Improving water use of annual crops and pastures—limitations and opportunities in Western Australia

2001 ◽  
Vol 52 (2) ◽  
pp. 171 ◽  
Author(s):  
David Tennant ◽  
David Tennant ◽  
David Hall ◽  
David Hall

As part of a wider analysis of the potential role for lucerne in farming systems being developed for containing the spread of salinisation, we have reviewed information generated in Western Australia on opportunities for improving the water use of annual crops and pastures. Substantial increases in water use have been shown to be possible in a number of situations and rainfall environments. Best gains, of the order of 40–70 mm, were reported on deep sand and loamy sand soil types. These were achieved from selection of deep-rooted and longer growing crop and pasture species, and from amelioration of widespread traffic pans and subsoil acidity, and/or selection of tolerant species. On more widespread gradational and duplex soils, soil physical and chemical properties that restrict water infiltration and/or root penetration to depth limit the potential to increase water use. Increases in production and water use are still possible, depending on the permeability of the lower horizons of these soils and on rainfall distribution. At best, recorded increases on these soils were of the order of 5–15 mm in short season, low rainfall environments, and around 40 mm in long season, high rainfall environments. These increases in water use were not invariable. Increases in water use were not noted in dry years on all soils and in all years on shallow duplex soils with impermeable B horizons. Seasonality impacts on all outcomes and is a key issue on all soils and in all rainfall environments.

2003 ◽  
Vol 54 (8) ◽  
pp. 751 ◽  
Author(s):  
Murray Unkovich ◽  
Kerrin Blott ◽  
Alex Knight ◽  
Ivan Mock ◽  
Abdur Rab ◽  
...  

Annual crops were grown in alleys between belts of perennial shrubs or trees over 3–4 years at 3 sites across low rainfall (<450 mm) south-eastern Australia. At the two lower rainfall sites (Pallamana and Walpeup), crop grain yields within 2–5 m of shrub belts declined significantly with time, with a reduction equivalent to 45% over 9 m in the final year of cropping. At the third, wetter site (Bridgewater), the reduction in crop grain yields adjacent to tree belts was not significant until the final year of the study (12% over 11 m) when the tree growth rates had increased. The reductions in crop yield were associated with increased competition for water between the shrub or tree belts and the crops once the soil profile immediately below the perennials had dried. At all 3 sites during the establishment year, estimates of water use under the woody perennials were less than under annual crops, but after this, trends in estimates of water use of alley farming systems varied between sites. At Pallamana the perennial shrubs used a large amount of stored soil water in the second summer after establishment, and subsequently were predominantly dependent on rainfall plus what they could scavenge from beneath the adjacent crop. After the establishment year at the Walpeup site, water use under the perennial shrubs was initially 67 mm greater than under the annual crop, declining to be only 24 mm greater in the final year. Under the trees at Bridgewater, water use consistently increased to be 243 mm greater than under the adjacent annual crop by the final year. Although the shrub belts used more water than adjacent crop systems at Walpeup and Pallamana, this was mostly due to the use of stored soil water, and since the belts occupied only 7–18% of the land area, increases in total water use of these alley farming systems compared with conventional crop monocultures were quite small, and in terms of the extent of recharge control this was less than the area of crop yield loss. At the wetter, Bridgewater site, alley farming appeared to be using an increasing amount of water compared with conventional annual cropping systems. Overall, the data support previous work that indicates that in lower rainfall environments (<350 mm), alley farming is likely to be dogged by competition for water between crops and perennials.


2005 ◽  
Vol 56 (7) ◽  
pp. 743 ◽  
Author(s):  
Heping Zhang ◽  
Neil C. Turner ◽  
Michael L. Poole

Water use of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), canola (Brassica napus L.), and lucerne (Medicago sativa L.) was measured on a duplex soil in the high rainfall zone (HRZ) of south-western Australia from 2001 to 2003. Rainfall exceeded evapotranspiration in all years, resulting in transient perched watertables, subsurface waterlogging in 2002 and 2003, and loss of water by deep drainage and lateral flow in all years. There was no significant difference in water use among wheat, barley, and canola. Lucerne used water at a similar rate to annual crops during the winter and spring, but continued to extract 80−100 mm more water than the annual crops over the summer and autumn fallow period. This resulted in about 50 mm less drainage past the root-zone than for annual crops in the second and third years after the establishment of the lucerne. Crop water use was fully met by rainfall from sowing to anthesis and a significant amount of water (120−220 mm) was used during the post-anthesis period, resulting in a ratio of pre- to post-anthesis water use (ETa : ETpa) of 1 : 1 to 2 : 1. These ratios were lower than the indicative value of 2 : 1 for limited water supply for grain filling. High water use during the post-anthesis period was attributed to high available soil water at anthesis, a large rooting depth (≥1.4 m), a high proportion (15%) of roots in the clay subsoil, and regular rainfall during grain filling. The pattern of seasonal water use by crops suggested that high dry matter at anthesis did not prematurely exhaust soil water for grain filling and that it is unlikely to affect dry matter accumulation during grain filling and final grain yield under these conditions.


