Mixture Of Oats Research Articles

Soil mineral nitrogen and microbial parameters as influenced by catch crops and straw management

Agricultural management can affect soil chemistry, nutrient cycling and microbial properties, but the relationship among them is not well explored. Catch crops play an important role in decreasing nitrogen (N) leaching in the autumn, and thereby reduce undesirable environmental effects, improve soil physical and microbiological properties. We investigated the effect of catch crops and straw management on soil mineral nitrogen (N min ) and microbial activity on a clay loam Gleyic Cambisol (CMg). A two-factor experiment was set up: 1) catch crops (narrow-leafed lupin, mixture of narrow-leafed lupin and oats, white mustard and without catch crops), and 2) straw management methods (with and without). The total amount of bacteria and fungi, dehydrogenase and urease activity, and potential nitrification rate were assayed during two successive spring barley growing seasons. Also we determined N in the soil and soil leachate. Our experimental findings indicated that the N min dynamics in the soil and nitrate nitrogen (N-NO 3 ) leaching depended on the catch crops, the amount of decomposers and the weather conditions. Cultivation of post-harvest catch crops in a clay loam Cambisol reduced N min content by 50–62% at the 0–40 cm soil layer, stubble breaking in the autumn by 23–41%, compared with the soil where the stubble had not been broken and no catch crops had been grown. Also, cultivation of catch crops reduced nitrate (N-NO 3 ) concentration in the soil leachate by 32–62%. The biological variables differed among all treatments, especially among years. Higher counts of heterotrophic bacteria and fungi and greater enzymatic activity were recorded in the plots with catch crops. Higher nitrification activity was established in the plots without catch crops. The amount of cellulose degrading bacteria did not differ significantly between the treatments. Further research is needed to get a better insight into the processes of mineralization and immobilization of catch crops’ residues and soil N min and N-NO 3 leaching in agricultural ecosystems.

THE EFFECT OF MIXTURE RATES AND CUTTING STAGES ON SOME YIELD AND QUALITY CHARACTERS OF PEA (Pisum sativum L.)+OAT (Avena sativa L.) MIXTURE

This research was conducted to determine the effects of seed rates in mixtures of pea+oat and cutting stages on the hay yield and its quality. The experiment was performed over two years (2003-2005) at Uludag University, Faculty of Agriculture, Agricultural Research and Application Center, Bursa, using five different mixture rates of pea and oat crops (100% Pea+0% Oat, 75% Pea+25% Oat, 50% Pea+50% Oat, 25% Pea+75% Oat and 0% Pea+100% Oat) and three different cutting stages (the jointing stage of oat, the stage oat in scabbard and milkdough stage of oat). According to the results, it may be suggested that the mixture of 25% pea+75% oat should be grown to obtain higher hay yield and the mixture of 50% pea+50% oat to obtain higher level of crude protein. In addition, the pea+oat mixture should be harvested at oat milk-dough stage.

Smother Crop Mixtures for Canada Thistle (Cirsium arvense) Suppression in Organic Transition

Canada thistle poses a particular threat to organic producers in temperate agriculture due to its ability to reproduce through an extensive system of underground roots. The Canada thistle life cycle, growth, and development are seasonally affected, and exploiting this biology may be useful for weed management. The objective of this study was to evaluate smother crop mixtures, seeded at different times, for Canada thistle control. Field trials were established in 2009 and 2010 to evaluate the ability of smother crop mixtures to suppress Canada thistle growth and development. Canada thistle aboveground biomass was suppressed 50% in 2009 and 87% in 2010 by the sorghum–sudangrass mixture, averaged over planting times. The oat mixture suppressed annual weed biomass more than 58% in 2009 and 67% in 2010 in all planting dates. Percent cover of Canada thistle was affected by crop mixture in 2009 and 2010, with sorghum–sudangrass being the most suppressive. The sorghum–sudangrass mixture was more suppressive of Canada thistle, probably because it included soybean and sunflower, all high-biomass, competitive crops. Planting date affected smother crop suppression of Canada thistle growth, but the effect was not consistent between 2009 and 2010 due to differences in weather conditions.

