Water use by annual crops. 1. Role of dry matter production

2007 ◽  
Vol 58 (12) ◽  
pp. 1159 ◽  
Author(s):  
P. R. Ward ◽  
D. J. M. Hall ◽  
S. F. Micin ◽  
K. Whisson ◽  
T. M. Willis ◽  
...  

In southern Australia, expanding dryland salinity is the result of increased deep drainage associated with widespread replacement of native perennial vegetation by annual agricultural crops and pastures. Although perennial pastures have been shown to assist in slowing salinisation, their adoption has been slow, and annual crops and pastures are likely to remain as the dominant land use for the foreseeable future. Therefore, understanding the water balance of annual crops and pastures, and how it can be manipulated, is important in trying to manage salinity. In this research we investigate the effect of varying levels of dry matter production on components of the water balance (soil evaporation, transpiration, soil water storage, and drainage) for annual crops at contrasting sites and soil types in south-western Australia. Dry matter production was controlled by fertiliser addition and crop rotation, and varied by a factor of up to 2, depending on seasonal conditions. Deep drainage was zero for most sites and years, but where it was greater than zero, there was no discernible effect due to production level. Out of a total of 14 site/year comparisons, the difference in soil water extraction associated with greater dry matter production averaged 5 mm, and was greater than 20 mm on only 1 occasion. However, high dry matter production was associated with greater transpiration, at the expense of soil evaporation. Manipulating dry matter production is unlikely to have a substantial effect on deep drainage and the expansion of dryland salinity in south-western Australia.


2004 ◽  
Vol 44 (2) ◽  
pp. 151 ◽  
Author(s):  
M. Bethune ◽  
Q. J. Wang

The dairy industry is a major user of water in northern Victoria and southern New South Wales. Water is typically applied to pasture using the border-check irrigation system. The border-check system is largely gravity driven and thus energy efficient. However, deep drainage can potentially be high because the system allows only limited control over the depth of water applied in each irrigation event. For this reason, heavy soils are regarded as the most suitable for border-check irrigation. This study quantified net deep drainage (deep drainage less capillary rise) under border-check irrigated pasture on a Goulburn clay loam soil. Additionally, the study investigated the extent to which irrigation frequency and watertable conditions influence water use, dry matter production and deep drainage. The water balance and dry matter production were monitored over 2.5 years in a lysimeter facility in northern Victoria. The Goulburn clay loam is representative of the heavier textured soils used for border-check irrigation of pasture in northern Victoria. The average measured net deep drainage was 4 mm/year. This indicates that relatively small levels of net deep drainage can be achieved under well-managed border-check irrigation on a Goulburn clay loam soil. Net deep drainage losses were greatest following winter, when rainfall exceeded pasture water use for an extended period. Increasing the interval between irrigation events resulted in reduced plant water use, infiltration of irrigation water, rainfall runoff and pasture production. However, increasing the interval did not impact on net deep drainage or water use efficiency. Depth of watertable had a relatively minor impact on the water balance.







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.



2002 ◽  
Vol 42 (8) ◽  
pp. 1043 ◽  
Author(s):  
M. Seymour ◽  
K. H. M. Siddique ◽  
N. Brandon ◽  
L. Martin ◽  
E. Jackson

The response of Vicia sativa (cvv. Languedoc, Blanchefleur and Morava) and V. benghalensis (cv. Barloo) seed yield to seeding rate was examined in 9 field experiments across 2 years in south-western Australia. There were 2 types of field experiments: seeding rate (20, 40, 60, 100 and 140 kg/ha) × cultivar (Languedoc, Blanchefleur, and Morava or Barloo), and time of sowing (2 times of sowing of either Languedoc or Blanchefleur) × seeding rate (5,�7.5, 10, 15, 20, 30, 40, 50, 75 and 100 kg/ha).A target density of 40 plants/m2 gave 'optimum' seed yield of vetch in south-western Australia. In high yielding situations, with a yield potential above 1.5 t/ha, the 'optimum' plant density for the early flowering cultivar Languedoc (85–97 days to 50% flowering) was increased to 60 plants/m2. The later flowering cultivar Blanchefleur (95–106 days to 50% flowering) had an optimum plant density of 33 plants/m2 at all sites, regardless of fitted maximum seed yield. Plant density in the range 31–38 plants/m2 was found to be adequate for dry matter production at maturity of Languedoc and Blanchefleur. For the remaining cultivars Barloo and Morava we were unable to determine an average optimum density for either dry matter or seed yield due to insufficient and/or inconsistent data.