2006 ◽  
Vol 57 (3) ◽  
pp. 347 ◽  
Author(s):  
P. R. Ward ◽  
S. F. Micin ◽  
F. X. Dunin

The incorporation of perennials in general, and lucerne in particular, into farming systems of southern Australia has been proposed as a possible means to slow or stop the spread of dryland salinity. In order to be effective, lucerne roots must remove substantially more water from the soil than roots produced by annual crops and pastures. The term ‘buffer’ is used here to denote the extra water storage created by lucerne in addition to that normally created by an annual crop or pasture. In trials across southern Australia, lucerne has proved variable in its ability to create a buffer. In this research, we established 3 new trials, and collated results from current and published trials across Australia, to determine the effect of various edaphic (soil pH, texture, depth, and density for A and B horizons), climatic (average and actual seasonal rainfall), and agronomic (lucerne age, plant density, dry matter production, and rooting depth) factors on buffer size created by lucerne. Data from 26 trials were analysed, representing 84 site × year comparisons. The mean lucerne buffer for all comparisons was 91 mm, and increased with lucerne age. Buffers were generally greater for heavier-textured soils, but standard deviations of the means were large. Within a broad soil type, regression equations were developed to predict buffer size from climatic, edaphic, and agronomic factors, with r2 values ranging between 0.96 and 0.84, and standard errors ranging between 40 and 44 mm. For all soil types, average summer rainfall (but not actual summer rainfall) was a significant component of the regression, suggesting that management of the lucerne stand, in terms of maintaining leaf area during summer, may have an important role in buffer development.


2014 ◽  
Vol 65 (10) ◽  
pp. 1016 ◽  
Author(s):  
P. R. Ward ◽  
R. A. Lawes ◽  
D. Ferris

Pasture cropping is a farming system in which annual crops are sown into established perennial pastures. It may provide environmental benefits such as increased groundcover and reduced deep drainage, while allowing traditional crop production in the Mediterranean-style climate of south-western Australia. In this research, we investigated deep drainage and the temporal patterns of water use by a subtropical perennial grass, annual crops, and a pasture-cropping system over a 4-year period. Both the pasture and pasture-cropped treatments reduced deep drainage significantly, by ~50 mm compared with the crop treatment. Competition between the pasture and crop components altered patterns of average daily water use, the pasture-cropped treatment having the highest water use for July, August and September. Consequently, water-use efficiency for grain production was lower in the pasture-cropped plots. This was offset by pasture production, so that over a full 12-month period, water-use efficiency for biomass production was generally greater for the pasture-cropped plots than for either the pasture or crop monocultures. Pasture cropping may be a viable way of generating sustainable economic returns from both crop and pasture production on sandy soils of south-western Australia.


2001 ◽  
Vol 52 (2) ◽  
pp. 305 ◽  
Author(s):  
P. J. Dolling

Rising water tables in southern Western Australia are causing waterlogging and salinity problems. These issues are related to a lower level of water use by annual plants than by the native vegetation. Phalaris can use more water than annual pastures and crops because of deeper rooting characteristics and longer growing season. However, there is limited information on the water use of phalaris in the Western Australian environment. There is also very little information on water balances under annual crops and pastures outside the growing season. A field experiment was carried out on a duplex soil between March 1994 and March 1999. Annual rainfall varied between 321 and 572 mm. The study examined soil water content, deep drainage, and productivity of phalaris-based pasture, continuous annual pasture, annual pasture–wheat rotation, and a wheat–lupin rotation. The results showed that the phalaris-based pasture after the establishment year was 25% (1.9 t dry matter/ha) more productive than continuous annual pasture, with the main difference occurring in late spring–early summer. The phalaris-based pasture used, on average, 45 mm/year more water and reduced drainage below 1 m by 44 mm/year compared with the annual pastures and crops. Total drainage below 1 m was 30 mm under the phalaris-based pasture and 74 mm under annual pasture. The greater water use in the phalaris-based pasture occurred in late spring and early summer. Although differences in total biomass per year occurred between wheat in different rotations there was no difference in the soil water storage prior to the break of the season. There was also no difference in the soil water balance between any of the annual crops and pastures. Differences in soil water storage did occur in some years in October but disappeared by May the following year.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alexia Stokes ◽  
Guillermo Angeles ◽  
Fabien Anthelme ◽  
Eduardo Aranda-Delgado ◽  
Isabelle Barois ◽  
...  

