Predicting nitrogen mineralisation in Australian irrigated cotton cropping systems

Soil Research ◽  
2019 ◽  
Vol 57 (3) ◽  
pp. 247 ◽  
Author(s):  
Richard Brackin ◽  
Scott Buckley ◽  
Rhys Pirie ◽  
Francois Visser
Keyword(s):  
Cropping Systems ◽  
Farming Systems ◽  
Total Carbon ◽  
Ex Situ ◽  
Organic N ◽  
N Mineralisation ◽  
Total N ◽  
Agricultural Industries ◽  
Mineralisation Potential

Cotton cropping systems in Australia have poor nitrogen (N) use efficiency, largely due to over-application of N fertiliser. The N mineralisation from soil organic N reserves is often overlooked, or underestimated despite recent studies indicating that it may contribute the majority of N exported with the crop. Predicting N mineralisation is a major challenge for agricultural industries worldwide, as direct measurements are time-consuming and expensive, but there is considerable debate as to the most reliable methods for indirect estimation. Additionally, laboratory incubations assess potential (rather than actual) mineralisation, and may not be representative of N cycling rates in the field. We collected 177 samples from most major Australian cotton growing regions, and assessed their mineralisation potential using ex situ laboratory incubations, along with an assessment of potential indicators routinely measured in soil nutrient tests. Additionally, at three unfertilised sites we conducted in situ assessment of mineralisation by quantifying soil N at the beginning of the growing season, and soil and crop N at the end of the season. We found that Australian cotton cropping soils had substantial mineralisation potential, and that soil total N and total carbon were correlated with mineralisation, and have potential to be used for prediction. Other potential indicators such as carbon dioxide production and ammonium and nitrate concentrations were not correlated with mineralisation. In parallel studies of ex situ and in situ mineralisation, we found ex situ laboratory incubations overestimated mineralisation by 1.7 times on average. We discuss findings in terms of management implications for Australian cotton farming systems.

Using active fractions of soil organic matter as indicators of the sustainability of Ferrosol farming systems

Soil Research ◽  
1999 ◽  
Vol 37 (2) ◽  
pp. 279 ◽  
Author(s):  
M. J. Bell ◽  
P. W. Moody ◽  
S. A. Yo ◽  
R. D. Connolly
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Management Practices ◽  
Cropping Systems ◽  
Cropping System ◽  
Farming Systems ◽  
Total Carbon ◽  
Critical Concentrations ◽  
Aggregate Breakdown ◽  
Eastern Australia

Chemical and physical degradation of Red Ferrosols in eastern Australia is a major issue necessitating the development of more sustainable cropping systems. This paper derives critical concentrations of the active (permanganate-oxidisable) fraction of soil organic matter (C1) which maximise soil water recharge and minimise the likelihood of surface runoff in these soils. Ferrosol soils were collected from commercial properties in both north and south Queensland, while additional data were made available from a similar collection of Tasmanian Ferrosols. Sites represented a range of management histories, from grazed and ungrazed grass pastures to continuously cropped soil under various tillage systems. The concentration of both total carbon (C) and C1 varied among regions and farming systems. C1 was the primary factor controlling aggregate breakdown, measured by the percentage of aggregates <0·125 mm (P125) in the surface crust after simulated rainfall. The rates of change in P125 per unit change in C1 were not significantly different (P < 0·05) for soils from the different localities. However, soils from the coastal Burnett (south-east Queensland) always produced lower P125 (i.e. less aggregate breakdown) than did soils from the inland Burnett and north Queensland locations given the same concentration of C1. This difference was not associated with a particular land use. The ‘critical’ concentrations of C1 for each region were taken as the C1 concentrations that would allow an infiltration rate greater than or equal to the intensity of a 1 in 1 or 1 in 10 year frequency rainfall event of 30 min duration. This analysis also provided an indication of the risk associated with the concentrations of C1 currently characterising each farming system in each rainfall environment. None of the conventionally tilled Queensland Ferrosols contained sufficient C1 to cope with rainfall events expected to occur with a 1 in 10 frequency, while in many situations the C1 concentration was sufficiently low that runoff events would be expected on an annual basis. Our data suggest that management practices designed both to maximise C inputs and to maintain a high proportion of active C should be seen as essential steps towards developing a more sustainable cropping system.

