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A pecuaria e uma atividade economica fundamental para a regiao semiarida, porem e diretamente influenciada por fatores como as caracteristicas do solo, qualidade da forragem e a sazonalidade pluviometrica. A irregularidade desses fatores reduz os niveis de produtividade, tornando-os dependentes das condicoes climaticas. Nesse sentido, o conhecimento das principais causas redutoras da produtividade e a adocao de praticas agricolas resilientes sao essenciais na reducao dos efeitos sazonais do clima, aumentando a oferta de forragem no periodo de escassez hidrica. O uso de forrageiras adaptadas e com potencial produtivo constitui-se com eficiente pratica de resiliencia agricola, dentre elas destacam-se a palma forrageira, sorgo, milheto, feijao guandu e girassol. Essas constituem-se com elevada capacidade de conversao hidrica em materia seca, complementacao nutricional e aumento produtivo. Adicionalmente, a implementacao de praticas (e.g. consorciacao, irrigacao, adensamento, cobertura, etc.) contribuem na otimizacao dos recursos naturais e proporcionam melhores resultados no subsidio continuo da producao de forragem. Com isso, o presente estudo teve como objetivo apresentar as caracteristicas ambientais do semiarido brasileiro, expor conceitos sobre os niveis de produtividades e os principais fatores das lacunas de producao, alem de difundir estrategias mitigatorias de producao de forragem. Apos compilacao dessas informacoes, destaca-se a importância de plantas forrageiras adaptadas e a adocao de praticas de manejo agricola como estrategias para atenuar os efeitos sazonais do clima, contribuindo no subsidio continuo da producao de forragem. Paralelamente, a analise de Yield Gap permite o conhecimento mais amplo dos fatores limitantes de producao, direcionando o planejamento agricola de forma mais eficiente. Yield Gap and cultivation strategies in improving forage production for the Brazilian semi-arid region - Review A B S T R A C T Livestock farming is a fundamental economic activity for the semi-arid region, but it is directly influenced by factors such as soil characteristics, forage quality and rainfall seasonality. The irregularity of these factors reduces productivity levels, making them dependent on climatic conditions. In this sense, the knowledge of the main causes that reduce productivity and the adoption of resilient agricultural practices are essential in reducing the seasonal effects of the climate, increasing the supply of forage in the period of water scarcity. The use of adapted forage crops and with productive potential constitutes an efficient agricultural resilience practice, among which stands out the forage cactus, sorghum, millet, pigeon pea and sunflower. These are constituted with a high capacity for water conversion into dry matter, nutritional complementation and increased production. In addition, the implementation of practices (e.g. intercropping, irrigation, densification, mulch, etc.) contribute to the optimization of natural resources and provide better results in the continuous subsidy of forage production. With this, the present study aimed to present the environmental characteristics of the Brazilian semiarid region, to expose concepts about the levels of productivity and the main factors of the production gaps, in addition to disseminating mitigation strategies of forage production. After compiling this information, it highlights the importance of adapted forage crops and the adoption of agricultural management practices as strategies to mitigate the seasonal effects of the climate, contributing to the continuous subsidy of forage production. At the same time, the Yield Gap analysis allows for a broader knowledge of the limiting factors of production, directing agricultural planning more efficiently. Keywords: forage crops; Brazilian semi-arid; agriculture

The use of irrigation can improve the productivity and nutritional quality of the forage cactus in environments with a water deficit, resulting in profit to the producer. The productive performance, bromatological composition and economic benefits of using irrigation were investigated in this study with forage cactus clones regulated deficit irrigation (RDI). The study was conducted in an experimental design of randomised blocks, in a factorial scheme with subdivided plots. The plots consisted of water regimes based on the crop evapotranspiration (ETc) (rainfed, 40, 80 and 120% ETc). The cactus clones [?Miúda? (MIU), ?Orelha de Elefante Mexicana? (OEM) and ?IPA Sertânia? (IPA)] comprised the subplots. The total number of cladodes per plant, the fresh and dry matter yields and the bromatological composition were evaluated. Economic viability was assessed using the net revenue and benefit to cost ratio (BCR). The irrigation depths did not increase the yield of the clones. The OEM clone showed 276 and 343% greater fresh and dry matter production, respectively, when compared to the IPA clone; however, when compared with the MIU clone, it was 63%, both on a fresh and dry matter production. The water regimes had no effect on the nutritional quality of the cactus. Only IPA showed no profit during the first cycle (BCR < 1). It can be concluded that planting one irrigated hectare with the OEM and MIU clones offer economic returns starting from the first production cycle (18 months). Made available in DSpace on 2021-02-18T12:21:14Z (GMT). No. of bitstreams: 1 Productivity-bromatological-composition-and-economic-2021.pdf: 613598 bytes, checksum: 6132a3a540aa5c647c24a2e2331e0274 (MD5) Previous issue date: 2021

