Deep drainage and land use systems. Model verification and systems comparison

2005 ◽  
Vol 56 (9) ◽  
pp. 995 ◽  
Author(s):  
Zahra Paydar ◽  
Neil Huth ◽  
Anthony Ringrose-Voase ◽  
Rick Young ◽  
Tony Bernardi ◽  
...  
Keyword(s):  
Land Use ◽  
Production Systems ◽  
Farming Systems ◽  
Model Verification ◽  
Experimental Results ◽  
Moist Soil ◽  
Deep Drainage ◽  
Systems Model ◽  
Drainage Rate ◽  
South Wales

Deep drainage or drainage below the bottom of the profile usually occurs when rain infiltrates moist soil with insufficient capacity to store the additional water. This drainage is believed to be contributing to watertable rise and salinity in some parts of the Liverpool Plains catchment in northern New South Wales. The effect of land use on deep drainage was investigated by comparing the traditional long fallow system with more intense ‘opportunity cropping’. Long fallowing (2 crops in 3 years) is used to store rainfall in the soil profile but risks substantial deep drainage. Opportunity cropping seeks to lessen this risk by sowing whenever there is sufficient soil moisture. Elements of the water balance and productivity were measured under various farming systems in a field experiment for 4 years in the southern part of the catchment. The experimental results were used to verify APSIM (Agricultural Production Systems Simulator) by comparing them with predictions of production, water storage, and runoff. The verification procedure also involved local farmers and agronomists who assessed the credibility of the predictions and suggested modifications. APSIM provided a realistic simulation of common farming systems in the region and could capture the main hydrological and biological processes. APSIM was then used for long-term (41 years) simulations to predict deep drainage under different systems and extrapolate experimental results. The results showed large differences between agricultural systems mostly because differences in evapotranspiration contributed to differences in profile moisture when it rained. The model predicted that traditional long fallow farming systems (2 crops in 3 years) are quite ‘leaky’, with average annual deep drainage of 34 mm. However, by planting crops in response to the depth of moist soil (opportunity or response cropping), APSIM predicted a much smaller annual drainage rate of 6 mm. Opportunity cropping resulted in overall greater water use and increased production compared with long fallowing. Furthermore, modelling indicated that average annual deep drainage under continuous sorghum (3 mm) is much less than under either long fallow cropping or continuous wheat (39 mm), demonstrating the importance of including summer cropping, as well as increasing cropping frequency, to reducing deep drainage.

If long fallow cropping is leaky then shallow groundwaters on the Liverpool Plains should be of recent origin

2004 ◽  
Vol 44 (10) ◽  
pp. 1051 ◽  
Author(s):  
R. R. Young ◽  
A. Broughton ◽  
J. M. Bradd ◽  
J. F. Holland
Keyword(s):  
Cropping Systems ◽  
New South ◽  
Shallow Groundwater ◽  
Agricultural Practices ◽  
Farming Systems ◽  
Deep Drainage ◽  
Site Specific ◽  
South Wales ◽  
Recent Origin ◽  
Unexpected Outcome

Previous groundwater studies have indicated that up to 195 000 ha of the Liverpool Plains catchment, south of Gunnedah, New South Wales, Australia, are at risk from shallow saline watertables. Replacement of hydraulically stable, native perennial grasslands with more ‘leaky’ annual cropping systems since the 1950s, particularly long fallow wheat–sorghum rotations, has been held responsible for an apparent increased frequency of shallow watertables and saline discharge. If so, then it follows that shallow groundwater in the alluvium will be recent (less than about 30 years old) and the solution to the problem is a straightforward reduction in deep drainage under farming systems via increased evapotranspiration. However, in this study, we have found levels of bomb pulse tritium in shallow groundwaters that indicate that about half of the shallow groundwaters in the Mooki subcatchment pre-date current agricultural practices. A hypothesis for this unexpected outcome suggests that the problem is complex and that solutions need to be site-specific.

Recharge estimation for the Liverpool Plains

Soil Research ◽  
1998 ◽  
Vol 36 (2) ◽  
pp. 335 ◽  
Author(s):  
K. Abbs ◽  
M. Littleboy
Keyword(s):  
Land Use ◽  
Root Zone ◽  
Cropping Systems ◽  
Farming Systems ◽  
Soil Survey ◽  
Soil Types ◽  
Weather Data ◽  
Dryland Salinity ◽  
Systems Model ◽  
Cropping Rotation

