The production and persistency of different grass species cut at different heights

The effect of two heights of cutting (5 and 8 cm) on the dry matter harvested and persistency of a range of different grass species and varieties were monitored over a 3-year period (1976 to 1978). Dry matter harvested was measured in the second and third harvest year and persistence of sown grass was assessed at the end of the first and third harvest year. The grasses were managed under a frequent cutting system, i.e. simulated grazing. Results showed that at the low cutting height tetraploid hybrid ryegrasses and diploid Italian ryegrasses in the third harvest year gave lower annual dry matter harvests of sown grass and were less persistent than at the high cutting height, whilst, in contrast, perennial ryegrasses gave higher annual harvests of sown grass but persistency was unaffected. In general at the low cutting height varieties of cocksfoot, meadow fescue and tall fescue gave comparatively higher annual harvests of sown grass in the second harvest year but lower yields of sown grass in the third harvest year. A notable exception was Cambria cocksfoot which in the second harvest year gave higher yields of sown grass and was more persistent at the low cutting height.
However, at 5 cm cutting height, the proportions of weed grasses (mainly Poa spp.) in swards sown to tetraploid hybrid ryegrasses and diploid Italian ryegrasses were generally greater, particularly in mid-season.     

Potato top growth as influenced by temperatures

A study was conducted to establish a growth rate response of potato plant (Solanum tuberosum L.) tops to exposure to 72-hr periods of six constant temperature treatments (10, 15, 20, 25, 30, 35°C) and to determine a thermal optimum for vegetative potato growth rates. The plants were maintained under “no stress” soil moisture conditions throughout the study. The temperature treatments were accomplished by inserting the plants into a growth chamber for 72 hours at selected temperatures. Maximum growth (as measured by percent change in leaf area) occurred at 25°C with temperature growth differences significant at the 5% level. Plant height measurements (percent change occurring during treatment time) showed maximum stem elongation at 30°C during an early growth stage and 25°C during stage 2 (4 weeks later). Predictive models developed from the data indicate maximum rates of leaf area increase in both growth stages occur at 24.7°C and that maximum rates of stem elongation occur at 31.3 and 27.4°C for growth stages 1 and 2, respectively. Leaf water potential and stomatal resistance measurements taken at the end of each treatment period indicated that no water stress occurred.     

Prevalence of Listeria species as related to chemical quality of farm-ensiled grass

The occurrence of Listeria spp. in pasture grass and grass silage made with various additives and preservation techniques is reported. Silage samples were collected three times (in November, February and May) from eighty dairy farms. The prevalence of Listeria spp. in pasture grass samples was 0.647 and in silage samples 0.227. Only two species, L. monocytogenes and L. innocua were observed. Listeria spp. Were isolated from the silage at least once at thirtynine farms (0.488), and L. monocytogenes at twenty-seven farms (0.338). The occurrence of Listeria was highest among the silage samples collected in November (0.288). Silages preserved with acids had the lowest prevalence of Listeria (0.194). Silages preserved in tower silos were most often free of Listeria, only 0.056 being positive. The highest prevalence of the Listeria spp. (0.324) was detected in clamp silage. The results of chemical analyses of silage statistically reflect the frequency of Listeria.     

Reseeding in the Falkland Islands. Herbage production of a range of grass species and cultivars

The productivity of 20 cultivars from a range of 13 grass species was compared by harvesting four times during each of three successive growing seasons. In the experiment, 120 kg N ha⁻¹, 42 kg P₂O₅ ha⁻¹ and 42 kg K₂O ha⁻¹ were applied annually.
Mean annual yield was 3229 kg DM ha⁻¹ and 2147 kg DOM ha⁻¹. Cultivars were arranged in seven groups for comparison. Three of the groups, Lolium, Phleum and 'others' (the latter consisted of Festuca arundinacea cv. Dovey and Poa pratensis cv. Bensun A.34) appeared significantly lower yielding than the Dactylis, Festuca (fine-leaved), Agrostis and Holcus groups.
In the Lolium group, cv. Gremie outyielded cv. Melle every year. No cultivar of Dactylis was significantly better than any other in its group. Phleum CVS Motim and Eskimo were similar and superior to cv. S.50. Festuca ovina cv. Novina and Agrostis canina cv. Kingstown were marginally the best in their respective groups. The two cultivars of Holcus performed virtually identically. Festuca arundinacea cv. Dovey was a good producer of early spring grass. Poa pratensis cv. Bensun A.34 was generally low yielding and subject to fungal rust attack in autumn. The pattern of seasonal DM production was 16% in early spring (cut in October/November), 39% in mid-season (cut in December), 40% in late summer (cut in February/March) and 5% in autumn (cut in April/May). Quality of the herbage was superior to the main indigenous grass Cortaderia pilosa.
It was concluded that although the experiment was conducted under a cutting regime it provided useful guidance for seeds mixture formulation and stock carrying capacity calculations.     

