Lupin Yield Research Articles

Phosphorus fertiliser placement for lupins in southern New South Wales

Research in Western Australia and South Australia indicated that fertiliser phosphorus (P) banded below the seed of narrow leaf lupin (Lupinus angustifolius L.) at sowing was a more effective method of applying P�fertiliser than the usual placement of P with the seed. This technology has not been investigated in southern New South Wales where lupins have been known to be unresponsive to fertiliser P.We conducted 4 field experiments to examine the effect on lupin yield of applying 6 rates of P (0, 5, 10, 15, 20 and 40 kg/ha) either by placement with or below the seed. To further test responsiveness to P, an additional set of treatments was used; applying P at 40 kg/ha before sowing and then placing additional P below the seed at the 6�rates of application. The grain yield of lupin was increased by P application at all sites, despite the medium to high P�status of 3 of the 4 sites used in these experiments. However, the technique of banding P fertiliser below the seed depth rather than placing it in direct seed contact had only a small advantage in grain yield responsiveness to applied fertiliser P (P = 0.09). Fitted response curves indicated that when P was applied at 15 kg/ha, grain yield increased by 60 kg/ha at one site and 30 kg/ha at the other 3 sites, if P was deep-placed rather than applied in seed contact. This advantage of deep placement of P fertiliser was much smaller than has been reported in Western Australia.Placement of P below the seed of lupin when sown on the red earth and red-brown earth soils of southern New South Wales slightly enhanced the availability of fertiliser P. This applied even when sowing was quite shallow (2–3�cm), provided recommended rates of P fertiliser were used at conventional row spacing (17 cm). Separation of seed and fertiliser to avoid reduced germination may be an advantage when using double row spacing and higher P�application rates.

The effects of seed rate and row spacing on light interception, dry matter accumulation and seed yield, in non-dwarf and dwarf genotypes of autumn-sown determinate white lupins (Lupinus albus) in north-west Europe

Two non-dwarf and two dwarf, autumn-sown determinate genotypes of white lupin (Lupinus albus L.) were sown at three sites in north-west Europe in the crop years, 1995–96, 1996–97 and 1997–98. Fully factorial experimental designs were used to analyse all combinations of genotype, seed rate and row spacing. Canopy expansion, expressed as the percentage of Photosynthetically Active Radiation (PAR) intercepted, and above ground dry matter (DM) accumulation were measured at frequent intervals during the main growing season at Rothamsted in the UK and Lusignan in France. The data from Rothamsted were used to derive models for the two processes, which were compared to the data from Lusignan, France.Crops with more than 23 plants/m2, 25 main stem leaves per plant or 1400 leaves/m2 were able to intercept more than 80% of the incident PAR. There were small differences in canopy expansion between genotypes. The non-dwarf genotypes began expansion slightly earlier (100–150 °Cd or thermal time in °Cdays, base temperature = 3 °C) than the dwarf genotypes. Crops sown on rows wider than 40 cm apart or with low plant densities (less than 23 plants/m2) were also slower to expand the canopy and intercept the PAR.The maximum quantity of dry matter accumulated by a genotype in the season (476–1044 g/m2) was related by a conversion efficiency (e) to the cumulative quantity of PAR intercepted. Values of e were generally in the range 0·92–1·65 g DM/MJ PAR during the early part of the growing season, which was comparable with other work on temperate-zone grain legumes. The non-dwarf genotype Ludet achieved an unusually large value of e (3·13 g DM/MJ PAR) and accumulated 1355 g DM/m2 at Lusignan in 1998. Late season drought in 1995–96 at Rothamsted produced some low values of e (0·75 and 0·88 g DM/MJ PAR).The seed yield was not related to the quantity of dry matter accumulated as harvest index varied from 22·3% to 49·7%. Maximum seed yield (4·54 t/ha) was produced from a low plant density (15·9 plants/m2). Mutual shading, caused by any combination of high plant densities, large numbers of leaves per plant or sowing on wide rows (>40 cm; at high plant densities within the rows) appeared to limit seed yield potential.

