Grazing Vetch Research Articles

Evaluation of Tillage and Mulch Practices on the Growth of Selected Cereal and Legume Crops in the Foothills Agro-ecological Zone of Lesotho

The trial was conducted to evaluate the influence of tillage and mulch practices on growth response of maize and selected forage legumes. With three replications, the experiment was carried out using a split-plot design. Mulch and no mulch were used as the major plot treatments Mulch was maize straw left from the previous cropping season. The subplot treatments were different tillage practices namely Minimum (0.2 m) and Deep tillage (0.35 m).The research was carried out in the Foothills of Lesotho in Ha-Matela in Nazareth, east of Maseru District, during summer season for four months (December, January, February, and March). A mouldboard plough was used to prepare the experimental field, and it was harrowed to get fine tilth. The broadcasting method was used to plant the legume species namely soybean (Glycine max L), lablab (Lablab purpureus L) and grazing vetch (Vicia villosa), whereas a planter was used to sow maize seeds at a rate of two per hole, 0.25 m apart, and 0.05 m deep. For maize and the forage legumes, 12.5 kg of NPK inorganic fertilizer was applied per plot. Low moisture content and poor soil conditions under minimum tillage and no-mulch resulted in low plant growth. Maize and forage legumes plant height was significantly (P<0.05) higher under deep tillage and mulch. Vegetative characteristics in respect of leaf, stem, and root lengths were also significantly (P<0.05) higher under deep tillage and mulch. Cereal maize had a low and positive correlation relationship between its growth indices whereas; legume crops had a high correlation relationship and were significant. Therefore, maize and forage legumes may be produced under deep tillage and mulch to support improved plant growth.

English

A field trial was conducted to determine the effect of tillage and mulch practices on the biomass response of cereal maize and soybean, lablab and grazing vetch which are legumes, when planted as fodder crops. The experiment was conducted using split-plot design with three replications. The main plot treatments were two mulch levels (Mulch and No-Mulch). The mulch was maize straw left from previous cropping season. The subplot treatments were minimum tillage (0.2 m) and deep tillage (0.35 m). The parts of the four crops quantified were leaf, stem and roots. The combination of deep tillage and mulch practices resulted in significant (P<0.05) increase in the leaf, stem and root biomass of maize and, soybean, lablab and grazing vetch. Minimum tillage and no-mulch combined depressed (P<0.0.5)  the leaf, stem and root yield of maize while, for soybean, lablab and grazing vetch there was no definite trend of  significantly (P<0.05) depressed biomass for the leaf, stem and root yield under minimum tillage and no-mulch, and deep tillage and no-mulch. There was low correlation and positive significant relationship between leaf, stem and root and legume crops whereas, maize had a high correlation relationship with its biomass parameters. It is recommended that maize, soybean, lablab and grazing vetch can be grown as forage crops under combined deep tillage and mulch practices in the Foothills agro-ecological zone of Lesotho to obtain enhanced biomass. Key words: Cereal, legume, leaf, stem root, forage.

Foraging behaviour, digestion and growth performance of sheep grazing on dried vetch pasture cropped under conservation agriculture.

This study aimed to investigate the replacement value of half time grazing of wheat stubbles by vetch, which had been cropped under the context of conservation agriculture (CA). Three grazing treatments were evaluated on Barbarine lambs (initial BW 18±1.42kg). Treatment 1 consists of 6-hr grazing on dried vetch only (V). For treatment 2, the sheep were grazing 3hr on wheat stubbles in morning and 3hr on dried vetch in the afternoon (VWS). Treatment 3 consists of 6-hr grazing of wheat stubbles only (WS). At grain maturity stage, biomass yield of vetch averaged 7 tons DM/ha allowing a grazing period of 2 consecutive months. Along this period, vetch conserved its pods indehiscent. Biomass and nutritive value of vetch and wheat stubbles were decreasing from the start to the end of the grazing period. Residual biomass was higher in vetch and wheat stubble assigned to treatment VWS. WS lambs spent more time on walking and standing, while V and VWS lambs allocated more time on biomass uptake. The DM, OM and CP intakes were higher in animal grazing vetch alone or combined to wheat stubble. Rumen fermentation parameters (pH, ammonia nitrogen concentration and protozoa count) were not affected (p>.05) by any of the three treatments. The average daily gain of lambs on V and VWS lambs was three times greater (p<.05) than that of WS lambs (164, 152 and 49.5g respectively). Cold carcass yield averaged 444, 428 and 388g/ kg for lambs assigned to V, VWS and WS treatments respectively. It is concluded that grazing vetch alone or combined with WS increased substantially the growth performance and carcass yield of lambs compared with WS grazing only. Therefore, dried vetch grazing could be a solution to make possible mulching and biomass uptake by sheep under the context of CA.

