1,343 publications from this institution
The main objective of this study was to investigate the accumulation and distribution of strontium (Sr) in 26 cultivars of wheat (Triticum aestivum L.), husk oat (Avena sativa L) and naked oat (Avena nuda), and barley (Hordeum vulgare L.) for their potential use in phytoremediation.Sr levels had no effect on the accumulation of shoot biomass at tillering or at maturity. Mean shoot Sr concentration of naked oat and barley at tillering was significantly (P<0.05) higher than that of wheat; Neimengkeyimai-1, a naked oat cultivar, had the highest Sr concentrations. At maturity, of four naked oat cultivars, Neimengkeyimai-1 had the highest Sr content at all measured Sr levels. Leaves had the highest Sr concentrations, followed by roots and straw, and then grain with the lowest. Mean enrichment coefficients from soil to shoots ranged from 0.521 to 1.343; the percentage of stable Sr removed from the soil to the shoots at harvest time was more than 1.4% after 120 days. Neimengkeyimai-1 could be used as a model for further research to find more effective cultivars; and naked oat plants could be selected for phytoremediation to clean up contaminated soil.
Crop residue retention on the soil surface in no-tillage system can intercept pre-emergent herbicides and reduce their efficacy. Three experiments were conducted to investigate the effect of crop residue amount (0, 1, 2 and 4 t ha-1), moisture (wet versus dry), type (wheat, barley, canola, chickpea and lupin) and age (fresh or aged for one year) on the interception and subsequent leaching of prosulfocarb, pyroxasulfone, and trifluralin from the residue into soil. Bioassays, using cucumber and annual ryegrass as indicator plants, were used to assess herbicide activity/availability in the soil and on the residue. Herbicide interception increased considerably as residue quantity increased from 2 to 4 t ha-1. After simulated rainfall, which washed herbicide into the soil, complete control of ryegrass occurred for trifluralin with 0 t ha-1 residue, for prosulfocarb with 0 and 1 t ha-1 residue, and for pyroxasulfone with all residue rates. Therefore, with rain or irrigation, pyroxasulfone was the herbicide least affected by high residue loads. Less chemical leached from the crop residue into the soil after rainfall, when prosulfocarb and trifluralin were applied to wet residue compared with dry residue, but the initial moisture condition had no effect on the leaching of pyroxasulfone from residue. If practically possible, farmers should minimise spraying prosulfocarb and trifluralin onto wet crop residue. Barley and wheat residues intercepted more herbicide than an equivalent mass of canola, chickpea or lupin residue, which was largely due to the increased ground cover with cereal residues. The effect of residue age on herbicide interception and leaching was relatively small and variable. Overall, more herbicide reached the soil when sprayed on one-year old residue than new residue, which was largely due to reduced ground cover with aged residue. A strong positive linear relationship existed between ground cover percentage and growth of bioassay species (r2 = 0.75). This means that there was little difference in the ability of residue to adsorb and retain herbicide between crop residue types and ages, such that farmers can simply use the ground cover of the crop residue to assess interception.
The beneficial aspects of legumes in sustainable cropping systems have long been known \nand extensively documented. Although grain legumes generally contribute less fixed N \nthan pasture legumes, due to removal from the field of grain and stover of grain legumes, \nthere is increasing evidence of their positi"e contribution to N balances and increased yields \n
The yield and zinc (Zn) content response of faba bean (Vicia faba L.), chickpea (Cicer arietinum L.), lentil (Lens culinaris Medik.) and wheat (Triticum aestivum L.) to applications of Zn fertilizer was compared in a glasshouse experiment using two alkaline soils from southwestern Australia. Comparative Zn requirements were determined from yields of 46-day-old dried shoots when no Zn fertilizer was applied, the amount of Zn required to produce the same percentage of the maximum (relative) yield of dried shoots, and the Zn content of dried shoots (Zn concentration multiplied by yield of dried shoots). The concentration of Zn in youngest tissue and in dried shoots was used to determine critical concentrations for Zn in tissue. Faba bean used indigenous soil Zn more effectively than chickpea, followed by wheat and then lentil. The Zn requirement was lowest for faba bean, and increased in the order faba bean < chickpea < wheat < lentil. Zinc concentration in dried youngest tissue and in dried shoots increased with an increase in the amount of added Zn. The critical Zn concentration in the youngest tissue, associated with 90% of the relative yield, was (mg Zn kg−1): 25 for lentil, 18 for faba bean, 17 for chickpea and 12 for wheat; corresponding values for dried whole tops (mg Zn kg−1) were: 30 for lentil, 19 for faba bean, 17 for chickpea, and 20 for wheat. Information on comparative responses of the grain legumes to Zn additions relative to wheat, and critical tissue test values, will aid in the fertilizer management of Zn in cool-season grain legumes in the southwestern Australian farming systems.
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 (&lt;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 &gt;6.0 and clay contents &gt;15%. Seed yields were positively correlated with dry matter production at maturity across a number of sites ( r 2 = 0.40, P &lt; 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.
Heterogeneity of soil nutrients, particularly phosphorus (P), is widespread in modern agriculture due to increased adoption of no-till farming, but P-use efficiency and related physiological processes in plants grown in soils with variable distribution of nutrients are not well documented. In a glasshouse column experiment, wheat (Triticum aestivum L.) and white lupin (Lupinus albus L.) were subjected to 50 mg P/kg at 7–10 cm depth (hotspot P) or 5 mg P/kg in the whole profile (uniform P), with both treatments receiving the same amount of P. Measurements were made of plant growth, gas exchange, P uptake, and root distribution. Plants with hotspot P supply had more biomass and P content than those with uniform P supply. The ratios of hotspot to uniform P supply for shoot parameters, but not for root parameters, were lower in L. albus than wheat, indicating that L. albus was better able than wheat to acquire and utilise P from low-P soil. Cluster roots in L. albus were enhanced by low shoot P concentration but suppressed by high shoot P concentration. Soil P supply decreased root thickness and the root-to-shoot ratio in wheat but had little effect on L. albus. The formation of cluster roots in low-P soil and greater proliferation and surface area of roots in the localised, P-enriched zone in L. albus than in wheat would increase plant P use in heterogeneous soils. L. albus also used proportionally less assimilated carbon than wheat for root growth in response to soil P deficiency. The comparative advantage of each strategy by wheat and L. albus for P-use efficiency under heterogeneous P supply may depend on the levels of P in the enriched v. low-P portions of the root-zone and other soil constraints such as water, nitrogen, or potassium supply.