Broadacre crop yield in the lee of windbreaks in the medium and low rainfall areas of south-western Australia

In Western Australia, the paucity of documented information detailing crop yield in the lee of windbreaks is a constraint to the adoption of tree windbreaks in dryland farming systems. This paper presents grain yield data for crops growing in the lee of windbreaks in the medium to low rainfall areas of the south-west of Western Australia for 64 field years between 1994 and 1997. Two distinct areas were identified in the lee of windbreaks: a zone of reduced crop yield extending 3–5 times the windbreak height (H) from the trees (competition zone), and a zone of unchanged or improved yield extending 15–20 H (sheltered zone). Yield between 1 and 20 H was less than unsheltered yield in years with average rainfall, similar to unsheltered yield in years, or areas, with low rainfall and higher than unsheltered yield if the unsheltered crop was subjected to sandblasting. Changes in microclimate in shelter appeared to be of benefit in increasing crop yields in drier years or areas. Lupin yield was generally increased in the sheltered zone while cereal yield was generally unchanged. The rate of canopy development may be critical to crop response. In dry years, reduced wind speed in shelter reduced evaporation of soil moisture, increasing the amount of soil water available to establishing crops and reducing sandblasting damage. The principle benefit of windbreaks was their ability to reduce wind erosion and subsequent crop damage. As such, windbreaks are best regarded as a form of insurance.

Soil factors influencing growth and yield of narrow-leafed lupin and field pea in Western Australia

Crop growth and grain yield of narrow-leafed lupin and field pea were compared in 40 field trials in the Western Australian wheatbelt in 1988, 1989, and 1990. Trials were arranged in clusters of 2 or 3 in close proximity, but on contrasting soil types. This enabled seasonal effects on growth and yield to be separated from soil type effects. Soil pH ranged from 4.1 to 5.8 at the surface and from 3.7 to 8.4 at 50 cm, A-horizon depth from 9 cm to >70 cm, and clay content at 50 cm from 0 to 54%. Other soil properties also varied across wide ranges. Some soil properties were closely correlated with one another; pH, electrical conductivity (EC), gravimetric water content (θg) at field capacity and at wilting point, and depth of the A-horizon were all correlated. Narrow-leafed lupin grain yield was 2.6 times as variable between trials within locations as field pea yield, which, on average, was 32% greater than narrow-leafed lupin yield. The pH, EC, θg) at field capacity, and θg) at wilting point each explained a large proportion of lupin yield variability on their own, but because they were closely correlated with one another, it was not possible to determine which had the primary effect on grain yield. I believe, on the basis of other work, that pH is an important factor in its own right. A-horizon depth explained 9% of the lupin trial variance but this was largely due to its correlation with pH and other related soil properties. When the effects of these were removed, depth still reduced the between-trial variance within locations but did not affect species differentially. Bulk density also reduced between-trial variance within locations without affecting species differentially. Altogether soil properties explained 42% of the lupin site variance but none of the pea site variance. The pH and correlated soil properties also explained much of the species site variance in dry matter production at maturity, but not in harvest index. Bulk density and A-horizon depth had small, but significant, effects on harvest index. Therefore, soil type affects grain yield in these species largely through its effect on dry matter production. I conclude that field pea is equally well adapted to the full range of soils in this study. Narrow-leafed lupin does not yield as well on soils with subsoil pH greater than 6.5 as on more acid soils. The depth of the A-horizon is only useful as a criterion for judging the suitability of a soil for growing narrow-leafed lupin insofar as it is correlated with pH.