The influence of the soil matrix on nitrogen mineralisation and nitrification. I. Spatial variation and a hierarchy of soil properties

Soil Research ◽  
1998 ◽  
Vol 36 (3) ◽  
pp. 429 ◽  
Author(s):  
D. T. Strong ◽  
P. W. G. Sale ◽  
K. R. Helyar
Keyword(s):  
Soil Properties ◽  
Water Content ◽  
Organic N ◽  
Small Field ◽  
N Mineralisation ◽  
Mineral N ◽  
Conceptual Tool ◽  
Soil Matrix ◽  
Total N ◽  
Soil Variables

Natural heterogeneity of soil properties was used to explore their influence on nitrogen (N) mineralisation and nitrification in undisturbed small soil volumes (soil cells; c. 1 · 7 cm3 ) sampled from a small field plot (2 m by 3 m). Soil cells (840) were randomly ascribed to 1 of 6 treatments in which soils were retained continuously moist (M10 and M30 treatments) and amended with organic N from clover (Cl10 and Cl30 treatments), dried and rewetted (DW10), or treated with urea (Ur10) (subscripts indicate soil incubation at matric potential - 10 or - 30 kPa). After 20 days of incubation at 24C, each soil cell was analysed for NO-3 -N, NH + 4 -N, pH, bulk density (BD), volumetric water content (θv), water content at - 490 kPa (θv490), and pH buffer capacity (pHBC). On 25 soil cells from each treatment, % clay, % silt, % sand, total N (% N), organic carbon (% C), and 7 cations and anions were also determined. Net N mineralisation and net nitrification occurred in all treatments, and the total mineral N at the end of the incubation was 497, 81, 73, 31, 27, and 31 µg N/g in the Ur10 Cl10, Cl30, M10, M30, and DW10 treatments, respectively. Net N mineralisation in the M30 treatment was 84% of that in the M10 treatment, and net N mineralisation in the Cl30 treatment was 86% of that in the Cl10 treatment. Fluctuations in soil pH varied markedly between treatments and over time, and it was apparent that alkaline processes were occurring in all soil cells. The heterogeneity between soil samples was substantial for all of the soil variables. Soil variables were classified in a hierarchy from the least to the most fundamental based on their stability through time. This ranking provides a conceptual tool for understanding interrelationships between soil properties and for interpreting results of regression analyses. The sampling approach adopted in this study was designed to harness the natural heterogeneity of soil properties in the small field site while keeping other properties and environmental factors, that usually vary over larger distances, constant. Both the extent of heterogeneity of soil properties and the nature of their correlations with NO-3 -N suggested that this technique would be useful in the exploration of how soil properties influence N mineralisation and nitrification.

scholarly journals Duck Genetic Resources, Their Improvement And Conservation In Bangladesh: A Review

2020 ◽  
Vol 17 (2) ◽  
pp. 31-42
Author(s):  
MA Hamid
Keyword(s):  
Genetic Resources ◽  
Present Article ◽  
Egg Production ◽  
Genetic Characterization ◽  
Farming Systems ◽  
Ex Situ ◽  
Baseline Information ◽  
Research Institute

The present article addresses the scenario of duck genetic resources, their production and reproduction performances, their improvement and conservation in Bangladesh. The duck, among other poultry species available in the country, are used for meat and egg production. The duck germplasm available in the country are indigenous/native, improved native, exotic and their crosses. The native duck population is comprised of Indigenous Non-descript, Deshi White, Deshi Black, Nageshwari, Sylhet Mete etc. The improved native such as, BLRI-1 and BLRI-2 are developed by Bangladesh Livestock Research Institute. The exotic duck such as, Khaki Campbell, Indian Runner, Jending, Muscovy, White Pekin, Cherry Valley, Thailand Black etc. are also used at farms level. The crossbred of different ducks are used in the country at different farming systems. Improvement and conservation of native duck are ongoing both in-situ and ex-situ in vivo by DLS, BLRI, BAU and also by others. The present study provided baseline information on duck germplasm of Bangladesh which could be useful for future genetic characterization, improvement and conservation. SAARC J. Agri., 17(2): 31-42 (2019)

scholarly journals Subsoil nitrogen mineralisation and its potential to contribute to NH4 accumulation in a Vertosol

Soil Research ◽  
2003 ◽  
Vol 41 (1) ◽  
pp. 119 ◽  
Author(s):  
K. L. Page ◽  
R. C. Dalal ◽  
N. W. Menzies ◽  
W. M. Strong
Keyword(s):  
Organic Nitrogen ◽  
Microbial Population ◽  
Surface Soil ◽  
Organic N ◽  
Native Vegetation ◽  
Potential Contribution ◽  
N Mineralisation ◽  
Low Concentrations ◽  
High Concentrations

