An evaluation of the tactical use of lucerne phase farming to reduce deep drainage

2007 ◽  
Vol 58 (12) ◽  
pp. 1142 ◽  
Author(s):  
K. Verburg ◽  
W. J. Bond ◽  
L. E. Brennan ◽  
M. J. Robertson
Keyword(s):  
Soil Water ◽  
Root Zone ◽  
Phase Changes ◽  
Soil Water Storage ◽  
Deep Drainage ◽  
Gross Margin ◽  
Annual Crops ◽  
Fixed Phase ◽  
Phase Systems ◽  
Storage Buffer

Lucerne phase farming has been suggested as a way of reducing deep drainage in the cereal belt of southern Australia. It is based on the concept that lucerne (Medicago sativa L.), a perennial pasture with a deep root system, creates a soil water storage buffer below the root zone of the annual crops, which gradually refills during the subsequent cropping phase, temporarily reducing the risk of deep drainage. The rate of refilling is variable because it is affected by the amount and distribution of rainfall as well as management of the crop and the summer fallow. There is, therefore, uncertainty about the optimum phase durations that will maximise the effect of the lucerne phase. Computer simulations were applied to evaluate the use of a soil water measurement below the root zone of annual crops to schedule the phase changes, referred to as tactical phase farming. The results confirmed that phase farming reduced average annual deep drainage significantly, but at the cost of lower average annual gross margin. In most cases, tactical phase farming improved the trade-off between deep drainage and gross margin relative to fixed duration phases; for a given amount of average annual deep drainage the average annual gross margin was larger, and for a given gross margin the drainage was smaller. The benefits of tactical phase systems were greatest in soils with a large available water-holding capacity and when the variability of the refilling rate was large. Overall, however, the benefits of the tactical approach relative to fixed phase systems were small.

Comparative assessment of soil water balance under wheat in a subtropical environment with simplified models

1997 ◽  
Vol 128 (4) ◽  
pp. 461-468 ◽  
Author(s):  
V. K. ARORA ◽  
CHARANJIT SINGH ◽  
KULDEEP SINGH
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Root Zone ◽  
Balance Model ◽  
Soil Water Storage ◽  
Water Evaporation ◽  
Deep Drainage ◽  
Water Balance Components ◽  
Area Index ◽  
Empirical Coefficients

Water balance components under wheat were assessed by employing two simple models, differing in their structure and data requirements, namely the soil-plant–atmosphere–water (SPAW) model of Saxton (1989) and the water balance model (WBM) of Arora et al. (1987). A few modifications based on the SPAW model procedure for the estimation of green canopy were used in a modified WBM and its performance was also tested. Soil water loss (the sum of interception evaporation, soil evaporation, plant transpiration and deep drainage) from sowing to harvest, simulated with the WBM, modified WBM and the SPAW model, had a close correspondence with the measured sum of profile water depletion, rainfall and irrigation for values ranging between 18·3 and 42·7 cm. Estimates of drainage with the WBM and modified WBM using empirical coefficients were greater than those calculated using the SPAW model for situations where the upward flow of water into the root-zone was negligible. Estimates of soil water evaporation using the WBM and modified WBM were invariably smaller than those using the SPAW model. A comparison of simulated and measured soil water storage and a correlation analysis of simulated transpiration with measured biomass at harvest showed that the performance of the WBM was the most realistic of the three models. However, it requires the input of leaf area index values to infer green canopy for each water supply regime. In the absence of this information, the modified WBM and SPAW models are more useful for assessing water balance components in cropped soils.

Drainage and change in soil water storage below the root-zone under long fallow and continuous cropping sequences in the Victorian Mallee

2003 ◽  
Vol 54 (7) ◽  
pp. 663 ◽  
Author(s):  
Mark G. O'Connell ◽  
Garry J. O'Leary ◽  
David J. Connor
Keyword(s):  
Soil Water ◽  
Root Zone ◽  
Sandy Loam ◽  
Water Storage ◽  
Soil Water Storage ◽  
Annual Rainfall ◽  
Continuous Cropping ◽  
Deep Drainage ◽  
Mean Annual Rainfall ◽  
Fallow System

