High Forage Production Research Articles

Manejo da desfolha de duas variedades de trevo-persa cultivadas em solo hidromórfico

Foram estudados os efeitos de três frequências e duas intensidades de desfolhação nas características morfogênicas e estruturais, na produção de forragem e na relação folha/caule de duas variedades de trevo-persa (Trifolium resupinatum L. var. resupinatum Gib & Belli. cv. Kyambro e var. majus Boiss cv. BRS Resteveiro). O delineamento utilizado foi de blocos completos ao acaso, em esquema fatorial 3 × 2 × 2, com cinco repetições. Foram avaliadas as seguintes variáveis: taxa de aparecimento de folhas, filocrono, taxa de alongamento e alargamento de folíolos, largura e comprimento de folíolos, número de ramificações, altura de planta, número de folhas vivas abertas, produção de matéria seca total e relação folha/caule. Apesar de a pastagem apresentar maior número de folhas vivas em intervalos de desfolhação maiores e a maior produção de forragem ter sido obtida na altura residual de 5 cm e no intervalo de 6 folhas surgidas, cortes mais frequentes proporcionam melhora da relação folha/caule, maior número de ramificações, maior taxa de surgimento de folhas e maior tamanho de folíolos.

Produção e valor nutritivo da forragem de capim-elefante em dois sistemas de produção

Esta pesquisa foi realizada com o objetivo de avaliar a produção e o valor nutritivo da forragem de capim-elefante cultivado em sistemas convencional e agroecológico. No sistema convencional, o capim-elefante foi estabelecido em cultivo exclusivo, em linhas com espaçamento de 1,4 m e, no sistema agroecológico, em linhas afastadas 3 m. Nas entrelinhas, estabeleceu-se azevém no período hibernal para desenvolvimento de espécies de crescimento espontâneo no período estival. Avaliaram-se a massa, a produção e a composição botânica e estrutural da forragem e a carga animal. Amostras de simulação de pastejo foram coletadas para determinação dos teores de proteína bruta e fibra em detergente neutro e da digestibilidade in vitro da matéria seca e matéria orgânica. O delineamento experimental foi o inteiramente casualizado com dois tratamentos (sistemas convencional e agroecológico) e duas repetições (piquetes). Valores mais elevados para massa de forragem, produção de forragem, taxa de acúmulo diário e carga animal foram observados no sistema convencional. A relação folha: colmo foi similar entre os sistemas. Valor mais elevado de proteína bruta foi observado no sistema agroecológico. O capim-elefante sob manejo convencional apresenta maior produção de forragem, com menores teores de proteína bruta. O sistema agroecológico apresenta melhor distribuição da produção de forragem no decorrer do ano.

Desempenho agronômico de genótipos de capim-braquiária em sucessão à soja

O objetivo deste trabalho foi avaliar o desempenho agronômico de genótipos de capim-braquiária [Urochloa brizantha (Syn. Brachiaria brizantha)] em sucessão à soja, para uso em sistemas de integração lavoura-pecuária. Os genótipos Marandu, MG 4, Xaraés, Piatã, Arapoty e B 6, foram avaliados na safrinha, durante a estação seca, e a soja na safra de verão, em esquema de sucessão, de 2007 a 2010. Em cada ano, as forrageiras foram semeadas em março, avaliadas em cortes sucessivos até o final de setembro e dessecadas em outubro para a realização do plantio direto da soja em novembro. Utilizou-se o delineamento de blocos ao acaso, com quatro repetições. Xaraés e B 6 estiveram entre os genótipos com maior produção de forragem. A cultivar Xaraés apresentou menores teores de proteína bruta, digestibilidade in vitro da matéria orgânica, cálcio e fósforo, embora esses teores possam ser considerados bons para o gênero, uma vez que o solo de cultivo apresentava boa fertilidade. Há variação entre os genótipos de U. brizantha quanto ao desempenho na safrinha. A cultivar Xaraés e o genótipo B 6 destacam-se para compor sistemas de produção integrados com lavoura. Os genótipos MG 4 e B6 são facilmente dessecados com o herbicida glifosato. A produtividade de grãos de soja não é significativamente afetada pelo cultivo em sucessão aos genótipos de U. brizantha.