Properties of sugar-snap cookies as influenced by lauric-based shortenings

The objective of this work was to assess the effect of different lauric-based shortenings with varying solid fat content (SFC) on sugar-snap cookie dough properties and cookie quality. Shortenings were produced by blending high oleic sunflower oil, palm kernel oil and palm stearin in different ratios, obtaining shortenings with different SFCs. It was observed that the SFC of the shortening largely influences the rheological properties of the cookie dough. At small deformations, fat crystals add elasticity to the dough; while at large deformations, fat-structure is disrupted, and it does not contribute to dough hardness. Fats with intermediate SFCs decrease dough resistance due to an enhanced shortening ability. Nevertheless, this effect is only obtained when shortening is homogeneously distributed in the dough. The SFC of the shortening influences dough and cookie structure by preventing gluten polymerization which was observed by a decrease in cookie break strength. A prerequisite for this effect is that shortening is finely dispersed in the dough. Good quality cookies were obtained using lauric-based shortenings, and best results were obtained with SFC between 20 and 25%. Higher SFC (around 45–50%) led to the production of unacceptable sugar-snap cookies.     

Nutritive characterization of purslane accessions as influenced by planting date

The uniqueness of purslane (Portulaca spp.) asthe richest vegetable source of omega-3 (-3)fatty acids is well documented. However, purslane hasnot been domesticated or fully evaluated for itsnutritive value. The objective of this study was todetermine the influence of planting date on chemicalcomposition of purslane accessions. Eight accessionsfrom different geographical locations were planted 12days apart, and whole plants harvested at full bloom. Chemical analysis (DM basis) of leaves showedsignificant differences among varieties for all thecharacteristics measured. Accession by planting dateinteraction influenced (p < 0.05) levels of crudeprotein, total lipids, and carbohydrate contents. Wild Greek accession had the highest, while aBeltsville (Maryland) wild type had the lowest crudeprotein content (27.1 vs 20.5%) at the secondplanting date. Crude protein, lipid and ash levelswere most influenced (p < 0.05) by planting date. Total lipids varied from 4.0–5.8% and 3.7–5.1% forthe first and second planting dates, respectively. Selected fatty acid content indicated significantly(p < 0.05) higher levels of 18: 26, and18: 33 in the Dutch Garden accession comparedwith other varieties. The Egyptian wild accession hadthe lowest level of 18: 33. The ratio of 3 to 6 acids, which ranged from 5.5 to22.3 indicated a highnutritive value of purslane compared to other oilcrops such as soybeans and perrilla. The high levelsof protein in purslane compete with those of othercommercially important vegetable crops. The studyshows that, in spite of its genetic diversity, purslaneremains one of the most abundant terrestrial vegetablesources of Omega-3 fatty acids and other essentialnutrients potentially beneficial for humans as well asanimals.     

In vitro fermentation patterns and methane production as influenced by cultivar and season of harvest of Lolium perenne L.

