Growth, water use efficiency, and adaptive features of the tree legume tagasaste (Chamaecytisus proliferus Link.) on deep sands in south-western Australia

2001 ◽  
Vol 52 (2) ◽  
pp. 221 ◽  
Author(s):  
E. C. Lefroy ◽  
J. S. Pate ◽  
R. J. Stirzaker

Four-year-old tagasaste trees in dense plantation and wide-spaced alley cropping layouts at Moora, Western Australia, were cut back to 0.6 m high and their patterns of coppice regrowth and water use monitored over 3 years. Trees reached a permanent fresh watertable at 5 m depth by means of deeply penetrating sinker roots. Dry matter (DM) accumulation and transpiration loss were closely similar at the 2 planting densities despite higher soil water contents in alley plots. Yearly transpiration at plantation density amounted to 0.55 and 0.63 of Penman-Montieth potential evapotranspiration (E0) in the second and third years, respectively. Mean water use efficiency over the 3 years was 247 L/kg DM, compared with values in the range 186–320 L/kg for younger pot-and column-grown trees. Using a combination of neutron moisture metre (NMM) assays of soil moisture and deuterium: hydrogen ratios of groundwater and xylem water of tagasaste and annual weeds, it was shown that trees became increasingly dependent on groundwater over time and had the capacity to switch rapidly between soil and groundwater sources. Seasonal changes in carbon isotope composition of new shoot tip dry matter indicated that plantation trees were less stressed than alley trees by the third summer as they adapted to heavy dependence on groundwater. In the third season, when plantation trees were transpiring at rates equivalent to 2.3 times annual rainfall, NMM profiles and time domain reflectometry (TDR) assays indicated that no free drainage occurred and that trees were capable of hydraulically lifting groundwater to near surface soil in the dry season. Additional adaptive features of importance to this environment included heat stress induced leaf shedding, development of perennial root nodules on lower parts of tap roots, and an ability to respond in summer to artificial irrigation or a seasonal rainfall by rapidly increasing transpiration 2–3-fold to values equalling E0.

2013 ◽  
Vol 119 (1-2) ◽  
pp. 119-129 ◽  
Author(s):  
Hsien Ming Easlon ◽  
Krishna S. Nemali ◽  
James H. Richards ◽  
David T. Hanson ◽  
Thomas E. Juenger ◽  
...  

2016 ◽  
Vol 46 (7) ◽  
pp. 1145-1150 ◽  
Author(s):  
Daniel Fonseca de Carvalho ◽  
Dionizio Honório de Oliveira Neto ◽  
Luiz Fernando Felix ◽  
José Guilherme Marinho Guerra ◽  
Conan Ayade Salvador

ABSTRACT: The aim of the present study was to evaluate the effect of different irrigation depths on the yield, water use efficiency (WUE), and yield response factor (Ky) of carrot (cv. 'Brasília') in the edaphoclimatic conditions of Baixada Fluminense, RJ, Brazil. Field trials were conducted in a Red-Yellow Argisol in the 2010-2011period. A randomized block design was used, with 5 treatments (depths) and 4 replicates. Depths were applied by drippers with different flow rates, and the irrigation was managed by time domain reflectometry (TDR) technique. The reference (ETo) and crop (ETc) evapotranspiration depths reached 286.3 and 264.1mm in 2010, and 336.0 and 329.9mm in 2011, respectively. The root yield varied from 30.4 to 68.9t ha-1 as a response to treatments without irrigation and 100% replacement of the soil water depth, respectively. Values for WUE in the carrot crop varied from 15 to 31kg m-3 and the mean Ky value was 0.82. The mean values for Kc were obtained in the initial (0.76), intermediate (1.02), and final (0.96) stages. Carrot crop was influenced by different water depths (treatments) applied, and the highest value for WUE was obtained for 63.4% of soil water replacement.


1999 ◽  
Vol 50 (6) ◽  
pp. 1035 ◽  
Author(s):  
T. P. Bolger ◽  
N. C. Turner

There is a perception in the farming and research communities that annual pastures have low produc- tivity and water use, and contribute disproportionately to problems of rising watertables and dryland salinity. Our aim was to determine potential pasture production in relation to water use and the influence of management factors on this relationship. Experiments were initiated at 4 locations along a gradient of 300–1100 mm annual rainfall across the Western Australian agricultural zone. At each site a high input treatment was compared with a low input control. There was a strong linear relationship between water use and pasture production up to 440 mm of growing- season water use. After 30 mm of water use the potential pasture production was 30 kg/ha.mm. An upper limit to pasture production may be reached at about 12 000 kg/ha in this environment due to rainfall distribution patterns and soil water holding capacity in the root-zone. Although pasture production was increased by as much as 3500 kg/ha, water use was generally similar or only slightly more for high input compared with control plots. The marginally higher water use by the high input pastures resulted in an extra 18 mm of water extracted from the subsoil at one location by the end of the third season. A drier subsoil may provide a buffer for storing excess rainfall and reduce deep drainage. Estimated drainage was small at low rainfall sites so even marginal increases in water use by highly productive annual pastures could play a significant role in reducing water loss to deep drainage and mitigating water-table rise and secondary salinisation in low rainfall regions. Management practices aimed at promoting early growth and adequate leaf area should maximise water use, water use efficiency, and yield. The linear relationship defining potential pasture production provides a useful benchmark to farmers.


