The association of dry-matter yield with nitrogen and soluble-carbohydrate concentration in perennial ryegrass (Lolium perenne L.)

1979 ◽  
Vol 93 (3) ◽  
pp. 657-667 ◽  
Author(s):  
J. Valentine ◽  
A. H. Charles

SUMMARYThe associations between yield, nitrogen and soluble-carbohydrate concentration within S. 23 perennial ryegrass were investigated at three levels of nitrogen application. Controlled growth room conditions were used.The simple correlation between yield and nitrogen concentration was negative at the low rate of nitrogen application, not present at the intermediate rate of nitrogen and positive though not significant at the high rate of nitrogen. Yield and soluble-carbohydrate concentration were only correlated (positively) at the low nitrogen rate.At low nitrogen there were ‘efficient’ genotypes with relatively high yield and low nitrogen concentration. ‘Inefficient’ genotypes had relatively low yields and high nitrogen concentration. The majority of genotypes were neither markedly efficient or inefficient. The efficient genotypes at low nitrogen maintained their yield advantage at higher nitrogen levels with average nitrogen concentration and high numbers of tillers. Inefficient genotypes remained relatively stable in yield, numbers of tillers and nitrogen concentration.Partial correlation indicated an underlying high degree of dependence between yield, nitrogen and soluble-carbohydrate concentration at all nitrogen levels. The association of yield and nitrogen concentration showed a similar trend over nitrogen levels to that obtained using simple correlation. Yield and soluble-carbohydrate concentration were positively related, and nitrogen and soluble-carbohydrate concentration inversely related, when the effects of the remaining attribute were eliminated.Data extracted from Lee et al. (1977) confirmed that yield and nitrogen concentration for varieties under field conditions varied with level of nitrogen application in a similar manner to genotypes in the controlled growth room. The variety (Melle) could be characterized as being particularly efficient.Both sets of results indicate that selection for high yield of nitrogen in herbage can best be achieved through selection for yield alone.

1958 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
LF Myers ◽  
J Lipsett

The effect of skeleton weed competition on the yield of wheat and oats was investigated in seasons when rainfall was plentiful. Nitrogen was found to be the major factor limiting crop yields. In soils with comparable nitrogen-supplying powers, skeleton weed density governed the crop's response to applied nitrogen. Competition between skeleton weed and crop was severe at low nitrogen levels, but minor at the high nitrogen levels achieved either by nitrogen application, or when the crop followed a legume-rich pasture. Competition had its effect early in the crop's growth. Temporary removal of competition, by spraying with plant growth regulating substances (JICPA) at different times, was used to determine when competition was critical, and measure its effects. Skeleton weed reduced nitrogen supply early in the crop's growth, and so depressed yield. An application of 1 lb MCPA per acre in the fallow 54 days before sowing, or 10 days after crop emergence, increased the yield of oats from 710 to 1350 lb grain per acre: a response equal to that from 32 lb nitrogen per acre applied at planting in the same experiment. In each case, the response to spraying at the different times was analogous to the effect of a nitrogen application at these times. Early spraying gave responses in yield; later spraying gave responses in grain nitrogen. The results provide a new estimate of the reduction in crop yield due to skeleton weed.


1995 ◽  
Vol 60 (3) ◽  
pp. 337-345 ◽  
Author(s):  
A. Cushnahan ◽  
C. S. Mayne

AbstractTwelve lactatiug dairy cows were offered either fresh grass (G) or grass silage prepared from the same pasture which had undergone either an extensive (E) or restricted (R) fermentation, in a three-period change-over design experiment. Ensilage resulted in a reduction in forage pH and water-soluble carbohydrate concentration and an increase in ammonia-nitrogen concentration. The ensiling techniques used ensured that both silages were well preserved with pH values for E and R of 3.81 and 4.08 respectively, while the respective lactic acid concentrations were 124.6 and 27.0 g/kg dry matter respectively. Whilst there were no significant differences in dry-matter intake between treatments, when corrected for losses of volatile compounds, animals offered silage with a restricted fermentation consumed their food at a higher rate of intake (P < 0.001) than did animals on the other treatments. It was also found that while there was no significant difference in milk yield between animals offered fresh or ensiled forage, both butterfat and protein concentration and yields of butterfat were significantly higher (P < 0.01 or greater) with grass and restricted fermented silage than with extensively fermented silage. Ensiling of herbage had no significant effect on apparent digestibility. It is concluded that ensiling of herbage per se had little effect on overall animal performance but pattern of silage fermentation resulted in alterations in milk composition.


HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1061C-1061
Author(s):  
Justine E. Vanden Heuvel ◽  
Joan R. Davenport

Five fertilizer treatments were applied to a `Stevens' cranberry bed in a 3-way split application (roughneck, 75% bloom, and 3 weeks after bloom) in Spring 2004 at State Bog in E. Wareham, Mass. Nitrogen rates were 0, 22, 45, 67, and 90 kg/ha; P was applied at 22 kg/ha, and K at 44 kg/ha. At mid-fruit development and again at preharvest, 20 vegetative and 20 fruiting uprights were collected from each plot in mid-morning. The N concentration per upright increased linearly with increased N application. Increased upright N concentration had no effect on soluble carbohydrate (sucrose + glucose + fructose) concentration, but decreased starch concentration, more so in vegetative uprights than in fruiting uprights on both sampling dates. Total nonstructural carbohydrate concentration (TNSC) was negatively impacted by increased N in vegetative and fruiting uprights at mid-fruit development, but N did not impact TNSC in either type of upright by harvest. Vegetative uprights contained greater concentrations of N, soluble carbohydrates, starch, and TNSC at both sampling dates, but contained lower concentrations of chlorophyll A and chlorophyll B.


Author(s):  
S. Bardehji ◽  
H. R. Eshghizadeh ◽  
M. Zahedi ◽  
M. R. Sabzalian ◽  
M. Gheisari

Abstract A field experiment was carried out for over two seasons (autumn and spring) as a split–split plot scheme based on a randomized complete block design with three replications. The main plots included two irrigation levels of the maximum available water depletion (maximum allowable depletion (MAD)) of 55 and 85% as non-stress and drought-stress environments, respectively, and the subplot accommodated two levels of nitrogen (0 and 62.5 kg N/ha, urea fertilizer); also, 20 barley genotypes were assigned to the sub-subplots. The biplot analysis of both sowing seasons showed that grain yield (GY) had a high positive correlation with total biomass (TB), whereas it had a high negative correlation with proline and total soluble carbohydrate as drought-tolerance-determinant characteristics. The genotypes which had the lowest and highest GY ranked significantly (P ≤ 0.01) different with changing the sowing season under each irrigation level, indicating a larger plant interaction and non-stability in response to the season change (about two-fold), as compared to the change in the irrigation conditions. It could also be concluded that barley genotypes might experience a higher decrease in GY and sensitivity to water deficit in the autumn sowing season, as compared to the spring planting season, which was also intensified by nitrogen application. However, the response to nitrogen application depends on the plant genotype.


2019 ◽  
Vol 1 (1) ◽  
pp. 09-13
Author(s):  
Hakoomat Ali ◽  
Asad Abbas ◽  
Shabir Hussain ◽  
Shoukat Ali Abid ◽  
Shazia Khaliq ◽  
...  

Cotton is an important cash crop and source of foreign exchange. Nitrogen is a critical nutrient for plant growth throughout the life span of the crop. Wheat straw mulch not only source of nitrogen supply but also improves soil fertility and reduces soil erosion. The current study was performed to investigate the effects of mulches and nitrogen application on cotton productivity and fiber quality at the Central Cotton Research Institute (CCRI), Multan. Two crop residues i.e. wheat straw and non wheat straw were used in main plots while nitrogen levels viz. 0,50, 100 and 150 kg ha-1 were randomized in subplots. The highest seed cotton yield (22.99 t ha-1) was obtained by the combination of nitrogen fertilizer application highest level (150 kg N ha-1) along with the wheat straw (20.27 t ha-1). The fiber quality was also affected by the wheat straw along with nitrogen application 150 kg N ha-1 and gave maximum results. In conclusion, wheat straw along with 150 kg ha-1 of Nitrogen application gave maximum results on cotton production as compared to non straw with low nitrogen application.


2005 ◽  
Vol 62 (4) ◽  
pp. 357-365 ◽  
Author(s):  
Giovani Benin ◽  
Fernando Irajá Félix de Carvalho ◽  
Antônio Costa de Oliveira ◽  
Claudir Lorencetti ◽  
Igor Pires Valério ◽  
...  

Several studies have searched for higher efficiency on plant selection in generations bearing high frequency of heterozygotes. This work aims to compare the response of direct selection for grain yield, indirect selection through average grain weight and combined selection for higher yield potential and average grain weight of oat plants (Avena sativa L.), using the honeycomb breeding method. These strategies were applied in the growing seasons of 2001 and 2002 in F3 and F4 populations, respectively, in the crosses UPF 18 CTC 5, OR 2 <FONT FACE=Symbol>´</FONT> UPF 7 and OR 2 <FONT FACE=Symbol>´</FONT> UPF 18. The ten best genetic combinations obtained for each cross and selection strategy were evaluated in greenhouse yield trials. Selection of plants with higher yield and average grain weight might be performed on early generations with high levels of heterozygosis. The direct selection for grain yield and indirect selection for average grain weight enabled to increase the average of characters under selection. However, genotypes obtained through direct selection presented lower average grain weight and those obtained through the indirect selection presented lower yield potential. Selection strategies must be run simultaneously to combine in only one genotype high yield potential and large grain weight, enabling maximum genetic gain for both characters.


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