Defoliation frequency and genotype effects on stolon and root reserves in white clover

1998 ◽  
Vol 49 (6) ◽  
pp. 983 ◽  
Author(s):  
A. R. Lawson ◽  
P. W. G. Sale ◽  
K. B. Kelly

The effect of defoliation frequency (1 or 3 defoliations over a 42-day period) on the starch, water soluble carbohydrate (WSC), and nitrogen contents of 3 white clover cultivars (Haifa, Irrigation, and S184) was examined. The clover plants consisted of single stolons growing in a sand/scoria mix in an unheated glasshouse and fertilised weekly with a nitrogen-free solution. Starch concentrations ranged from 1·3% in frequently defoliated Haifa to 15·3% in infrequently defoliated S184 plants. However, there was no interaction between cultivar and defoliation frequency, with the starch concentration in S184 (11·2%) being twice that in Irrigation (6·0%) and 3 times that in Haifa (3·8%). The starch concentration was also less with frequent (3·7%) than with infrequent (10·3%) defoliation. The starch was localised in the old stolon material (12·2%), with lower levels of starch in both the young stolon (6·0%) and roots (4·0%). Furthermore, the cultivar and defoliation frequency effects on the starch concentrations were most pronounced in the old stolon. More frequent defoliation also resulted in a small reduction in the WSC and nitrogen concentrations in both the young and old stolons of Haifa, but not of Irrigation. It was concluded that although starch reserves were the principal method of reserve storage in white clover, WSC and nitrogen reserves will form a relatively large fraction of the reserve pool when starch reserves are depleted under conditions such as frequent defoliation.

2000 ◽  
Vol 51 (8) ◽  
pp. 1039 ◽  
Author(s):  
A. R. Lawson ◽  
K. B. Kelly ◽  
P. W. G. Sale

The effects of defoliation frequency (2 or 6 defoliations over a 91-day period) on the reserve status and growth rate of 2 white clover cultivars, cvv. Irrigation (medium-leafed) and Haifa (large-leafed), were examined over the final 42 days of the defoliation treatments. The clover plants consisted of single stolons growing in a sand/scoria mix in an unheated glasshouse, and were fertilised weekly with a solution containing essential nutrients excluding nitrogen. More frequent defoliation reduced the leaf appearance rate, stolon elongation rate, and plant size, and increased stolon death, with all of these effects being less pronounced in Irrigation than in Haifa (18% v. 30%, 60% v. 80%, and 23% v 34%, respectively, for leaf appearance rates, stolon elongation rates, and the proportion of stolon length that died). With infrequent defoliation, the combined utilisation of starch and water-soluble carbohydrate (WSC) reserves in the first 14 days after defoliation was equivalent to 15% of the plant weight at defoliation, and to 95% of the new leaf produced during that period. Frequent defoliation reduced the reserve content and remobilisation less in Irrigation than in Haifa, with the combined mass of remobilised starch and WSC over the first 14 days after defoliation being 2.9% and 2.0% of the plant weight at defoliation, and 29% and 19% of leaf production over that period, for Irrigation and Haifa, respectively. The greater reserve mobilisation in Irrigation than in Haifa plants under frequent defoliation probably contributed to their higher growth rates and reduced stolon death. These cultivar differences with frequent defoliation suggest that Irrigation is more suited to frequent defoliation than Haifa.