2002 ◽  
Vol 42 (7) ◽  
pp. 945 ◽  
Author(s):  
J. L. Jacobs ◽  
G. N. Ward ◽  
A. M. McDowell ◽  
G. Kearney

Effect of cultivation practice and sowing time on soil moisture retention at sowing, growth rates, dry matter yield, water use efficiency and nutritive characteristics (metabolisable energy, crude protein, neutral detergent fibre, water-soluble carbohydrates and starch) of turnip, pasja and rape was determined on 2 soil types (site A and B) over 2 years. Cultivation treatments were: optimum full inversion, an optimum non-inversion cultivation and over cultivated. At each site, cultivation treatments were imposed at 2 different times (early and late).Results showed few differences in soil moisture at sowing between the 3 cultivation systems. Where seedbeds were prepared earlier rather than later, soil moisture at sowing was higher. Given that there was relatively little difference in soil moisture between cultivation treatments within a sowing time, it is likely that rainfall events may have confounded cultivation effects.Apart from year 2 at site A, the water use efficiency of turnip was higher than for pasja and rape. It is proposed that the lower value in year 2 may be due to root development being retarded by low moisture availability, particularly at the later sowing date, thus leading to a lower dry matter yield.Despite no cultivation effects on soil moisture at sowing, there appeared to be clear advantages for the full inversion technique in terms of subsequent weed germination. Generally, weed numbers post germination were lower for this cultivation method compared with both non-inversion techniques. In conclusion, the cultivation techniques used had little effect on soil moisture at sowing and subsequent dry matter yields, provided the resultant seedbed was well-prepared, fine, firm and weed free. Full inversion cultivation techniques in areas where broad-leaved weeds are a problem may substantially reduce subsequent weed burdens. Early sowing where possible may reduce the likelihood of crop failure through the provision of adequate soil moisture at sowing and increase the incidence of rain during the growing period. Timing of sowing will vary according to paddock requirements during early spring (e.g. grazing or forage conservation), soil type, and trafficability for cultivation.


1997 ◽  
Vol 37 (6) ◽  
pp. 667 ◽  
Author(s):  
W. M. Strong ◽  
R. C. Dalal ◽  
J. E. Cooper ◽  
J. A. Doughton ◽  
E. J. Weston ◽  
...  

Summary. Continuous cereal cropping in southern Queensland and northern New South Wales has depleted native soil nitrogen fertility to a level where corrective strategies are required to sustain grain yields and high protein content. The objective of this study was to examine the performance of chickpea in chickpea–wheat rotations in terms of yields, water use and N2 fixation. The effects of sowing time and tillage practice have been studied. Chickpea grain yields varied from 356 kg/ha in 1995 to 2361 kg/ha in 1988; these were significantly correlated with the total rainfall received during the preceding fallow period and crop growth. Almost 48% of total plant production and 30% of total plant nitrogen were below-ground as root biomass. Mean values of water-use efficiency for grain, above-ground dry matter, and total dry matter were 5.9, 14.2 and 29.2 kg/ha.mm, respectively. The water-use efficiency for grain was positively correlated with the total rainfall for the preceding fallow and crop growth period although cultural practices modified water-use efficiency. The potential N2 fixation was estimated to be 0.6 kg nitrogen/ha.mm from 1992 total dry matter nitrogen yields assuming all of the nitrogen contained in chickpea was derived from the atmosphere. Sowing time had a much larger effect on grain yield and N2 fixation by chickpea than tillage practice (conventional tillage and zero tillage) although zero tillage generally increased grain yields. The late May–early June sowing time was found to be the best for chickpea grain yield and N2 fixation since it optimised solar energy use and water use, and minimised frost damage. Nitrogen fixation by chickpea was low, less than 40% nitrogen was derived from atmosphere, representing less than 20 kg nitrogen/ha.year. The potential for N2 fixation was not attained during this period due to below-average rainfall and high soil NO3-N accumulation because of poor utilisation by the preceding wheat crop. Increased soil NO3-N due to residual from fertiliser N applied to the preceding wheat crop further reduced N2 fixation. A simple soil nitrogen balance indicated that at least 60% of crop nitrogen must be obtained from N2 fixation to avoid continued soil nitrogen loss. This did not occur in most years. The generally negative soil nitrogen balance needs to be reversed if chickpea is to be useful in sustainable cropping systems although it is an attractive cash crop. Sowing time and zero tillage practice, possibly combined with more appropriate cultivars, to enhance chickpea biomass, along with low initial soil NO3-N levels, would provide maximum N2 fixation.


1993 ◽  
Vol 33 (2) ◽  
pp. 245 ◽  
Author(s):  
PG Tow

The persistence and water use efficiency of Digitaria eriantha spp. eriantha and Hunter river lucerne were compared on red solodic soil with a hardsetting surface and poor internal drainage, on the North- West Slopes of New South Wales. After prolonged watering, the profile was wet to a depth of 48 � 1.5 cm, with an available moisture store of 90 mm. Over 3 years, persistence of digitaria was excellent. The population of lucerne was reduced following flooding at summer temperatures, Dry matter production of nitrogen (N) fertilised digitaria per mm warm season rainfall was similar to that of tropical grasses adapted to comparable rainfall environments in subtropical Queensland. Lucerne dry matter per mm rainfall was only about half that of digitaria (3.2 v. 6.3 kg). Lucerne grew well in mixture with digitaria except under prolonged wet soil conditions in summer. Artificial solodic profiles were constructed in the glasshouse to compare digitaria and lucerne in monoculture and mixture under varying temperature, moisture, and N regimes. Lucerne showed sensitivity to both high and low moisture levels at summer temperatures but performed very well at spring temperatures and moderate moisture levels where the mean evapotranspiration ratio was 400 g water per g dry matter. Water use efficiency was higher in digitaria than in lucerne, except at spring temperatures without added N. Water use efficiency of the mixture was always similar to that of the most efficient monoculture of the particular treatment.


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