봄과 가을 파종시 귀리 품종별 생육, 수량 및 사료가치 비교

귀리는 단기 다수성 작물로서 잎의 비율이 높을 뿐만 아니라 가축의 기호성도 양호하며 다른 총체맥류에 비하여 파종시기의 선택폭이 넓다. 따라서 본 시험은 내한성이 강하여 중부 지방에서도 월동이 가능한 귀리 3품종과 옥수수 뒷그루 재배에 알맞은 3품종에 대하여 10월 중순 가을 파종과 3월 상순 봄 파종시 생육, 수량 및 사료가치를 비교하고자 실시하였다. 출수기는 봄 파종시 가을 파종에 비하여 평균 12일 늦었고, 품종간에는 약 8일의 차이가 있었다. 봄 파종은 가을 파종에 비하여 이삭과 잎의 비율이 감소하고 줄기가 차지하는 비율이 증가되는 경향이었다. 품종별로는 동한귀리가 다른 품종에 비하여 이삭의 비율이 높고 줄기의 비율이 낮은 경향이었다. ADF 함량은 봄파종에서 높았고, NDF 함량과 가소화 건물 함량은 가을파종에서 높았다. 가소화 건물함량은 가을 파종시 동한귀리와 스완에서, 봄 파종에서는 삼한귀리가 높았다. 삼한, 동한, 조한귀리 3품종의 생초수량이 가을 파종이 봄 파종에 비하여 높았으나 건물수량은 비슷한 경향이었다. 스완, 다크호스, 하이스피드는 봄 파종이 가을 파종에 비하여 생초수량 및 건물수량이 월등히 높았다. 품종별로는 가을 파종과 봄 파종 모두 동한귀리가 건물수량과 가소화 건물수량이 높았는데, 이는 상대적으로 많은 이삭수의 확보와 이삭이 차지하는 비율이 높았기 때문이었다. Oats are an important crop for forage production with good palatability of livestock. Compared with other winter cereals crops for forage, oats may be widely sowing, autumn (October), spring (early of March) and summer (late of August). The objectives of this study were to compare the effects of sowing dates and varieties on the growth, forage yield and feed quality. Oat were sown in 14 October and 10 March, and harvested 20 days after heading in middle region of Korea. Varieties used were the 3 winter oat cultivars with cold tolerant and 3 cultivars for summer sowing. Heading was delayed about 12 days in spring sowing than in autumn sowing and the difference among varieties was 8 days. The rate of spike and leaf above aerial parts reduced and the rate of culm increased in spring sowing than in autumn. The variety 'Donghan' was higher the rate of spike and lower the rate of culm than that of other varieties. In spring sowing than in autumn, acid detergent fiber (ADF) content was higher, and neutral detergent fiber (NDF) and digestible dry matter (DDM) content was lower. In DDM content surveyed on 20 days after heading, 'Donghan' was higher in autumn sowing and 'Samhan' in spring sowing than that of other varieties. The oat variety 'Samhan', 'Donghan' and 'Chohan' were higher fresh yield in autumn than in spring, but similar dry matter yield. The variety 'Swan', 'Darkhorse' and 'Hispeed' were higher fresh and dry matter yield in spring than in autumn. The variety 'Donghan' can supplement high quality forage production in middle region at October and March because of the high-tillering and rate of spike per aerial part.

Management‐Intensive Rotational Grazing Enhances Forage Production and Quality of Subhumid Cool‐Season Pastures

Management‐intensive rotational grazing is used by many farmers seeking to balance profitability, environmental stewardship, and quality of life. Productivity of pastures in much of the upper Midwest is limited to April through October, so promoting high quality forage production during the grazing season and for winter storage is critical to dairy and beef farm profitability. We conducted an experiment on pastures dominated by Kentucky bluegrass (Poa pratensisL.), orchardgrass (Dactylis glomerataL.), meadow fescue [Schedonorus pratensis(Huds.) P. Beauv.], perennial ryegrass (Lolium perenneL.), and white clover (Trifolium repensL.) to compare forage production, forage quality, and root production under management‐intensive rotational grazing, continuous grazing, haymaking, and land with no agronomic management. Rotational paddocks were grazed by cow‐calf pairs monthly for ∼2 d and then allowed to rest for ∼28 d. Plots designated for haymaking were harvested two times per growing season. Potential utilizable forage, quantified by incorporating the estimates of refused and nonutilized biomass, and relative forage quality were significantly greater under management‐intensive rotational grazing when compared to the other treatments. Root production in the surface 15 cm was significantly lower under both grazing treatments compared to the undefoliated control site. The perception of improved production has been used to advocate for rotationally grazed over continuously grazed systems in subhumid pasture, but experimental results have been equivocal. Our results point to managed grazing as a viable alternative to continuous grazing and haymaking in terms of both forage production and quality but not root production.