Abstract Objectives Altitude integrates changes in environmental conditions that determine shifts in vegetation, including temperature, precipitation, solar radiation and edaphogenetic processes. In turn, vegetation alters soil biophysical properties through litter input, root growth, microbial and macrofaunal interactions. The belowground traits of plant communities modify soil processes in different ways, but it is not known how root traits influence soil biota at the community level. We collected data to investigate how elevation affects belowground community traits and soil microbial and faunal communities. This dataset comprises data from a temperate climate in France and a twin study was performed in a tropical zone in Mexico. Data description The paper describes soil physical and chemical properties, climatic variables, plant community composition and species abundance, plant community traits, soil microbial functional diversity and macrofaunal abundance and diversity. Data are provided for six elevations (1400–2400 m) ranging from montane forest to alpine prairie. We focused on soil biophysical properties beneath three dominant plant species that structure local vegetation. These data are useful for understanding how shifts in vegetation communities affect belowground processes, such as water infiltration, soil aggregation and carbon storage. Data will also help researchers understand how plant communities adjust to a changing climate/environment.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Pia Montanucci ◽  
Silvia Terenzi ◽  
Claudio Santi ◽  
Ilaria Pennoni ◽  
Vittorio Bini ◽  
...  

Alginate-based microencapsulation of live cells may offer the opportunity to treat chronic and degenerative disorders. So far, a thorough assessment of physical-chemical behavior of alginate-based microbeads remains cloudy. A disputed issue is which divalent cation to choose for a high performing alginate gelling process. Having selected, in our system, high mannuronic (M) enriched alginates, we studied different gelling cations and their combinations to determine their eventual influence on physical-chemical properties of the final microcapsules preparation,in vitroandin vivo. We have shown that used of ultrapure alginate allows for high biocompatibility of the formed microcapsules, regardless of gelation agents, while use of different gelling cations is associated with corresponding variable effects on the capsules’ basic architecture, as originally reported in this work. However, only the final application which the capsules are destined to will ultimately guide the selection of the ideal, specific gelling divalent cations, since in principle there are no capsules that are better than others.


2017 ◽  
Vol 21 (9) ◽  
pp. 4551-4562 ◽  
Author(s):  
Bruce C. Scott-Shaw ◽  
Colin S. Everson ◽  
Alistair D. Clulow

Abstract. In South Africa, the invasion of riparian forests by alien trees has the potential to affect the country's limited water resources. Tree water-use measurements have therefore become an important component of recent hydrological studies. It is difficult for South African government initiatives, such as the Working for Water (WfW) alien clearing program, to justify alien tree removal and implement rehabilitation unless hydrological benefits are known. Consequently, water use within a riparian forest along the Buffeljags River in the Western Cape of South Africa was monitored over a 3-year period. The site consisted of an indigenous stand of Western Cape afrotemperate forest adjacent to a large stand of introduced Acacia mearnsii. The heat ratio method of the heat pulse velocity sap flow technique was used to measure the sap flow of a selection of indigenous species in the indigenous stand, a selection of A. mearnsii trees in the alien stand and two clusters of indigenous species within the alien stand. The indigenous trees in the alien stand at Buffeljags River showed significant intraspecific differences in the daily sap flow rates varying from 15 to 32 L day−1 in summer (sap flow being directly proportional to tree size). In winter (June), this was reduced to only 7 L day−1 when limited energy was available to drive the transpiration process. The water use in the A. mearnsii trees showed peaks in transpiration during the months of March 2012, September 2012 and February 2013. These periods had high average temperatures, rainfall and high daily vapor pressure deficits (VPDs – average of 1.26 kPa). The average daily sap flow ranged from 25 to 35 L in summer and approximately 10 L in the winter. The combined accumulated daily sap flow per year for the three Vepris lanceolata and three A. mearnsii trees was 5700 and 9200 L, respectively, clearly demonstrating the higher water use of the introduced Acacia trees during the winter months. After spatially upscaling the findings, it was concluded that, annually, the alien stand used nearly 6 times more water per unit area than the indigenous stand (585 mm a−1 compared to 101 mm a−1). This finding indicates that there would be a gain in groundwater recharge and/or streamflow if the alien species are removed from riparian forests and rehabilitated back to their natural state.


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