In some European countries, the majority of annual enteric methane (CH₄) emissions by ruminants occur at pasture – a direct result of the predominance of grazing within ruminant production systems. However, there are only limited data available as to the effect of perennial ryegrass cultivar and season of harvest on CH₄ production. Using the in vitro gas production technique, the effect of perennial ryegrass cultivar on fermentation characteristics and CH₄ production was determined (Experiment 1) and the persistence of these traits throughout the growing season for two cultivars, identified from Experiment 1 as having either a high or low methanogenic potential, was examined (Experiment 2). In Experiment 1, organic matter (OM) digestibility and cumulative total gas production profiles were unaffected by cultivar but, with regard to the kinetics of CH₄ production, the asymptote value (A), cumulative CH₄ yield at 72 h, and the fractional rate (μ) of CH₄ production at both time of 0·5A(T)(μCH₄T) and at 48 h (μCH₄48h) were significantly (P < 0·05) different. The amount of digested OM, as a proportion of cumulative CH₄ production (DigOM/CH₄) at 24 and 72 h after commencement of inoculation, revealed that the amount of substrate required to produce 1 ml of CH₄ also differed significantly between cultivars (P < 0·01). In Experiment 2, regrowth number significantly modified the majority of measured samples (P < 0·01); cultivar effects were limited to the lag phase of the cumulative CH₄ production curve and DigOM/CH₄ at 8 h only (P < 0·05). These results suggest that differences exist between cultivars in how OM is partitioned following microbial fermentation and that these differences demonstrate persistency throughout the growing season. In the course of time it may be possible to exploit these differences through cultivar selection and plant breeding programmes, and thereby reduce enteric CH₄ emissions within pastoral production systems.     

Herbage production and quality of a range of secondary grass species at five rates of fertilizer nitrogen application

The productivity of ten grasses was measured under six cuts per annum for 3 years and three cuts for a fourth harvest year in comparison with a perennial ryegrass (Lolium perenne) control. The grasses were Yorkshire fog (Holcus lanatus), two red fescues (Festuca rubra), creeping bent (Agrostis stolonifera), bent (Agrostis castellana), bent (Agrostis capillaris), smooth meadow-grass (Poa pratensis), crested dogstail (Cynosurus cristatus), sweet vernal (Anthoxanthum odoratum) and timothy (Phleum bertolonii). Another grass sown, rough meadow-grass (Poa trivialis), did not persist after the first harvest year. Annual N rates were 0, 120, 240, 360 and 480 kg ha^?1. Classified by DM production, the grasses grouped into: high (perennial ryegrass, Yorkshire fog and red fescue), intermediate (creeping bent, bent (A. castellana), crested dogstail and smooth meadow-grass) and low (bent (A. capillaris), sweet vernal and timothy. With frequent cutting, production ranking interacted with N rate: Yorkshire fog. red fescue and creeping bent were more productive than ryegrass at the 0 N and 120 N rates but not at higher N rates; crested dogstail and sweet vernal outperformed ryegrass at 0 N; ryegrass and smooth meadow-grass performed relatively better at moderate to high N. DM production of ryegrass was matched or exceeded by some of the other grasses during different parts of the season particularly at low N rates. Notable features from the 3-cut regime were the outstanding DM production of Yorkshire fog at all N rates and the poor production of bent (A. capillaris) and crested dogstail. High DM response to applied N in both cutting regimes was given by perennial ryegrass. smooth meadow-grass, red fescue cv. Boreal, timothy, crested dogstail and Yorkshire fog. N concentrations were highest in less productive grasses such as the bents and lowest in highly productive ryegrass and Yorkshire fog. Ryegrass was superior in digestibility to the other grasses, but especially to the red fescues, bents and smooth meadow-grass. The other grasses, especially Yorkshire fog and bent (A. capillaris) were superior to ryegrass in P, K and Mg concentrations, but not Ca. It is concluded that the annual and/or seasonal production of some of the secondary grasses at low to moderate N rates, e.g. the performance of Yorkshire fog and red fescue, warrant a reconsideration of their poor reputation, particularly within the context of increasing grassland extensification. Breeding to improve selected characteristics, such as digestibility in red fescue, seems justified. Assessment of the grazing and ensiling qualities of secondary grasses require further study.     

Identifying suitable temperate grass species and cultural practices for herbage production in the mountain regions of North Vietnam

