Wild oat and barley interactions: varietal differences in competitiveness in relation to phosphorus supply

1989 ◽  
Vol 67 (11) ◽  
pp. 3366-3371 ◽  
Author(s):  
D. W. Konesky ◽  
M. Y. Siddiqi ◽  
A. D. M. Glass ◽  
A. I. Hsiao
Keyword(s):  
Plant Biomass ◽  
Sand Culture ◽  
Phosphorus Concentration ◽  
Wild Oat ◽  
Herbicide Application ◽  
Hordeum Vulgare L ◽  
Total Phosphorus Concentration ◽  
Barley Cultivars ◽  
Selection Of ◽  
Phosphorus Levels

Nine cultivars of barley (Hordeum vulgare L.) were separately planted with wild oat (Avena fatua L.) in sand culture at two external phosphorus concentrations. Barley cultivars differed substantially in their ability to compete with wild oat. Relative competitive abilities of the barley cultivars were strongly influenced by external phosphorus levels. The greatest effect of competition, particularly at low external phosphorus, was upon plant biomass rather than on internal total phosphorus concentration. The selection of cultivars that are able to compete effectively with wild oat may represent an alternative (biological) strategy to the traditional one of herbicide application.

Patterns in the Submerged Macrophyte Biomass of Lakes and the Importance of the Scale of Analysis in the Interpretation

1990 ◽  
Vol 47 (2) ◽  
pp. 357-363 ◽  
Author(s):  
Carlos M. Duarte ◽  
Jacob Kalff
Keyword(s):  
Plant Biomass ◽  
Phosphorus Concentration ◽  
Total Phosphorus Concentration ◽  
Site Specific ◽  
Light Levels ◽  
Threshold Phenomena ◽  
Site Characteristics ◽  
Specific Biomass ◽  
Regulation Mechanisms ◽  
Lake Characteristics

The relative contributions of lake characteristics (i.e. alkalinity, chlorophyll A concentration, total phosphorus concentration, conductivity, and morphometry) and site characteristics (i.e. depth, littoral slope, exposure to waves, and underwater light levels) to the variability in submerged biomass were examined in 25 Canadian and American lakes. Lake-average submerged biomass is a function of water alkalinity and the lake-average littoral slope whereas site-specific biomass is a function of both site and lake characteristics. Plant biomass decreased with increasing slope and wave exposure and increased with increasing alkalinity and light levels. However, these relationships are complex because submerged biomass is also influenced by threshold phenomena (e.g. critical littoral slopes and transparency-dependent critical depths) that set limits to macrophyte colonization and because the relative contributions of the most relevant environmental factors studied (i.e. littoral slope, exposure, water transparency, and alkalinity) are depth dependent. By demonstrating the importance of lake-average and site-specific scales of variation and the existence of noncontinuous (e.g. threshold) regulation mechanisms the findings provide a new conceptual framework for the study of the relationship between submerged macrophytes, and their associated biota as well as their environment.

RELATIONSHIP OF ADVENTITIOUS ROOTS AND AGRONOMIC CHARACTERISTICS IN BARLEY

1986 ◽  
Vol 66 (2) ◽  
pp. 257-280 ◽  
Author(s):  
E. A. HOCKETT
Keyword(s):  
Hordeum Vulgare ◽  
Adventitious Root ◽  
Adventitious Roots ◽  
Root Number ◽  
Seeding Rate ◽  
Hordeum Vulgare L ◽  
Barley Cultivars ◽  
Agronomic Characteristics ◽  
Relationship Of ◽  
Selection Of

The number of adventitious roots of two- and six-row barleys (Hordeum vulgare L.) grown under irrigation at Bozeman, Montana in 1970 and 1971, was related to yield and other agronomic characteristics. Adventitious roots were counted shortly before heading and at maturity and correlated with 15 agronomic characteristics. Adventitious root number was not correlated with yield of barley, except for two out of six cases in two-row barley. Roots per tiller, per plant and per square metre were all positively correlated with each other. The number of kernels per spike increased as roots per tiller increased but decreased with a high number of tillers per plant. Kernel plumpness and numbers of tillers were negatively correlated in two-row barley, but not in six-row barley. Cultivars differed significantly in yield and adventitious root number. Six-row barley had more roots per tiller but fewer tillers per square metre than two-row barley. Roots per tiller and roots per square metre measurements had the best repeatability between years for six-row barley, but no root measurements were consistent over years for the two-row type. Tillers per plant measurements for both two-row and six-row barleys and tillers per square metre for just two-row barley were consistent over years. Tiller and root number interact and are usually positively related. The genetic variation for root number shown here could be used in crosses for selection of superior genotypes.Key words: Barley, Hordeum vulgare, adventitious roots, subcrown internode, yield components, seeding rate