1999 ◽  
Vol 50 (3) ◽  
pp. 375 ◽  
Author(s):  
K. H. M. Siddique ◽  
S. P. Loss ◽  
K. L. Regan ◽  
R. L. Jettner

A range of cool season grain legume species have shown considerable potential for soils unsuitable for the production of narrow-leafed lupin (Lupinus angustifolius L.) at limited sites in the Mediterranean-type environments of south-western Australia. In this study the adaptation of these grain legume species was compared by measuring crop phenology, growth, and yield in field experiments at a total of 36 sites over 3 seasons, with the aim of identifying species with suitable adaptation and seed yield for specific environments. The grain legumes examined appeared to fall into 3 categories: (i) field pea (Pisum sativum L.), faba bean (Vicia faba L.), common vetch (Vicia sativa L.), and narbon bean (Vicia narbonensis L.) clearly had superior seed yield to the other species over a wide number of sites and years across south-western Australia (mean 1.0–2.3 t/ha); (ii) albus lupin (Lupinus albus L.), desi chickpea (Cicer arietinum L.), and Lathyrus cicera, L. sativus, and L. ochrus produced seed yields of 1–1.3 t/ha; and (iii) red lentil (Lens culinaris L.), bitter vetch (Vicia ervilia), and kabuli chickpea (Cicer arietinum L.) generally produced the lowest yields (0.6–1.0 t/ha). There were clear species × environment interactions. At low-yielding sites (<1.4 t/ha), field pea was the highest yielding species, while faba bean often produced the highest seed yields under more favourable conditions at high yielding sites. Lentil, bitter vetch, Lathyrus spp., and desi chickpea showed average response to increasing mean site yield. Soil pH and clay content and rainfall were the environmental factors identified as the most important in determining seed yields. Soil pH and clay content appeared to be especially important in the adaptation of lentil, narbon bean, bitter vetch, and kabuli chickpea, with these species performing best in soils with pH >6.0 and clay contents >15%. Seed yields were positively correlated with dry matter production at maturity across a number of sites (r2 = 0.40, P < 0.01). Future improvements in seed yield of these species are likely to come from management practices that increase dry matter production such as increased plant density and early sowing, and through the development of genotypes with greater tolerance to low winter temperatures, and more rapid phenology, canopy development, and dry matter production than existing commercial cultivars.



1994 ◽  
Vol 34 (1) ◽  
pp. 93 ◽  
Author(s):  
GJ Lewis ◽  
N Thurling

Representative lines of Brassica napus, B. campestris, and B. juncea were compared at East Beverley in the central wheatbelt of Western Australia on the basis of agronomic and physiological characters known to affect seed yield. Seed yield of B. juncea line 81794 was 32% higher than the locally adapted B. napus cv. Wesbrook (76 g/m2). Yields of B. napus cv. Eureka and the 2 B. campestris populations were not significantly different from Wesbrook and were lower than 81794. The higher yield of 81794 was due to higher dry matter production, particularly after first open flower. Yield superiority of 81794 was not associated with any single yield component. Under the water-stressed conditions of this experiment, seed yield had a strong positive correlation with dry matter production after first open flower. Differences in dry matter production during this period were due to variation in crop growth rates among the lines, not to variations in duration of the period. There was no relationship between flowering time and seed yield in this experiment, suggesting earlier reproductive development is not obligatory for high yield of oilseed Brassicas in low rainfall mediterranean environments. Total water use throughout the season differed little among populations, but there were differences in water use patterns over time. The greater rate of dry matter accumulation of 81794 is due to its ability to extract more water from the soil profile after anthesis; postanthesis water use of 81794 was 20% higher than that of Wesbrook. Water use efficiency of 81794 was also higher than that of Wesbrook, because soil evaporation comprised a smaller proportion of evapotranspiration. Further increases in seed yield of oilseed brassicas in this environment should be possible if higher postanthesis water use could be combined with lower soil evaporation and improved water use efficiency.



Sign in / Sign up

Export Citation Format

Share Document