A comparison of the adaptation of yellow lupin (Lupinus luteus L.) and narrow-leafed lupin (L. angustifolius L.) to acid sandplain soils in low rainfall agricultural areas of Western Australia

Almost the entire lupin industry of Western Australia is based on the single species Lupinus angustifolius L. (narrow-leafed lupin), which is very well adapted to coarse-textured, mildly acid soils. However, L. angustifolius is not well suited to the strongly acid sand plain soils along the low rainfall fringe of Western Australia’s agricultural areas, and alternative grain legume species may be preferable. These soils, known locally as wodjil soils, have very low nutrient contents, often high levels of extractable Al in the subsoil, and are common in areas where severe brown spot and root rot disease is caused byPleiochaeta setosa. Yellow lupin, Lupinus luteus L., may be a better species on these soils. This paper describes a series of trials comparing the grain yields of narrow-leafed lupin and yellow lupin on a range of soils in the agricultural areas of Western Australia. These trials were sown on a range of dates and in a range of rotational backgrounds between 1995 and 1998. With current cultivars, narrow-leafed lupin clearly has higher yield potential than yellow lupin when soil-extractable [Al] at a depth of 15–25 cm (measured in a 1 :5 extract of soil in 0.01 M CaCl2) is <10 mg/kg. When extractable [Al] at this depth is greater, yellow lupin can produce greater yields than narrow-leafed lupin, depending on other environmental characteristics, especially when extractable [Al] exceeds 28 mg/kg, but its yield advantage is often small. Yellow lupin is less sensitive to delayed sowing than narrow-leafed lupin, and more tolerant of brown spot, but narrow-leafed lupin is more responsive to good seasonal conditions and less sensitive to frost. We conclude that yellow lupin has a place in Western Australian farming systems on soils with >10 mg/kg extractable [Al] where these soils are in close lupin rotations, in areas where brown spot is severe, or in low rainfall areas where narrow-leafed lupin yield potential does not often exceed 1 t/ha on these soils. However, yellow lupin has had relatively little breeding effort in Australia and its place will remain precarious until better adapted, higher yielding cultivars become available.

Water repellency: a whole-farm bio-economic perspective

A whole-farm bio-economic model was used to assess the profitability of innovations aimed at improving agricultural production on the non-wetting sands of wheatbelt farms of Western Australia. It was found that amelioration of water repellency might be an economical option for some farms in the northern wheatbelt of Western Australia. It was shown that a minimum of 30% increase in lupin yields and a 10% increase in wheat yields would be required before expenditure on innovations aimed at improving production on non-wetting soils could be justified. However, due to costs of amelioration of repellency much higher crop yield responses may be required for economical adoption of such innovations on most farms.The decision to ameliorate water repellency depends not only on the consideration of direct benefits and costs per hectare of ameliorated sand but also on other whole-farm factors. One such factor found to be important was the scale of relevance or the soil mix of the farm. It was found that farms with proportionately large areas of non-wetting sands were more likely to benefit from adoption of innovations aimed at amelioration of repellency. Another important factor in the decision to adopt innovations for amelioration of water repellency is availability of alternative enterprises on the non-wetting soils. In particular, whether or not sandplain lupins (lupinus cosentinii) and tagasaste (chamaecystisus proliferus) were options that a farmer could consider determined the profitability of taking remedial measures against water repellency.This study identified, through a series of sensitivity analyses, the magnitude of production responses that may be required for profitable amelioration of water repellency. Some gaps in our knowledge of biological and economic parameters related to costs and benefits of various innovations have also been highlighted and discussed.

Planting Date and Seeding Rate Effects on White Lupin Yield in Alabama and Virginia

