Relationship between Rainfall and Annual Forage Biomass to Build a Forage-Balance Guarantee System in Brazilian Semiarid

Semiarid regions around the world are characterized by elevated annual evapotranspiration and irregular rainfalls (Creswell and Martin, 1998), resulting in a negative water balance in most part of the year. The high rainfall variability associated to a high pressure on natural resources generated a scenario of degradation, which is worrying for the future of many rangelands. In this sense, it is urgent to understand the processes involved in the sustainability of vulnerable ecosystems to keep them productive and profitable. Among the rural activities in the semiarid regions, the raising of livestock has been contributed to become the farms viable. To cope with this potential, it is necessary to develop a tool to quantify the rangeland production pattern in response to rainfall (Lukomska et al., 2010), thus, optimizing the use of the available natural resources. In this context, the aim of this study was to establish a relationship between rainfall and annual forage biomass in Brazilian semiarid rangelands, considering those variables as a base to maximize the potential of such a guaranteed production syste

Morfogênese e produção de biomassa de capim 'BRS Tamani' manejado sob doses crescentes de nitrogênio

The objective of this work was to evaluate the morphogenic and structural characteristics of Megathyrsus maximus 'BRS Tamani', subjected to increasing nitrogen doses, as well as the components of its biomass. The experiment was carried out in a  randomized complete block design with four treatments (0, 300, 600, and 1,200  kg ha-1 N per year) and three replicates, in 12 experimental units of 12.5 m² each. The evaluations were performed in the rest period of the pasture, after defoliation to a residual leaf area index of 1.0, until the pasture reached the number 3.0 of new leaves produced per tiller. Leaf and stem elongation rates increased with the increment in N doses up to 1,200 kg ha-1 N per year. There was a decreasing linear response for phyllochron and leaf life span. Increases of 704% were observed for the harvestable green leaf biomass, at the dose equivalent to 1,200 kg ha-1 N per year. The biomasses of dead forage and harvestable stem were not affected by the N doses. Nitrogen fertilization shows a positive effect on the morphogenic, structural, and productive characteristics of 'BRS Tamani' guinea grass up to the dose equivalent to 1,200 kg ha-1 N per year.O objetivo deste trabalho foi avaliar as características morfogênicas e estruturais de Megathyrsus maximus 'BRS Tamani', submetido a doses crescentes de adubação nitrogenada, assim como os componentes de sua biomassa. O experimento foi realizado em delineamento de blocos ao acaso, com quatro tratamentos (0, 300, 600 e 1.200 kg ha-1 de N por ano) e três repetições, em 12 unidades experimentais de 12,5 m² cada uma. As avaliações ocorreram ao longo do período de descanso do pasto, após a desfolhação para um índice de área foliar residual de 1,0, até o momento em que o pasto atingiu o número 3,0 novas folhas produzidas por perfilho. As taxas de alongamento foliar e de colmo aumentaram com o incremento das aplicações de N até a dose equivalente a 1.200 kg ha-1 de N por ano. Houve resposta linear decrescente do filocrono e do tempo de vida das folhas. Incrementos de 704% foram observados na biomassa de folhas verdes passíveis de colheita, para a dose equivalente a 1.200 kg ha- 1 de N por ano. As biomassas de forragem morta e caule colhido não foram afetadas pelas doses de N. A adubação nitrogenada apresenta efeito positivo sobre as características morfogênicas, estruturais e produtivas do capim 'BRS Tamani' até a dose equivalente a 1.200 kg ha-1 de N por ano

Parâmetros nutricionais de cabritas alimentadas com dieta contendo torta de mamona detoxificada