A field study investigated drainage and changes in soil water storage below the root-zone of annual crops on a sandy loam soil in the Victorian Mallee for 8 years. It was designed to compare the effects of the common long (18-month) fallow in a 3-year rotation (fallow–wheat–pea, FWP) with a rotation in which the fallow was replaced with mustard (Brassica juncea), viz. mustard–wheat–pea (MWP). Drainage was measured over 2 periods (1993–98 and 1998–2001) using 9 in situ drainage lysimeters in each rotation. The first period of ~5 years was drier than average (mean annual rainfall 298 cf. 339 mm) and drainage was low and variable. Drainage was greater under the fallow rotation (average 0.24 mm/year) than under the non-fallow rotation (average <0.01 mm/year). The result for the fallow rotation did, however, include one lysimeter that recorded substantial drainage (10.6 mm over the 5 years). During the second period of measurement (~3 years), rainfall was above average (mean annual rainfall 356 cf. 339�mm) and drainage was greater. On average, drainage from the fallow rotation was 6.7 mm/year compared with the non-fallow rotation at 4.0 mm/year. There was again substantial variation between lysimeters. One lysimeter under MWP recorded 31.4 mm/year, and as in the earlier drier period, there were many lysimeters that recorded no drainage. During the drier first period (1993–98), changes in soil water storage between 1.5 and 5.5 m depth confirmed the tendency of the fallow rotation to increase deep drainage. Despite increases and decreases in subsoil water storage during the study, the cumulative change in water storage was positive and greatest under FWP (range: 2.8–14.8 mm/year, ave. 9.6 mm/year) compared with MWP (range: 5.3–9.8 mm/year, ave. 7.4 mm/year) cropping sequences. Overall, the long fallow system has the potential to increase deep drainage by approximately 2 mm/year compared with a fully cropped system, over a wide annual rainfall range (134–438 mm). Further, this experiment reinforces the focus for the reduction of fallow practices for dryland salinity control in the Mallee region.

Lucerne in crop rotations on the Riverine Plains. 3. Model evaluation and simulation analyses

2007 ◽  
Vol 58 (12) ◽  
pp. 1129 ◽  
Author(s):  
K. Verburg ◽  
W. J. Bond ◽  
J. R. Hirth ◽  
A. M. Ridley
Keyword(s):  
Field Experiment ◽  
Soil Water ◽  
Root Zone ◽  
Water Storage ◽  
Crop Rotations ◽  
Soil Water Storage ◽  
Annual Rainfall ◽  
Large Variability ◽  
The Creation ◽  
Storage Buffer

The use of a lucerne phase in crop rotations can reduce water lost as drainage past the root zone under dryland agriculture in southern Australia. During the lucerne phase the perenniality of lucerne and its deep rooting ability allow extraction of soil water from below the root zone of annual crops and the creation of a soil water storage buffer against deep water loss. The longevity of the soil water storage buffer depends on rainfall patterns, management of the crops and summer fallows, as well as the magnitude of the buffer created during the lucerne phase. Results from a previously reported field experiment in north-eastern Victoria (average annual rainfall 600 mm) suggested that a 2-year lucerne phase could be insufficient to prevent drainage under subsequent crops for more than 1 year. Computer simulations were used to explore the implications of climatic variability on the creation and refilling of the soil water storage buffer. After first testing that the simulations described the experimental data satisfactorily, they were then used to extend the results and conclusions of the field experiment. These showed that the outcome of the experimental evaluation was affected by the climatic conditions experienced during the experiment and that a lucerne phase duration of 2 years was not appreciably less effective than a 3-year lucerne phase in reducing drainage past 1.8 m (the depth evaluated in the experiment). This conclusion was, however, sensitive to the depth at which drainage was evaluated and also depended on management factors such as the timing of lucerne removal and weed control during the summer fallows. For example, when drainage was evaluated to the maximum depth of lucerne rooting (3.6 m), lucerne was removed in December rather than April, and weeds were permitted, a third year of lucerne allowed a longer cropping phase without refilling of the profile in 47% of years. As a general recommendation a 3-year lucerne phase might, therefore, be an appropriate option for maximising the prevention of drainage. The large variability in the longevity of the soil water storage buffer (from 3 to > 45 months) and its sensitivity to management suggest, however, that it may be more beneficial to link phase changes to local assessment of the status of soil water storage buffer.

scholarly journals Determining and Comparing Deep Drainage between Two Years – Dry (2012) and Wet (2013) – using Darcy’s Law

SURG Journal ◽  
2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Archana Tamang
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Root Zone ◽  
Darcy’S Law ◽  
Plant Root ◽  
Water Storage ◽  
Darcy's Law ◽  
Soil Water Storage ◽  
Deep Drainage ◽  
Unsaturated Hydraulic Conductivity