Different species of legumes grown in combination with oats as green forage

Green fodder mixture trials were carried out with GK Impala, a winter hardy, fall sown oat variety registered in 2005 intercropped either with winter vetch or winter pea in a crop year when the spring was dry (2003) and in another one (2004) when the precipitation was optimal in spring. The two components of mixtures were sown 50% each. A four-replicate randomised complete block design was used with 50 m2 plots. The results were compared to the mixtures of spring oats and vetch; and spring oats and pea, respectively. The green matter of fall sown crops was cut by scythe late May, whereas that of spring crops early June.Data demonstrate that the green forage yield and protein production of fall sown oats as a monocrop and intercropped with vetch was higher than those of spring types. Green matter and dry matter yield varied with season, and were more advantageous in the year 2004, when there was more precipitation. The crude protein content of winter vetch and the crude protein production of the mixture fa...

Environmental factors associated with American cutaneous leishmaniasis in a new Andean focus in Colombia

To evaluate the environmental and ecological factors associated with Leishmania transmission and vector abundance in Chaparral, Tolima-Colombia. First, we compared the ecological characteristics, abundance of phlebotomies and potential reservoir hosts in the peridomestic environment (100 m radius) of randomly selected houses, between two townships with high and low cutaneous leishmaniasis incidence. Second, we examined peridomestic correlates of phlebotomine abundance in all 43 houses in the higher risk township. The high transmission township had higher coverage of forest (23%vs. 8.4%) and shade coffee (30.7%vs. 11%), and less coffee monoculture (16.8%vs. 26.2%) and pasture (6.3%vs. 12.3%), compared to the low transmission township. Lutzomyia were more abundant in the high transmission township 2.5 vs. 0.2/trap/night. Lutzomyia longiflocosa was the most common species in both townships: 1021/1450 (70%) and 39/80 (49%). Numbers of potential wild mammal reservoirs were small, although four species were found to be infected with Leishmania (Viannia) spp. In the high transmission township, the overall peridomiciliary capture rate of L. longiflocosa was 1.5/trap/night, and the abundance was higher in houses located nearer to forest (ρ = -0.30, P = 0.05). The findings are consistent with a domestic transmission cycle with the phlebotomies dependent on dense vegetation near the house.

Effects of continuous and rotational grazing of different forage species on ewe milk production

The aim of this research was to evaluate the effects of continuous and rotational grazing of different forage species on milk production in ewes. The forage species were chicory (Cichorium intybus L.), a mixture of oat (Avena sativa L.) and berseem clover (Trifolium alexandrinum L.), and sulla (Hedysarum coronarium L.). Forty ewes were divided into 5 groups, and subjected to one of the following treatments: continuous grazing on chicory, continuous grazing on the mixture, continuous grazing on sulla, rotational grazing on the mixture, or rotational grazing on sulla. Among the species continuously grazed, chicory showed a lower biomass than the mixture, or sulla. Ewes grazing chicory produced more milk than ewes grazing the mixture (1243 vs. 1003g/d; P≤0.01), whereas ewes grazing the sulla showed an intermediate milk yield (1136g/d). During the experiment there was a gradual decrease in milk yield which was less pronounced for chicory, than for the other species. The fat, protein, and casein contents in the milk increased as the milk yield decreased. Compared with continuous grazing, rotational grazing produced a greater forage biomass. Moreover, ewes on continuous grazing produced a higher milk yield than those under rotational conditions (1070 vs. 951g/d; P≤0.05). The grazing period also influenced milk production: in the first period (April), when more forage was available, the ewes produced more milk than during the second period (May). Furthermore, the ewes grazing sulla recorded a higher milk yield in the first period, compared to those grazing the mixture (1377 vs. 1159g/d; P≤0.05), but this difference was not evident during the second period. These results highlight the productivity of sulla, and the potential of chicory in providing a lasting good-quality herbage, and therefore the positive effect of these species on dairy performance in grazing ewes. Although rotational grazing produced more forage biomass, the results indicate that it does not always lead to increased milk production in animals, because of the lower nutritional value of forage grazed in an advanced phenological stage.