High concentrations of NH4+ (up to 270 kg N/ha) have been observed in a Vertosol below 1 m depth in south-east Queensland. This study examined the possibility that mineralisation associated with the removal of native vegetation (Acacia harpophylla) for cropping was responsible for the production of NH4+. Particularly, the potential contribution of decomposing root material and/or dissolved organic nitrogen (DON) leached into the subsoil after clearing was investigated. The amount of N that was contained within native vegetation root material was determined from an area of native vegetation adjacent to the cleared site containing elevated NH4+ concentrations. In addition, the amount of NH4+ that could be mineralised in the native vegetation soil was determined by monitoring NH4+ concentrations over 360 days in intact cores, and by conducting waterlogged incubations. To determine the rate at which a source of DON leached into the subsoil would mineralise, soil was amended with glutamic acid at a rate of 250 mg N/kg and placed under waterlogged incubation. The possibility that the acidic pH of the subsoil, or the lack of a significant subsoil microbial population, was inhibiting mineralisation was also examined by increasing soil pH from 4.4 to 7.0, and inoculating the subsoil with surface soil microorganisms during waterlogged incubations. Low concentrations of N, approximately 90 kg N/ha between 1.2 and 3 m, were found in the native vegetation root material. In addition, no net N mineralisation was observed in either the extended incubation of intact cores or in the control samples of the waterlogged incubations. Net N mineralisation was also not detected when the subsoil was amended with a source of organic N. Results indicate that this lack of mineralisation is largely due to pH inhibition of the microbial population. It is concluded that the mineralisation of either in situ organic material, or DON transported to the subsoil during leaching events, is unlikely to have significantly contributed to the subsoil NH4 accumulation at the study site.

scholarly journals Conservation of Genetic Diversity of Tomatoes (Lycopersicon esculentum Mill.)

2021 ◽  
Vol 78 (1) ◽  
pp. 11
Author(s):  
Cristian ALBU ◽  
Aurel MAXIM ◽  
Raluca Maria PÂRLICI
Keyword(s):  
Genetic Diversity ◽  
Genetic Resources ◽  
Western Europe ◽  
Genetic Erosion ◽  
Farming Systems ◽  
Ex Situ ◽  
International Convention ◽  
High Productivity ◽  
Convention On Biodiversity

Among the main problems encountered with crop plants, the most important one is represented by genetic erosion. At world level this issue has been debated within the Convention on Biodiversity adopted in UN Conference of Rio de Janeiro and The International Convention regarding Genetic Resources of Plants for Alimentation and Agriculture. In Europe, the regulations in this field are made by the European Directive 98/95 EEC. Across time tomatoes have suffered a heightened process of genetic diversity, phenomenon caused by industrialized farming which is based on the use of very uniform varieties with high productivity. The extension of green agriculture, has led to the use of landraces, because they respond best to the traditional farming systems. In Western Europe organizations of peasants had been founded and, they are involved in different activities aiming at conservation of traditional forms of agriculture and the use of old varieties. In Romania the institutions with continuous preoccupations in the field of vegetal genetic conservation, especially landraces, are the Gene Bank from Suceava and UASMV Cluj-Napoca. By using conservation methods (in situ and ex situ), the genetic erosion surely phenomenon of vegetal genetic resources, implicitly tomatoes, is reduced, the future generations will benefit from valuable genetic resources.

scholarly journals Management Drives Differences in Nutrient Dynamics in Conventional and Organic Four-Year Crop Rotation Systems

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 764
Author(s):  
Sharon L. Weyers ◽  
David W. Archer ◽  
Jane M.F. Johnson ◽  
Alan R. Wilts
Keyword(s):  
Nutrient Dynamics ◽  
Cropping Systems ◽  
Triticum Aestivum L ◽  
Animal Manure ◽  
Organic N ◽  
N Availability ◽  
Mineral N ◽  
Environmental Liabilities ◽  
Total N ◽  
Organic C

Application of exogenous N fertilizers provides agronomic benefits but carries environmental liabilities. Managing benefits and liabilities of N-based fertilizers in conventional (CNV) and organic (ORG) cropping systems might be improved with better knowledge of nutrient dynamics, the generation of intrinsic N, and maintenance of soil organic matter. This study evaluated mineral N dynamics, yields, residue inputs, and change in soil organic C (SOC) and total N (TN) in strip-tilled, four-year crop rotations [corn (Zea mays L.)-soybean (Glycine max [L.] Merr.)-wheat under-seeded with alfalfa (Triticum aestivum L./Medicago sativa L.)-alfalfa] over eight years of production under CNV management using mineral-N (NO3NH4) and chemical pesticides or ORG management using organic-N (animal manure) and no chemical treatments. In ORG, N availability increased over time, but did not benefit ORG yields due to poor control of insects and weeds. Corn, soybean, and wheat grain yields were 1.9 to 2.7 times greater in CNV. In general, SOC was lost in CNV but did not change in ORG. Cumulative yield N removals exceeded cumulative fertilizer-N inputs by an average of 78% in CNV and 64% in ORG. These results indicated ORG management supported N availability by generating intrinsic N.