The objective of this work was to evaluate the effect of replacing soybean meal (SM) by detoxified castor bean cake (DCC), containing different alkaline solutions, on the nutritional parameters of Saanen and Anglo-Nubian female goat (Capra aegagrus hircus) kids. The treatments consisted of three diets: one based on corn and SM; and two with DCC with Ca(OH)2 or NaOH. Intake and digestibility data were analyzed in two phases according to the growth curves of the goats, which showed: a linear accelerated growth (phase I, from 60 to 298 days of life) and a reduction in the intensity of body growth (phase II, from 299 to 345 days). During phase I, the goat kids fed DCC with NaOH showed a lower intake of dry matter (DM) and nutrients. During phase II, there was significant effect of diets on the intake of nutrients, with the exception of ether extract (EE), total digestible nutrients, and metabolizable energy (ME). A diet effect was observed on the digestibility of DM, crude protein, EE, and neutral detergent fiber, mainly for goat kids fed diets with DCC. Despite their lower intake, the diets formulated with DCC do not negatively affect the nutritional performance of female goats kids in both growth phases, since they result in a greater feed efficiency.O objetivo deste trabalho foi avaliar o efeito da substituição do farelo de soja (FS) pela torta de mamona detoxificada (TMD), contendo diferentes soluções alcalinas, nos parâmetros nutricionais de cabritas (Capra aegagrus hircus) Saanen e Anglonubiana. Os tratamentos consistiram de três dietas: uma à base de milho e FS; e duas com TMD por Ca(OH)2 ou NaOH. Os dados de consumo e digestibilidade foram analisados em duas fases, de acordo com as curvas de crescimento das cabritas, que mostraram: crescimento acelerado linear (fase I, de 60 a 298 dias de vida) e redução na intensidade do crescimento corporal (fase II, de 299 a 345 dias). Durante a fase I, as cabritas alimentadas com TMD por NaOH apresentaram menor consumo de matéria seca (MS) e nutrientes. Durante a fase II, houve efeito das dietas sobre a ingestão de nutrientes, com exceção de extrato etéreo (EE), nutrientes digestíveis totais e energia metabolizável. Observou-se efeito da dieta na digestibilidade da MS, da proteína bruta, do EE e da fibra em detergente neutro, principalmente nas cabritas que consumiram as dietas com TMD. Embora menos consumidas, as dietas formuladas com TMD não afetam negativamente o desempenho nutricional das cabritas em ambas as fases de crescimento, uma vez que resultam em maior eficiência alimentar

Agro-Climatic Aptitude for Tanzania Guinea Grass Cultivation in Brazilian Semiarid Environment

Tanzania guinea grass is a forage plant recognized in Brazil and part of Latin America due to high forage production in intensive production systems (Jank et al., 2010). In irrigation conditions, this plant has also shown excellent performance in semiarid areas. In general, this grass develops well in regions with above 700 mm rainfall, medium texture soils and good fertility, and the main limitation for its production in the tropics is the rainfall (Jank et al., 2010). Future scenarios point to temperature increases, directly impacting evapotranspiration, and there are also many uncertainties in relation to precipitation, with studies indicating increasing droughts in semiarid regions and droughts in areas where this is not currently common. Using tools that can predict this grass productivity in drought situation is very useful in the decision-making process and in the search for pasture use more sustainable strategies. Simulation models use based on biomass production data is a tool that has helped technicians, producers and governments in fast decision-making processes. This study type has evolved along with geographic information systems, enabling geo processing techniques application, allowing crops productive potential areas delimitation in a quick manner and with reliable results. Suitable areas predetermination allows cost, time and risk reduction with Tanzania guinea grass pastures formation. This research was conducted in order to carry out a simulation to determine suitable areas for Tanzania guinea grass cultivation under rainfed conditions, using forage production data in a Brazilian semiarid environment

Morphogenesis of Cynodon cultivars fertilized with nitrogen

To evaluate the biomass flow of two cultivars of Cynodon (Tifton 85 grass and vaquero grass) fertilized with increasing levels of nitrogen (N) (control – without nitrogen; 200; 400 and 600 mg dm-3) under greenhouse conditions, this study was carried out, in a completely randomized design, with factorial arrangement. Forages were examined during three regrowth cycles, with results presented as mean values of the cycles. In the analysis of the effect of nitrogen fertilization, the Tifton 85 grass showed an increasing response to nitrogen levels for the leaf elongation rate (LER). The vaquero grass had a quadractic response for the LER with increasing levels of N. As for the stem elongation rate, there was an increasing linear response in both grasses according to increasing levels of N. The leaf senescence rate (LSR) of the Tifton 85 grass has been enhanced by nitrogen fertilization. The vaquero grass revealed a quadractic response for this variable LSR with nitrogen fertilization, with a minimum value of 0.96 cm tiller-1 day-1 with nitrogen level of 42.5 mg dm-3. The phyllochron and the total number of leaves of both grasses have been influenced by nitrogen fertilization, with downward and upward linear responses, respectively, with increasing levels of nitrogen. For the final mean leaf length (MLL) of both forages, we verified an increasing response with increasing levels of nitrogen. Tifton 85 grass and vaquero grass presented similar LER in the absence of nitrogen, but higher values were observed for the fertilized Tifton 85 grass. The fertilization using nitrogen leads to positive responses of the biomass flow of Tifton 85 grass and vaquero grass under the conditions of the present study

Composição química de cladódios de palma forrageira sob diferentes manejos de adubação e colheita