Dryland salinity is recognised as a major environmental concern on the Liverpool Plains in north-eastern New South Wales. Previous hydrogeological and dryland salinity studies have highlighted the importance of adopting appropriate farming systems to reduce recharge into shallow aquifers. In this study, we applied the cropping systems model PERFECT to investigate the effects of climate, soil, and land use on recharge. Model inputs were derived from a range of sources including historical weather data, soil survey data, and information from landholder surveys. We investigated 47 different soils identified in a published soil survey covering approximately 280 000 ha of the Liverpool Plains. This study demonstrated a significant variation in soil physical properties and estimated recharge within soil types and illustrates the dangers of generalising soils into broad groupings. For example, under a wheat-sorghum rotation, predicted average annual recharge for soils classified as black earths ranged from 28 to 80 mm. Similar variability of predicted drainage is evident within other Great Soil Groups. The results reveal that response cropping alone will not significantly reduce recharge for all soils. Considering one black earth soil, average annual recharge is predicted to be 48 mm for a wheat-sorghum rotation, 22 mm for a response cropping rotation, and 8 mm for a lucerne{response cropping rotation. Therefore, including lucerne within a response cropping system is of benfit in reducing recharge. For all soil types, least recharge is predicted for permanent pasture but this land use is not an attractive option to farmers given the diversity of farming systems in the region. However, for some soils, continuous pasture is appropriate because excessive recharge is estimated for all cropping systems. This study has extended previous modelling work in the region as it considered a much wider range of soil types and cropping systems than previously investigated. Such a modelling approach permits the quantification of the effects of climate, soil type, and land use on recharge below the root-zone.

Yaw Galloping of a TLWP Platform Under High Speed Currents by Analytical Methods and its Comparison With Experimental Results

2017 ◽  
Author(s):  
Francisco Lamas ◽  
Miguel A. M. Ramirez ◽  
Antonio Carlos Fernandes
Keyword(s):  
High Speed ◽  
Production Systems ◽  
Experimental Tests ◽  
Experimental Results ◽  
Analytical Methodology ◽  
New Approach ◽  
Laboratory Facilities ◽  
Polynomial Curve ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.

scholarly journals Rural Roads Are Paving the Way for Land-Use Intensification in the Uplands of Laos

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 330
Author(s):  
Jean-Christophe Castella ◽  
Sonnasack Phaipasith
Keyword(s):  
Land Use ◽  
Management Practices ◽  
Management Strategies ◽  
Farming Systems ◽  
Long Term Effects ◽  
Group Discussions ◽  
Rural Roads ◽  
External Resources ◽  
Hybrid Maize ◽  
The Impact

Road expansion has played a prominent role in the agrarian transition that marked the integration of swidden-based farming systems into the market economy in Southeast Asia. Rural roads deeply altered the landscape and livelihood structures by allowing the penetration of boom crops such as hybrid maize in remote territories. In this article, we investigate the impact of rural road developments on livelihoods in northern Laos through a longitudinal study conducted over a period of 15 years in a forest frontier. We studied adaptive management strategies of local stakeholders through the combination of individual surveys, focus group discussions, participatory mapping and remote-sensing approaches. The study revealed the short-term benefits of the maize feeder roads on poverty alleviation and rural development, but also the negative long-term effects on agroecosystem health and agricultural productivity related to unsustainable land use. Lessons learnt about the mechanisms of agricultural intensification helped understanding the constraints faced by external interventions promoting sustainable land management practices. When negotiated by local communities for their own interest, roads may provide livelihood-enhancing opportunities through access to external resources, rather than undermining them.

scholarly journals Homegarden agroecosystems managed by Salar people on Qinghai-Tibet Plateau

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Mingjing Zhu ◽  
Binsheng Luo ◽  
Ben La ◽  
Ruijie Chen ◽  
Fenggui Liu ◽  
...  
Keyword(s):  
Plant Species ◽  
Rural Areas ◽  
Production Systems ◽  
Farming Systems ◽  
Field Investigation ◽  
Tibet Plateau ◽  
Ecosystem Functions ◽  
Structured Interviews ◽  
Services Research ◽  
Qinghai Tibet Plateau