This study investigated the water and radiation use efficiencies by Erythrina velutina and Enterolobium contortisiliquum under four water regimes. The experiment was carried out in the municipality of Serra Talhada, PE, Brazil. The experimental design was completely randomized with a 2 x 4 factorial arrangement and three replications. The water regimes were imposed from water replenishments based on the reference evapotranspiration (25, 50, 75 and 100% ET0). Water and radiation use efficiencies were calculated to the 120 days of growth. E. velutina showed a greater accumulated dry biomass (4.89 g pl-1) than E. contortisiliquum (2.22 g pl-1). The 75% ET0 water regime can be adopted without damage to the growth of both species. E. velutina was more efficient in the conversion of water (0.42 g l-1) and radiation in dry biomass (0.028 g MJ-1), indicating high environmental resilience, which is important features to choose species more adequate for reforestation activities. Made available in DSpace on 2021-02-18T12:20:39Z (GMT). No. of bitstreams: 1 Water-and-Radiation-Use-Efficiencies-2021.pdf: 1982612 bytes, checksum: 98fc2b7f813dd0af800e29f2f85136b2 (MD5) Previous issue date: 2021

The aim of this study was to evaluate morphophysiological indices, phenology and cutting time of forage cactus (Opuntia and Nopalea spp.) clones intercropped with sorghum cultivars (Sorghum bicolor). The experiment was carried out from 2017 to 2018, in two cropping systems (monocropping and intercropping), comprising 12 treatments, consisted of three cactus clones: ‘IPA Sertânia’—IPA, ‘Miúda’—Miu and ‘Orelha de Elefante Mexicana’— OEM, in a monocropping system and nine combinations the cacti and sorghum (cultivars 467, SF11 and 2502) to comprise each of the intercropping systems. Cladodes morphophysiological indices were obtained: absolute growth rate, relative growth rate, net assimilation rate (NAR), specific cladode area rate (SCAR) and the cladode area index rate. OEM showed higher absolute growth rates at the beginning of the cycle, compared with IPA and Miu. NAR was higher in the monocropped OEM and in the OEM-2502 intercrop than under all the IPA and Miu systems (monocropping and intercropping), but the SCAR rate was higher for IPA (monocrop and intercropped). Miu showed a shorter duration of phenophase 2, but OEM had a higher rate of cladode emission during this phase. Cactus-sorghum intercropping systems cause a significant reduction in growth rates of the forage cactus. Intercropping has an earlier cutting time than the monocropping.

Comprehending the relation between climatic variables and the productive and morphological characteristics of the forage cactus is essential to the adjustment of the management of its production in different agro-climatic areas. The aim of this study was to evaluate the interrelationship between the meteorological variables and the water regime with the growth dynamics and accumulation of forage mass of three different forage cactus clones. We submitted the clones Miuda–MIU; Orelha de Elefante Mexicana–OEM and IPA Sertânia–IPA to three water regimes (40 %ETc, 80 %ETc and 120 %ETc), plus the non-irrigated condition (0 %ETc), during 18 months, in the municipality of Serra Talhada, Pernambuco, Brazil. Morphological, structural, and productive characteristics of the plants, and environmental variables were supervised throughout the experimental period. Pearson’s correlation, multicollinearity test, canonical correlation and path analysis were applied to these data. It was observed that the minimum air temperature, the relative air humidity, and the irrigation were the variables that affected the growth dynamics and the accumulation of fodder mass of the forage cactus clones the most. The clone OEM presented more sensitivity to the environmental conditions (climate and irrigation) in comparison to the other clones MIU and IPA. The environmental conditions affected the growth dynamics more than the productivity of the clone from the genus Nopalea. It was determined that the species of forage cactus presented differentiated morphological and productive responses among themselves, under semiarid conditions in Brazil.