Cover Crop Management in a Chardonnay/99 Richter Vineyard in the Coastal Region, South Africa. 2. Effect of Different Cover Crops and Cover Crop Management Practices on Grapevine Performance

The trial was conducted over a period of 10 years (1993/94 to 2002/03) on a medium textured soil in a Chardonnay/99 Richter vineyard near Stellenbosch (33°55’S, 18°52’E), situated in the Coastal Wine Grape Region of the Western Cape. Sixteen treatments, consisting of three grain species and five legumes, managed according to two cover crop management practices, were included. The one cover crop management practice consisted of cover crops being sown annually and full surface post-emergence chemical control being applied before bud break and when the berries reached pea size (BB). The other management practice consisted of cover crops being sown biennially and postemergence chemical control applied to the vine row before bud break and full surface when the berries reached pea size (AB). From 1999/2000 to 2002/03 the cover crops were sown annually, while the full surface post-emergence chemical control applied at the end of November was advanced to mid-October. These treatments were compared to a control, in which no cover crop was sown and the weeds were controlled mechanically in the work row and chemically in the vine row from bud break to harvest (approximately the first week of February). A treatment in which no cover crop was sown and full surface post-emergence chemical weed control was applied from before bud break to harvest (weedchem) was also included. During the 1994/95 season, the shoot mass of the two-year-old grapevines in the BB treatments was significantly higher than that of the control and the AB treatments. In the following season, the shoot mass and grape yield of the BB treatments was, with the exception of Vicia faba L. v. Fiord (faba bean) and Avena sativa L. v. Overberg, significantly higher than that of the control and weedchem. The grape yield of the control and AB treatments was significantly less than that of weedchem. Although significant differences in shoot mass (2000/01 and 2002/03) and grape yield (2002/03) were detected between treatments, no significant differences could be detected between the BB and AB treatments, with the exception of the shoot mass of Medicago scuttelata v. Kelson (‘Kelson’ medic). The mean petiole NO3-N concentration for the period 1994/95 to 1998/99 tended to be lower in the AB treatment of a cover crop species compared to that of the BB treatment of the same species. In the case of ‘Kelson’ medic (BB) the petiole NO3-N and juice N concentrations were significantly higher than that of the control and weedchem. The juice N concentration of the control and weedchem was significantly less than that of the faba bean treatments during 2000/01 and 2001/02, the Vicia dasycarpa Ten (grazing vetch) and ‘Kelson’ medic treatments during 2000/01, as well as that of Medicago truncatula Gaertn. (BB) and Trifolium subterraneum L. v. Woogenellup (BB) during the 2001/02 season. Wine quality did not differ between treatments.

Cover Crop Management in a Sauvignon Blanc/Ramsey Vineyard in the Semi-Arid Olifants River Valley, South Africa. 2. Effect of Different Cover Crops and Cover Crop Management Practices on Grapevine Performance

