CARBOFURAN EFFECTS ON ESTABLISHMENT OF LEGUMES IN RELATION TO PLANT GROWTH, NITROGEN FIXATION, AND SOIL NEMATODES

1985 ◽  
Vol 65 (2) ◽  
pp. 423-433 ◽  
Author(s):  
G. BELANGER ◽  
J. E. WINCH ◽  
J. L. TOWNSHEND

Field experiments were conducted to determine the effects of carbofuran on the establishment and subsequent yields of sod-seeded legumes. The effects of carbofuran on plant growth, nodulation and nitrogen fixation of birdsfoot trefoil (Lotus corniculatus L.) in non-sterilized and sterilized soil were evaluated in growth cabinet experiments. In the field experiments carbofuran, applied immediately after seeding, had a positive effect on plant stand and seedling dry matter production of birdsfoot trefoil and alfalfa (Medicago sativa L. ssp. falcata L.) in the weeks following seeding. In the first production years of these field trials, there was a trend for the total and legume yields to be higher in the carbofuran plots than where carbofuran was not used. In either growth cabinet experiment, however, shoot growth was not affected by carbofuran but a reduction in the number of plants in the non-sterilized and carbofuran pots occurred. A toxic effect of carbofuran on seedlings may have been involved. No correlation between soil nematode numbers and plant stand or dry matter production was found in either field or growth cabinet experiments. In the growth cabinet experiments, carbofuran did not affect the number of nodules but improved nitrogen fixation in sterilized pots of exp. B. Carbofuran increased the dry weight of individual nodules in the sterilized pots of exp. A but a decrease was observed in exp. B. These effects of carbofuran on the dry weight of individual nodules and specific nodule activity were also observed in the nematode-free environment created by sterilization. In view of these responses in sterile soil, it was suggested that the effect of carbofuran was not as a nematicide but rather a positive physiological effect on the plant component of the plant-rhizobium system.Key words: Carbofuran, establishment, legumes, nitrogen fixation, nematodes

Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 784-789 ◽  
Author(s):  
Ian N. Morrison ◽  
Ken M. Nawolsky ◽  
George M. Marshall ◽  
Allan E. Smith

The relationship between trifluralin dosages detected in the soil at seeding, initial crop injury, and subsequent recovery of spring wheat during the growing season was investigated in field experiments in 1986 and 1987. As the amount of trifluralin in the soil increased, both crop density and dry matter production decreased such that at 1 kg/ha the two were reduced by 37 and 50%, respectively, early in the season. As the season progressed, crop growth rates (CGRs) of wheat in trifluralin-treated plots exceeded those of wheat in the untreated plots. Maximum CGRs occurred between Zadok's growth stages 30 and 45 where trifluralin levels in the soil were 0.3 to 0.5 kg ai/ha at seeding. Recovery from trifluralin injury was characterized by enhanced net assimilation rates of surviving plants, increased tillering and greater dry matter production per plant. Wheat seed yield was only weakly correlated with trifluralin levels in the soil at seeding. From a linear regression model it was determined that a 35% reduction in plant dry weight from the trifluralin injury at the beginning of tillering would result in no more than a 10% reduction in seed yield at final harvest.


1969 ◽  
Vol 20 (3) ◽  
pp. 417 ◽  
Author(s):  
JH Silsbury

Lolium rigidum Gaud. and a summer-dormant and a non-dormant form of Lolium perenne L. were grown as seedling plants for 32 days in controlled environment cabinets at constant temperatures of either 10, 20, or 30°C and in all cases with a 16-hr photoperiod at a light intensity of 3600 lm ft-2. Sampling at 4-day intervals permitted the detailed examination of dry matter growth curves. Differences in total dry matter production were related to initial differences in seedling dry weight, and the general responses to temperature were similar for each ryegrass. Total dry matter production was greatest at 20°C and lowest at 10°. A temperature of 30° did not induce dormancy in the summer-dormant ryegrass but did depress growth. Relative growth rate fell with time at each temperature.


2018 ◽  
Vol 85 (0) ◽  
Author(s):  
Suzete Fernandes Lima ◽  
Leandro Spíndola Pereira ◽  
Gustavo Dorneles Sousa ◽  
Simonny Araújo Vasconcelo ◽  
Adriano Jakelaitis ◽  
...  