Effect of legume-cereal mixtures on the diversity of bacterial communities in the rhizosphere

Aboveground plant diversity is known to influence belowground diversity and ecosystem processes. However, there is little knowledge of soil microbial succession in legume-grass mixtures. Therefore, this study was designed to determine the effect of oat and common vetch binary mixtures at three seeding rates on soil bacterial communities. Denaturing gradient gel electrophoresis (DGGE) of 16S rDNA fragments was used to profile the structure of the bacterial community in the rhizosphere. Compared with a monoculture of common vetch and oat, the Shannon-Weaver index and species richness of the mixtures were increased. Thirteen cloned monocultures and mixtures of oat and common vetch soil 16S rDNA sequences were deposited to NCBI. Based on the sequencing results, the bands could be identified as related to Proteobacteria, Bacteroidetes and Cyanobacteria. Common vetch did not have some bacteria relatives to Sphingomonas spp. Some bacterial taxa could be detected in the ratio of 1:1 and 1:2, but not in the ratio of 1:3, e.g. Myxococcales. The results suggested that the belowground diversity could be promoted by mixed cropping systems.  

Abstract P073: Increased Consumption of Wheat and Oat-based Wholegrain Foods does not Affect Serum Lipids and Lipoprotein Size and Distribution in Healthy Middle Aged People

Epidemiological studies suggest three daily servings of whole-grain foods (WGF) might lower cardiovascular disease (CVD) risk, at least partly by lowering serum lipid levels. Wheat and oats, the main WGF consumed in the UK, might induce different lipid responses. We aimed to assess the effects of three daily portions of WGF (provided as a mixture of wheat and oats or only wheat) on lipoprotein subclasses size and concentration. A dietary randomised controlled trial involving 233 middle aged healthy individuals was carried out. After a 4weeks run-in period on a refined diet, volunteers were randomly allocated to a control (refined diet), wheat or wheat + oats group for 12 weeks. Outcome measures were serum cholesterol as well as lipoprotein subclasses size and concentration, as measured by nuclear magnetic resonance. Blood lipid levels remained unchanged after 12 weeks intervention with WGF, whereas serum total- and LDL- cholesterol concentrations decreased slightly but significantly in the refined group compared with the wheat group. However, these changes were not associated with differences in lipoprotein subclasses’ size and concentration. Our results indicate that three portions of WGF, irrelevant of the type (wheat or oat-based) do not reduce cardiovascular risk by altering beneficially the size and distribution of lipoprotein subclasses.

Effects of tillage and winter cover cropping on microbial substrate-induced respiration and soil aggregation in two Japanese fields

We hypothesized that cover cropping could increase soil microbial activities under various tillage systems and that increased microbial activities would improve soil properties. Soil sampling was conducted at two fields in Japan in 2009. At the Ibaraki field (Andosol, clay loam), three tillage practices (no-tillage, plowing to 30 cm, and rotary tillage to 15 cm) and three types of winter cover cropping [bare fallow as control, hairy vetch (Vicia villosa Roth), and rye (Secale cereale L.)] were conducted from 2003 to 2009. At the Hokkaido field (Fluvisol, light clay), two tillage practices (autumn tillage and rotary tillage with a rotary tiller to a depth of 15 cm once in autumn and twice in a year, respectively), and four types of winter cover cropping (bare fallow, hairy vetch, bristle oat (Avena strigosa L.), and a mixture of hairy vetch and bristle oat) were conducted from 2006 to 2009. Soil microbial activities and the fungal-to-bacterial activity ratio (F/B ratio) were estimated by the substrate-induced respiration (SIR) method with the use of selective antibiotics. At the Ibaraki field, rye cover cropping showed higher microbial SIR than bare fallow at depths of 0–30 cm and rotary tillage maintained higher microbial SIR than no-tillage or plowing at depths of 7.5–15 cm. There was no meaningful interaction effect between cover cropping and tillage on microbial SIR. At the Hokkaido field, cover cropping and tillage had only limited effects on microbial SIR. High F/B ratios (indicating fungal dominance) were recorded with the use of cover crops in both fields. Fungal SIR, estimated from the microbial SIR and F/B ratio, was closely related to the content of total soil organic carbon (SOC) and the mean weight diameter (MWD) of water-stable aggregates. Based on SOC, fungal SIR was significantly higher under rye cover cropping. The relationship between fungal SIR and MWD was affected by tillage. We conclude that rye cover cropping and rotary tillage were very effective in increasing fungal SIR, SOC, and MWD in the Ibaraki soil. Field practices that enhance fungal activities might be effective in improving certain types of arable soil.