White lupin (Lupinus albus L.) has high potential as a winter grain (33 bu/acre), silage (15 tons/acre), wildlife, and cover crop in the southeastern USA. Management recommendations have to be developed for producers. We examined planting date and seeding rate effects on grain and biomass yield in winter-type white lupin. From 1991 to 1993, seeds were sown in north Alabama on a Wynnville fine sandy loam (fine-loamy, siliceous, thermic, Glossic Fragiudult), in central Alabama on a Norfolk sandy loam (fine-loamy, kaolinitic, thermic, Typic Kandiudult), and in south Alabama on a Lucedale fine sandy loam (fine-loamy, siliceous, thermic, Rhodic Paleudult). In 1994 and 1995, a study was sown in north Virginia on a Davidson silty clay (clayey, kaolintic, thermic, Rhodic Kandiudult). Treatments were three planting dates, three seeding rates (35 000, 70 000, and 105 000 seeds/acre) and two to five cultivars in Alabama. In Virginia, one or two cultivars were sown on three planting dates at 70 000 seeds/acre. Grain yield in 1995 in north Virginia averaged 60 bu/acre while the Alabama locations were less than 30 bu/acre. These differences are due to the more moderate, maritime climate in north Virginia. The second planting date and middle seeding rate produced acceptable grain yield across environments; we advise higher seeding rates for delayed planting. The highest biomass yields were achieved at earlier planting dates and the highest seeding rate. Based on these recommendations, producers should obtain acceptable grain, silage, wildlife, and cover crop yields. Problem Although white lupin is not yet a commercial crop in the southern USA, it has potential as a grain and silage crop, as a wildlife feed, and as a cover crop. Planting date and seeding rate information is needed to optimize production practices. Background White lupin is a self-pollinated, large-seeded legume, native to the Mediterranean region. Over the past 2000 to 3000 yr, white lupin has been cultivated as a minor grain and cover crop. The minor crop status has resulted in very little breeding effort toward improvement of white lupin as an agronomic crop. In spite of this, white lupin shows considerable promise as a winter grain crop in the southeastern USA; grain yields in experimental trials from 1987 to 1989 averaged 33 bu/acre. Most crops are susceptible to low temperatures during the seedling and flowering stages. It is imperative, therefore, to establish seeding dates which enable plants to escape low temperatures during critical phases of development. Study Description We established seeding date experiments at three locations in Alabama, and at one location in Virginia. The latest seeding date coincided with the average date of the first 28°F temperature at each location in Alabama. In Alabama, we also seeded lupin at 4 and 8 wk prior to that date so the time for seeding could be determined for each location. In Virginia, seeding dates were made 2, 4, and 5 wk prior to the first 28°F temperature. For the Alabama locations, we also seeded each date at rates of 35 000, 70 000, and 105 000 seeds/acre, whereas in Virginia only the 70 000 rate was used. Rows were seeded 36 in. apart in Alabama and 12 in. apart in Virginia. The center rows of each four-row plot were hand-harvested for grain yield (bu/acre at 58 lb/bu and corrected to 13% moisture). Total biomass yield was also measured in Alabama. Applied Questions Does planting date affect grain yield? Yes, it certainly does. The optimum planting date was the middle date at all locations. Early seeding at more northern locations reduced grain yields in some cultivars because (i) plants developed too much biomass before the onset of winter, resulting in the destruction of the growing point on the main axis, and (ii) plants were damaged by late-winter freezes caused by bolting too early in late winter. In south Alabama, delayed seeding resulted in reduced grain yield because the steep temperature increase in late April limited pod set. White lupin is a cool season crop that does not perform well at higher temperatures. Does seeding rate affect grain yield? It depends. With a wide row spacing at the optimum (middle) planting date, seeding rate had little effect on grain yield, although total biomass yield increased substantially with seeding rate, irrespective of planting date. This biomass yield increase could be important when lupin is used as a silage or cover crop. Increasing seeding rates at the latest planting date increased both grain and biomass yields, thus overcoming some of the effects of smaller plants associated with the latest planting dates. What is the recommendation for producers? Seed approximately 4 wk prior to the average date of the first 28°F temperature; your local county extension personnel will be able to determine this date for you. If you have to delay planting, increase the seeding rate.