ABSTRACT: The use of herbicide underdoses allows minimizing the competition of grasses on annual crops, enabling simultaneous cultivation. In this context, the objective of this study was to investigate glyphosate underdoses on the suppression of the initial growth of three Panicum maximum cultivars aiming at the integrated cultivation, in addition to the effects of forage species on the incidence and development of weeds. Three field experiments were conducted. The experimental design was a randomized block design with four replications and eight treatments consisting of increasing glyphosate doses (0, 54, 108, 270, 378, 540, 756, and 1,080 g a.e. ha−1). An atrazine dose of 1,200 g a.i. ha−1 was added to each treatment. Plant phytotoxicity assessments were performed at 7, 14, 21, and 28 days after application. At 80 and 125 days after sowing, the assessments of total dry matter production, leaf dry matter, stem dry matter, and leaf to stem ratio were carried out, in addition to density and dry matter production of weed community. Glyphosate underdoses below 215, 65, and 90 g a.e. ha-1 have a potential to be investigated aiming at the management of P. maximum cv. Atlas, P. maximum cv. Mombasa, and P. maximum cv. Tanzania under intercropping. The three forage species are effective in suppressing weeds.


1985 ◽  
Vol 105 (1) ◽  
pp. 187-188 ◽  
Author(s):  
R. K. M. Hay

Work in controlled conditions (Cooper, 1964; østgård & Eagles, 1971) has indicated that, under short photoperiods and low temperatures, Scandinavian grass varieties tend to grow more slowly than those from lower latitudes, and are, therefore, more resistant to cold and freezing stresses. This has been confirmed in field experiments (Håbjørg, 1979). These grasses would therefore be expected to cease growth earlier in the autumn when grown in the British Isles. However, this mechanism does not appear to operate under lengthening days; indeed, there is evidence to suggest that their growth is particularly stimulated by the combination of cool temperatures and long days (Cooper, 1964; Hay & Heide, 1983, 1984). This raises the possibility that varieties from Norway and Sweden could produce more dry matter than grasses of more southern provenance in the spring in upland areas, when low temperatures are associated with rapidly lengthening photoperiod (12·5–15 h) and moderate to high levels of irradiance (> 200 W/m2) (Hay, 1985).


2002 ◽  
Vol 50 (2) ◽  
pp. 179-184
Author(s):  
P. M. Arthanari ◽  
P. Gnanamoorthy ◽  
S. Ramasamy

Field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India during the Rabi (November 1997-March 1998) and Kharif (July 1998-November 1998) seasons to identify the effect of silicon at panicle initiation on the growth of rice plant (Variety ADT-36) at different growth stages. Furnace slag was applied as a silicon source at 2 t/ha at the panicle initiation stage along with other nutrients. The dry matter production was recorded at the active tillering, panicle initiation, booting, flowering, one week after flowering and maturity stages in both the seasons. The total dry matter production was greater in the Kharif season than in the Rabi season. The application of slag at the panicle initiation stage along with N and K at the flowering stage had a significant influence over the dry matter production. A similar trend was observed in both the seasons. The silicon uptake was recorded at the panicle initiation and maturity stages. About 30-40% of the silicon absorbed during the early stages and the maturity stage was present in the shoot, whereas 20-30 % of the silicon absorbed during the maturity stages was present in the leaf blades. Based on the results, it is concluded that the supply of silicon during the panicle initiation stage is most important for plant growth.


1969 ◽  
Vol 49 (3) ◽  
pp. 339-349 ◽  
Author(s):  
H. Gasser ◽  
L. Lachance ◽  
P. Gervais

In two experiments, one with alfalfa and the other with birdsfoot trefoil, we have been able to show that a late cut in October does not adversely affect dry matter yield (DAI) of the legumes. Three cuts during a harvesting season ending on September 5 were detrimental to alfalfa, since lower yields were obtained the following year of harvest. Birdsfoot trefoil varieties were affected differentially. Three cuts did not affect the yield of Viking the following year, but did so of Empire. Significant differences in dry matter yields were obtained between DuPuits and Vernal and between Viking and Empire. Protein in the forage followed inversely the same pattern as that of DM yields, that is, where the intervals were shortest, the protein content was highest, and conversely. The total available carbohydrate and the nitrogen content of the roots were lowest following the treatments which had the shortest intervals between them.