The trial was conducted over a period of ten years (1993/94 to 2002/03) on a sandy soil in a Sauvignon blanc/ Ramsey vineyard near Lutzville (31o35’S, 18o52’E), situated in the semi-arid Olifants River Valley of the Western Cape. Fourteen treatments, consisting of three grain species and four legumes, managed according to two cover crop management practices, were included. One management practice consisted of cover crops which were sown annually and full surface, post-emergence chemical control which was applied before bud break and when the berries reached pea size (BB). The second management practice consisted of cover crops which were sown biennially. Post-emergence chemical control was applied to the vine row before bud break and full surface when the berries reached pea size (AB). From 1999/2000 to 2002/03 the cover crops were sown annually, while the full surface post-emergence control applied at the end of November was advanced to mid-October. Two treatments in which Avena sativa L. v. Saia (‘Saia’ oats) and Vicia dasycarpa Ten. (grazing vetch) were sown annually, controlled mechanically in the work row and chemically in the vine row from bud break to harvest (MC), were also applied. These treatments were compared to a control, in which no cover crop was sown and MC was applied. A treatment in which no cover crop was sown and BB was applied (weedchem), was also included. During the third growing season of the vines (1994/95), the grapevine shoot mass of the BB treatments of grazing vetch and Medicago truncatula Gaertn. v. Paraggio (‘Paraggio’ medic) was significantly more than that of the AB and MC treatments, with the exception of Secale cereale L. v. Henog (AB) and grazing vetch (MC). The first harvest (1994/95) from the grapevines in the BB treatments was significantly higher than that of weedchem and the MC treatments. The grape yield of the BB treatments, grazing vetch (AB) and Ornithopus sativus L. v. Emena (pink Seradella) (AB) was significantly more than that of weedchem and the control during the 1997/98 season. The NO3-N concentration in the leaf petioles in all the cover crop treatments was, with the exception of the AB treatments of rye, M. truncatula Gaertn. v. Parabinga (‘Parabinga’ medic) and grazing vetch, significantly higher than that in weedchem and the control, as measured during the 1994/95 season. The NO3-N concentration in the leaf petioles of the BB and AB treatment of a species differed significantly. The N concentration in the juice of the cover crop treatments during the 1995/96 season was, with the exception of ‘Saia’ oats (MC) and ‘Parabinga’ medic (AB), significantly higher than that of weedchem and the control. During the 1998/99 season, the N concentration of the juice in the BB and AB treatments of grazing vetch and pink Seradella was significantly higher than that of the MC treatments, two rye treatments, weedchem and the AB treatments of the other cover crops. The concentration of Ca in the juice of the cover crop treatments was, with the exception of the pink Seradella treatments, significantly higher than that of weedchem and the control. Wine quality did not differ between treatments.

Cover Crop Management in a Sauvignon Blanc/Ramsey Vineyard in the Semi-Arid Olifants River Valley, South Africa. 3. Effect of Different Cover Crops and Cover Crop Management Practices on the Organic Matter and Macro-Nutrient Contents of a Sandy Soil