The effect of gypsum and other salts on the growth of narrow‐leafed lupins

Glasshouse experiments were conducted to establish the cause of poor lupin growth in the presence of gypsum in field trials which had been conducted in Western Australia. In the first experiment, Bradyrhizobium‐inoculated lupins were grown in nutrient solutions with varying concentrations (1, 3, 5, and 10 mM) of calcium (Ca) and sulfate (SO4) added as either CaSO4, K2SO4, or CaCl2 to establish whether gypsum caused Ca or SO4 toxicity to the plants. Although a general decrease in lupin plant growth was observed as the concentration of each salt increased, there was no evidence that either Ca or SO4 directly caused toxicity to the plants. Two soil experiments were therefore conducted to investigate lupin growth responses to the salts in a soil environment. The first soil experiment was conducted in a yellow earth— the same soil in which lupins had been adversely affected by gypsum in the field. The second soil experiment was conducted in the topsoil of a siliceous sand. Basal nutrients and different rates of CaSO4, K2SO4, and CaCl2 were added so that similar amounts of Ca and SO4 were present for each treatment at a given application rate. In both soils, lupin growth generally decreased as the application rate of treatments increased, although the magnitude of the decrease in growth was higher in the yellow earth than the siliceous sand. The strongest correlation between lupin growth and a soil solution chemical property was a log‐linear relationship between the shoot or root dry weight and the electrical conductivity (EC) of the soil solution. Plant nutrition was affected by different treatments, particularly with respect to nutrient balances. It is suggested that a high ionic strength in the soil, which results when gypsum is applied in the field, may contribute to the lupin yield decline. Possible reasons for the effect are discussed.

Lupins : Comparison with soya bean as a protein source for young beef cattle

Recent work on the agronomy and the genetic make-up of a new strain of lupin, which could be grown on almost half the agricultural land in England and Wales, has resulted in improvements in the yield and protein content of lupins. The protein content of lupins, at 37 % of the dry matter, is higher than that of either peas or beans and therefore lupins could be an important source of home-grown protein. There is little information available on the potential of new strains of lupins as a protein source in the feed of ruminants, particularly in conjunction with forage maize.

Lupins : Comparison with soya bean as a protein source for young beef cattle

Recent work on the agronomy and the genetic make-up of a new strain of lupin, which could be grown on almost half the agricultural land in England and Wales, has resulted in improvements in the yield and protein content of lupins. The protein content of lupins, at 37 % of the dry matter, is higher than that of either peas or beans and therefore lupins could be an important source of home-grown protein. There is little information available on the potential of new strains of lupins as a protein source in the feed of ruminants, particularly in conjunction with forage maize.

Response of narrow-leafed lupin (Lupinus angustifolius L.) to foliar application of growth regulators in Western Australia

Four experiments were conducted during 1991-93 in the south coastal and lakes regions of Western Australia, to test the hypothesis that foliar application of a range of growth regulators will improve the pod set and seed yield of narrow-leafed lupins (Lupinus angustifolius L.). The chemicals tested (not all in any 1 year) were: Cultar (250 g paclobutrazol/L), Pursuit (240 g imazethapyr/L), Cytokinin (21 g 6-benzyladenine/L), Legumex (400 g 2,4-DB/L), Cytolin (20 g gibberellins A4 and A7/L and 20 g 6-benzyladenine/L), Bladex (500 g cyanizine/L), Diuron 500F (500 g diuron/L), Lexone (750 g Metribuzin/kg), NAA (40 g 1-napthalene acetic acid/L), Pix (38 g mepiquat chloride/L), Gesatop 500 (500 g simazine/L), High Yield (unknown active ingredient), Lontrel (300 g clopyralid/L), a Cultar-Lontrel mix, and a Lexone-Brodal(500 g diflufenicad) mix. Chemicals were applied from as early as 6 weeks before flowering on the main stem to as late as flowering on the 1st-order branches. Any gross physical effects were visually assessed. Canopy height and components of yield were measured at some of the experimental sites. In 2 experiments, no chemical had any significant effect on seed yield (P>0.05). At the 2 remaining sites, Cultar, Lontrel, and the Lexone-Brodal mix increased seed yield of lupins by 230-250 kg/ha. Seed yield increases were related to improvements in pod set. No chemical had any significant effect (P>0.05) on dry weight production. Timing of application was critical, with application 6 weeks before flowering giving the most consistent positive responses.