In North Vietnam, during winter, shortage of herbage constrains the profitability of dairy farming. The first objective of this study was to evaluate the potential of alternative temperate (C₃) forage species, namely common oat ( Avena sativa L.), lop-sided oat ( Avena strigosa Schreb.), Italian ryegrass ( Lolium multiflorum L.) and a commercial forage mixture (Avex), to address the shortage of herbage during winter in the mountain regions of North Vietnam. The second objective was to measure the effects of cultural practices (sowing rate, harvest interval and irrigation level) on yield of dry matter (DM), chemical composition, digestibility of DM and metabolizable energy (ME) concentration of herbage from the best adapted C₃ species previously tested (lop-sided oat). Four experiments were conducted. Oat species proved to be the best adapted species and produced the highest annual yield of herbage (7600 kg DM ha⁻¹) with a high nutritive value. Yields of DM of lop-sided oat were not affected by sowing rate of seed but increased as the length of harvest intervals increased from 30 to 45 and 60 d ( P  <   0·001). Crude protein concentration, digestibility of DM and ME concentration decreased as the harvest interval increased ( P  <   0·01). Irrigation increased the yields of DM of lop-sided oats by 1·3 ( P  <   0·05) but had no effect on the nutritive value of herbage. It is concluded that both common oat and lop-sided oat are suitable species to provide herbage in the winter for the mountain regions of North Vietnam.     

Herbage production from swards containing a range of grass, forb and clover species and under extensive management

Three small plot experiments were conducted to investigate the effects of species of grass and forbs, defoliation regime, inclusion of white clover and forb blend on the herbage dry matter (DM) yield, botanical composition and mineral content of swards managed with zero fertilizer inputs. The results of all three experiments were characterized by decline in herbage production and large variations in treatment effects over the harvest period.
When sown singly with a standard grass mix the species that competed well with grasses and produced annual forb herbage yields greater than 20 t DM ha⁻¹ were black knapweed, oxeye daisy, ribwort plantain, burnet, birdsfoot trefoil, chicory, kidney vetch, red clover and white clover. When sown singly with a standard forb mix, grass species significantly affected the annual yield of total ( P <005). grass ( P <001) and forb ( P <0.001) herbage. The species that most surpressed the yield of forbs were common bent, Yorkshire fog and perennial ryegrass. Those that allowed for the highest yield of forbs were rough meadow grass, sweet vernal grass and crested dogstail. Averaged over the three harvest years, defoliation regime did not significantly affect herbage production, but the inclusion of white clover in mixtures increased the yield of grasses ( P <0.01) The use of rosette-type forb blends increased forb yield ( P <0.01), compared with erect-type blends.
The effects of treatments on herbage N and mineral contents and yields were inconsistent. However, there was some evidence to support the view that the presence of forb species in swards can result in greater contents of minerals in herbage, compared with grass-only swards.     

Herbage growth rates on heterogeneous swards as influenced by sward-height classes

The contribution of four classes of sward height to daily herbage growth rates of a heterogeneous sward in eight periods throughout a grazing season was investigated in two continuous cattle-grazing systems differing in intensity (moderate stocking rate: MC; lenient stocking rate: LC). At the beginning and end of periods of 12 to 28 d, the compressed sward height (CSH) was measured in exclusion cages at eighteen fixed points per cage to derive daily growth rates for the four classes of sward height. Stratified calibrations were made to relate sward height to herbage mass for each treatment in each period. Quadratic regressions described the relationship between herbage growth rate and initial CSH for each treatment in each period. For scaling up to the scale of the plot, CSH was measured monthly at 100 points per plot. Daily herbage growth rates declined from more than 100 kg dry matter (DM) ha⁻¹ d⁻¹ on both treatments at the beginning of the grazing season to 20 kg DM ha⁻¹ d⁻¹ or less, especially on treatment LC. This was due to the larger area covered by tall herbage on treatment LC than on treatment MC. On treatment MC, daily herbage growth rate was predominantly derived from short sward areas of up to 12 cm in height while sward areas taller than 12 cm contributed most to daily growth rates on treatment LC in early summer. The method used is considered suitable for estimating daily herbage growth rates of different classes of sward height in extensively managed pastures and can easily be adapted to deal with more heterogeneous swards than used in this study.     

Alfalfa establishment without tillage as influenced by insecticide and vegetation suppression