Inorganic Fertilizers after Broiler Litter Amendment Reduce Surplus Nutrients in Orchardgrass Soils

The common producer practice to dispose of broiler litter at high rates to forage crops allow excessive accumulation of soil nutrients. A remediation study was developed to examine if inorganic fertilizer application over the residual fertility of broiler litter would reduce surplus soil nutrients in orchardgrass (Dactylis glomerata L.) soils and to study the resulting biomass production. Three remediation treatments; inorganic fertilizer on antecedent broiler litter at the nitrogen rate (R‐PLN), phosphorus rate (R‐PLP), phosphorus rate with inorganic nitrogen (R‐PLP+N), and inorganic fertilizer (INORG) were tested and results were compared with broiler litter at nitrogen rate (PLN) phosphorus rate (PLP), and phosphorus rate with inorganic nitrogen (PLP+N). Repeated broiler litter application at N rate led to elevate soil P, Cu, and Zn contents >200% from the initial levels. Implementing an alternative inorganic fertilizer application cycle in such soils can reduce P, Cu, and Zn levels respectively by 32 mg P kg−1 yr−1, 1.9 mg Cu kg−1 yr−1, and 2.4 mg Zn kg−1 yr−1 Remediation by inorganic fertilizer application may take at least 5 yr to reduce P, Cu, and Zn levels back to the normal range. In addition, inorganic fertilizer application over broiler litter at N rate can offer similar forage production as inorganic fertilizer and N rate broiler litter amendment. An alternative cycle of inorganic fertilizer application after broiler litter amendment can be recommended as a best management practice to remediate surplus soil nutrients in highly broiler litter impacted soils while assuring high forage production benefits.

Effects of seeding rates on forage yield and quality of oat (<i>Avena sativa</i> l.) vetch (<i>Vicia sativa</i> l.) mixtures under irrigated conditions of Madagascar

Forage availability and quality during the dry and cool season is a major constraint to dairy development in the Highlands of Madagascar. The objective of the present study was to determine optimal seeding of oat and common vetch mixtures for increased production and quality of forage. The study was conducted under irrigated conditions in two agro-ecological zones of the Vakinankaratra region in the Highlands of Madagascar. Seed proportions studied were oat-vetch 100:0; 0:100; 50:50 and 50:75. Pure stands of oat and vetch were seeded at the rate of 100 and 60kg ha -1 , respectively. Standard fertilization for forage oat production was uniformly applied on each plot. Pure stands and mixtures were given two successive cuts at flag leaf stage of oat. For both sites and their average, dry matter (DM), feed unit for lactation (UFL), crude protein (CP), and protein digested in the small intestine (PDI) yields were not significantly (p>0.05) different among mixtures and pure stands. The highest yields were obtained from the 50:50 mixture at the first site and from the 50:75 mixture at the second site. According to the two sites’ results’ average, the highest DM (7.71 t ha-1), UFL (6.08x103 units ha-1), CP (1.64 t ha -1 ) and PDI (597.1kg ha -1 ) yields were obtained from 50:50 mixture. There were no significant differences (p>0.05) in forage quality characteristics except for CP and protein digested in the small intestine when rumen-fermentable nitrogen is limiting (PDIN). Mean CP concentration varied from 15.20% for pure stand of oat to 27.01% for pure stand of vetch. The highest value (178.8 g/kg DM) and the lowest value (103.5g/kg DM) in PDIN content were obtained from pure stand of oat and pure stand of vetch, respectively. Mixtures had 4.6 to 6.3% more CP content and 15.6 to 39.1% more PDIN content than pure stand of oat. Combined land equivalent ratio values exceeded unity in both mixtures which showed an advantage of intercropping over sole system in terms of the use of environmental resources. As intercropping of oat with vetch at 50:50 (50:30 kg ha -1 ) mixture achieved maximum yield advantage and forage quality, it could be used as alternative practice of oat sole cropping for high forage and protein production in the Vakinankaratra region. Key words: mixture, forage, quality, oat, vetch

Effects of planting date on sugar and ethanol yield of sweet sorghum grown in Arizona

