributes, except MBC, much more. For example, WSOC is degraded by 22%, Cmin and Nmin by 45% and LFC and LFN by 60–75%. Organic C and TN were constant during the season because one year's C and N inputs are small compared to the total soil C or N. All the labile attributes varied markedly throughout the seasons. We explained most of the seasonal variability in soil biochemical attributes in terms of C and N inputs from crop residues and rhizodeposition, and the influences of soil moisture, precipitation and temperature. Using multiple regression, we related the biochemical attributes to soil moisture and the weather variables, accounting for 20% of the variability in MBC, 27% of that of Nmin, 29% for LFC, 52% for Cmin, and 66% for WSOC. In all cases the biochemical attributes were negatively related to precipitation, soil moisture, temperature and their interactions. We interpreted this to mean that conditions favouring decomposition of organic matter in situ result in decreases in these attributes when they are measured subsequently under laboratory conditions. We concluded that when assessing changes in OC or TN over years, measurements can be made at any time during a year. However, if assessing changes in the labile soil attributes, several measurements should be made during a season or, measurements be made near the same time each year. Key words: Microbial biomass, carbon, nitrogen, mineralization, water-soluble-C, light fraction, weather variables


Author(s):  
Enzhu Hu ◽  
Zhimin Ren ◽  
Xiaoke Wang ◽  
Hongxing Zhang ◽  
Weiwei Zhang

Abstract Elevated tropospheric ozone concentration ([O3]) may substantially influence the belowground processes of the terrestrial ecosystem. Nevertheless, a comprehensive and quantitative understanding of the responses of soil C and N dynamics to elevated [O3] remains elusive. In this study, the results of 41 peer-reviewed studies were synthesized using meta-analytic techniques, to quantify the impact of O3 on ten variables associated with soil C and N, i.e., total C (TC, including soil organic C), total N (TN), dissolved organic C (DOC), ammonia N (NH4 +), nitrate N (NO3 -), microbial biomass C (MBC) and N (MBN), rates of nitrification (NTF) and denitrification (DNF), as well as C/N ratio. The results depicted that all these variables showed significant changes (P < 0.05) with [O3] increased by 27.6 ± 18.7 nL/L (mean ± SD), including decreases in TC, DOC, TN, NH4 +, MBC, MBN and NTF, and increases in C/N, NO3 - and DNF. The effect sizes of TN, NTF, and DNF were significantly correlated with O3 fumigation level and experimental duration (P < 0.05). Soil pH and climate were essential in analyses of O3 impacts on soil C and N. However, the responses of most variables to elevated [O3] were generally independent of O3 fumigation method, terrestrial ecosystem type, and additional [CO2] exposure. The altered soil C and N dynamics under elevated [O3] may reduce its C sink capacity, and change soil N availability thus impact plant growth and enhance soil N losses.


Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 820 ◽  
Author(s):  
K. A. Conrad ◽  
R. C. Dalal ◽  
D. E. Allen ◽  
R. Fujinuma ◽  
Neal W. Menzies

Quantifying the size and turnover of physically uncomplexed soil organic matter (SOM) is crucial for the understanding of nutrient cycling and storage of soil organic carbon (SOC). However, the C and nitrogen (N) dynamics of SOM fractions in leucaena (Leucaena leucocephala)–grass pastures remains unclear. We assessed the potential of leucaena to sequester labile, free light fraction (fLF) C and N in soil by estimating the origin, quantity and vertical distribution of physically unprotected SOM. The soil from a chronosequence of seasonally grazed leucaena stands (0–40 years) was sampled to a depth of 0.2m and soil and fLF were analysed for organic C, N and δ13C and δ15N. On average, the fLF formed 20% of SOC and 14% of total N stocks in the upper 0.1m of soil from leucaena rows and showed a peak of fLF-C and fLF-N stocks in the 22-year-stand. The fLF δ13C and fLF δ15N values indicated that leucaena produced 37% of fLF-C and 28% of fLF-N in the upper 0.1m of soil from leucaena rows. Irrespective of pasture type or soil depth, the majority of fLF-C originated from the accompanying C4 pasture-grass species. This study suggests that fLF-C and fLF-N, the labile SOM, can form a significant portion of total SOM, especially in leucaena–grass pastures.


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