DIFFERENTIAL TOLERANCE OF TWO BARLEY CULTIVARS TO METRIBUZIN

1985 ◽  
Vol 65 (2) ◽  
pp. 415-421 ◽  
Author(s):  
C. D. CALDWELL ◽  
P. A. O’SULLIVAN
Keyword(s):  
Hordeum Vulgare ◽  
Relative Humidity ◽  
Opposite Effect ◽  
Dark Period ◽  
Light Period ◽  
Barley Cultivar ◽  
Herbicide Application ◽  
Hordeum Vulgare L ◽  
Barley Cultivars ◽  
Dark Regime

In greenhouse and growth cabinet studies, two cultivars of barley (Hordeum vulgare L. ’Klondike’ and ’Summit’) were found to differ in their tolerance to postemergence applications of metribuzin. Klondike was more susceptible than Summit, although both displayed varying amounts of injury depending on environmental conditions. Klondike was most susceptible following herbicide application at the three-leaf stage; when soil was moist at application; and when application was followed by a period of cold (0 °C). For both cultivars, high relative humidity and increasing duration of a dark period following spraying increased the injury from metribuzin. Increasing the duration of a light period following spraying had the opposite effect. The magnitude of the light/dark regime response was greater for Klondike than for Summit.Key words: Barley cultivar tolerance, metribuzin, environmental factors

Empirical Relationships of Phytomacrofaunal Abundance to Plant Biomass and Macrophyte Bed Characteristics

1988 ◽  
Vol 45 (6) ◽  
pp. 976-984 ◽  
Author(s):  
Hélène Cyr ◽  
John A. Downing
Keyword(s):  
Organic Matter ◽  
Total Phosphorus ◽  
Plant Biomass ◽  
Organic Matter Content ◽  
Matter Content ◽  
Rooting Depth ◽  
Phosphorus Concentration ◽  
Regression Equations ◽  
Lake Area ◽  
Total Phosphorus Concentration

The abundance of phytophilous invertebrates was measured in 13 macrophyte beds and was related, using multiple regression analysis, to the biomass of macrophytes among which the invertebrates were collected, the average plant biomass growing per unit lake area, water and organic matter content of the sediments, total phosphorus concentration in the water, rooting depth of the macrophyte bed, and sampling date. Quantitative analyses are presented for chironomids, cladocerans, cyclopoid copepods, gastropods, water mites (Hydracarina), ostracods, and trichopterans. R2 values for the regression equations ranged from 0.43 to 0.81. The abundance of invertebrates was best related to the biomass of separate plant species, but equations based only on total plant biomass sometimes had equivalent R2 values, in general, the abundance of phytophilous invertebrates was positively related to areal plant biomass, sediment organic matter, and lake trophic status and negatively related to depth. The abundance of phytophilous invertebrates generally rose throughout the sampling season. The sign of the relationship with sediment water content, however, varied among invertebrate taxa. Macrophyte beds with high areal plant biomass, in lakes with high total phosphorus concentration, support the greatest abundance of potential invertebrate food for fish and waterfowl.

Plant tests for diagnosing phosphorus deficiency in barley (Hordeum vulgare L.)

1999 ◽  
Vol 39 (7) ◽  
pp. 857 ◽  
Author(s):  
S. D. Hoppo ◽  
D. E. Elliott ◽  
D. J. Reuter
Keyword(s):  
Total Phosphorus ◽  
Field Experiments ◽  
Lignin Content ◽  
Phosphorus Deficiency ◽  
Plant Age ◽  
Phosphorus Concentration ◽  
Growth Stages ◽  
Hordeum Vulgare L ◽  
Total Phosphorus Concentration ◽  
Phosphorus Fertiliser

