Variation in plasticity within the S. 23 cultivar of Lolium perenne L.

1975 ◽  
Vol 85 (1) ◽  
pp. 111-121 ◽  
Author(s):  
J. Valentine ◽  
A. H. Charles

SUMMARYThe S. 23 cultivar of Lolium perenne L. has the ability to perform well in a wide range of environments and an experiment was designed to examine the phenotypic plasticity of S. 23 genotypes with particular reference to the level of nitrogen application.Genotypes of S. 23 grown in a controlled growth room at close spacing (5 cm) showed a wide range of dry-matter yields with the highest yielding 144 times that of the lowest at the last of six cuts taken at 4-week intervals. Genotypes maintained much the same order of yield from one nitrogen level to another, but there were exceptions. Regression techniques were used to further quantify genotype-environment behaviour and to measure response to the environment in which the plants were grown. Considerable variation in this character occurred and the correlation of mean yield and response was incomplete. Some of the genotypes combined the desirable characters of high mean yield and good response to improved environments, while others had high mean yields, but were not as well adapted to the highest N level.In the experiment no significant effects could be traced to differences in age of seed, but plants which had been maintained vegetatively for 7 years showed reduced vigour.

2010 ◽  
Vol 61 (5) ◽  
pp. 353 ◽  
Author(s):  
L. L. Burkitt ◽  
D. J. Donaghy ◽  
P. J. Smethurst

Pasture is the cheapest source of feed for dairy cows, therefore, dairy pastures in Australia are intensively managed to maximise milk production and profits. Although soil testing commonly suggests that soils used for dairy pasture production have adequate supplies of phosphorus (P), many Australian dairy farmers still apply fertiliser P, often by applying smaller rates more frequently throughout the year. This study was designed to test the hypotheses that more frequent, but lower rates of P fertiliser applied strategically throughout the growing season have no effect on dry matter production and P concentration in perennial ryegrass (Lolium perenne L.), when soil extractable P concentrations are above the critical value reported in the literature. Three field sites were established on rain-fed dairy pasture soils ranging in P sorption capacity and with adequate soil P concentrations for maximising pasture production. Results showed that applied P fertiliser had no effect on pasture production across the 3 sites (P > 0.05), regardless of rate or the season in which the P was applied, confirming that no P fertiliser is required when soil extractable P concentrations are adequate. This finding challenges the viability of the current industry practice. In addition, applying P fertiliser as a single annual application in summer did not compromise pasture production at any of the 3 sites (P > 0.05), which supports the current environmental recommendations of applying P during drier conditions, when the risk of surface P runoff is generally lower. The current results also demonstrate that the short-term cessation of P fertiliser application may be a viable management option, as a minimal reduction in pasture production was measured over the experimental period.


1978 ◽  
Vol 90 (3) ◽  
pp. 447-457 ◽  
Author(s):  
D. Reid

SummaryIn a 3-year experiment on a sward of S. 23 perennial ryegrass 21 rates of nitrogen fertilizer ranging from 0 to 897 kg/ha were applied annually on plots cut three, five or ten times per year. The cutting dates within each frequency were decided on the basis of herbage growth stage. Four-parameter exponential curves fitted to the herbage yield data show that the pattern of response to nitrogen application in the five cuts per year treatment was markedly similar to that reported for a previous experiment (Reid, 1970). Alterations in the cutting frequency affected the pattern of dry-matter yield response to nitrogen, but not that of crude-protein yield response. The combined effects of cutting frequency and nitrogen rate are illustrated by response surfaces fitted to the dry-matter yield results using an extension of the equation for the curves fitted to the individual frequency results. These surfaces show that as the number of cuts per year was increased the total yield and the response to nitrogen decreased, but the response was maintained to an increasingly high nitrogen rate. The practical implications of the results are discussed in relation to intensive grazing managements for dairy cows.