Conventional alfalfa ( Medicago sativa L.) establishment methods may create considerable potential for erosion. Conservation tillage practices that result in stand establishment without disturbing the soil greatly would be beneficial in reducing soil losses. Thus, field experiments were conducted to evaluate the success of alfalfa establishment without tillage in a perennial grass sod. Variables included rate of carbofuran (2, 3-dihydro-2, 2-dimethyl-7 benzofuranyi methylcarbamate) insecticide and control of existing vegetation with chemicals. Establishment without tillage was compared with a conventional method of establishment. Carbofuran at 1.1 kg ha⁻¹ applied in the row with the seed, when compared with a control, increased yields during the year of planting but no response was observed in the year after seeding. Yields of alfalfa established without tillage using either glyphosate ( N -(phosphonomethyl)glycine) or paraquat (1,1-dimethyl-4, 4-bipyridinium chloride) for sod suppression were equivalent to or better than yields obtained from conventional sowings except for the 2 April sowing. Paraquat was more effective for tall fescue (Festuca arundinacea Schreb.) suppression when applications were made on 26 April after spring tiller emergence was complete than on 2 April when some of the tillers may have been protected from the spray by basal sheath tissue.
Broadcast application of paraquat resulted in higher alfalfa yields and decreased non-alfalfa components due to more complete sod suppression than application in bands over the row.     

Inheritance of tuber initiation in tuber bearingSolanum as influenced by photoperiod

Eight potato clones (three day-neutral (DN) Tuberosum, one dayneutral and four short-day (SD) Andigena) were used as parents. Eight genetic sets bearing P₁, P₂, P_1?, P_2?, F₁, F₂, BC₁, and BC₂ generations were developed. Two sets were DN×DN crosses, four SD×DN, and two SD×SD. Tuber initiation (TI) was evaluated in growth chambers with daylengths of 11, 13, and 15 hours. The stolons of each genotype were examined every eight days between the 38th and 86th day after planting. F₁ generation means from SD×DN crosses showed complete dominance of SD reaction (late TI) over DN reaction (early TI). F₁ generation means from DN × DN and SD× SD crosses showed either no dominance or a slight tendency towards the late TI parent. Within plot variances of the selfed generations suggested a variable degree of parental heterozygosity for the loci controlling TI. Andigena clones showed the greatest heterozygosity. Bell shaped frequency distributions in the segregating generations indicated that TI was under the control of several genes. It appears also that major and minor genes were involved. Broad sense heritability estimates of about 90% at 11 hours and 55% at 15 hours of daylength were computed.     

Physicochemical characteristics of flours of faba bean as influenced by processing methods

Wet- and dry-processing with and without heating treatments were used to dehull faba beans for preparation of flours from the cotyledons. Flour qualities were assessed by levels of tannin and trypsin inhibitor and other measures of proximate composition. High roasting temperature and shorter process time that improved the recovered cotyledon yields were verified significant by path analysis methodologies. In turn, the higher cotyledon recoveries correlated with higher protein levels and inversely with the measured tannin levels. Ash reductions were correlated to the wet processing options in hull removal while reductions in the insoluble dietary fiber were notably influenced by level of heating temperatures applied. Trypsin inhibitor levels ranged from 42 to 56% of the original with reductions tied to applications of wet and/or heat processing in each case improved by increased durations and temperatures of treatments.     

Characterizing N uptake and use efficiency in rice as influenced by environments

To compare N uptake and use efficiency of rice among different environments and quantify the contributions of indigenous soil and applied N to N uptake and use efficiency, field experiments were conducted in five sites in five provinces of China in 2012 and 2013. Four cultivars were grown under three N treatments in each site. Average total N uptake was 10–12 g m^?2 in Huaiji, Binyang, and Haikou, 20 g m^?2 in Changsha, and 23 g m^?2 in Xingyi. Rice crops took up 54.6–61.7% of total plant N from soil in Huaiji, Binyang, and Haikou, 64.3% in Changsha, and 63.5% in Xingyi. Partial factor productivity of applied N and recovery efficiency of applied N in Changsha were higher than in Huaiji, Binyang, and Haikou, but were lower than in Xingyi. Physiological efficiency of soil N and fertilizer N were lower in Changsha than in Huaiji, Binyang, and Haikou, while the difference in them between Changsha and Xingyi were small or inconsistent. Average grain yields were 6.5–7.5 t ha^?1 (medium yield) in Huaiji, Binyang, and Haikou, 9.0 t ha^?1 (high yield) in Changsha, and 12.0 t ha^?1 (super high yield) in Xingyi. Our results suggest that both indigenous soil and applied N were key factors for improving rice yield from medium to high level, while a further improvement to super high yield indigenous soil N was more important than fertilizer N, and a simultaneous increasing grain yield and N use efficiency can be achieved using SPAD-based practice in rice production.