Competition between Wimmera ryegrass and narrow-leafed lupins

1985 ◽  
Vol 25 (4) ◽  
pp. 824 ◽  
Author(s):  
GW Arnold ◽  
J Weeldenberg ◽  
A Grassia

The ways in which Wimmera ryegrass (Lolium rigidum) affects the growth and yield of narrow-leafed lupins (Lupinus angustifolius) were studied in two experiments at Baker's Hill, W.A. (average annual rainfall 650 mm). In the first experiment, Uniharvest lupins and Wimmera ryegrass were grown alone and together starting at two dates. The three rates of ryegrass produced similar biomasses (total dry matter) at maturity (about 8000 kg/ha) but lupin grain yield decreased significantly with ryegrass sowing rate. One effect of ryegrass at the highest sowing rate was to alter the distribution of dry matter in the lupin canopy so that, at the end of the growing season, there was a lower percentage of leaf in the lower part of the canopy and this was associated with less light being received. Water stress in lupins at the end of the growing season was higher at the later planting with ryegrass. A multiple regression analysis showed that 74% of the variation in lupin grain yield between plots was due to variation in lupin height and biomass, and ryegrass tiller numbers in October. Lupins had little effect on ryegrass yield; although there were fewer tillers in the presence of lupins, weights of tillers were higher. In the second experiment, the effects of 38 ryegrass plants/m2 on growth of both Uniharvest and Unicrop lupins grown at a density of 40 plants/m2 were studied. Lupin biomass was unaffected until October but was then reduced significantly by the ryegrass, which yielded 4000 kg/ha dry matter. Grain yield was reduced because fewer pods were produced on lateral branches in both varieties, and on main stems in Uniharvest. The experiments showed that in good growing seasons, in high rainfall areas, lupins will yield grain even when grown with very high densities of ryegrass.

Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.


2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2387
Author(s):  
Santiel Alves Vieira Neto ◽  
Fábio Ribeiro Pires ◽  
João Carlos Madalão ◽  
Douglas Gomes Viana ◽  
Carlos César Evangelista de Menezes ◽  
...  

Given the high costs of agricultural production, especially due to the price of fertilisers, particularly nitrogen, the use of inoculants to supply nitrogen to soybean crops is a widely recommended practice. The objective of this study was to evaluate the feasibility of applying inoculants through seed and planting furrow in soil previously cultivated with soybean and Brazilian native “cerrado” biome soil under greenhouse conditions. Seven treatments were tested: 1) inoculation via seed (inoculant + fungicide + micronutrient), 2) treatment via seed (fungicide + micronutrient), 3) control (only seed), 4) inoculation via furrow-dose 1 (recommended dose), 5) inoculation via furrow-dose 2 (twice the recommended dose), 6) inoculation via furrow-dose 3 (three times the recommended dose) and 7) inoculation via furrow-dose 1 + seed inoculation. We evaluated plant height, fresh and dry matter weight of the aerial part and nodules, number of total, viable and non-viable nodules, number of pods per plant and grain yield. Inoculation was more effective when used in cerrado soil, but soybean performance in treatments without inoculation was higher in previously cultivated soil. Application through furrow proved to be a viable practice due to the similarity of the results obtained with the traditional application by seed.


1978 ◽  
Vol 91 (1) ◽  
pp. 47-60 ◽  
Author(s):  
J. N. Gallagher ◽  
P. V. Biscoe

SummaryAnalysis of measurements of absorbed radiation and leaf area indices of wheat and barley crops showed that throughout most of growth the fraction of absorbed solar radiation could be described by a simple exponential equation.For several of these crops grown under a wide range of weather and husbandry at Sutton Bonington and Rothamsted, 2-weekly values of crop growth rate (C) were closely related to radiation absorbed until ear emergence and about 3·0 g of dry matter (D.M.) were produced by each MJ of photosynthetically active radiation (PAR) absorbed. Final crop weight was closelyrelated to total PAR absorbed during growth (SA); on average about 2·2 g D.M. were produced per MJ absorbed, equivalent to a growth efficiency (Eg) of approximately 3·9%. Unfertilized and drought-stressed crops had a smaller Eg.The fraction of total crop D.M. harvested as grain (harvest index) varied more for wheat than for barley. Calculations of a maximum realizable grain yield made using the largest values of Eg and SA for the crops measured and assuming a harvestindex of 0.53 (achieved in an experimental crop) showed a grain D.M. yield of 10·3 t D.M./ha to be possible. To achieve such a yield would require full crop cover from the beginning of April until the end of July in a typical English growing season.