Understanding of the downward flux of water below the plant root zone, known as deep drainage (DD), is significant in agriculture and soil water conservation. It plays a key role to determine the amount of water that travels below the plant root zone and can potentially cause groundwater recharge. The DD in soil varies with location, soil texture, and topography. Thus, the objectives of this study were to determine the unsaturated hydraulic conductivity, soil water storage, and DD for the years 2012 (dry year) and 2013 (wet year) at the University of Guelph’s Arboretum. The depths to the water table data were collected using a Mini Water Level Meter. CS616 sensors were used to determine the soil volumetric water content. The soil temperature was extracted with the use of T107 Temperature Probes. The slug test, based on the Hvorslev method, was performed to determine the field saturated hydraulic conductivity. The soil moisture retention curve was produced based on the data collected in the lab with the use of pressure plate systems, using van Genuchten’s equation. The unsaturated hydraulic conductivity was also determined using van Genuchten’s equation. Darcy’s law was used to determine the specific discharge, which was then converted to the total DD. In general, the soil water storage was 38.5 mm higher in 2013 relative to 2012. The unsaturated hydraulic conductivity was approximately 2 times higher in 2013 than 2012. The average DD was approximately 25 mm higher in 2013. This study provides information needed to better understand the movement and amount of water flux and DD in larger details.

A decreasing trend in global soil water storage from 1981 to 2017

2021 ◽  
Author(s):  
XinRui Luo ◽  
Shaoda Li ◽  
Wunian Yang ◽  
Liang Liu ◽  
Xiaolu Tang
Keyword(s):  
Soil Water ◽  
Water Loss ◽  
Root Zone ◽  
Carbon Sink ◽  
Temporal Trends ◽  
Water Storage ◽  
Terrestrial Ecosystems ◽  
Environmental Drivers ◽  
Soil Water Storage ◽  
Soil Drought

&lt;p&gt;Soil water storage serves as a vital resource of the terrestrial ecosystems, and it can significantly influence water cycle and carbon cycling with the frequent occurrence of soil drought induced by land-atmosphere feedbacks. However, there are high variations and uncertainties of root zone soil water storage. This study applied comparison map profile (CMP), Mann-Kendall test, Theil-Sen estimate and partial correlation analysis to (1) estimate the global root zone (0~1 m) soil water storage, (2) and investigate the spatial and temporal patterns from 1981 to 2017 at the global scale, (3) and their relationships with environmental drivers (precipitation, temperature, potential evaportranspiration) using three soil moisture (SM) products &amp;#8211; ERA-5, GLDAS and MERRA-2. Globally, the average annual soil water storage from 1981 to 2017 varied significantly, ranging from 138.3 (100 Pg a&lt;sup&gt;-1&lt;/sup&gt;, 1 Pg = 10&lt;sup&gt;15&lt;/sup&gt; g) in GLDAS to 342.6 (100 Pg a&lt;sup&gt;-1&lt;/sup&gt;) in ERA-5. Soil water storage of the three SM products consistently showed a decreasing trend. However, the temporal trend of soil water storage among different climate zones was different, showing a decreasing trend in tropical, temperate and cold zones, but an increasing trend in polar regions. On the other hand, temporal trends in arid regions differed from ERA-5, GLDAS and MERRA-2. Spatially, the SM products differed greatly, particularly for boreal areas with D value higher for 2500 Mg ha&lt;sup&gt;-1&lt;/sup&gt; a&lt;sup&gt;-1&lt;/sup&gt; and CC value lower for -0.2 between GLDAS and MERRA-2. Over 1981 to 2017, water storage of more than 50% of the global land area suffered from a decreasing trend, especially in Africa and Northeastern of China. Precipitation was the main dominated driver for variation of soil water storage, and distribution varied in different SM products. In conclusion, a global decreasing trend in soil water storage indicate a water loss from soils, and how the water loss affecting carbon sink in terrestrial ecosystems under ongoing climate change needs further investigation.&lt;/p&gt;

Water balance changes in a crop sequence with lucerne

2001 ◽  
Vol 52 (2) ◽  
pp. 247 ◽  
Author(s):  
F. X. Dunin ◽  
C. J. Smith ◽  
S. J. Zegelin ◽  
R. Leuning
Keyword(s):  
Soil Water ◽  
Water Uptake ◽  
Soil Depth ◽  
Water Storage ◽  
Growing Season ◽  
Soil Water Storage ◽  
Annual Rainfall ◽  
Root Extension ◽  
Annual Crops ◽  
Lower Productivity