The influence of the soil matrix on nitrogen mineralisation and nitrification. IV.Texture

Soil Research ◽  
1999 ◽  
Vol 37 (2) ◽  
pp. 329 ◽  
Author(s):  
D. T. Strong ◽  
P. W. G. Sale ◽  
K. R. Helyar
Keyword(s):  
Negative Relationship ◽  
Negative Influence ◽  
Organic N ◽  
N Mineralisation ◽  
Linear Regression Models ◽  
Undisturbed Soil ◽  
Soil Matrix ◽  
Total N ◽  
Material Texture ◽  
Microbial Attack

Small undisturbed soil volumes (c. 1·7 cm3) were collected from the surface of a small field plot. Soil volumes were treated with clover-derived substrate, dried and rewetted, or retained continuously moist from the field. These soil volumes were then incubated for 20 days at a matric water potential of either –10 or –30 kPa. At the end of the incubation the soil was analysed for volumetric water content (θv), NO-3 -N, NH+4 -N, total N (%N), and percentages of sand, silt, and clay. The texture terms were included in linear regression models, together with %N and θv as predictors of N mineralisation and nitrification. Clay and sand were often observed to have a significant influence on N mineralisation and nitrification, but silt rarely appeared to influence these processes. In soils retained continuously moist, %clay had a negative relationship with N mineralisation and nitrification, but this relationship was positive in soils that had been dried and rewetted. The results suggest that during periods of relatively high moisture content, soils that are higher in clay are able to protect organic N more effectively from microbial attack. However, on drying and rewetting, the protective mechanisms of clay are undermined, the relatively large protected reservoirs of organic N in high clay soils become more vulnerable to microbial attack, and these soils therefore experience a greater flush of N mineralisation than soils with lower clay levels. The negative influence of clay in the continuously moist soils was not as clearly observed in the soils incubated at –10 kPa as in soils incubated at –30 kPa, suggesting that the decomposition of organic N resident in larger pores (10–30 µm neck diameter) may not be as strongly regulated by clay as that resident in smaller pores. When soils were treated with clover-derived substrate, clay had a positive relationship with N mineralisation and nitrification rates. This may have been because clay limited the diffusion of partially decomposed organics away from the decomposing microbial population, thereby helping to facilitate more complete decomposition of the organic material. Texture had very little influence on the nitrification of urea-derived ammonium.

Nitrogen cycling in muddy sediments of Great Peconic Bay, USA: Seasonal N reaction balances and multi-year flux patterns

2021 ◽  
Vol 79 (4) ◽  
pp. 149-179
Author(s):  
Stuart Waugh ◽  
Robert C. Aller
Keyword(s):  
Algal Blooms ◽  
Field Studies ◽  
N Cycling ◽  
Ex Situ ◽  
Total N ◽  
Membrane Inlet Mass Spectrometry ◽  
N Fluxes ◽  
Muddy Sediments ◽  
Tracer Experiments

To better understand the capacity of sediments to serve as both source and sink of nitrogen (N) and to identify any evidence of evolving changes in sedimentary N cycling, N2 production, N remineralization, and N2 fixation were studied over a multi-year period (2010–2015) in bioturbated mud of Great Peconic Bay, a temperate northeastern U. S. estuary. Benthic fluxes and rates of organic matter remineralization were measured using in situ and ex situ incubations. Net annual NH+ 4, NO–3/NO–2, and N2–N fluxes (μ = 1.1, 0.03, and 1.2 mmol m –2d –1) were close to averages for comparable sedi- mentary environments from surveys of published field studies. Net N2 fluxes (by membrane inlet mass spectrometry) were influenced in different periods by temperature, oxygenation of sediment, pulsed Corg, and the activity of benthic macrofauna and benthic microalgae, although no single physical or biogeochemical variable showed a strong, direct relationship with net N2 fluxes over all sampling periods. In situ measurements sometimes showed more dynamic and higher amplitude diurnal N flux cycles than did ex situ incubations, suggesting ex situ incubations did not fully capture impacts of bioirrigation or benthic photosynthesis.15 N tracer experiments indicated anammox was < 7% of total N2 production. Acetylene reduction assays demonstrated C2 H4 production to depths ≥ 15 cm and suggested N2 fixation may have approached 25% of gross N2 production(3:1 C2 H4 : N2). Mass balances incorporating independently measured N remineralization estimates were consistent with measured levels of N2 fixation. Overall, complex balances of competing processes governed sedimentary N cycling seasonally, and N2 production dominated N2 fixation. Measured N2 fixation was consistent with constraints from N remineralization rates and net N fluxes except in episodic conditions (e. g., algal blooms). There was no indication of progressive changes in N cycling magnitudes or relative N reaction balances over the study period.