Growth of shoots and roots, and interception of radiation by wheat and lupin crops on a shallow, duplex soil in response to time of sowing

Crops of lupin (Lupinus angustifolius L. cv. Gungurru) and wheat (Triticum aestivum cv. Kulin or Spear) sown close to the break of the season and 3-6 weeks later were grown on a duplex soil at East Beverley, WA, over 3 seasons. The overall aim of the work was to examine the influence of time of sowing on growth and water use of the crops, and this paper reports their growth and yield. Early sowing resulted in greater shoot weight of all crops (up to 2.8 t/ha for lupin and 1.7 t/ha for wheat at maturity) and grain yield of lupin, but grain yield of wheat was increased in only 1 of the 3 seasons. The principal effect of the delayed sowing was to reduce the duration of linear growth; the rate of the initial exponential phase was slightly reduced by later sowing as was the rate of growth during the linear phase in lupin (by about 1.5 g/m2day) but not in wheat. Late sowing generally reduced both the number of pod/ears per unit area and the number of grains per pod/ear. Doubling the density of sowing in one of the seasons had no effects on the shoot weight and grain yield of lupin with early or late sowing but decreased those of wheat. Downward root growth of early-sown crops averaged 5.2 mm/day for lupin and 8.7 mm/day for wheat in the 3 seasons and ceased at about 0.8 m; time of sowing had no effect on these measures. Root weight at flowering was greater in lupin than in wheat crops, and root weight of lupin was about 0.5 of total plant weight during vegetative growth compared with 0.25-0.3 in wheat. Typically, only 5-6% of the root length of both crop species was present in the clay layer at flowering irrespective of sowing time. The proportion of radiation intercepted reached a higher maximum value for early-sown crops (about 0.75 in 1991 and 0.90 in 1992) than late-sown crops (about 0.60 in 1991 and 0.8 in 1992). The conversion coefficients of radiation to dry matter were very similar (about 1.8 g/MJ) for both species, but the greater partitioning of dry matter to roots in lupin than wheat meant that conversion coefficients for shoot dry matter were greater in wheat (1.43-1.68 g/MJ) than in lupin (0.93-1.16 g/MJ). The results demonstrate that early sowing produced larger crops of both lupin and wheat; this resulted in larger lupin yields, but yield of wheat was affected by disease and drought during grain filling.

Genetic and environmental variation in architecture and yield components in determinate white lupin (Lupinus albus L.)

Determinate architecture is of great interest for lupin production in Europe but the extent of genetic and environmental variation in the structure and yield of determinate lupins must be evaluated. Forty-three genotypes of determinate autumn-sown white lupin were studied in four environments in France in 1991/92 and 1992/93. Wide variation was observed for phenological (dates of mainstem and branch flowering, date of end of flowering and date of maturity), morphological (numbers of branch orders, branches and leaves) and seed characters (seed yield, mean seed weight, number of seeds/m2). Both genetic and environmental effects contributed to the observed variation. Heritabilities were high for all characters, and the interaction between genotype and location effects was low. There were significant positive correlations of flowering dates with vegetative plant development including the number of branches, number of leaves and number of branch orders. Seed yield and phenological and archtectural characters were significantly correlated. Distribution of yield on the vegetative orders showed important variations according the genotype, and the variations were related to variation for the architecture. There are possibilities for yield improvement using morphological characters in determinate autumn-sown lupin.

Nutrient sprays applied to the foliage of narrow-leafed lupins (Lupinus angustifolius L.) during flowering and podding do not increase seed yield

Nitrogen (N), phosphorus (P), potassium (K), sulfur (S), manganese (Mn), magnesium (Mg), and boron (B) were applied as foliar sprays to narrow-leafed lupins (Lupinus angustifolius L. cv. Gungunu) grown in Esperance in 1991 and 1992. Applied individually, no nutrient increased the seed yield of lupins. In 1992, the application of 15 kg N/ha at 2 growth stages [flowering and 2 weeks after flowering (2WAF)I and 4 kg S/ha at 2WAF reduced the seed yield by about 10% (300 kg/ha), despite no evidence of damage to the foliage of the lupins. Nutrient mixes of N, P, K, S, and B were applied in both years at 3 growth stages (flowering, 2WAF, 6WAF), and no combination at any time of application increased the seed yield. In 1992, one combination treatment of (kg/ha) 15 N, 8 P, 12 K, 4 S, and 1 Mn applied 2 weeks before the start of flowering reduced yield by 14%. Where no foliar nutrients were applied, seed yields (t/ha) were 2.6 in 1991 and 3.2 in 1992. Foliar-applied nutrients sprayed during flowering and podding, in addition to some fertilisers applied to soil at seeding, are unlikely to increase the seed yield of lupin crops in the south coastal districts of Western Australia.