Suitability of Oat, Millet and Sorghum in Breadmaking

Challenges and opportunities of minor cereals with poor viscoelastic value deserve a special attention in breadmaking applications due to their unique nutritional components. In a preliminary stage, the suitability of oat, millet and sorghum in breadmaking was assessed in simple binary wheat flour matrices in which wheat flour was replaced from 0% to 60%. The research allowed the quantification of grains (up to 30% for millet and sorghum and up to 50% for oat of wheat flour replacement) to be incorporated into the binary blended matrices providing minimization of techno-functional impairment and sensory depreciation of breads. Combinations of gluten, vegetable fat and a commercial mix of surfactants, ascorbic acid and antistaling enzymes were used to make breads with 10% increased level of wheat flour replacement by single oat, millet and sorghum in binary mixed samples. The quality profile of binary mixtures of oat–wheat (60:40 w/w), millet–wheat (40:60 w/w) and sorghum–wheat (40:60 w/w) was significantly improved in terms of keepability during storage, mainly for oat–wheat blends which stale at a similar rate than 100% wheat breads. Overall acceptability of highly replaced wheat breads deserved higher scores for oat and sorghum composite breads (7/10) than control wheat breads (6/10). Oat, millet and sorghum represent a viable alternative to make aerated breads with mitigated technological and sensory constraints based on non-viscoelastic cereals.

Introduction of cover crops in a maize–soybean rotation of the Humid Pampas: Effect on nitrogen and water dynamics

The agricultural system of the Humid Pampas consists of continuous cropping of soybean and maize under no tillage. This system may loose nitrogen (N) through leaching during the early and final stages of summer crops and during fallow. In this study (2005–2011) we evaluated the effect of fall–winter species (rescue grass, ryegrass, oats, barley, vetch, rape seed and forage radish) and a mixture of vetch and oats used as cover crops on water and N dynamics and main crop yield. Above-ground biomass production and N uptake by cover crops ranged from 1.1 to 11.9Mgha−1 and from 17 to 223kgNha−1, respectively, depending on sowing and killing dates and on the preceding crop. At killing, soil nitrate content in treatments with cover crops was 50–90% lower than in the control, reducing spring N leaching risk. When preceding maize, cover crops were killed in winter or early spring and their low C/N ratio (12–38) favored N release through residue decomposition. Vetch and rape seed as predecessors of fertilized maize increased residual N by ≈50kgNO3-N compared to the control, posing the risk of fall N leaching. When preceding soybean, cover crops were killed in spring and, although their C/N ratios were higher (13–85), crucifers and legumes increased soil nitrate content. Maize yield was related to soil N availability at sowing (control and legumes>crucifers>grasses) which was inversely related to the preceding cover crop C/N ratio at killing. In normal to high rainfall years there were no differences in soybean yield among treatments. Water use by cover crops did not affect the main crop production except during an exceptionally dry year. Best synchronicity between N release from cover crop residues and harvest crop demand was achieved with the oats–vetch mixture before maize and with grasses before soybean.