The objective of this work was to evaluate the effects of combined phosphorus and nitrogen fertilization and of harvesting frequency on the chemical composition of 'Gigante' cactus pear (Opuntia ficus‑indica) cladodes. The experiment was carried out in two municipalities, Quixadá and Tejuçuoca, in the state of Ceará, Brazil. Fertilization with nitrogen (urea) and phosphorus (single superphosphate) was done with nine doses, respectively: 10 and 70, 70 and 10, 70 and 70, 70 and 130, 100 and 100, 130 and 70, 130 and 130, 130 and 190, and 190 and 130 kg ha-1 per year, besides 100 kg ha-1 N and P2O5 per year as the control. The harvesting frequencies evaluated were annual and biannual. A randomized complete block design was adopted, in split plot, with four replicates. The effect of fertilization on the contents of total dry matter, crude protein, neutral detergent fiber, organic matter, and total carbohydrates in the cladodes varies with harvesting frequency and site. Regarding harvesting frequency, there were higher contents of organic matter, total carbohydrates, and neutral detergent fiber, but lower contents of crude protein for the biannual harvesting in both municipalities. Annual harvesting improves the nutritional quality of primary and secondary cladodes in the municipality of Quixadá and of secondary and tertiary cladodes in Tejuçuoca.O objetivo deste trabalho foi avaliar os efeitos da adubação combinada de nitrogênio e fósforo, e da frequência de colheita sobre a composição química de cladódios de palma forrageira 'Gigante' (Opuntia ficus-indica). O experimento foi realizado em dois municípios cearenses, Quixadá e Tejuçuoca. A adubação com nitrogênio (ureia) e fósforo (superfosfato simples) foi realizada em nove doses, respectivamente: 10 e 70, 70 e 10, 70 e 70, 70 e 130, 100 e 100, 130 e 70, 130 e 130, 130 e 190, e 190 e 130 kg ha-1 por ano, além de 100 kg ha-1 de N e P2O5 por ano como controle. As frequências de colheita avaliadas foram anual e bianual. Adotou-se o delineamento de blocos ao acaso, em arranjo de parcelas subdivididas, com quatro repetições. O efeito da adubação sobre os teores de matéria seca total, proteína bruta, fibra em detergente neutro, matéria orgânica e carboidratos totais dos cladódios varia com a frequência de colheita e com o local. Quanto aos períodos de colheita, foram observados maiores teores de matéria orgânica, carboidratos totais e fibra em detergente neutro, mas menores teores de proteína bruta para a colheita bianual, nos dois municípios. A colheita anual melhora a qualidade nutritiva de cladódios primários e secundários em Quixadá e de cladódios secundários e terciários em Tejuçuoca

Resíduo agroindustrial da carnaúba como fonte de volumoso para a terminação de ovinos

The objective of this work was to evaluate the effects of ammonization with different levels of urea and the use of soybean grains as a urease source, for the improving of the chemical composition of carnaúba (Copernicia prunifera) agroindustrial residue (BC). The levels of urea were 0, 2.5, 5, 7.5 and 10% in relation to the percentage of total dry matter of BC and the levels of toasted soybean grains were 0 and 20%. Evaluations were also made for forage intake and performance of confined sheep subjected to diets with increasing levels of replacement of Tifton 85 grass (Cynodon spp.) hay (FT) by BC: 100% FT, 25% BC plus 75% FT, 50% BC plus 50% FT, 75% BC plus 25% FT, and 100% BC. Thirty crossbred 80-day old weaned sheep with 17 kg initial average weight were used. Crude protein in the forage increased with the increasing doses of urea. Increases were also observed for neutral detergent fiber and cellulose contents and reductions were observed for roughage digestibility. The highest daily intake of dry matter, organic matter, crude protein, ethereal extract and neutral detergent fiber were observed in animals fed only FT. Animal performance decreased with increase of BC in the diet.O objetivo deste trabalho foi avaliar os efeitos da amonização com diferentes níveis de ureia e do uso de grãos de soja como fonte de urease, na melhoria da composição químico-bromatológica do resíduo agroindustrial da carnaúba (Copernicia prunifera), conhecido como bagana (BC). Os níveis de ureia utilizados foram 0, 2,5, 5, 7,5 e 10%, em relação à percentagem de matéria seca total da BC; e os níveis de grãos de soja tostados foram de 0 e 20%. Foram também avaliados o consumo de ração e o desempenho de cordeiros confinados, submetidos a dietas com níveis crescentes de substituição de feno de capim Tifton 85 (Cynodon spp.) (FT) pela BC: 100 FT; 25% BC e 75% FT; 50% BC e 50% FT; 75% BC e 25% FT; 100% BC. Foram utilizados 30 cordeiros mestiços inteiros, recém-desmamados, com peso corporal médio de 17 kg e idade média em torno de 80 dias. Os teores de proteína bruta na forragem aumentaram com o aumento das dosagens de ureia. Foram observados, ainda, aumentos nos teores de fibra em detergente neutro e celulose e redução da digestibilidade da BC. Os consumos diários mais elevados de matéria seca, matéria orgânica, proteína bruta, extrato etéreo e fibra em detergente neutro foram observados nos animais que receberam apenas FT como volumoso. O desempenho animal foi reduzido com o aumento da BC na dieta