1986 ◽  
Vol 107 (3) ◽  
pp. 573-578 ◽  
Author(s):  
E. O. Lucas

SummarFARZ 27, a high-yield maize variety, was grown in 1984 and 1985 over a wide range of density treatments (1·9– 11·1 plants/m2) and with four rates of nitrogen application (0, 75, 100 and 150 kg N/ha) in Ibadan. south-western Nigeria.There was no significant density or fertilizer effect on morphological characters of number of leaves per plant, height or stem diameter. For total dry-matter yield, the highest density of planting gave the highest yield although less dry matter was obtained in the 1985 experiment than in the 1984 experiment. Optimum density for grain production in both years was 8·8 plants/m2. There is an indication that there is no need to increase density of planting of maize beyond 80000 plants/ha in the south-western part of Nigeria. Plants without applied nitrogen fertilizer gave significantly lower total dry-matter and grain yields than plants with applied nitrogen. Highest grain yield was obtained with 150 kg N/ha in both years. By doubling the nitrogen application rate from the present recommended level of 75 kg N/ha to 150 kg N/ha an average increase of 0·42t/ha of maize was obtained in both years. With the present prices of fertilizer and maize, this increase is economical. It seems therefore that more revenue would accrue to the farmers by using 150 kg N/ha on the ‘FARZ series’ of maize instead of the present recommendation of 75 kg N/ha.


1980 ◽  
Vol 60 (2) ◽  
pp. 491-500 ◽  
Author(s):  
S. CECCARELLI ◽  
M. FALCINELLI ◽  
F. DAMIANI

Selection for high and low dry matter yield within an ecotype of Lolium perenne L. was effective in producing two highly differentiated populations. The evaluation of the materials obtained after three cycles of selection snowed a realized heritability of 0.13 and a symmetrical response in the two directions of selection. The difference between populations selected in opposite directions was 448.9 mg/plant and was significant from early stages of development. After four cycles of selection, realized heritability was 0.10. The low heritability estimate suggested that more efficient selection criteria for the improvement of forage yield are needed.


1977 ◽  
Vol 88 (3) ◽  
pp. 711-721 ◽  
Author(s):  
P. W. Bartholomew ◽  
D. M. B. Chestnutt

SUMMARYA small-plot experiment was made to assess the influence on dry-matter output from grass of a wide range of fertilizer nitrogen and defoliation interval treatments. There were five defoliation treatments, 22, 28, 45, 75 and 112-day regrowth intervalsroughout the growing season each at six levels of nitrogen application, ranging by 300 kg increments from 0 to 1500 kg/ha/year.There was a marked interaction effect between treatments; a positive dry-matter response was maintained to a higher level of applied nitrogen with more frequent defoliation. In 2 years out of 3 maximum dry-matter yield was produced under a 75·day defoliation interval although the mean yield advantage over a 45-day defoliation system was only 11%. Mean yield of digestible dry matter appeared to reach a maximum under a 45·day defoliation interval at 600 kg N/ha but at the lower levels of N the maximum yield was reached at the longest growth interval.Seasonal response to nitrogen under the 22–day and 28–day defoliation systems measured as the increase in yield resulting from increased N at each cutting date reached its peak in July–August. Application for these short growth periods early and late in the growing season appeared to be a relatively inefficient use of nitrogen.The less frequently the sward was harvested and the higher the nitrogen application the greater was the reduction in ground cover as estimated by eye at the end of the growing season, this reached an estimated 25% reduction under 112·day defoliation at 300 kg N/ha/year.In relation to published figures nitrate content of herbage did not reach dangerous levels until nitrogen application reached levels beyond those at which maximum dry·matter yield was achieved.


2010 ◽  
pp. 35-39
Author(s):  
Andrea Balla Kovács ◽  
Anita Jakab

Pot experiment was performed to investigate the effects of increasing NH4NO3 doses with or without Microbion UNC bacterial fertilizerapplication on dry matter production of ryegrass (Lolium perenne L.). Experiment was set up on calcareous chernozem soil of Debrecen-Látókép and on humus sandy soil of Őrbottyán. The bi-factorial trials were arranged in a randomized complete block design with four replications. Grass was cut three times. Dry matter production was determined and the sum of biomass of cuts was calculated as cumulated dry weights. Analysis of variance was carried out on the data in order to provide a statistical comparison between the treatment means. The least significant difference (LSD5%) test was used to detect differences between means. On the basis of our results it can be concluded, that the dry weights of ryegrass cultivated on chernozem soil were higher than on sandy soil. With increasing nitrogen supply the dry matter production of grass significantly increased in both types of soils. In case of sandy soil the increasing effect was more expressed, but dry weights of this soil never reached the appropriate values of chernozem soil. Application of Microbion UNC had positive effect on dry matter production of ryegrass grown on both two types of soils but the effect was more expressed on chernozem soil. Finally it can be concluded that the increasing effect of NH4NO3 on biomass weights was more expressed in both types of soils, the biofertilizer application also increased the dry weights of plant in a small degree. 


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