Studies on potassium. IV. Interspecific differences in the uptake of non-exchangeable potassium

Soil Research ◽  
1974 ◽  
Vol 12 (2) ◽  
pp. 147 ◽  
Author(s):  
IF Fergus ◽  
AE Martin
Keyword(s):  
Soil Solution ◽  
Clay Soil ◽  
Plant Roots ◽  
Exchangeable Potassium ◽  
Swelling Clay ◽  
Rhodes Grass ◽  
Interspecific Differences ◽  
Chloris Gayana ◽  
Macroptilium Atropurpureum ◽  
Plant Removal

Five soils were cropped with four plant species in pot experiments in the glasshouse, without addition of potassium, until growth virtually ceased, after which the depleted soils were replanted with either the same species, or a different one, to test the reproducibility of the 'exhaustion' conditions imposed. Uptake of potassium by the plants exceeded the changes in exchangeable potassium in four soils; the excess amounts taken up differed markedly between species and these differences were reproducible on replanting. Uptake by setaria (Setaria anceps) and siratro (Macroptilium atropurpureum) exceeded that by Rhodes grass (Chloris gayana) and lucerne (Medicago sativa), except for one swelling clay soil from which uptake by lucerne equalled that by siratro. Most of the differences between species were attributed to the uptake of initially non-exchangeable potassium, which was removed in significant amounts from three of the soils. For these three soils, uptake from non-exchangeable sources was detected only after about 80% of the exchangeable potassium had been removed. It is postulated that the efficiency of plant removal of non-exchangeable potassium from soil is directly related to the degree to which plant roots can lower the concentration of potassium in the soil solution.

Soil treatment, plant species, and management effects on improved pastures on a solodic soil in the semi-arid subtropics: 3. Improving cool season plant and cattle productivity

1994 ◽  
Vol 34 (2) ◽  
pp. 145 ◽  
Author(s):  
JS Russell
Keyword(s):  
Treatment Plant ◽  
Cool Season ◽  
Rhodes Grass ◽  
Plant Nitrogen ◽  
Long Term Experiment ◽  
Exchangeable Magnesium ◽  
Chloris Gayana ◽  
Macroptilium Atropurpureum ◽  
The Cost

Seasonal analyses of grasses and legumes in a long-term experiment on a solodised solonetz soil (Natrustalf) in southern Queensland showed that the large liveweight losses of steers in the cool months (June-August) appeared to be broadly correlated with low plant nitrogen (N), phosphorus (P), and potassium (K) concentrations. Annual variation in the N, P, and K percentages of Rhodes grass (Chloris gayana) and volunteer grasses [medics (Medicago spp.) and siratro (Macroptilium atropurpureum)] as affected by soil and plant treatments were examined by fitting a Fourier series to the data. Cool season liveweight losses of steers ranged from 391 glday with sown grasses alone to 11 g/day with sown grasses and medics plus lime and gypsum. The N content of volunteer and sown grasses ranged from 0.56 to 0.70% in the cool months, which is below the accepted N requirement of 1%. The P concentration of volunteer grasses was only 0.08%, but where P fertiliser was applied, concentrations in Rhodes grass were 0.10-0.11%. Potassium levels were also low in the cool months, with values of 0.23-0.43% in grasses. Exchangeable magnesium (Mg) and sodium increased from 1.3 and 0.48 mLJ100 g at 0-10 cm depth to 8.5 and 5.2, respectively, at 40-70 cm. Exchangeable calcium decreased from 2.5 mL/100 g at 0-10 cm to 0.40 at 40-70 cm. The Mg levels in siratro (0.58-0.60%) were higher than those in Rhodes grass (mean 0.12%). Medics responded markedly to lime, resulting in a 54% increase in steer liveweight gains on Rhodes grass-medic pastures. The use of lime on solodic soils for reducing both surface soil acidity and exchangeable aluminium increased plant and steer productivity. The cost of lime transportation can be high in inland areas, but small limestone deposits have been identified on the Darling Downs and these merit closer attention.

Productivity of grazed Makarikari grass-lucerne, Rhodes grass-lucerne and lucerne pastures in the northern wheat belt of Australia

1983 ◽  
Vol 23 (123) ◽  
pp. 383 ◽  
Author(s):  
DL Lloyd ◽  
JG Nation ◽  
TB Hilder ◽  
PK O'Rourke
Keyword(s):  
Dry Matter ◽  
Clay Soil ◽  
Stocking Rate ◽  
Rhodes Grass ◽  
Grazing System ◽  
Dry Conditions ◽  
Chloris Gayana ◽  
Stocking Rates ◽  
Grain Farms ◽  
Better Than