Soil nitrogen mineralisation changes rapidly when pine is planted into herbicide-treated pasture—the first two years of growth

Soil Research ◽  
2003 ◽  
Vol 41 (3) ◽  
pp. 459 ◽  
Author(s):  
R. L. Parfitt ◽  
D. J. Ross ◽  
L. F. Hill
Keyword(s):  
Mineral Soil ◽  
Total Carbon ◽  
N Mineralisation ◽  
Soil Nitrification ◽  
Hill Country ◽  
Nitrate N ◽  
Pine Trees ◽  
C And N ◽  
Microbial C

The conversion of hill country pastures to exotic forest plantations has occurred rapidly in New Zealand over the last 10 years. This land-use change affects properties of the mineral soil, especially nitrogen (N) cycling. Here we studied the changes in soil in situ N mineralisation, in leaching, and microbial biomass, when Pinus radiata D. Don is planted into pasture; sheep were used to reduce pasture herbage before planting, and then herbicide was used to control the rank growth of grass around the trees. Total net N mineralisation in soil (0–100 mm) under pasture was 325 kg/ha.year. Net N mineralisation in the herbicide-treated areas was about double that under pasture or rank grass in the first 2 months. The concentration of nitrate-N in soil solution in the herbicide-treated areas was then 81 mg/L, compared with <2 mg/L under pasture. During this time, the pH under the pine trees decreased very rapidly as nitrification increased. Soil nitrification and nitrate leaching were enhanced for 15 months after application of herbicide. After this 15-month period, soil total carbon (C) was slightly lower (P < 0.10) under trees than rank grass, whereas microbial C and N were markedly lowest (P < 0.05) under the trees. Over this period, about 18 kg N/ha was leached to 250 mm in the tree-planted area. The data also give additional insights into processes that occur when soil cores in buried bags are used to estimate N mineralisation.

scholarly journals Soil hydrolase activities and kinetic properties as affected by wheat cropping systems of Northeastern China

2010 ◽  
Vol 56 (No. 11) ◽  
pp. 526-532 ◽  
Author(s):  
Y.L. Zhang ◽  
L.J. Chen ◽  
C.X. Sun ◽  
Z.J. Wu ◽  
Z.H. Chen ◽  
...  
Keyword(s):  
Cropping Systems ◽  
Reaction Rates ◽  
Total Carbon ◽  
Kinetic Properties ◽  
Total N ◽  
Alpha Galactosidase ◽  
Beta Glucosidase ◽  
Alpha Glucosidase ◽  
Beta Galactosidase ◽  
Sequential Cropping

Agricultural practices that reduce soil degradation and improve agriculture sustainability are important particularly for dry hilly land of Chaoyang County in the Liaoning Province, North-east China, where cinnamon soils are widely distributed and mainly for wheat production. The impacts of 10-year cropping systems (wheat-cabbage sequential cropping, wheat-corn intercrop, wheat-sunflower rotation, wheat-soybean rotation) on soil enzyme properties of surface-soil (0&ndash;20 cm) were studied. Total carbon, nitrogen, phosphorus and sulfur, and nine soil hydrolases related to nutrient availabilities (&beta;-galactosidase, &alpha;-galactosidase, &beta;-glucosidase, &alpha;-glucosidase, urease, protease, phosphomonoesterase, phosphodiesterase, arylsulphatase) and five enzymes kinetic characters were examined. Wheat-corn intercrop systems had higher total C, total N, total P and total S concentrations than wheat-soybean and wheat-sunflower rotation systems. Most test enzyme activities (&alpha;-galactosidase, &beta;-galactosidase, &alpha;-glucosidase, &beta;-glucosidase, urease, protease, phosphomonoesterase and arylsulphatase) showed the highest activities under wheat-corn intercropping system. Urease, protease and phosphodiesterase activities of wheat-cabbage sequential cropping system were significantly higher than two rotation systems. The maximum reaction rates of enzymes (V<sub>max</sub>) were higher than apparent enzyme activity, which suggests larger potential activity of enzymes, while not all kinetic parameters were adaptive as soil quality indicators in dry hilly cinnamon soil.

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