2017 ◽  
Vol 14 (2) ◽  
pp. 155-160
Author(s):  
MAR Sharif ◽  
MZ Haque ◽  
MHK Howlader ◽  
MJ Hossain

The experiment was conducted at the field laboratory of the Patuakhali Science and Technology University, Patuakhali, Bangladesh during the period from November, 2011 to March 2012 under the tidal Floodplain region to find out optimum sowing time for the selected three cultivars (BARI Sharisha-15, BINA Sharisha-5 and BARI Sharisha-9). There were four sowing dates viz. 30 November, 15 December, 30 December and 15 January. Significant variations due to different sowing dates were observed in plant height, total dry matter, leaf area index, number of siliqua plant-1, seeds silique-1, 1000-grain weight, grain yield and HI. Results showed that the highest grain yield (1.73 t ha-1) was obtained from the first sowing (30 November) with BINA Sharisha-5 and it was significantly different from the yields of all other combination.J. Bangladesh Agril. Univ. 14(2): 155-160, December 2016


1982 ◽  
Vol 22 (115) ◽  
pp. 76 ◽  
Author(s):  
KA Boundy ◽  
TG Reeves ◽  
HD Brooke

The effect of serial planting on dry matter production, leaf area, grain yield and yield components cf Lupinus angustifoiius (cvv. Uniwhite, Uniharvest and Unicrop) and L. albus (cv. Ultra) was investigated in field plots at Rutherglen in 1973 and 1974. Delayed planting reduced dry matter production of all cultivars, and leaf area for Ultra. Differences in dry matter partitioning were observed between the late flowering Uniharvest, and the early flowering Unicrop and Ultra. In Uniharvest, delayed plantings resulted in a greater proportion of total dry matter being produced during the flowering phase, whereas the reverse was true for Unicrop and Ultra. The later flowering cultivars showed marked grain yield and yield component reduction with later sowing. Yields were reduced by 160.6 kg/ha and 222.5 kg/ha for each week's delay in sowing Uniharvest and Uniwhite, respectively. This effect was offset in the early flowering cultivars by greater development of lateral branches. In addition, when Unicrop and Ultra were planted in April, pod and flower abortion on the main stem resulted from low temperatures at flowering time. Optimum sowing time was early April for Uniwhite and Uniharvest, and early May for Unicrop and Ultra. Excellent vegetative growth under ideal moisture conditions highlighted the poor harvest indices of lupins and the scope for genetic improvement in the genus.


1990 ◽  
Vol 115 (3) ◽  
pp. 313-320 ◽  
Author(s):  
J. T. Baker ◽  
L. H. Allen ◽  
K. J. Boote

SUMMARYRice plants (Oryza salivaL., cv. IR30) were grown in paddy culture in outdoor, naturally sunlit, controlled-environment, plant growth chambers at Gainesville, Florida, USA, in 1987. The rice plants were exposed throughout the season to subambient (160 and 250), ambient (330) or superambient (500, 660, 900 μmol CO2/mol air) CO2concentrations. Total shoot biomass, root biomass, tillering, and final grain yield increased with increasing CO2concentration, thegreatest increase occurring between the 160 and 500 μmol CO2/mol air treatments. Early in the growing season, root:shoot biomass ratio increased with increasing CO2concentration; although the ratio decreased during the growing season, net assimilation rate increased with increasingCO2concentration and decreased during the growing season. Differences in biomass and lamina area among CO2treatments were largely due to corresponding differences in tillering response. The number of panicles/plant was almost entirely responsible for differences in final grain yield among CO2treatments. Doubling the CO2 concentration from 330 to 660 μmol CO2/mol air resulted in a 32 % increase in grain yield. These results suggest that important changes in the growth and yield of rice may be expected in the future as the CO2concentration of the earth's atmosphere continues to rise.


1990 ◽  
Vol 41 (3) ◽  
pp. 449 ◽  
Author(s):  
GK McDonald

The growth and yield of two lines of uniculm barley, WID-103 and WID-105, were compared over a range of sowing rates (50-400 kg/ha) with the commercial varieties Galleon and Schooner. The experiments were conducted at Strathalbyn, S.A., in 1986, 1987 and 1988 and at the Waite Agricultural Research Institute in 1987. A third tillered variety, Clipper, was included in the comparison in 1988. Over the three years plant populations measured early in the season ranged from 39/m2 to 709/m2, and grain yields from 97 to 41 1 g/m2. Dry matter production at ear emergence increased with greater plant density, and both the tillered varieties and the uniculm lines showed similar responses to higher sowing rates. At maturity, dry matter production of the tillered barleys was greater than or equal to that of the uniculms and the harvest indices (HIs) of the two types were similar. Consequently, grain yields of the tillered types were greater than or equal to the yields of the uniculms. Over the four experiments the tillered varieties had a 6% higher yield. The number of ears/m2 was the yield component most affected by plant density in both the tillered and uniculm barleys. The uniculm lines had more spikelets/ear, but tended to set fewer grains/spikelet and produce smaller kernels. The experiments failed to demonstrate any advantage of the uniculm habit to the grain yield of barley. These results differ from previous experiments that showed that a uniculm line, WID-101, had a higher yield than the tillered variety Clipper. It is suggested that the uniculm habit per se was not the cause of this higher yield, but its higher HI resulted in it outyielding Clipper. Current varieties, however, have HIs similar to the uniculm lines and yield equally to or more than the uniculm barleys examined. To further improve the grain yield of uniculm barley, greater dry matter production is necessary as the HIs of these lines are already high.