Sweet sorghum ( Sorghum bicolor (L.) Moench) is an annual crop currently being investigated for biofuel production in the arid southwest United States (U.S.). Sweet sorghum is an ideal candidate because it can be grown under reduced inputs (water, fertilizer) and responds more efficiently to stresses than traditional crops. Many varieties have been bred for high sugar, syrup, and forage production, but much biodiversity still remains to be utilized. Studies performed in 2006 and 2007 found that high biomass and percent juice extracted were the best predictors of potential ethanol yield per area. This investigation was undertaken to determine what effects planting dates have on overall sugar and predicted ethanol yields. Four varieties (Dale, M81E, Theis, and Topper) were planted in April, May, June, and July of 2008. They were harvested at physiological maturity, with dates ranging from August 26 to December 2. Biomass, juice weight, and Brix of the juice were recorded in the field. Samples were analyzed in the laboratory by High Performance Liquid Chromatography (HPLC) for fructose, glucose, and sucrose. Theoretical ethanol yields were calculated based on biomass, juice weight, and percent sugar. These were compared to actual yields obtained from laboratory-scale fermentations of the harvested juice, which ranged from 7.4% to 11.2% (58.1–88.6 g L −1). Since our predictive model uses the maximum conversion rate of sugar to ethanol and this was not reached in the lab, the predicted yields were always higher than the actual yields. However, the model can be a useful tool for estimating ethanol yield per area. Total sugars and predicted ethanol production were influenced by planting date, but the degree of the effects depended on the cultivar planted. Overall a May planting date at this location is preferable due to consistently higher values for the yield components analyzed, and Theis is not recommended due to its high susceptibility to heat. Sweet sorghum juice has been successfully fermented into ethanol, which indicates this crop may be able to play a transitory role in the emerging biofuel market.

Half-sib progenies evaluation in velvet grass

Velvet grass (Holcus lanatus L.) has a great potential use for winter pasture in subtropical regions due to its good establishment, persistence, high forage production, cold resistance, palatability and tillering ability. The objective of this work was to estimate genetic variability and heritability of agronomic traits and to identify superior progenies. Sixty half-sib progenies were assessed for natural height at the vegetative stage (NH), plant diameter (diameter), heading date (cycle), final height (after flowering) (FH), and tiller number (tillers). Difference among progenies was observed for all traits. Heritability estimates were 38%, 32%, 92%, 57% and 64% for NH, diameter, cycle, FH and tillers, respectively. The highest genetic gain estimate was 30.77 % for the tiller number. There is genetic variability for all the traits and gains after selection among half-sib progenies can be expected.

Forage Yield and Competition Indices of Berseem Clover Intercropped with Barley

Berseem clover (Trifolium alexandrinum L.) should be intercropped with cereals for forage quality improvement, livestock bloat avoidance, and fertilizer requirements reduction. A 2‐yr field study was conducted using a cultivar of berseem clover and two barley (Hordeum vulgare L.) cultivars as sole crops compared to six berseem clover–barley intercrops planted at three seeding rates (250–338, 500–225, or 750–113 seeds m−2). The objective of the study was to compare forage and protein yield productivity for sole crops with crop mixtures. Land equivalent ratio (LER), relative crowding coefficient (RCC), aggressivity (A) which indicates the relative yield increase of legume in comparison with that of cereal in an intercropping system, and competition ratio (CR) were also assessed. Barley was cut once, while berseem clover was cut four times. Total dry matter (DM) yield produced by most intercrops was similar with that of berseem clover sole crop averaged 24.9 Mg ha−1, but greater than that of barley sole crops averaged 12.7 Mg ha−1. Berseem clover sole crop and its intercrop with barley at 750–113 seeds m−2 provided the greatest total protein yield. Total LER or RCC did not exceed unity for the intercrop, which indicated that there was no advantage of the intercrops over sole cropping systems. The results of this study indicated that intercropping of berseem clover with barley at the seeding rate of 750–113 seeds m−2 could be used as alternative practice of berseem clover sole crop for high forage and protein production.