The trial was conducted over a period of ten years (1993/94 to 2002/03) on a sandy soil in a Sauvignon blanc/Ramsey vineyard near Lutzville (31o35’S, 18o52’E), situated in the semi-arid Olifants River Valley of the Western Cape. Fourteen treatments, consisting of three cereals and four legumes, managed according to two cover crop management practices, were included. One management practice consisted of cover crops which were sown annually. Full surface post-emergence chemical control was applied before bud break and again when the berries reached pea size (BB). The second management practice consisted of cover crops which were sown biennially. Post-emergence chemical control was applied to the vine row before bud break and full surface control was applied when the berries reached pea size (AB). From 1999/2000 to 2002/03 the cover crops were sown annually, while the full surface post-emergence control applied at the end of November (berries at pea size) was advanced to mid-October. Two treatments in which Avena sativa L. v. Saia (‘Saia’ oats) and Vicia dasycarpa Ten. (grazing vetch) were sown annually, controlled mechanically in the work row and chemically in the vine row from bud break to harvest (MC), were also applied. These treatments were compared to a control, in which no cover crop was sown and MC was applied. A treatment in which no cover crop was sown and BB was applied (weedchem), was also included. After five years (1997/98), the soil organic matter (SOM) in the 0-150 mm soil layer of the BB and AB treatments of grazing vetch was significantly higher than that of the control and weedchem. During March 2003, the SOM content in the 0-600 mm soil layer of grazing vetch (AB), as well as the 0-150 mm soil layer of Ornithopus sativus L. v. Emena (pink Seradella) (AB) and Secale cereale L. v. Henog (rye) (BB), was significantly higher than that of the control and weedchem. The total inorganic N concentration (TIN) of pink Seradella (BB) was the highest in the 0-150 mm soil layer during the full bloom stage of the grapevines in 1995/96 and significantly higher than that of the other treatments in the 150-300 mm soil layer. The TIN measured in the AB treatments of grazing vetch and pink Seradella as measured after the grapevine harvest (1995/96), was significantly higher than that of the control, weedchem and cereal treatments in the 0-300 mm and 0-150 mm soil layers, respectively. The TIN in the 0-150 mm soil layer of the legumes was, with the exception of pink Seradella (BB), significantly higher than that of the control, weedchem and the BB treatments of the cereals during March 2003. The TIN in the 150-300 mm soil layers of the AB treatments of pink Seradella and the two Medicago truncatula Gaertn. varieties, namely, Parabinga and Paraggio, was significantly higher than that of the control, weedchem and the grain treatments. Potassium concentrations in the 0-150 mm soil layer of the two pink Seradella treatments, the AB treatment of rye, Medicago truncatula Gaertn. v. Paraggio and grazing vetch, as well as the 150-300 mm soil layer of grazing vetch (BB) and pink Seradella (BB), were significantly higher than that of the control, weedchem and ‘Saia’ oats (MC) during March 1997.

Bicultures of oat (Avena sativa L.) and grazing vetch (Vicia dasycarpa L.) cover crops increase contents of carbon pools and activities of selected enzymes in a loam soil under warm temperate conditions

ABSTRACTThis study evaluated effects of oats (Avena sativa L.) and grazing vetch (Vicia dasycarpa L.), bicultures, in rotation with summer maize (Zea mays), on soil organic matter fractions and activities of selected enzymes. The trial was initiated in April 2009. The treatments were 100% oat, 100% vetch, 90% oat + 10% vetch, 70% oat + 30% vetch, 50% oat + 50% vetch, and weedy fallow, in a randomized complete block design (RCBD) with three replications. Soil samples were collected in October 2011, from the 0–5 and 5–20 cm depths, and analyzed for total carbon (C), particulate organic matter (POM), water-soluble carbon (WSC), microbial biomass carbon (MBC) and activities of selected enzymes. Total C was higher in bicultures, particularly the 70% oat + 30% vetch, and 100% vetch than in 100% oats and the control. The greatest MBC, WSC, dehydrogenase, aryl-sulphatase and phosphomonoesterase activities were in the 70% oat + 30% vetch biculture, and declined where the proportion of oats or vetch was higher. Increasing proportions of vetch resulted in increases in urease and β-glucosidase activity and decrease in POM. The findings suggested that, in addition to increased maize yields, bicultures of oats and vetch also have synergistic effects on soil carbon pools and enzyme activities, with potential benefits of improved soil physical condition and nutrient cycling compared with the individual crops, under warm temperate conditions.

English

English

Conservation agriculture effects on plant nutrients and maize grain yield after four years of maize–winter cover crop rotations

The effects of maize rotation with oat (Avena sativa cv. Sederberg) and grazing vetch (Vicia dasycarpa cv. Max) winter cover crops on nutrient availability, maize grain yield and maize grain nutrient concentration were investigated. Soil samples were collected from the 0–5 and 5–20 cm depths of experimental plots after four years of continuous maize–winter cover crop rotations. Winter cover crops caused small increases of extractable soil Cu, Mn, P and Zn, but not Ca and K, concentrations. A small dose of fertiliser applied to maize (60, 30, 40 and 1.5 kg ha−1 of N, P, K and Zn, respectively) also caused a significant increase in P and Zn, as well as mineral N, concentrations but only in the vetch–maize rotations. Stratification of Mn, K and Zn in the 0–5 cm soil depth occurred in all treatments. Vetch additionally increased maize grain yield, grain N concentration and soil acidity more than either oat or fallow. Non-fertilisation of maize reduced maize grain yield on oat and fallow–maize rotations more than it did on vetch–maize rotations. A combined application of vetch winter cover crops and small doses of fertiliser could significantly improve sustainability of low input maize-based conservation agriculture systems.