Abstract Background Salar is a Turkic-speaking Islamic ethnic group in China living mainly in Xunhua Salar Autonomous County (Xunhua or Xunhua County), Qinghai-Tibet Plateau. Salar people are skilled in horticulture and their homegarden (HG) management. They are regarded as the first people on the Qinghai-Tibet Plateau to practice horticulture, especially manage their HGs, traditional farming systems, and supplementary food production systems. Traditional knowledge of Salar people associated with their HGs always contributes significantly to the local livelihood, food security, ornamental value, and biodiversity conservation. The cultivation of different plants in HGs for self-sufficiency has a long tradition in China’s rural areas, especially in some mountainous areas. However, Salar traditional HGs have not been described. The present paper aims to report the features of Salar HGs mostly based on agrobiodiversity and its ecosystem services. Methods The methods used in this work included semi-structured interviews and participatory observation. A total of 60 households in three townships, 9 villages were surveyed. There are 4–12 family members in each household, aged from 20 to 86 years old. The homestead size is between 200 and 1200 m2. Plant species cultivated in Salar HGs were identified according to Flora of China. Based on a comprehensive survey of Salar HGs and related to background data, we identified and characterized the most important services and functions provided by Salar HGs. Results According to primary production systems, there are 4 different types of Salar HGs, including ornamental focus, product focus, dual-purpose and multi-purpose. In total, 108 (excluding weeds and bonsai) plant species were recorded in Salar HGs, within 43 plant families. The most important and frequently used plants are Rosa chinensis, Armeniaca vulgar, Prunus salicina, and Ziziphus jujuba. About 4 to 32 plant species were recorded in each homegarden. We found that the Salar HGs, as a typical agroecosyste, prossess multiple servcices and functions that directly benefit households according to the field investigation. Conclusion This paper reveals the floristic diversity of Salar HGs. It presents useful information in the homegarden agroecosystem of Salar people, such as HG types and species diversity in Salar HGs. Ecosystem functions and services research suggested that the Salar HG agroecosystem provides agroecosystem services mainly related to supply and culture services. Salar HGs are important as food supplement resources, aesthetics symbol, and cultural spaces.

scholarly journals Within-Season Changes in Land-Use Impact Pest Abundance in Smallholder African Cassava Production Systems

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 269 ◽  
Author(s):  
Andrew Kalyebi ◽  
Sarina Macfadyen ◽  
Andrew Hulthen ◽  
Patrick Ocitti ◽  
Frances Jacomb ◽  
...  
Keyword(s):  
Land Use ◽  
Bemisia Tabaci ◽  
Large Scale ◽  
Production Systems ◽  
Smallholder Farmers ◽  
Negative Relationship ◽  
Central Africa ◽  
Sub Saharan Africa ◽  
Smallholder Farming ◽  
Manihot Esculenta Crantz

Cassava (Manihot esculenta Crantz), an important commercial and food security crop in East and Central Africa, continues to be adversely affected by the whitefly Bemisia tabaci. In Uganda, changes in smallholder farming landscapes due to crop rotations can impact pest populations but how these changes affect pest outbreak risk is unknown. We investigated how seasonal changes in land-use have affected B. tabaci population dynamics and its parasitoids. We used a large-scale field experiment to standardize the focal field in terms of cassava age and cultivar, then measured how Bemisia populations responded to surrounding land-use change. Bemisia tabaci Sub-Saharan Africa 1 (SSA1) was identified using molecular diagnostics as the most prevalent species and the same species was also found on surrounding soybean, groundnut, and sesame crops. We found that an increase in the area of cassava in the 3–7-month age range in the landscape resulted in an increase in the abundance of the B. tabaci SSA1 on cassava. There was a negative relationship between the extent of non-crop vegetation in the landscape and parasitism of nymphs suggesting that these parasitoids do not rely on resources in the non-crop patches. The highest abundance of B. tabaci SSA1 nymphs in cassava fields occurred at times when landscapes had large areas of weeds, low to moderate areas of maize, and low areas of banana. Our results can guide the development of land-use strategies that smallholder farmers can employ to manage these pests.

Is cross-breeding of cattle beneficial for the environment? The case of mixed farming systems in Central Java, Indonesia

2015 ◽  
Vol 57 ◽  
pp. 1-13 ◽  
Author(s):  
T.S.M. Widi ◽  
H.M.J. Udo ◽  
K. Oldenbroek ◽  
I.G.S. Budisatria ◽  
E. Baliarti ◽  
...  
Keyword(s):  
Land Use ◽  
Global Warming ◽  
Live Weight ◽  
Farming Systems ◽  
Cattle Production ◽  
Young Stock ◽  
Cross Breeding ◽  
Central Java ◽  
Feed Production ◽  
Cattle Farms

SummaryCross-breeding with European beef breeds has become a standard approach for the intensification of smallholder cattle production in Indonesia. This study assessed the environmental impact of cross-breeding, in terms of Global Warming Potential (GWP) and land use. We sampled 90 local Ongole and 162 cross-bred (Simmental × Ongole) cattle farms in four study areas. Expressed per kilogram of live weight of young stock produced, GWP (26.9 kg CO2–equivalents) and land use (34.2 m2) of farms with Ongole breeding stock were not significantly different from the GWP (28.9 kg CO2–equivalents) and land use (37.4 m2) of cross-bred farms. Cross-bred young stock grew faster, but in general cross-bred cattle required more feed. In the current smallholder production system, the dominant cross-breeding practice of using Simmental semen on Ongole andF1cross-bred cows does not result in lower greenhouse gas emissions or land use per kilogram of live weight produced compared with farms with Ongole cows. The advantage from the faster growth of cross-breds is counteracted by the higher emissions from feed production for cross-breds.

