In a two-course rotation experiment in north-eastern Syria over 10 seasons, the highest wheat grain yields were following fallow (2.57 t ha–1), followed by medic, vetch or lentil (1.90–2.22 t ha–1), and continuous wheat (1.14 t ha–1). The wheat–vetch and wheat–lentil rotations were at least twice as profitable as wheat–fallow, and three times continuous wheat. The inclusion of grain legumes is an excellent alternative to wheat–fallow and continuous wheat production.
Crop and Pasture Science
Volume 66 Number 2 2015
CP14223Confirmation of chloride deficiency as the cause of leaf spotting in durum wheat grown in the Australian northern grains region
Jandaroi, an Australian durum wheat variety, exhibited severe non-pathogenic leaf-spotting in some commercial northwest NSW crops. Leaf-spotting symptoms were reproduced in a glasshouse experiment of durum wheat varieties grown in nil-chloride nutrient solutions. Field experiments showed no significant yield response to chloride fertiliser, probably because plants accessed chloride deep in the soil profile. A strong varietal response to leaf-spotting at low soil chloride concentration demonstrated good potential for breeding to reduce the potential impact of chloride deficiency
CP14190Growth and yield responses in wheat and barley to potassium supply under drought or moderately saline conditions in the south-west of Western Australia
Potassium (K) deficiency is becoming increasingly common because the input of K through fertilisers is less than the removal of K at harvest. Two-year field experiments showed that applying K on low K soils enhanced wheat and barley growth and grain yield under drought and salinity. There was also partial K substitution by sodium (Na) in barley on moderately saline soils, which may need taking into account for K-fertiliser management.
CP14141Comparative effects of gibberellic acid, kinetin and salicylic acid on emergence, seedling growth and the antioxidant defence system of sweet sorghum (Sorghum bicolor) under salinity and temperature stresses
The combine stress of salinity and high temperature significantly reduced emergence percentage, seedling growth, fresh and dry seedling weight, and chlorophyll content. Malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were increased due to both environmental factors. All hormone treatments positively improved most of the morphological and physiological measurements under salinity and temperature stress, but salicylic acid (SA) was more effective than the other hormone treatments.
CP14184Root growth of irrigated summer crops in cotton-based farming systems sown in Vertosols of northern New South Wales
Root growth of cotton, maize and sorghum was evaluated using a combination of core sampling, and minirhizotrons and an image capture system. Rooting depth of cotton was shallow. Subsoil (0.6–0.9 m) root growth of cotton was sparse under continuous cotton but was greater with a cotton–wheat rotation. Surface root length density of a Bollgard® cotton variety was less than that of its non-Bollgard counterpart. Subsoil root growth of sorghum and maize ranged from moderate to high.
CP14181Management strategies for chicory (Cichorium intybus) and plantain (Plantago lanceolata): impact on dry matter yield, nutritive characteristics and plant density
Chicory and plantain cultivars used for dairying were managed under different defoliation regimes for 18 months. Chicory leaf production was maximised in swards defoliated at 250 mm extended leaf height. With plantain, longer defoliation intervals increased both leaf and stem yield, and reduced nutritive value. Defoliating plantain swards at 250 mm extended leaf height appeared to provide a balance between yield and nutritive value. Residual height had less of an effect on yield and nutritive characteristics than defoliation interval.
CP14079Grazing defoliation and nutritive value of Setaria pumila and Digitaria sanguinalis in Lolium perenne-based swards
Setaria pumila and Digitaria sanguinalis are undesirable, C4 annual grasses with a lower nutritive value than that of Lolium perenne. Setaria pumila was defoliated to a greater extent than D. sanguinalis. In addition, post-grazing cover and post-grazing height for both annual grasses increased over the grazing season and were associated with declining nutritive value of both species. Both species readily produced new panicles between grazings and are likely to spread in L. perenne-based dairy pastures unless interventions are used.
CP14164Effects of lucerne genotype on morphology, biomass production and nitrogen content of lucerne and tall fescue in mixed pastures
Legume–grass mixtures ensure a high, protein-rich forage yield without nitrogen fertilization. In an experiment that included 46 lucerne and two tall fescue genotypes tested in microplots, we analyzed how lucerne genetic variation affects agronomic traits. Both tall fescue genotypes grown with highly productive lucerne genotypes had an increased leaf elongation and N status but a reduced tiller number, which could limit their persistence.
Persistence is an important, but generally poorly defined trait of perennial pasture plants. Increases of up to AU$202 ha–1 year–1 in operating profit from pasture persistence—defined as a 1-year increase in duration of peak dry matter production of perennial ryegrass—were modelled for two temperate dairy farms of Australia, compared with up to a $21 ha–1 year–1 increase in operating profit for pasture persistence defined as a reduction in rate of decline in annual pasture production. Results of this study could be used by farmers and plant breeders to aid their decision-making to allocate resources towards improving pasture persistence.
CP13386Evaluation of the biochemical and physiological activity of the natural compound, 2,4-ditert-butylphenol on weeds
2,4-ditert-butylphenol caused excessive production of reactive oxygen. This leads to enhanced lipid peroxidation levels and membrane damage. Increased levels of scavenging enzymes indicate their induction as a secondary defense mechanism in response to 2,4-ditert-butylphenol.
CP14152Biomass, fruit yield, water productivity and quality response of processing tomato to plant density and deficit irrigation under a semi-arid Mediterranean climate
The impact of deficit irrigation on processing tomato at two plant densities was examined in a 2-year experiment. At 5 plants m–2 dry biomass and fruit yield per plant were reduced but fruit yield per unit area was greater than that at 2.5 plants m–2. Deficit irrigation enhanced WUE and allowed a water saving of >45%. A yield response factor Ky greater than Kss reveals a greater crop sensitivity to soil-water deficit in terms of fruit yield than dry biomass.