Biomass production, weed suppression, nitrogen and phosphorus uptake in white oat (Avena sativa L.) and grazing vetch (Vicia dasycarpa L.) cover crop bicultures under an irrigated no-till system

Cultivation of a multipurpose cover crop is of interest to Eastern Cape farmers experiencing soil infertility and weed pressures. The objective of the study was to investigate effects of oat–vetch bicultures on biomass production, weed suppression, and nitrogen (N) and phosphorus (P) uptake. The study was conducted between 2009 and 2010. Treatments included 90% oat + 10% vetch, 70% oat + 30% vetch, 50% oat + 50% vetch, 100% vetch, 100% oat and a weedy fallow as control. Bicultured cover crops had significantly (p < 0.05) higher biomass compared to sole vetch in both seasons but reduced biomass compared to sole oat only in 2010. Weed suppression increased with an increase in biomass. Weedy fallow had the least weed suppression (p < 0.05) at all sampling times, whereas sole oat provided the best early weed control compared to the rest of treatments. Nitrogen uptake by sole vetch was comparable to 50% oat + 50% vetch and 70% oat + 30% vetch. Phosphorus uptake differed only in the 2010 season and 90% oat + 10% vetch, 70% oat + 30% vetch and sole vetch had the best uptake. Weedy fallow had the least N and P uptake during the two seasons. Bicultures can be used for improved biomass, weed suppression, and N and P uptake with potential of alleviating soil degradation effects in the Eastern Cape province.

Conservation agriculture effects on soil organic matter on a Haplic Cambisol after four years of maize–oat and maize–grazing vetch rotations in South Africa

A study was conducted to determine the effects of oat (Avena sativa) and grazing vetch (Vicia dasycapa) winter cover crops and fertilization regimes on soil organic matter (SOM) in an irrigated maize-based (Zea mays L.) conservation agriculture (CA) system following four years of continuous practice. Separate plots of oat and grazing vetch cover crops were grown in winter and then maize was planted in all plots in the following summer season. The four fertilization regimes used were: (i) fertilizer applied to the cover crops and the maize crop (F1), (ii) fertilizer applied to cover crops only (F2), (iii) fertilizer applied to the maize crop only (F3) and (iv) no fertilizer applied (F4). Control plots (weedy fallows) were included and the treatments were laid out in a randomized complete block design with three replications. Soil samples from 0–5, 5–20 and 20–50cm depths were analyzed for total SOM, particulate organic matter (POM) fractions, hot water soluble C (HWC) and C-associated with water stable macro- and micro-aggregates (WSAC). While total SOM was more concentrated in the 0–5cm soil depth across treatments, a lack of maize fertilization (F2 and F4 regimes) significantly (P<0.05) reduced the stratification ratio. Oat and grazing vetch rotations produced significantly higher (P<0.05) fine POM, coarse POM and HWC than weedy fallow rotations at 0–5 and 5–20cm. When fertilized, oat was better able to support SOM sequestration in water stable aggregates at 0–20cm while grazing vetch was more effective at 20–50cm. The F3 regime had similar SOM levels as the F2. When no fertilizer was applied (F4-regime), there were significant (P<0.01) reductions in biomass input and total SOM on the oat–maize and weedy fallow–maize rotations whereas the grazing vetch–maize rotation did not respond, both at 0–5 and 5–20cm. The findings suggested that in the low fertilizer input CA system, targeting fertilizer to the winter cover crop as opposed to the maize crop could give similar SOM response, with less fertilizer invested and that grazing vetch cover crops may be better suited to low N input CA systems for SOM improvement.