Development of profitable milk production systems for northern Australia: a field assessment of the productivity of five potential farming systems using farmlets

2010 ◽  
Vol 50 (4) ◽  
pp. 246 ◽  
Author(s):  
R. G. Chataway ◽  
R. G. Walker ◽  
M. N. Callow
Keyword(s):  
Milk Production ◽  
Production Systems ◽  
Model Development ◽  
Farming Systems ◽  
Field Evaluation ◽  
Nutrient Inputs ◽  
Tropical Pastures ◽  
Mating Period ◽  
Learning Platform ◽  
Forage Base

Farmlets, each of 20 cows, were established to field test five milk production systems and provide a learning platform for farmers and researchers in a subtropical environment. The systems were developed through desktop modelling and industry consultation in response to the need for substantial increases in farm milk production following deregulation of the industry. Four of the systems were based on grazing and the continued use of existing farmland resource bases, whereas the fifth comprised a feedlot and associated forage base developed as a greenfield site. The field evaluation was conducted over 4 years under more adverse environmental conditions than anticipated with below average rainfall and restrictions on irrigation. For the grazed systems, mean annual milk yield per cow ranged from 6330 kg/year (1.9 cows/ha) for a herd based on rain-grown tropical pastures to 7617 kg/year (3.0 cows/ha) where animals were based on temperate and tropical irrigated forages. For the feedlot herd, production of 9460 kg/cow.year (4.3 cows/ha of forage base) was achieved. For all herds, the level of production achieved required annual inputs of concentrates of ~3 t DM/animal and purchased conserved fodder from 0.3 to 1.5 t DM/animal. This level of supplementary feeding made a major contribution to total farm nutrient inputs, contributing 50% or more of the nitrogen, phosphorus and potassium entering the farming system, and presents challenges to the management of manure and urine that results from the higher stocking rates enabled. Mean annual milk production for the five systems ranged from 88 to 105% of that predicted by the desktop modelling. This level of agreement for the grazed systems was achieved with minimal overall change in predicted feed inputs; however, the feedlot system required a substantial increase in inputs over those predicted. Reproductive performance for all systems was poorer than anticipated, particularly over the summer mating period. We conclude that the desktop model, developed as a rapid response to assist farmers modify their current farming systems, provided a reasonable prediction of inputs required and milk production. Further model development would need to consider more closely climate variability, the limitations summer temperatures place on reproductive success and the feed requirements of feedlot herds.

Resource use and environmental impacts from Australian export lamb production: a life cycle assessment

2016 ◽  
Vol 56 (7) ◽  
pp. 1070 ◽  
Author(s):  
S. G. Wiedemann ◽  
M.-J. Yan ◽  
C. M. Murphy
Keyword(s):  
Land Use ◽  
Fresh Water ◽  
Water Use ◽  
Water Consumption ◽  
Energy Demand ◽  
Production Systems ◽  
Arable Land ◽  
Ghg Emissions ◽  
Land Occupation ◽  
Fossil Fuel Energy

This study conducted a life cycle assessment (LCA) investigating energy, land occupation, greenhouse gas (GHG) emissions, fresh water consumption and stress-weighted water use from production of export lamb in the major production regions of New South Wales, Victoria and South Australia. The study used data from regional datasets and case study farms, and applied new methods for assessing water use using detailed farm water balances and water stress weighting. Land occupation was assessed with reference to the proportion of arable and non-arable land and allocation of liveweight (LW) and greasy wool was handled using a protein mass method. Fossil fuel energy demand ranged from 2.5 to 7.0 MJ/kg LW, fresh water consumption from 58.1 to 238.9 L/kg LW, stress-weighted water use from 2.9 to 137.8 L H2O-e/kg LW and crop land occupation from 0.2 to 2.0 m2/kg LW. Fossil fuel energy demand was dominated by on-farm energy demand, and differed between regions and datasets in response to production intensity and the use of purchased inputs such as fertiliser. Regional fresh water consumption was dominated by irrigation water use and losses from farm water supply, with smaller contributions from livestock drinking water. GHG emissions ranged from 6.1 to 7.3 kg CO2-e/kg LW and additional removals or emissions from land use (due to cultivation and fertilisation) and direct land-use change (due to deforestation over previous 20 years) were found to be modest, contributing between –1.6 and 0.3 kg CO2-e/kg LW for different scenarios assessing soil carbon flux. Excluding land use and direct land-use change, enteric CH4 contributed 83–89% of emissions, suggesting that emissions intensity can be reduced by focussing on flock production efficiency. Resource use and emissions were similar for export lamb production in the major production states of Australia, and GHG emissions were similar to other major global lamb producers. The results show impacts from lamb production on competitive resources to be low, as lamb production systems predominantly utilised non-arable land unsuited to alternative food production systems that rely on crop production, and water from regions with low water stress.

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