Evaluation of Herbicides for Sweet White Lupin (Lupinus albus)

The response of sweet white lupin to several herbicides was evaluated over five years at Charlottetown, Prince Edward Island (PEI) and two years at Cornhill, New Brunswick (NB). Excellent crop tolerance was found to the herbicides: chloramben, ethalfluralin, fluazifop-P, linuron, metobromuron, metolachlor, and trifluralin. None of the above herbicides affected crop grain yield or 1000 seed weight. Sweet white lupin was slightly injured by metribuzin at 500 g ai/ha but yields and 1000 seed weight were not affected. Higher rates of metribuzin reduced lupin yield and 1000 seed weight. Imazethapyr applied POST with 0.25% v/v Agral 90 and 1.0% v/v 28% N fertilizer caused severe crop injury and reduced lupin yields.

Amelioration of subsurface acidity in sandy soils in low rainfall regions .1. Responses of wheat and lupins to surface-applied gypsum and lime

Amelioration of subsoil acidity using gypsum (CaSO4.2H2O) or lime (CaCO3) was studied on sandy textured soils with low water holding capacity in a low rainfall environment. Field trials were established in 1989 at two sites on yellow sandplain soils to investigate whether different rates, sources and combinations of gypsum and lime application could be used to increase wheat and lupin yields. Gypsum increased wheat yields by up to 45% in the first two growing seasons whereas lime increased wheat yields by up to only 15% in the second season. The highest yields were generally recorded when gypsum and lime were applied together. The response of wheat to the various treatments varied both regionally and temporally and it is suggested that the inherent soil solution composition affected the magnitude and rapidity of wheat responses to gypsum. The rate of gypsum application affected the longevity of the wheat responses, with a low application rate (1 t ha-1) increasing yields for only one season. No differences in wheat yields were recorded between different sources of gypsum or application rates higher than 3 t ha-1. In contrast to wheat, lupin yields were substantially lower on gypsum-treated plots. The yield decline did not appear to be related to any simple nutritional factor and the gypsum effect was generally minimized when lime was added with the gypsum. The results indicated that lower rates of gypsum than used in previous subsoil amelioration studies were suitable for increasing wheat yields on sandy soils in low rainfall environments, and that gypsum should not be used if lupins are to be grown within at least 2 years of its application to the soil surface.

The number of Bradyrhizobium SP. ( Lupinus) applied to seed and its effect on rhizosphere colonization, nodulation and yield of lupin

In field experiments we investigated the roles of inoculum potential of Bradyrhizobium sp. ( Lupinus) and quantity of peat used to inoculate seed on the nodulation and yield of lupins. Within the range 0.125–3 times the Australian recommended rate of peat application (2.5 g peat kg −1 lupin seed), the amount of peat had no effect on nodulation or grain yield. In the first experiment, seven inoculum potentials were applied within the range log 10 0.32–6.28 bradyrhizobia per seed in 7, 10-fold increments which spanned the recommended rate of login 5.55 per seed. Inoculum potentials of log 10 6.27 and 5.27 improved the colonization of lupin rhizospheres and increased early nodulation, nodule number and nodule mass. Nodule mass was increased from 65 to 393 mg plant −1 at 43 days by increasing the inoculum from log 10 4.27 to 6.27 bradyrhizobia seed −1. Grain yield and % N in the grain were not significantly different ( P > 0.05) between potentials of logio 4.27 and 6.27. In the second experiment, higher potentials of 6.80 and 7.28 further improved rhizosphere colonization and increased nodule mass. Studies of the survival of the inoculum, during inoculation, sowing and in the soil, identified a large mortality factor; 95% of bacteria died between inoculation and sowing and of those surviving, 83% died after 22.5 h in the soil. These observations have important implications for setting new standards for commercial inoculants and for emphasizing the care needed in handling inoculated seed to reduce the death of bradyrhizobia in the period between inoculation and sowing.