The accumulation of dry biomass, its partitioning and the adjustment of equations were assessed for the initial growth of Piptadenia stipulacea (Benth) Ducke and Anadenanthera colubrina (Vell.) Brenan under water availability variation. The experiment was conducted in pots arranged in a completely randomized design with three replicates. Water conditions were evaluated using the percentages of reference evapotranspiration. Samples of the biomass were taken at 10-day intervals and used for the achievement of partitioning data and model adjustments. The short period of water scarcity in the initial growth phase of P. stipulacea and A. colubrina does not affect the establishment of these species, but different water regimes alter their root growth dynamics. The A. colubrina allocates more dry matter to the roots, while P. stipulacea sends more dry matter to the aerial part. The Gaussian, Lorentzian, Log-Normal and Gompertz models had excellent adjustments for the biomass variables of the P. stipulacea species, whereas for A. colubrina, we recommend the Exponential model. Made available in DSpace on 2019-10-31T18:15:31Z (GMT). No. of bitstreams: 1 PartitioningandModeling2019.pdf: 1791394 bytes, checksum: 5cc0890f59f464b0dffd3e849c073fda (MD5) Previous issue date: 2019

Esta revisao esta dividida em duas partes: a primeira busca contextualizar os aspectos relacionados ao clima na regiao de Semiarido, e a ocorrencia de deficit hidrico na sua influencia das especies da Caatinga, e na eficiencia do uso da agua (EUA). A segunda, trata-se de levantamento dos estudos que abordaram o conceito de eficiencia do uso da agua para especies vegetais da Caatinga por meio de um recorte para estudos desenvolvidos na ultima decada (2009-2019). Com estes, buscamos elucidar as seguintes questoes: como os estudos referentes a EUA foram realizados para as especies da Caatinga? Como estes foram explorados? E, quais as especies mais estudadas? Para realizacao desta revisao, utilizou-se uma estrategia de busca com o objetivo identificar artigos nos quais a eficiencia do uso da agua tenha sido analisada para especies da Caatinga no periodo de 2009 a 2019, em bases de artigos: periodicos da Capes, Google Academico e a base de dados ScienceDirect. Os termos da busca incluiram: “ Caatinga species and water use efficiency”, “Intrinsic water use efficiency of caatinga species ecophysiology”, “ Seasonal dry forest and water use efficiency ”. Foram eliminados todos os trabalhos que nao tinham relacao com especies nativas, alem dos duplicados. Apos esta analise, foram incluidos 20 trabalhos no total. Como resultado, observa-se que a maior quantidade de artigos publicados entre os anos avaliados, foi no ano de 2015 com 25% dos trabalhos. As especies de Fabaceae e Euphorbiaceae foram as mais estudadas com 42,8 e 10,7%, respectivamente. Os tratamentos de maior frequencia foram aqueles relativos ao deficit hidrico, especialmente em nivel de foliar, sendo incipientes as informacoes em nivel de ecossistemas. Informacoes desta natureza sao importantes para planejamento do meio e podem servir de subsidios para melhor compreensao da adaptacao destas especies frente a diferentes estresses ambientais portanto devem ser incentivados. Water Use Efficiency for Caatinga Species: A Review for the 2009-2019 Period A B S T R A C T This review is divided into two parts: The first seeks to contextualize the aspects related to the climate in the Semi-arid region, and the occurrence of water deficit in its influence of the Caatinga species, and in the water use efficiency (WUE). The second is a systematic review by means of an excerpt for studies developed in the last decade (2009-2019) that sought to understand, how were studies related to the WUE carried out for Caatinga species? How were these exploited? What are the most studied species? In order to carry out this review, a search strategy was used in order to identify articles in which the efficiency of water use has been analyzed for Caatinga species in the period from 2009 to 2019, based on articles: Capes Periodicals, Google Scholar and the ScienceDirect database. The search terms included: “ Caatinga species and water use efficiency”, “Intrinsic water use efficiency of caatinga species ecophysiology”, “Seasonal dry forest and water use efficiency” . All works that were not related to native species were eliminated, in addition to duplicates. After this analysis, 20 works were included in total. As a result, it is observed that the largest number of articles published between the years evaluated was in 2015 with 25% of the works. The species of Fabaceae and Euphorbiaceae were the most studied with 42.8 and 10.7%, respectively. The most frequent treatments were those related to water deficit, especially at the leaf level, with information at the ecosystem level being incipient. Information of this nature is important for planning the environment and can serve as a basis for a better understanding of the adaptation of these species to different environmental stresses, so they should be encouraged. Keywords: dry deciduous forest, ecophysiological parameters, environment, resilience, drought.