1980 ◽  
Vol 94 (1) ◽  
pp. 137-144 ◽  
Author(s):  
G. S. Chaturvedi ◽  
P. K. Aggarwal ◽  
S. K. Sinha

SummaryCowpea is an important food legume crop of arid and semi-arid regions of the tropics. In such climates whether a determinate or indeterminate type of growth habit would be more useful is not clear. In the present study a determinate and indeterminate cultivar of cowpea were grown at two population densities under rainfed conditions for 2 years. Grain yield was higher in the indeterminate variety for both years. At higher density more dry matter was produced but it had no effect on grain yield. Nitrogen analysis showed that it moved from leaves to developing pods. However, a large amount of nitrogen was still left in vegetative parts in contrast to cereals. Pod development was completed in 19 days and the rate of dry-matter accumulation during the peak period of growth was as high as 120 mg/day per fruit. It was difficult for the plant to cope with this high demand for photosynthates. It is suggested that more pods can develop on a plant provided the growth rate of individual pods is slower and extended to a longer period.


2007 ◽  
Vol 58 (1) ◽  
pp. 21 ◽  
Author(s):  
Heping Zhang ◽  
Neil C. Turner ◽  
Michael L. Poole ◽  
Senthold Asseng

The growth and yield of spring wheat (Triticum aestivum L.) were examined to determine the actual and potential yields of wheat at a site in the high rainfall zone (HRZ) of south-western Australia. Spring wheat achieved yields of 5.5−5.9 t/ha in 2001 and 2003 when subsurface waterlogging was absent or minimal. These yields were close to the estimated potential, indicating that a high yield potential is achievable. In 2002 when subsurface waterlogging occurred early in the growing season, the yield of spring wheat was 40% lower than the estimated potential. The yield of wheat was significantly correlated with the number of ears per m2 (r2 = 0.81) and dry matter at anthesis (r2 = 0.73). To achieve 5–6 t/ha of yield of wheat in the HRZ, 450–550 ears per m2 and 10–11 t/ha dry matter at anthesis should be targetted. Attaining such a level of dry matter at anthesis did not have a negative effect on dry-matter accumulation during the post-anthesis period. The harvest index (0.36−0.38) of spring wheat was comparable with that in drier parts of south-western Australia, but relatively low given the high rainfall and the long growing season. This relatively low harvest index indicates that the selected cultivar bred for the low- and medium-rainfall zone in this study, when grown in the HRZ, may have genetic limitations in sink capacity arising from the low grain number per ear. We suggest that the yield of wheat in the HRZ may be increased further by increasing the sink capacity by increasing the number of grains per ear.


2006 ◽  
Vol 46 (1) ◽  
pp. 93 ◽  
Author(s):  
G. K. McDonald

High spatial and temporal variability is an inherent feature of dryland cereal crops over much of the southern cereal zone. The potential limitations to crop growth and yield of the chemical properties of the subsoils in the region have been long recognised, but there is still an incomplete understanding of the relative importance of different traits and how they interact to affect grain yield. Measurements were taken in a paddock at the Minnipa Agriculture Centre, Upper Eyre Peninsula, South Australia, to describe the effects of properties in the topsoil and subsoil on plant dry matter production, grain yield and plant nutrient concentrations in two consecutive years. Wheat (Triticum aestivum L. cv. Worrakatta) was grown in the first year and barley (Hordeum vulgare L. cv. Barque) in the second. All soil properties except pH showed a high degree of spatial variability. Variability in plant nutrient concentration, plant growth and grain yield was also high, but less than that of most of the soil properties. Variation in grain yield was more closely related to variation in dry matter at maturity and in harvest index than to dry matter production at tillering and anthesis. Soil properties had a stronger relationship with dry matter production and grain yield in 1999, the drier of the two years. Colwell phosphorus concentration in the topsoil (0–0.15 m) was positively correlated with dry matter production at tillering but was not related to dry matter production at anthesis or with grain yield. Subsoil pH, extractable boron concentration and electrical conductivity (EC) were closely related. The importance of EC and soil extractable boron to grain yield variation increased with depth, but EC had a greater influence than the other soil properties. In a year with above-average rainfall, very little of the variation in yield could be described by any of the measured soil variables. The results suggest that variation in EC was more important to describing variation in yield than variation in pH, extractable boron or other chemical properties.


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