The effect of cover crops on plant parasitic-nematodes of sugarcane

Plant-parasitic nematodes cause significant yield losses to sugarcane crops in South Africa. The currently available chemicals for nematode control are both expensive and potentially detrimental to the environment. Various alternative crops have been reported to reduce the numbers of plant-parasitic nematodes. Mindful of this, we evaluated 27 cover crops in pot trials to assess their host status to important plant-parasitic nematodes of sugarcane. All of the crops tested in pots hosted significantly lower numbers of Pratylenchus than did sugarcane. Crops such as cowpeas, tomato and grazing vetch were good hosts for Meloidogyne and would not be good choices as part of a sugarcane rotation system in heavily-infested soils. Conversely, crops such as oats, wheat, forage peanuts and marigolds reduced numbers of Meloidogyne. Velvet beans increased the abundance of Helicotylenchus, a beneficial nematode genus. A field trial was also conducted to study the effect of different cover cropping sequences. Our results show that changes in nematode communities occurred within three months of growing these crops and often remained low for the duration (the remaining 15 months) of the crops' growth. Nematodes such as Pratylenchus and Tylenchorhynchus were significantly lowered and remained so for the duration of the trial.

Mulch effects on soil moisture and nitrogen, weed growth and irrigated maize productivity in a warm-temperate climate of South Africa

Low soil fertility and weeds reduce maize yields on most smallholder (SH) irrigation schemes in South Africa (SA). While cover cropping can increase maize productivity, benefits from different types of mulch are not well understood, leading to challenges in selecting the most appropriate cover crop species to grow. Field experiments investigating the effects of oat ( Avena sativa), grazing vetch ( Vicia dasycarpa), faba bean ( Vicia faba), Lupin ( Lupinus angustifolius) and forage pea ( Pisum sativum) mulch on maize grown at two fertilizer levels (0 and 60 kg N/ha) were undertaken in the 2007/08 and 2008/09 seasons. Plots where maize was grown without mulch were included as controls. Treatments were arranged in a randomised complete block design with three replications. Grazing vetch and forage pea mulch significantly ( P < 0.01) improved soil inorganic N at 0–5 cm soil depth, with a mean of 84 mg N/kg compared to a mean of 64 mg N/kg in other treatments at planting. Oat and grazing vetch mulch significantly ( P < 0.05) reduced weed biomass compared to plots with lupin mulch and the control. Lack of maize fertilization tended to reduce maize yields but not for maize grown on grazing vetch mulch which yielded 7477 kg/ha compared to 2409 kg/ha for unfertilized maize grown on oat mulch. From an economic perspective, grazing vetch mulch resulted in the highest returns with a benefit:cost (B:C) ratio of 1.9 for the treatment with no fertilizer inputs during cover crop growth and maize growth. Grazing vetch is an attractive cover crop for SH farmers in irrigation schemes in warm-temperate climates.

Decomposition, nitrogen and phosphorus mineralization from winter-grown cover crop residues and suitability for a smallholder farming system in South Africa

Increasing land degradation has prompted interest in conservation agriculture which includes growing cover crops. Besides providing soil cover, decaying cover crops may release substantial amounts of nutrients. Decomposition, N and P release from winter cover crops [grazing vetch (Vicia darsycarpa), forage peas (Pisum sativum) and oats (Avena sativa)] were assessed for suitability in a cropping system found in the smallholder irrigation sector of South Africa. Nitrogen and P contribution to maize growth by cover crop residues was also estimated. Decrease in mass of cover crop residues was highest in grazing vetch (7% remaining mass after 124 days) followed by forage peas (16%) and lastly oats (40%). Maximum net mineralized N and P were higher for grazing vetch (84.8 mg N/kg; 3.6 mg P/kg) than for forage peas (66.3 mg N/kg; 2.7 mg P/ha) and oats (13.7 mg N/kg; 2.8 mg P/kg). Grazing vetch and forage pea residues resulted in higher N contribution to maize stover than oat residues. Farmers may use grazing vetch for improvement of soil mineral N while oats may result in enhancement of soil organic matter and reduction land degradation because of their slow decomposition. Terminating legume cover crops a month before planting summer crops synchronizes nutrient release from winter-grown legume cover crops and uptake by summer crops.