1973 ◽  
Vol 13 (61) ◽  
pp. 165 ◽  
Author(s):  
PJ Michell

Neutral detergent fibre (NDF), acid detergent fibre (ADF) and water soluble carbohydrate (WSC) levels were determined on 80 samples of known apparent dry matter digestibility (DMD) and voluntary intake of dry matter (DMI). The pastures consisted of regrowths of six species: Trifolium repens (white clover cv. Grasslands Huia), Lolium perenne x L. multiflorum (short rotation ryegrass c.v Grasslands Manawa), Lolium perenne (long rotation ryegrass cv. Grasslands Ariki), Lolium perenne (perennial ryegrass cv. Tasmania No. I), Dactylis glomerata (cocksfoot cv. Currie) and Dactylis glomerata (cocksfoot cv. Grasslands Apanui), cut eight times between May 1969 and August 1970. Overall, white clover had a lower NDF and a lower WSC content than the ryegrasses but both groups had similar ADF contents. Cocksfoots had higher NDF and ADF, and lower WSC contents than the ryegrasses. NDF and ADF could be used to predict the DMD of all species in all seasons with residual standard deviations (RSD) of 3.0 and 3.2 DMD units (per cent) respectively. No significant relations (P < 0.05) were present between DMD and WSC content. Seasonal differences were present in the relations between DMI and chemical composition. The RSD of the overall regressions of intake with NDF, ADF, and WSC contents were 9.3, 9.4, and 8.9 DMI units (g/day/kg0.75) respectively. Within seasons, DMI was best predicted by regressions with detergent fibre content and here the RSD had a range of 3.4 to 5.2 DMI units. Within species over all seasons, DMI was predicted best by regressions with WSC content and the RSD had a range of 5.7 to 7.9 DMI units. The usefulness of the chemical composition measurements in explaining the reason for the low intakes, previously found with winter pasture, is discussed.


1979 ◽  
Vol 92 (3) ◽  
pp. 605-616 ◽  
Author(s):  
M. J. Ulyatt ◽  
A. R. Egan

SUMMARYThe extents and sites of digestion of organic matter (OM), and its constituent watersoluble carbohydrates, organic acids, pectin, cellulose, hemicellulose and crude protein have been studied in sheep prepared with re-entrant duodenal cannulas and fed four fresh herbage diets, Ruanui perennial ryegrass, Tama Westerwolds ryegrass, Pitau white clover and Fakir sainfoin, at each of two levels of intake.The water-soluble carbohydrate, organic acids and pectin of all diets were almost completely digested within the rumen. Some 10% of water soluble carbohydrate reached the duodenum on each diet, though this may not have been of dietary origin. Only on legume diets, where pectin concentration was higher, did measurable amounts of pectin reach the intestine, accounting for some 5% of the pectin.Hemicellulose and cellulose digestibilities differed between diets, being lowest for sainfoin, and next lowest for clover. Between 79 and 94% of digestible hemicellulose was digested in the stomach, but diet and intake had no significant effect on this partition. Of the digestible cellulose, 87–97% was digested in the stomach.Digestibility of N was lowest for sainfoin and highest for Tama ryegrass. There were no significant differences between herbage species or intake in the percentage of digested N digested in the stomach or intestines. The tannin contained in sainfoin had no effect on nitrogen digestion.Data from this and other studies reported in the literature were examined as a basis for establishing prediction equations whereby the partition of digestion of the major carbohydrate and nitrogenous constituents in stomach and intestines might be estimated from data obtainable from standard digestibility trials. Regressions were developed for predicting the amounts of OM, cellulose, and hemicellulose digested in the stomach. There are not yet enough suitable data available to predict the amount of nitrogen entering the small intestine.


2005 ◽  
Vol 2005 ◽  
pp. 194-194
Author(s):  
C. L. Marley ◽  
D. A. Davies ◽  
J. E. Vale ◽  
J. G. Evans ◽  
N. D. Scollan ◽  
...  

Grazing experiments have shown that using a ryegrass (Lolium perenne L.) variety bred by conventional techniques for high water-soluble carbohydrate (WSC) concentrations can improve liveweight gain in pre-weaned lambs (Lee et al., 2001) and increase milk yields and reduce N excretion in dairy cows (Miller et al., 2001) compared to conventional ryegrass. The aim of this study was to determine the effects of using reseeded upland pastures, sown with either a ryegrass variety bred for elevated levels of WSC or a control ryegrass on the production performance of grazing steers when compared to steers grazing permanent ryegrass/white clover pastures.