Primary production and carrying capacity of former salt ponds after reconnection to San Francisco Bay

Over 6,110 ha of the commercial production salt ponds surrounding South San Francisco Bay, CA, have been decommissioned and reconnected to the bay, most as part of the largest wetlands restoration program in the western United States. These open water ponds are critical habitat for millions of birds annually and restoration program managers must determine the appropriate balance between retention of ponds versus re-conversion to tidal salt marsh, knowing that both are essential ecosystems for endangered bird species. Our study describes the ecological value of the new open water pond ecosystems as feeding habitats for birds. We used the oxygen rate of change method to determine ecosystem metabolic parameters from high resolution time-series of dissolved oxygen concentration. Areal gross primary production (8.17 g O2 m−2 d−1) was roughly double the world’s most productive estuaries. High rates of phytoplankton photosynthesis were balanced by equally high rates of community respiration (8.25 g O2 m−2 d−1). Metabolic equilibrium was delicately poised: sharp irradiance and temperature shifts triggered short term photosynthesis reduction resulting in oxygen depletion. We converted net primary production (NPP) into potential carrying capacity of the forage biota that support targeted pond waterbirds. NPP was processed through both a pelagic food web, resulting in forage biota for piscivorous birds and a benthic food web, resulting in forage biota for shorebirds and diving benthivores. Both food webs included efficient algal-based and inefficient detrital trophic pathways. The result of all primary production being routed through simple food webs was high potential forage production and energy supply to waterbirds, equivalent to 11–163 million planktivorous fish or 19–78 billion small estuarine clams within the 330-ha pond between May and October. Food quantity does not necessarily equal quality and these systems have the potential to produce toxic or inedible algae. Our study provides the first measurement of primary production in the open water ponds of San Francisco Bay and presents a novel approach for transforming primary production into forage production as a metric of an ecosystem’s energetic carrying capacity.

Consumo de forragem e desempenho de vacas Holandesas sob pastejo em gramíneas tropicais

The structure of Dwarf Elephantgrass (Pennisetum purpureum Schum. cv. Mott) (DEG) and Tifton 85 (Cynodon dactylon x Cynodon nlemfuensis) (T85) pastures and its relation with forage intake and the performance of lactating cows were evaluated. The trial was conducted in the growth season of 2004/05, in an area belonging to the Celeste Gobbato State Technical School, in the city of Palmeira das Missões, State of Rio Grande do Sul, Brazil. Twelve Holstein cows were used as testers, fed exclusively on pasture under continuous grazing, in two paddocks per treatment. Forage density was higher on T85 than in DEG, due to its higher forage production. The most accessible pasture strata for animal intake (above 20 and 10 cm height for DEG and T85, respectively) presented different structures, but forage intake and milk production were similar in both treatments. The chemical composition of these pasture layers and of their respective samples were similar in both pasture types, indicating the analysis of chemical composition of the most accessible strata to grazing pasture as a useful tool for inferences about the quality of potentially consumable forage. Tropical pastures allow milk productions higher than 17 kg cow-1 day-1, even without the use of supplementation.

Forage Production and Nutritive Value of Oat in Autumn and Early Summer

Oat (Avena sativa L.) grown for forage in the northern USA usually is sown in spring and harvested in early summer, with rapid decline in quality after boot stage. This study was conducted to determine if there are differences in forage yield and forage quality between summer sown–autumn harvested and spring sown–early summer harvested oat, and to determine whether seasonal effect is similar among oat cultivars that vary in maturity classification. Oat was sown in summer 2001 and spring 2002 at two locations in Wisconsin and harvested in autumn and early summer, respectively. Oat sown in August produced 6.7 Mg ha−1 of forage when harvested 77 d later, about 1.0 Mg ha−1 less than that obtained from spring sown oat harvested 77 d after sowing. Autumn forage yield was similar among oat cultivars due to decreasing daylength and temperature. Maturation of summer‐sown oat was delayed, resulting in 10 to 15% less neutral detergent fiber (NDF), 18% greater digestibility, and 250% greater water soluble carbohydrate (WSC) concentration than spring‐sown oat. High WSC levels are of particular importance since oat forage harvested in autumn will likely be stored as silage due to poor drying conditions in autumn. Differences in forage quality among cultivars and between spring and autumn oat forage are associated with maturity differences. Oat sown in late summer, and especially the leafy, late maturing cultivar ForagePlus, can supplement high quality forage production in autumn.