Lichtaufnahme und Stoffproduktion eines konventionellen und eines epigonalen Genotyps der Weißen Lupine (Lupinus albus)

Abstract Light interception and dry matter production of a conventional and an epigonal genotype of the white lupine (Lupinus albus) Yield formation of two white lupin (Lupinus albus) genotypes differing substantially in growth habit was investigated. Grain production was quantified as the product of harvest index and dry matter production, the latter being a function of light interception and utilization. Experimental data were obtained from two‐year field experiments with a combined variation of plant density and distribution. The conventional, freely branching cultivar Kalina showed higher leaf area indices and growth rates than the “epigonal” (little branching) genotype. The higher growth rates of Kalina were partly due to increased light interception, but were mainly a result of a higher light use efficiency. This can be explained with a more even light distribution over a greater leaf area. The more rapid increase of the harvest index in the epigonal genotype compared to Kalina only partially compensated for the differences in dry matter production.

Limitations to growth and yield of cereal and lupin crops on duplex soils

The combination of soil physical and chemical properties in duplex soils can depress crop growth and yield, and cause considerable variability in yield within a paddock and from year to year. At an intensively monitored site at East Beverley, Western Australia, the sandy A horizon was found to be nutrient deficient, low in pH, and contained hard layers which impeded root growth. The clayey B horizon had a higher pH, and variable permeability which influenced waterlogging in winter, and root growth and water availability from the subsoil in spring. Growth of wheat and lupin crops reflected response to these stresses. Wheat yields in particular were very variable (0.7-4.2 t/ha in 1988), and as all components of yield were affected, this suggests that the crop in low yielding areas experienced stress throughout the growing season. Lupin yields varied more widely from year to year than wheat yields, but were less variable within a year, possibly because of a more limited exploration of the subsoil by roots. Treatments to overcome the chemical constraints to growth raised yields and reduced variability; wheat and lupin yields were increased by about 25% after application of potassium, and wheat yields increased by about 10% after application of lime. Ripping lowered soil strength in the A horizon, but had little effect on yield, suggesting that the subsoil plays a larger role in determining yield on this soil. Attempts to improve the permeability of the subsoil using gypsum were inconclusive in the year of application. Similar physical and chemical problems have been identified on other duplex soils throughout Australia. Responses to ameliorative treatments have been variable, and there have often been interactions between treatments. Further improvements in yield on these difficult soils requires a better understanding of the interaction of soil physical, chemical and biological properties, and their interactions with crop physiology.

Soil type influences the relative yields of different cereals and crop legumes in the Western Australian wheatbelt

Crop choice depends on the relative yields of different species, and will vary according to soil type and seasonal conditions. Crop legumes are a relatively new component of agriculture in southern Australia, especially on the drier fringe of the agricultural areas. In this study wheat, barley, field peas and narrow-leafed lupin were compared at Merredin, Western Australia (mean annual rainfall 310 mm) from 1984 to 1986 on a red brown earth, a solonised brown soil, a solodic soil and, in 1984 and 1985, on an acid earthy sand. Oats, cereal rye and triticale were included in 1984, and chickpeas in 1984 and 1986. Highest mean seed yields were produced on the red brown earth and solonised brown soil, although the red brown earth produced very low yields in a dry season. Lowest yields were produced on the earthy sand. Triticale, oats and cereal rye yielded less seed than wheat or barley on all soils except the earthy sand where triticale yielded more than wheat. Legumes yielded less seed than cereals, although the yield for peas was close to that for wheat on the red brown earth. Peas yielded more than lupins or chickpeas on all soils. Lupin yield was closest to pea yield on the solodic soil and earthy sand. A separate series of experiments comparing peas and lupins in different seasonal conditions but on similar soils showed that lupins yielded more than peas when growing season rainfall was high. Peas are the most suitable crop legume for the Merredin area on all fine-textured soils. Lupins remain the choice on coarse-textured soils until pea stubbles can be managed to minimise erosion. In wetter areas lupins are a better choice on coarse-textured soils.