Doença granulomatosa sistêmica em bovinos no Rio Grande do Sul associada ao pastoreio de ervilhaca (Vicia spp)

Dois surtos de uma doença associada ao pastoreio de duas espécies de ervilhaca (predominantemente Vicia villosa e, em menor grau, V. sativa) foram observados em agosto-setembro de 2001, em vacas Holandesas adultas de duas propriedades rurais do Rio Grande do Sul. Foram afetadas, em uma das propriedades, quatro de 42 vacas (9,5%) e, na outra, uma de oito vacas (12,5%). Os sinais clínicos incluíam, embora não em todos os casos, febre, prurido, espessamento e enrugamento da pele com placas multifocais de alopecia, conjuntivite, corrimento nasal seroso, perda de peso, acentuada queda na produção de leite e diarréia. O curso clínico foi de aproximadamente duas semanas. Todas as vacas afetadas clinicamente morreram, uma foi sacrificada; três foram necropsiadas. Em cada um desses animais havia um padrão de lesões sistêmicas que consistiam de nódulos multifocais ou coalescentes, macios ou moderadamente firmes e branco-acinzentados, que infiltravam vários órgãos, mas eram particularmente proeminentes no miocárdio, nos linfonodos, no baço, na glândula adrenal e no córtex renal. Essas lesões resultavam em aumento de volume e alteração na arquitetura do órgão invadido. Microscopicamente, as lesões consis-tiam de extensa infiltração celular composta de proporções variáveis de macrófagos epitelióides, linfócitos, plasmócitos, células gigantes multinucleadas e eosinófilos. Os números de eosinófilos eram geralmente altos. Essa infiltração granulomatosa causava degeneração e perda de células parenquimatosas no órgão afetado. A intensidade das lesões variou entre as três vacas e entre os vários órgãos de cada animal. Essa é a primeira documentação no Brasil de doença granulomatosa sistêmica em bovinos associada ao pastoreio de ervilhaca.

Forage and sheep production from oats, rape and vetch sown in autumn with or without nitrogen fertilizer

Oats (Avena sativa cv. Acacia), vetch (Vicia dasycarpa cv, Lana) and rape (Brassica napus cv. Rangi) were sown with or without 67 kg ha-1 nitrogen (N) in the autumns of 1969 and 1970 at Armidale, N.S.W. In both years the crops were rotationally grazed by sheep in late winter and spring at two fixed stocking rates (experiment 1). When grazing began in both years oat dry matter (DM) availability was approximately double that of vetch and rape. Oats remained highly productive in successive grazing periods whereas the recovery of vetch after the first grazing was slow. At the high stocking rates employed the rape crops were overgrazed and failed to regrow. Fertilizer N increased oat yields by more than 50 per cent and N content by 20 to 40 per cent, but neither vetch nor rape responded significantly. Minimum nitrogen contents of oats, rape and vetch were respectively 1.3, 2.7 and 4.0 per cent. Digestible organic matter content of the three forages exceeded 74 per cent throughout the experiment. Daily rates of liveweight gain per sheep were not significantly different on the three crops in the first grazing period. Daily gain per sheep responded significantly to fertilizer N only on oats in the second period in 1970 (P &lt; 0.05). The total liveweight gain ha-1 pooled over all periods was much greater on oats than on vetch or rape. Clean wool per day tended to be higher on vetch than on the other crops but total wool production per hectare was greatest from oats in both years because of the longer period of grazing it provided. In a supplementary experiment (experiment 2) in 1969 the crops were grazed at an initially uniform stocking pressure (1 sheep per 10 kg dry matter available). Sheep grazing vetch gained 146 g head-1 day-1 which was faster than sheep on oats (92 g head-1 day-1) or rape (66 g head-1 day-1) (P &lt; 0.05). The general effect of N fertilizer was to increase daily gain and almost double the mean gain per hectare.