In a detailed study of soil water storage and transport in a sequence of 1 year wheat and 4 years of lucerne, we evaluated drainage under the crop and lucerne as well as additional soil water uptake achieved by the subsequent lucerne phase. The study was performed at Wagga Wagga on a gradational clay soil between 1993 and 1998, during which there was both drought and high amounts of drainage (>10% of annual rainfall) from the rotation. Lucerne removed an additional 125 mm from soil water storage compared with wheat (root-zone of ~1 m), leading to an estimated reduction in drainage to 30–50% of that of rotations comprising solely annual crops and/or pasture. This additional soil water uptake by lucerne was achieved through apparent root extension of 2–2.5 m beyond that of annual crops. It was effective in generating a sink for soil water retention that was about double that of annual crops in this soil. Successful establishment of lucerne at 30 plants/m2 in the first growing season of the pasture phase was a requirement for this root extension. Seasonal water use by lucerne tended to be similar to that of crops in the growing season between May and September, because plant water uptake was confined to the top 1 m of soil. Uptake of water from the subsoil was intermittent over a 2-year period following its successful winter establishment. In each of 2 annual periods, uptake below 1 m soil depth began late in the growing season and terminated in the following autumn. Above-ground dry matter production of lucerne was lower than that by crops grown in the region despite an off-season growth component that was absent under fallow conditions following cropping. This apparent lower productivity of lucerne could be traced in part to greater allocation of assimilate to roots and also to late peak growth rates at high temperatures, which incurred a penalty in terms of lower transpiration efficiency. The shortfall in herbage production by lucerne was offset with the provision of timely, high quality fodder during summer and autumn. Lucerne conferred indirect benefits through nitrogen supply and weed control. Benefits and penalties to the agronomy and hydrology of phase farming systems with lucerne are discussed.

scholarly journals Effects of Wheat and Rapeseed Production on Soil Water Storage in Mongolian Rangeland

Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 888
Author(s):  
Katori Miyasaka ◽  
Takafumi Miyasaka ◽  
Jumpei Ota ◽  
Siilegmaa Batsukh ◽  
Undarmaa Jamsran
Keyword(s):  
Soil Water ◽  
Crop Production ◽  
Root Zone ◽  
Water Storage ◽  
Soil Water Storage ◽  
Matric Potential ◽  
Wheat Field ◽  
Long Time ◽  
Rapeseed Production ◽  
Wilting Point

In recent years, Mongolia has witnessed an increase in not only wheat fields, which have been present for a long time, but also rapeseed fields. This has led to increasing concerns about soil degradation due to inappropriate cultivation. This study aims to determine the impacts of rapeseed production on soil water storage in Mongolia. The soil water content and matric potential were measured in wheat and rapeseed fields and adjacent steppe rangeland for five years, including crop production and fallow years, and the soil water storages in the fields were compared. The results demonstrated that the matric potential below the root zone in the rapeseed field and both rangelands was drier than the wilting point, whereas the potential in the wheat field was usually almost the same or wetter than this point. The comparison of the amount of soil water storage during the fallow year with that of the adjacent rangeland showed it to be 5–10% higher for the wheat field and almost equal for the rapeseed field. Field management must consider the fact that rapeseed fields use more water than is required by wheat fields and that less water is stored during fallow periods.

ESTIMATING EVAPOTRANSPIRATION FROM IRRIGATED CROPS IN SOUTHWESTERN ONTARIO

1981 ◽  
Vol 61 (2) ◽  
pp. 425-435 ◽  
Author(s):  
C. S. TAN ◽  
J. M. FULTON
Keyword(s):  
Soil Water ◽  
Crop Yields ◽  
Root Zone ◽  
Sandy Loam ◽  
Sunshine Duration ◽  
Meteorological Data ◽  
Water Storage ◽  
Soil Water Storage ◽  
Climatic Data ◽  
Wide Range

Several years of daily evapotranspiration (ET) data for irrigated early potatoes, corn and processing tomatoes, grown on Fox sandy loam measured by floating lysimeters and estimated by meteorological data were used to evaluate an equilibrium evapotranspiration (ETeq) model. A reasonable relationship was obtained between values estimated by the model and those measured by floating lysimeters. The ETeq model can be used to estimate daily ET over a wide range of soil moisture and foliage cover conditions. ETeq can be estimated from readily available climatic data in the form: ETeq = (0.48 + 0.01 Ta) [(0.114 + 0.365n/N) K↓a − 0.039]; where Ta is the mean daily air temperature (°C); n is sunshine duration (h); N is maximum hours of bright sunshine (h); K↓a is solar energy received at the top of the atmosphere (mm/day). At high soil water storage in the root zone, the ET/ETeq remained constant, whereas, at low soil water storage, the ET/ETeq decreased linearly with decreasing soil water storage. The total crop yields were directly related to growing season accumulated ET.

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