Three Makarikari grasses (Panicum coloratum var. makarikariense) viz. 0.4634, cv. Pollock and cv. Bambatsi and Rhodes grass (Chloris gayana) cv. Pioneer, each grown with lucerne (Medicago sativa) cv. Hunter River, and sward lucerne were compared for productivity and stability in a rotational grazing system at three stocking rates (22.2, 14.8 and 7 . 4 Merino wethers/ha for grasslucerne pastures; 14.8, 11.1 and 7.4/ha for lucerne swards) on a cracking clay soil on the Darling Downs, Queensland over four years. There were no differences between the Makarikari grass cvv. Pollock and Bambatsi pastures. However, each produced more dry matter and animal liveweight, and persisted better, than Rhodes grass pasture during dry conditions that occurred during the first two years. Rhodes grass nevertheless recovered during two subsequent wet summers. During those two dry years, wool production from sward lucerne was equal to that of the grass-lucerne pastures at both 14.8 and 7.4 animals/ha. Animal liveweight from lucerne was greater than from grass-lucerne pastures at 7.4 animals/ha only. Wide variation, both between and within seasons, was measured in the quantity of feed produced by pastures in this study. This is discussed in relation to the concept of stocking rate of pasture grown on limited areas of grain farms in the northern wheat belt, and to the provision of a continuing feed supply in integrated crop-pasture systems.

Performance of Southern African Digitaria spp. in southern Queensland

1974 ◽  
Vol 14 (67) ◽  
pp. 186 ◽  
Author(s):  
RW Strickland
Keyword(s):  
Dry Matter ◽  
Mineral Content ◽  
Phosphorus Content ◽  
Clay Soil ◽  
Dry Matter Production ◽  
Cool Season ◽  
Rhodes Grass ◽  
Matter Production ◽  
Chloris Gayana

Dry matter production and quality of 45 Digitaria accessions were measured over the period 1964-70. In three experiments at Samford, south-east Queensland, the accessions were fertilized with either 336 or 672 kg ha-1 of N a year and cut four-weekly. Both total and cool season production was measured. Highest annual yields were produced by D. smutsii (40,000 kg ha-1), D. macroglossa (37,000 kg ha-1) and D. decumbens (30,000 kg ha-1). D. decumbens yielded up to 5000 kg ha-1 dry matter between May and September compared with up to 6800 kg ha-1 from D. pentzii, 6700 kg ha-1 from D. macroglossa and 6400 kg ha-1 from D. smutsii. In two other experiments persistence and production of nine accessions were compared with those of Rhodes grass (Chloris gayana) on heavy, gilgaied clay soil at Meandarra, Queensland and with Panicum coloratum var. makarikariense on a shallow, self mulching, sedentary black earth at Southbrook, Queensland. D. decumbens showed the greatest potential for persistence and production at Meandarra and one strain of D. smutsii had the greatest yields at Southbrook. Digestibility and mineral content varied little between species and were generally satisfactory for animal production. Digitaria tended to be higher in phosphorus content than P. coloratum and C. gayana.

Localization and Chemical Speciation of Pb in Roots of Signal Grass (Brachiaria decumbens) and Rhodes Grass (Chloris gayana)

2008 ◽  
Vol 42 (12) ◽  
pp. 4595-4599 ◽  
Author(s):  
Peter M. Kopittke ◽  
Colin J. Asher ◽  
F. Pax C. Blamey ◽  
Graeme J. Auchterlonie ◽  
Yanan N. Guo ◽  
...  
Keyword(s):  
Chemical Speciation ◽  
Brachiaria Decumbens ◽  
Rhodes Grass ◽  
Chloris Gayana ◽  
Signal Grass

Tropical grass/legume pastures in Northern Rhodesia

1962 ◽  
Vol 59 (1) ◽  
pp. 111-118 ◽  
Author(s):  
C. A. Smith
Keyword(s):  
Dietary Protein ◽  
Cajanus Cajan ◽  
Residual Effects ◽  
Maize Crop ◽  
Rhodes Grass ◽  
N Level ◽  
N Yield ◽  
Chloris Gayana ◽  
Tropical Grass ◽  
Leaf N

Three grass/legume pastures were evaluated under Northern Rhodesian conditions.A plot trial measured the herbage yields of Stylosanthes gracilis, velvet beans (Stizolobium deeringianum) and giant Rhodes grass (Chloris gayana) grown as pure stands, and in a mixed association with Rhodes grass. The herbage was harvested for 3 years, and the plots were then planted with a maize crop to test any residual effects.After the establishment year, the D.M. yields, and especially the C.P. yields of the legume and grass/legume treatments, were markedly superior to grass alone. The increased yield of the grass/legume mixtures was due to the net gain contributed by legume herbage. There was no evidence of an underground transference of N from the legume to the associated grass.Although there was no measurable treatment effect on soil N and C, the maize following the legume and grass/legume treatments had a higher leaf N level, and approximately double the yield, compared with the maize following the grass-alone treatments.There were no significant differences in cattle weight gains when Rhodes grass alone, Rhodes grass/Stylosanthes, Rhodes grass/velvet beans, and Rhodes grass/pigeon peas (Cajanus cajan) were utilized as hay and foggage in the dry season.Digestibility trials showed mature Rhodes grass hay to be a submaintenance feed, deficient in dietary protein. The addition of Stylosanthes raised the herbage digestible C.P. fourfold. The Rhodes grass/Stylosanthes hay was a maintenance feed.The N yield of the grass/legume mixtures, although low by temperate standards, was 2½ times the N yield of grass alone. The potential value of a tropical grass/legume pasture will depend on the efficiency of the legume to fix N.

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