Effect of dental correction on voluntary hay intake, apparent digestibility of feed and faecal particle size in horse

In nine adult Warmblood horses with mild to moderate dental findings (no signs of discomfort during chewing), voluntary hay intake before and after dental correction was examined. In a second experiment, digestibility of feed and faecal particle size were determined (3 days of total faecal collection) before and after dental correction. During both digestion trials including a 3-day adaptation period, the amount of hay and concentrate (mixture of oats, barley and maize) was kept constant in each individual horse before and after dental correction. Voluntary hay intake in individual horses ranged from 11 to 22 g DM/kg BW/day and did not differ before and after dental treatment. Apparent digestibility of DM, energy, crude fibre and Nfe increased significantly after dental correction (energy digestibility before dental correction 46.8 ± 7.4%, after dental correction 51.5 ± 8.5%). Apparent digestibility of feed was higher in horses eating more concentrates than in those eating less concentrates. Improvement of digestibility was more marked in horses eating larger amounts of grain. There was no relationship between severity or type of dental alterations and improvement of apparent feed digestibility. Dental correction had no effect on faecal particle size.

Nutritional and functional added value of oat, Kamut®, spelt, rye and buckwheat versus common wheat in breadmaking

Multicereal/pseudocereal blends based on major and minor seeds with high nutritional profile appear as a promising strategy, hardly explored, to obtain enhanced value grain-based foods such as bread. In a preliminary stage the suitability of minor/ancient cereals (rye, oat, Kamut wheat, spelt wheat) and pseudocereals (buckwheat) was assessed in single (100% of wheat flour replacement) and multigrain (from 20 to 44% of wheat flour replacement) matrices. The research allowed identification of the qualitative (oat, rye, buckwheat) and quantitative (up to 75% of wheat flour replacement) grains in the mixed matrices providing enhancement of nutritional quality (higher protein content, higher mineral content, lower digestible starch, higher viscous fibre content, higher resistant starch content, source of antioxidants) and minimisation of techno-functional impairment and sensory depreciation of the resulting breads. The quality profile of associated mixtures of oat, rye, buckwheat and common wheat flours (20:20:20:40 w/w/w/w) endorsed the proposed grain blend as suitable to make highly nutritious, modern and innovative baked goods meeting functional and sensory standards in terms of nutritional added value (improved dietary fibre fractions, minerals and antioxidant activity, slower starch hydrolysis), palatability (high sensory scores), convenience (extended keepability during storage) and easy handling during processing.

Effect of increased consumption of whole-grain foods on blood pressure and other cardiovascular risk markers in healthy middle-aged persons: a randomized controlled trial

Three daily portions of whole-grain foods could lower cardiovascular disease risk, but a comprehensive intervention trial was needed to confirm this recommendation. We aimed to assess the effects of consumption of 3 daily portions of whole-grain foods (provided as only wheat or a mixture of wheat and oats) on markers of cardiovascular disease risk in relatively high-risk individuals. This was a randomized controlled dietary trial in middle-aged healthy individuals. After a 4-wk run-in period with a refined diet, we randomly allocated volunteers to a control (refined diet), wheat, or wheat + oats group for 12 wk. The primary outcome was a reduction of cardiovascular disease risk factors by dietary intervention with whole grains, which included lipid and inflammatory marker concentrations, insulin sensitivity, and blood pressure. We recruited a total of 233 volunteers; 24 volunteers withdrew, and 3 volunteers were excluded. Systolic blood pressure and pulse pressure were significantly reduced by 6 and 3 mm Hg, respectively, in the whole-grain foods groups compared with the control group. Systemic markers of cardiovascular disease risk remained unchanged apart from cholesterol concentrations, which decreased slightly but significantly in the refined group. Daily consumption of 3 portions of whole-grain foods can significantly reduce cardiovascular disease risk in middle-aged people mainly through blood pressure-lowering mechanisms. The observed decrease in systolic blood pressure could decrease the incidence of coronary artery disease and stroke by ≥15% and 25%, respectively. This trial was registered at clinicaltrials.gov as ISRCTN27657880.

A research on determination of hay yields and silage qualities of some vetch+cereal mixtures.