Bioeconomic evaluation of pasture sheep finishing using castor bean cake

This study evaluates the economic viability of sheep finishing systems on irrigated Tamani grass pasture under continuous stocking, using castor bean cake. Four production systems were simulated: sheep supplemented with soybean meal on pasture fertilized with urea (SMUR), sheep supplemented with detoxified castor bean cake on pasture fertilized with urea (CCdUR), sheep supplemented with soybean meal on pasture fertilized with in natura castor bean cake (SMCC) and sheep supplemented with detoxified castor bean cake on pasture fertilized with in natura castor bean cake (CCdCC). A minimum unit of 3 hectares and an average slaughter weight of 28 kg were considered. A minimum selling price, at which the least profitable system would become profitable, was stablished: US$2.38 and US$ 4.45/kg per kilogram of body weight and carcass weight equivalent, adopting a minimum rate of return of 3.5% per year, based on the Selic rate. The costs for organic fertilization were 46.01% higher than in systems using chemical fertilization. The selling of live animals was not attractive in any of the systems evaluated, and the opposite was observed for the selling of carcasses and non-carcass components. System SMUR proved to be more profitable, with a gain of US$ 0.53 per kg carcass. Keywords: concentrated supplementation; internal rate of return; profitability; Ricinus communis L; Santa Inês

Componentes da biomassa e características estruturais em capim‑aruana sob diferentes frequências e intensidades de desfolhação

The objective of this work was to evaluate the effect of frequencies and intensities of defoliation on the biomass components and on the canopy structure of Guinea grass (Panicum maximum 'Aruana IZ‑5') pasture under intermittent sheep stocking. Two defoliation frequencies (DF), with 85 and 95% interception levels of the photosynthetically active radiation (Ipar) incident on the top of the canopy, and two defoliation intensities (DI), with residual leaf area index (LAIr) of 1.0 and 1.8 were evaluated. A completely randomized design was carried out, in a 2x2 factorial arrangement. Biomass components and the structural features in the pre‑grazing conditions were affected mainly by DF, with the reduction of green biomass of culms and of dead forage, and were also affected by the increase in the height of the first alive ligule. Pastures managed with lower DF provided lower leaf blade/culm ratio, with 1.65 average, while pastures managed with greater DF showed 2.40 mean leaf blade/culm ratio. Components of the residual biomass were affected by the DI, with a greater residual green forage biomass in pastures managed with LAIr of 1.8. Swards grazed at 95% Ipar and 1.8 LAIr showed residual green biomass of culms and residual dead forage biomass superior to those of the other managements. For grazing by sheep, 'Aruana' Guinea grass should be managed with a 85% Ipar frequency and defoliation intensity corresponding to LAIr of 1.0.O objetivo deste trabalho foi avaliar o efeito de frequências e intensidades de desfolhação sobre os componentes da biomassa e a estrutura do dossel em capim‑aruana (Panicum maximum 'Aruana IZ‑5'), pastejado sob lotação rotativa com ovinos. Avaliaram-se duas frequências de desfolhação (FD), com níveis de interceptação de 85 e 95% da radiação fotossinteticamente ativa (Irfa) incidente no topo do dossel, e duas intensidades de desfolhação (ID), com índices de área foliar residual (IAFr) de 1,0 e 1,8. Utilizou-se o delineamento inteiramente casualizado, com arranjo fatorial 2x2. Os componentes da biomassa e as características estruturais nas condições de pré‑pastejo foram afetados principalmente pela FD, com a redução da biomassa de colmos verdes e de forragem morta, e, ainda, pela elevação da altura da primeira lígula viva. Pastos manejados com menor FD proporcionaram menor relação lâmina foliar/colmo, com média de 1,65, e os pastos com maior FD apresentaram média de lâmina foliar/colmo de 2,40. Os componentes da biomassa residual foram afetados pela ID, com maior biomassa de forragem verde residual em pastos manejados com IAFr de 1,8. Os pastos manejados com 95% de Irfa e IAFr de 1,8 apresentaram biomassa de colmo verde residual e biomassa de forragem morta residual superiores aos dos demais manejos. Para pastejo por ovinos, o capim‑aruana deve ser manejado com frequência de 85% de Irfa e intensidade de desfolhação correspondente a IAFr de 1,0.