Summary. Six field experiments were conducted in the Murraylands and Mid North regions of South Australia between 1986 and 1988 to develop plant tests for diagnosing the phosphorus status of barley. The effects of applied phosphorus level on total phosphorus concentrations in youngest emerged leaf blades or whole shoots, and on shoot yield, were examined and critical ranges were established during vegetative growth. Experiments were conducted on a range of soil phosphorus levels with several methods of phosphorus placement and 2 barley cultivars. During early tillering, shoot yield and phosphorus concentrations in youngest emerged leaf blades and whole shoots were increased more by drilling phosphorus fertiliser with the seed (banded) than by spreading the same phosphorus rate over the soil surface and partially incorporating the fertiliser while sowing (broadcast). However, these methods of phosphorus placement did not affect diagnostic relationships between relative shoot yield and phosphorus concentrations in youngest emerged leaf blades and, as a result, critical total phosphorus concentrations were similar for both methods of applying phosphorus fertiliser. Estimated critical total phosphorus concentrations for both Schooner and Galleon barley were similar at each sampling time when allowances were made for minor differences in growth stages between the cultivars; even though phosphorus concentrations in youngest emerged leaf blades and whole shoots were higher in Schooner than in Galleon at adequate phosphorus supply. Between Zadoks scale 13.5 and 16.5 there was a linear decline in critical total phosphorus concentration in youngest emerged leaf blades with increasing plant age. A more variable, but steeper, decline was found for critical total phosphorus concentration in whole shoots. Critical ranges are proposed for total phosphorus concentrations in youngest emerged leaf blades and whole shoots of barley. The decline in critical total phosphorus concentration in youngest emerged leaf blades with advancing plant age was mainly caused by a higher functional requirement for phosphorus at early stages of growth and by increasing dry weight, cellulose and lignin content of youngest emerged leaf blades as plants age. Changes in the spatial distribution of applied phosphorus in relation to root growth did not seem to be important.

Field evaluation of regression equations to estimate crop yield losses due to weeds

2005 ◽  
Vol 85 (4) ◽  
pp. 955-962 ◽  
Author(s):  
J. T. O’Donovan ◽  
R. E. Blackshaw ◽  
K. N. Harker ◽  
G. W. Clayton ◽  
D. C. Maurice
Keyword(s):  
Triticum Aestivum L ◽  
Regression Equations ◽  
Wild Oat ◽  
Economic Threshold ◽  
Herbicide Application ◽  
Hordeum Vulgare L ◽  
Relative Time ◽  
Brassica Napus L ◽  
Weed Density ◽  
Crop Density

Various regression equations based on weed density alone, or relative time of weed and crop emergence or crop density in addition to weed density have been developed in western Canada to estimate the effects of wild oat (Avena fatua L.) and volunteer cereals on yield loss of field crops, and to advise farmers on the economics of weed control with herbicides. In 1997, 1998, and 1999, several of these equations were evaluated in 9 barley (Hordeum vulgare L.), 9 wheat (Triticum aestivum L.) and 11 canola (Brassica napus L.) fields in Alberta. Wild oat was the dominant weed in the barley and wheat fields, and wild oat or volunteer cereals in the canola fields. In barley and wheat, more complex equations based on both weed density and either crop density or relative time of weed and crop emergence were more reliable in estimating yield losses due to wild oat than those based on weed density alone. In canola, an equation based on volunteer barley and canola density provided the most reliable estimates. Under the assumed crop prices and herbicide costs, these equations also resulted in the best estimates of whether or not a herbicide application resulted in a net profit or loss. Herbicide application was rarely economical in barley, but usually economical in wheat and canola reflecting the different market value of the crops. The implementation of the weed economic threshold concept is likely to be more feasible in low-value crops such as feed barley than in higher-value crops such as canola. Key words: Barley (Hordeum vulgare L.), canola (Brassica napus L.), volunteer cereals, weed economic threshold, wheat (Triticum aestivum L.), wild oat (Avena fatua L.)

Lake Paranoá, Brasília, Brazil: Integrated Management Plan for its Restoration

1992 ◽  
Vol 27 (2) ◽  
pp. 271-286 ◽  
Author(s):  
Sonia Paulino Mattos ◽  
Irene Guimarães Altafin ◽  
Hélio José de Freitas ◽  
Cristine Gobbato Brandão Cavalcanti ◽  
Vera Regina Estuqui Alves
Keyword(s):  
Total Phosphorus ◽  
Drainage Basin ◽  
Integrated Management ◽  
Algal Growth ◽  
Nutrient Content ◽  
Management Plan ◽  
Cylindrospermopsis Raciborskii ◽  
Phosphorus Concentration ◽  
Limiting Factor ◽  
Total Phosphorus Concentration