Genetic diversity among varieties of the native forage grass Trichloris crinita based on AFLP markers, morphological characters, and quantitative agronomic traits

We assessed the genetic diversity in Trichloris crinita (Poaceae) varieties from South America, using AFLPs, morphological characters, and quantitative agronomic traits. Owing to the importance of this species for range grazing, we first characterized the varieties based on forage productivity. Biomass production varied 9 fold among the materials evaluated. Analysis of AFLP fingerprints allowed the discrimination of all varieties with a few selected primer combinations. Pair-wise genetic similarities, using marker data, ranged from 0.31 to 0.92 (Jaccard coefficients). Marker-based unweighted pair group method with arithmetic averaging (UPGMA) cluster analysis did not show geographical clustering, but rather grouped the varieties according to their biomass production. We identified 18 markers associated with biomass production, of which 8 showed complete correlation (r = 1.00) with this trait. These DNA markers can be used to assist selection for high forage productivity in T. crinita. Cluster analysis using morphological and quantitative characters revealed 4 distinct groups of varieties, clearly separated according to their biomass yield. The variables foliage height and basal diameter were strongly correlated with biomass production and these phenotypic markers can be used to select productive plants. The relations among the varieties based on AFLP data were significantly correlated with those based on agronomic and morphological characters, suggesting that the 2 systems give similar estimates of genetic relations among the varieties.

Conditions and stimulation for germination in Bromus auleticus seeds

Bromus auleticus Trin. ex Nees is a perennial species with high forage production, good nutritional quality in a critical period of the year (autumn – winter), and long persistence. This work studied: I) the effect of temperature and light on B. auleticus seed germination, II) the effect of laboratory seed treatments on germination stimulation immediately after harvest. In I), three alternating temperatures: 20-30, 15-25 and 10-20°C (the lower temperature maintained by 16 hours), and two constant temperatures: 10 and 20°C were tested. Light treatments were: a) no light, and b) 8 hours of light followed by 16 hours of darkness. The following treatments were tested to stimulate germination: a) control: with distilled water, b) 0.2% potassium nitrate solution instead of water, c) 0.05% gibberellic acid solution instead of water, and d) prechilling at 7°C for 7 days. Results showed that B. auleticus can germinate in a range of temperatures between 10 and 25°C, either constant or alternating, with light or without it. For germination trials, constant temperature at 20°C gave the highest germination velocity. Germination was increased by prechilling and use of gibberellic acid, probably because of the hormonal nature of dormancy in this species.

Yield and quality of forage type pea lines of contrasting leaf types

Two semi-leafless and five leafed pea ( Pisum sativum L.) lines were evaluated for 4 years for dry matter, seed and crude protein yield under rainfed conditions in the Bursa region of Turkey. All the lines used in this study were forage type with indeterminate growing habit. Several yield components such as spring vigor, plant height, lodging scores, pods/plant, seeds/pod, seeds/plant, 1000-seed weight, and harvest index were measured. Forage, dry matter and seed yield, and dry matter digestibility of the lines were determined. Under humid conditions and cool temperatures in early spring, high forage production was observed in all the lines. Fall seeded peas attained average 1.5 m height and produced 8.4 t ha −1 dry matter. Dry matter yields varied significantly among lines; however, leaf type had no effect on forage yield. Significant differences in seed yield were found among the lines. An overall seed yield averaged 1.4 t ha −1. Prior to flowering, semi-leafless lines had significantly better standing ability than leafed peas. Leaf-type had no effect on lodging scores at seed harvesting stage. Dry matter digestibility percentages were similar between leafed and semi-leafless pea lines.

Clasificación de triticales forrajeros por rendimiento de materia seca y calidad nutritiva en dos localidades de Coahuila

A study was carried out during the 1996/97 fall/winter cycle io arder to assess dry matter yield of 86 triticale lines and varieties across three clippings, compared to commercial controls: oats cv Coker 234, rye grass cv Alamo and Beetbuilder and barley at Matamoros and Zaragoza, Coahuila. An alfa-lattice design with tour replications was used. Based on dry matter mean yield, the best eight lines were selected for nutritional value anaIysis togetber with commercial controls, AN-31 and AN-34 Tridcale, oats cv Coker 234 and ryegrass cv Alamo. Nutritional value parameters, plus dry matter yields and phenological stages were analyzed by means of the Cluster Analysis and the Principal Component Analysis techniques. Results showed that the two identified triticale types outyielded ryegrass, which had the highest nutritional value. Facultative type triticales equaled oats' nutritional value and yield. On the other hand, intermediate-winter triticales yielded almost the same and showed simOar nutritional values in the first and second clippings. In cooc1usion, triticales constitute an excellent alternative for high quality winter forage production when compared to ryegrass and may replace oats in tbose Breas having frost problems. The existence of triticale types different from those previously reported is confirmed.