1980 ◽  
Vol 10 (3) ◽  
pp. 426-428
Author(s):  
S. Thompson

The components of shoot growth and dry matter production in 1 + 0 lodgepole pine (Pinuscontorta Dougl. ex Loud. spp. contorta) seedlings raised under clear polythene cloches for 12 weeks at five seedbed densities (180–720 plants/m2) were studied. The greater plant height found at the highest seedbed density was the result of increased stem unit length, not increased number of stem units. The increase in plant dry weight as seedbed density decreased was largely due to greater dry weight of roots, branchwood, and branch foliage, and not to increases in stemwood and stem foliage weight. Seedbed densities of less than 460 seedlings/m2 are required to produce yields of suitably sturdy seedlings in excess of 50% of the crop.


2002 ◽  
Vol 42 (8) ◽  
pp. 1043 ◽  
Author(s):  
M. Seymour ◽  
K. H. M. Siddique ◽  
N. Brandon ◽  
L. Martin ◽  
E. Jackson

The response of Vicia sativa (cvv. Languedoc, Blanchefleur and Morava) and V. benghalensis (cv. Barloo) seed yield to seeding rate was examined in 9 field experiments across 2 years in south-western Australia. There were 2 types of field experiments: seeding rate (20, 40, 60, 100 and 140 kg/ha) × cultivar (Languedoc, Blanchefleur, and Morava or Barloo), and time of sowing (2 times of sowing of either Languedoc or Blanchefleur) × seeding rate (5,�7.5, 10, 15, 20, 30, 40, 50, 75 and 100 kg/ha).A target density of 40 plants/m2 gave 'optimum' seed yield of vetch in south-western Australia. In high yielding situations, with a yield potential above 1.5 t/ha, the 'optimum' plant density for the early flowering cultivar Languedoc (85–97 days to 50% flowering) was increased to 60 plants/m2. The later flowering cultivar Blanchefleur (95–106 days to 50% flowering) had an optimum plant density of 33 plants/m2 at all sites, regardless of fitted maximum seed yield. Plant density in the range 31–38 plants/m2 was found to be adequate for dry matter production at maturity of Languedoc and Blanchefleur. For the remaining cultivars Barloo and Morava we were unable to determine an average optimum density for either dry matter or seed yield due to insufficient and/or inconsistent data.


1969 ◽  
Vol 73 (1) ◽  
pp. 75-86 ◽  
Author(s):  
A. B. Hearn

SUMMARYVariety, water and spacing were treatments in two experiments with cotton in 1963 and 1964 in which fruiting points, flowers and bolls were counted and the dry weights and leaf areas of plants were measured at intervals during the season.Until leaf-area index, L, started to decrease, the equation described how dry weight, W, changed. The equation gave smoothed estimates of crop growth rate, C, which were consistent with estimates of photosynthesis made with de Wit's (1965) model. The relationship between G and L conformed to , derived from Beer's Law, rather than C = aL — bL2 derived from the linear regression of E on L. When L > 3 the crop appeared to use most of the available light, so that C approached a maximum. Treatments initially affected dry-matter production through the numbers and types of branches and nodes, which in turn affected the sinks available and thus the proportion of dry matter reinvested in new leaf. This initial period, when growth was simple to describe in conventional terms, was denned as the vegetative phase of growth.The start of the reproductive phase of growth overlapped the vegetative phase. The change from one to the other was completed when the rate of dry weight increase of the bolls, CB, equalled C. This indicated that the sink formed by the bolls had increased sufficiently in size to use all the assimilates available for growth. Sink size increased as the crop flowered and was estimated from the product of the number of bolls and the growth rate of a single boll.When CB equalled C, bolls were shed which prevented the size of the sink to increase beyond the ability of the plant to supply it with assimilates. This agrees with Mason's nutritional theory of boll shedding. Because of the crop's morphology and because age decreased the photosynthesis of the crop, the size of the sink inevitably increased out of phase with the supply of assimilates. The extent to which this was so determined when CB equalled C. It is postulated that environment, genotype and agronomic practice affect yield according to whether they increase or decrease the extent to which the sink size and the supply of assimilates are out of phase.


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