The hay yields and silage qualities of the mixtures of common vetch and hungarian vetch with rye, barley, wheat, oat and triticale were investigated under Isparta conditions, during the 2006-2007 and 2007-2008 growing seasons. The highest hay yield (9.08 tons ha -1 ) and crude protein yield (1.11 tons ha -1 ) were obtained from hungarian vetch+rye mixture. The least NDF and ADF contents (50.11% and 31.92%, respectively) were achieved in common vetch+oat mixtures. Silages from the mixtures of common vetch, barley and oat, and hungarian vetch, barley, oat and wheat were rated very good, and all other vetch and cereal silages were rated good according to fleig scores. All silage combinations, with the exception of common vetch and rye silage, were rated very good based on physical analysis.

The effect of mixing and changing the order of feeding oats and chopped alfalfa to horses on: glycaemic and insulinaemic responses, and breath hydrogen and methane production

The aim of this study was to investigate the effects of feeding oats alone before or after feeding chopped alfalfa or, in admixture with the alfalfa on the glycaemic and insulinaemic responses of horses as well as post-prandial breath hydrogen and methane excretion. Horses were fed in a randomized order, chopped alfalfa as a source of dietary fibre and unprocessed oats as a source of starch. Chopped alfalfa intake was adjusted to a crude fibre intake of 0.5 g/kg bodyweight (BW) per meal and the oats intake was adjusted to a starch intake of 2 g/kg BW per meal. The feeds were offered in three different ways: (i) alfalfa followed by oats (A/O), (ii) oats followed by alfalfa (O/A) or (iii) a mixture of alfalfa and oats (A + O). Oats alone were used as a control. Blood and breath were collected after the test meal was fed at the end of a 11.5-h overnight fast following a 10-day acclimatization period. The highest glycaemic and insulinaemic responses were measured when the A/O and O/A diets orders were fed, whereas most hydrogen was produced after feeding oats alone. It was concluded that adding alfalfa chaff to a meal of oats prolonged the pre-caecal digestion of starch, but there was no evidence for any effect on pre-caecal starch digestibility.

Integrating Winter Annual Forages into a No‐Till Corn Silage System

The benefits of cover crops within crop rotations are well documented, but information is limited on using cover crops for forage within midwestern United States cropping systems, especially under no‐tillage management. Our objective was to evaluate plant, animal, and soil responses when integrating winter cover crop forages into no‐till corn (Zea mays L.) silage production. Three cover crop treatments were established no‐till after corn silage in September 2006 and 2007 at Columbus, OH: annual ryegrass (Lolium multiflorum L.), a mixture of winter rye (Secale cereale L.) and oat (Avena sativa L.), and no cover crop. Total forage yield over autumn and spring seasons was 38 to 73% greater (P ≤ 0.05) for oat + winter rye than for annual ryegrass. Soil penetration resistance (SPR) in May 2007 was 7 to 15% greater (P ≤ 0.10) in the grazed cover crops than in the nongrazed no cover crop treatment; however, subsequent silage corn yield did not differ among treatments, averaging 10.4 Mg ha−1 in August 2007. Compared with the no cover crop treatment, cover crops had three‐ to fivefold greater root yield, threefold greater soil microbial biomass (MB) in spring 2008, and 23% more particulate organic carbon (POC) concentrations in the 0‐ to 15‐cm soil depth. Integration of forage cover crops into no‐till corn silage production in Ohio can provide supplemental forage for animal feed without detrimental effects on subsequent corn silage productivity, with the added benefit of increasing labile soil C.