2017 ◽  
Vol 79 ◽  
pp. 111-118
Author(s):  
L.A. Box ◽  
G.R. Edwards ◽  
R.H. Bryant

Chicory and plantain have been suggested as alternative grazed forages to perennial ryegrass for New Zealand dairy systems. While diurnal changes in plant chemical composition have been described for ryegrass there is currently little information for herbs. This experiment aimed to compare the effect of nitrogen inputs (low and high) and harvesting time (am versus pm) on the chemical composition of four forages (ryegrass, plantain, chicory and white clover). The effect of harvest time was greater than N fertiliser inputs on chemical composition for all forages. Ryegrass showed the greatest increase in water soluble carbohydrate diurnally, at the expense of neutral detergent fibre and to a lesser extent crude protein. This suggests afternoon allocation of ryegrass may be beneficial to improve the nutritive value of pasture on offer; allocation timing is less important for white clover, chicory and plantain. Keywords: chicory, clover, crude protein, plantain, ryegrass, water soluble carbohydrate


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1333
Author(s):  
Javier García-Favre ◽  
Yongmei Zhang ◽  
Ignacio F. López ◽  
Daniel J. Donaghy ◽  
Lydia M. Cranston ◽  
...  

Bromus valdivianus Phil. (Bv) is a water stress-tolerant species, but its competitiveness in a diverse pasture may depend on defoliation management and soil moisture levels. This glasshouse study examined the effect of three defoliation frequencies, based on accumulated growing degree days (AGDD) (250, 500, and 1000 AGDD), and two soil water levels (80–85% of field capacity (FC) and 20–25% FC) on Bv growth as monoculture and as a mixture with Lolium perenne L. (Lp). The treatments were applied in a completely randomised block design with four blocks. The above-ground biomass of Bv was lower in the mixture than in the monoculture (p ≤ 0.001). The Bv plants in the mixture defoliated more infrequently (1000 AGDD) showed an increase in root biomass under 20–25% FC compared to 80–85% FC, with no differences measured between soil water levels in the monoculture. Total root length was highest in the mixture with the combination of infrequent defoliation and 20–25% FC. Conversely, frequent defoliation treatments resulted in reduced water-soluble carbohydrate reserves in the tiller bases of plants (p ≤ 0.001), as they allocated assimilates mainly to foliage growth. These results provide evidence that B. valdivianus can increase its competitiveness relative to Lp through the enhancement of the root growth and the energy reserve in the tiller base under drought conditions and infrequent defoliation in a mixture.


2017 ◽  
Vol 77 (3) ◽  
pp. 218-225 ◽  
Author(s):  
Luis Inostroza ◽  
Iris Lobos ◽  
Hernán Acuña ◽  
Catalina Vásquez ◽  
Gerardo Tapia ◽  
...  

Author(s):  
K.H. Widdup ◽  
J.L. Ford ◽  
B.A. Barret ◽  
D.R. Woodfield

Water soluble carbohydrate (WSC) provides readily available energy in the rumen that improves the efficiency of crude protein (CP) utilisation, partitioning of dietary N towards animal growth, and reduces the loss of N as urea.


1994 ◽  
Vol 45 (6) ◽  
pp. 1309 ◽  
Author(s):  
WJ Fulkerson ◽  
K Slack ◽  
KF Lowe

A glasshouse study was undertaken to determine the effect of defoliation frequency (three times at one leaf stage or once at three leaf stage of the regrowth cycle) and height (20, 50 or 120 mm) on regrowth, plant water soluble carbohydrate (WSC) reserves and root growth of seven Lolium perenne and two Lolium multiflorum cultivars. The sensitivity to defoliation was in decreasing order: biennial, PI perennials (cv. Ellett, AN2327, LP30, LP31), P2 perennials (cv. Kangaroo Valley, Yatsyn, Pacific). The effect of frequent, compared to infrequent, defoliation was to suppress regrowth by l00%, 95% and 80%; stubble WSC (mg/plant) by 97, 89 and 81%; root DM (g/plant) by 76, 60 and 6%, for biennial, P1 and P2, respectively. The effect of defoliation height accentuated this response, with biennials defoliated frequently at 20 mm stubble height all dying. Under defoliation conditions producing optimal yield, the yield was positively related to sensitivity to defoliation, giving regrowths of 2.90, 2.68, 1.53 g DM per plant for biennial, P1 and P2 plants, respectively. In view of the marked defoliation by cultivar interaction, response to defoliation should be considered as a possible selection criterion in any evaluation process.


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