Abstract Built in 1959, Lake Paranoá, in Brasilia, Brazil, has been undergoing an accelerated process of nutrient enrichment, due to inputs of inadequately treated raw sewage, generated by a population of 600,000 inhabitants. Consequently, it shows high nutrient content (40 µg/L of total phosphorus and 1800 µg/L of total nitrogen), low transparency (0.65 m) and high levels of chlorophyll a (65 µg/L), represented mainly by Cylindrospermopsis raciborskii and sporadic bloom of Microcystis aeruginosa, which is being combatted with copper sulphate. With the absence of seasonality and a vertical distribution which is not very evident, the horizontal pattern assumes great importance in this reservoir, in which five compartments stand out. Based on this segmentation and on the identification of the total phosphorus parameter as the limiting factor for algal growth, mathematical models were developed which demonstrate the need for advanced treatment of all the sewage produced in its drainage basin. With this, it is expected that a process of restoration will be initiated, with a decline in total phosphorus concentration to readings below 25 µg/L. Additional measures are proposed to accelerate this process.

scholarly journals Phytase-Producing Rahnella aquatilis JZ-GX1 Promotes Seed Germination and Growth in Corn (Zea mays L.)

2021 ◽  
Vol 9 (8) ◽  
pp. 1647
Author(s):  
Gui-E Li ◽  
Wei-Liang Kong ◽  
Xiao-Qin Wu ◽  
Shi-Bo Ma
Keyword(s):  
Seed Germination ◽  
Plant Growth ◽  
Biomass Accumulation ◽  
Root Surface ◽  
Phosphorus Concentration ◽  
Maize Seedlings ◽  
Total Phosphorus Concentration ◽  
Rahnella Aquatilis ◽  
Maize Seeds

Phytase plays an important role in crop seed germination and plant growth. In order to fully understand the plant growth-promoting mechanism by Rahnella aquatilis JZ-GX1，the effect of this strain on germination of maize seeds was determined in vitro, and the colonization of maize root by R. aquatilis JZ-GX1 was observed by scanning electron microscope. Different inoculum concentrations and Phytate-related soil properties were applied to investigate the effect of R. aquatilis JZ-GX1 on the growth of maize seedlings. The results showed that R. aquatilis JZ-GX1 could effectively secrete indole acetic acid and had significantly promoted seed germination and root length of maize. A large number of R. aquatilis JZ-GX1 cells colonized on the root surface, root hair and the root interior of maize. When the inoculation concentration was 107 cfu/mL and the insoluble organophosphorus compound phytate existed in the soil, the net photosynthetic rate, chlorophyll content, phytase activity secreted by roots, total phosphorus concentration and biomass accumulation of maize seedlings were the highest. In contrast, no significant effect of inoculation was found when the total P content was low or when inorganic P was sufficient in the soil. R. aquatilis JZ-GX1 promotes the growth of maize directly by secreting IAA and indirectly by secreting phytase. This work provides beneficial information for the development and application of R. aquatilis JZ-GX1 as a microbial fertilizer in the future.

scholarly journals Efficiency of Recycled Biogas Digestates as Phosphorus Fertilizers for Maize

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 553
Author(s):  
Inga-Mareike Bach ◽  
Lisa Essich ◽  
Torsten Müller
Keyword(s):  
Biomass Production ◽  
Plant Biomass ◽  
Nutrient Content ◽  
Phosphorus Concentration ◽  
Available Phosphorus ◽  
Phosphorus Fertilizers ◽  
Future Supply ◽  
Application Techniques ◽  
Phosphorus Recycling ◽  
Fertilizing Effect

Despite phosphorus resources on Earth being limited, over fertilization in many agricultural situations causes significant resource consumption. Phosphorus-recycling within agricultural production can reduce global dilution into the environment and is thus essential to secure sustainable future supply. This study investigated the fertilization efficacy of phosphorus fertilizers recycled from biogas digestates in maize shoots grown under controlled greenhouse conditions, in two soils, in a pot experiment. Variables investigated were plant-available phosphorus in soil, plant biomass production, and concentration of phosphorus, calcium, and magnesium in shoots. Soils were treated with three different fertilizer fractions, separated from biogas digestates, at equivalent phosphorus concentrations, using different combinations and application techniques, isolated or in combination, and compared to triple superphosphate (TSP) as a reference. One of the fractions (P-Salt) had effects on biomass production and plant phosphorus concentration equivalent to TSP in agricultural surface soil. In the second soil (with less active soil life and nutrient content), equivalence to TSP was achieved with combinations of two recycled fractions (P-Salt and dried solids). The enhancement of the phosphorus fertilizing effect by the solids was synergistic, indicating that the solids had a soil conditioning effect. The results show that biogas digestates are a valuable source for phosphorus recycling of fractions that have equivalent or even superior fertilizing properties compared to TSP.

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