Omasal sampling technique in estimation of the site and extent of mineral absorption in dairy cows fed rapeseed and soybean expellers

The effects of rapeseed and soybean expeller on digestion of sodium, potassium, calcium, magnesium, phosphorus and sulphur in dairy cows were investigated in a study conducted as an incomplete Latin square. The experimental diets consisted of five concentrates fed at a rate of 9 kg d-1: a mixture of barley and oats (control), which was replaced either with rapeseed or soybean expeller both at two levels (130, 180 and 230 g crude protein per kg dry matter). A mixture of grass and red clover silage (1:1) was fed ad libitum. No mineral supplements except for NaCl and trace minerals were used. Ruminal digestion was estimated by omasal sampling technique and total digestion from total faecal collection. Intake of all minerals except sodium increased with the level of protein supplementation and it was generally higher when rapeseed compared with soybean expeller diets were offered. Reticulo-rumen was the major site of net absorption of magnesium, whereas calcium, phosphorus, sodium and potassium were absorbed postruminally. Net absorption of sulphur took place both in the rumen and postruminally. Omasal flow of sodium and phosphorus indicated substantial secretion of these minerals into the rumen via saliva. Compared with the published data based on duodenal sampling, the results indicated that omasum has an important role in the absorption of minerals, especially sodium and phosphorus. Omasal sampling technique is a useful tool in studying ruminal mineral metabolism.;

Organic and conventional management of mixtures of wheat and spring cereals

Cereal mixtures may provide both organic and conventional producers with a more sustainable approach in reducing weed pressure, crop rotation flexibility, improved yield stability, buffering against pests and diseases, minimizing soil variability and increasing animal feed value. We examined the response of small grain mixtures containing wheat, oats, barley and triticale to varying degrees of natural competition and environmental stress at three locations in central Alberta, Canada. One modern and one heritage hard-red spring wheat cultivar, along with one cultivar each of oats, barley and triticale and eighteen two-way mixtures, were planted on organic and conventional land at seven location-years between 2003 and 2005. Average yields were 30% to 70% lower on organically managed sites. Monocrop barley yielded 43% and 16% higher than the site average at two organic locations. Our results suggest two main conclusions: (1) on conventionally managed land, wheat-barley mixtures exhibited potential for yield maintenance and weed suppression, and; (2) on organically managed land, competition with weeds had a large negative effect on yield (>30%). The 25:75 mixtures of wheat and oats, and all mixtures of Park (a heritage) wheat and Manny barley exhibited yield potential similar to or (up to 1.0 t ha−1) greater than monocrop yield. Manny barley mixtures exhibited weed suppressive capabilities.

Análise da viabilidade econômica da produção de leite a pasto e com suplementos na região dos Campos Gerais - Paraná

Com o objetivo de avaliar a rentabilidade da produção de leite no sistema de produção integração lavoura-pecuária, foi conduzido um experimento, no período de julho de 2004 a abril de 2005, em Castro, Paraná. O delineamento utilizado foi de blocos ao acaso com quatro tratamentos e três repetições, com os tratamentos correspondendo a diferentes níveis de suplementação. Os tratamentos utilizados foram: 1 - pastagem + 20% de suplementação, com Dieta Total Misturada (DTM), suficiente para mantença e produção de 28 litros vaca-1dia-1; 2 - pastagem + 45% de suplementação; 3 - pastagem + 65% de suplementação; e 4 - pastagem + 100% de suplementação. A área experimental utilizada foi de 32,40ha, com 22,4ha no inverno, implantada com o consórcio azevém anual (Lolium multiflorum L.) e aveia preta (Avena strigosa Schreb.), dividida em 12 piquetes. No verão foi utilizada área de 10,0ha, com Quicuio (Pennisetum clandestinum), dividida também em 12 piquetes. Em cada repetição, foram utilizados quatro animais "testers", sendo três vacas da raça HPB e uma da raça Jérsei. O sistema de pastejo adotado foi o de lotação contínua, com carga variável. Foram utilizados animais reguladores para controlar a altura do pasto, mantida em torno de 20cm. Foram avaliadas, duas vezes por semana, a produção individual de leite das vacas, e a cada duas semanas a percentagem de gordura, a percentagem de proteína e a contagem de células somáticas no leite. A análise econômica foi realizada utilizando a metodologia proposta pelo Sistema de Acompanhamento do Custo de Produção de Leite no Paraná - FAEP. O tratamento 1, com 20% de suplementação, apresentou o melhor resultado econômico, com custo operacional total de R$ 0,4635 litro-1, e margem líquida de R$ 0,13 litro-1.