Produção de forrageiras anuais de estação fria no litoral sul do Rio Grande do Sul

Forrageiras anuais de estação fria, Avena strigosa Schreb cv. IAPAR-61 Ibiporã, Lolium multiflorum Lam cv. Comum, Lotus subbiflorus Lag. cv. El Rincón, Avena sativa L. cv. UPF-16, Trifolium subterraneum L. cv. Woogenellup, Trifolium resupinatum L. var. resupinatum cv. Kyambro, Secale cereale L. cv. BR-1, Trifolium vesiculosum Savi cv. EMBRAPA-28 Santa Tecla e Vicia angustifolia L. foram avaliadas usando um delineamento experimental de blocos ao acaso com três repetições, no período de 1994 a 1996, na Estação Experimental Terras Baixas da EMBRAPA - Clima Temperado, Pelotas, RS, em Planossolo, unidade de mapeamento Pelotas. A área recebeu preparo convencional e adubação conforme análise do solo. Os cortes foram efetuados a cada 28 dias, sendo o primeiro 60 dias após a emergência. Os rendimentos médios anuais de MS (kg/ha•ano) e os teores médios de PB e FDN foram determinados. Houve efeito da interação entre anos e espécies. Avena strigosa IAPAR-61, L.multiflorum Comum e L.subbiflorus Rincón foram destaque, pelo alto potencial de produção de forragem, assim como pelo crecimento nos períodos outono/inverno, inverno/primavera e primavera, respectivamente. Todas as espécies avaliadas produziram forragem de alto valor nutricional, em termos dos teores de PB e FDN. Vicia angustifolia teve sempre o mais alto teor de PB e a maior produção relativa de inverno. Trifolium subterraneum Woogenellup foi a única espécie que produziu sementes viáveis suficientes para assegurar adequada regeneração natural da planta no início do segundo ano.

Plant and Soil Responses to Source, Rate, and Timing of Applied N for Plains Bluestem Production

In western Oklahoma, one of the most popular grass species being used for pastureland is Plains bluestem (Bothriochloa ischaemum L.). Despite the current importance of this species, N fertilizer sources, rates, and timing of application have not been thoroughly evaluated for this species. The objective of this 3-yr study was to evaluate the effect of source, rate, and timing of applied N on Plains bluestem forage production. Two established stands of Plains bluestem in Stillwater and Bessie, OK, were selected as experimental sites. A randomized complete block design with three replications was employed at each location. Urea and ammonium nitrate were evaluated at rates of 50, 100, 200, and 400 lb N/acre. Time of fertilizer application was evaluated using late April and early May applications. Dry matter yield, crude protein (CP), and N uptake increased with applied N up to 200 lb N/acre for both sources. The maximum average (3-yr) yields were 4112 and 3370 lb dry matter/acre at Stillwater and Bessie, respectively. No effect on production was found to exist due to N source. Applying 50 and 100 lb N/acre in early May increased yields at Stillwater 25 and 14%, respectively, compared with the same rates applied in late April. This study indicated that Plains bluestem forage yield, N uptake, and CP content increased significantly when up to 200 lb Nlacre was applied in the spring. Dry matter production was further increased when N was applied in early May compared with late April.

Variation in the nutritional value of leaf and stem fractions of nineteen leucaena lines

In two experiments, 2.5-month-old edible regrowth of the genus Leucaena (varying in tolerance to the leucaena psyllid pest attack) were analysed for nutritive value. In Experiment 1, forage of nine lines was separated into young leaves, young stems (within woody fraction <5 mm diameter), old leaves and old stems (within a woody fraction 5–10 mm diameter) whereas in Experiment 2, forage of the other 10 lines was separated in main stem leaves, branch leaves, young branches, young main stems, old main stems and old branches for analysis. Major differences were recorded between lines and forage fractions. Nutrient contents in dry matter were: nitrogen 0.7–4.8%, phosphorus 0.1–0.3%, potassium 0.2–2.5%, calcium 0.2–1.6%, magnesium 0.1–0.6%, acid detergent fibre 20–63%, lignin 8–23% and in vitro dry matter digestibility 15–69%. The leaves and immature fractions were higher in nitrogen, phosphorus, potassium and digestibility but lower in calcium, magnesium and fibre. Nutrient content in L. Leucocephala lines exceeded that in L. esculenta, L. diversifolia, leucaena hybrids and the composites. Based on the data, a management strategy that will promote young growth is suggested as appropriate for high quality forage production.