O crescimento da carcinicultura tem contribuído para diversificação alimentar, geração de empregos e renda, destacando-se assim a sua importância socioeconômica. Dentre as espécies mais cultivadas destaca-se o camarão marinho Litopenaeus vannamei, por apresentar alta resistência a diferentes condições, além de rápido crescimento e sobrevivência. Fatores ambientais como fotoperíodo podem contribuir com melhorias no sistema de produção. Este trabalho compreende uma revisão sistemática para a compreensão dos trabalhos já realizados sobre a influência do fotoperíodo em Litopenaeus vannamei. Os trabalhos foram obtidos por meio das bases: Google Scholar, Periódico da Capes e Science Direct e se referiram aos últimos quinze anos. Os termos de busca utilizados em todas as bases foram Litopenaeus vannamei and fotoperíodo e Litopenaeus vannamei and photoperiod. A busca retornou a 6.531 registros, mas apenas 5 artigos foram incluídos devidos atender os critérios de elegibilidade utilizados neste trabalho. Destes foi possível observar que 40% foram desenvolvidos em 2019. Com o resultado constatou-se que o Litopenaeus vannamei apresenta melhor desenvolvimento para alimentação, taxa de crescimento e sobrevivência, em tratamentos com exposição à luz. No entanto, esta revisão converge para o fato de que novos trabalhos devem ser desenvolvidos de modo a contemplar as relações entre a luminosidade e estágios de vida, sistemas de cultivo, parâmetros fisiológicos.

The aim of this study was to evaluate the effect of different controlled water regimes on the morphophysiological indicators, phenophases, and ideal cutting time of forage cacti clones grown in a semiarid environment. From 2016 to 2018, in the semi-arid region of Brazil, the Miuda (MIU), Orelha de Elefante Mexicana (OEM) and IPA Sertânia (IPA) clones were submitted to three regimes (40%, 80% and 120% ETc, where ETc is crop evapotranspiration) and to rainfed conditions (0% ETc). Cladode area index and the dry matter yield (DM) were used for calculating the morphophysiological indices. The cladode emission aided in delimiting the phenophases and, based on the DM accumulation, defined the ideal time for cutting the crop. The OEM clone excelled in terms of dry matter accumulation with a maximum value of 0.0441 Mg ha−1 °Cday−1. The water regimes above 80% ETc rise the number of phenophases in MIU and IPA clones. Cultivating forage cactus under water regime up to 40% ETc for OEM (895 °Cday) and 80% ETc for MIU and IPA (737 °Cday and 708 °Cday, respectively) anticipates the harvest time. Thus, a controlled reduction in the amount of water no negatively impact the growth dynamics, phenology, or cutting time.

A palma (Opuntia e Nopalea) é uma das forrageiras mais importantes do mundo, nativa do México, pertencendo à família Cactaceae, e possui uma alta eficiência no uso da água. No Brasil é cultivada principalmente no Nordeste, onde é considerada estratégica devido as condições climáticas da região. Pesquisas indicam que a adubação orgânica induz um melhor desempenho produtivo da palma forrageira. Neste sentido, o uso de biofertilizante para suprir as necessidades nutricionais das culturas agrícolas, tem sido uma importante ferramenta para os produtores rurais, por se tratar de um insumo orgânico de baixo custo, resultante da fermentação aeróbica de matéria orgânica e água, e que pode influenciar positivamente as propriedades químicas e físicas do solo. Esta revisão de literatura tem por objetivo apresentar alternativas de práticas agrícolas com adubação orgânica como o uso de biofertilizantes em sistemas de cultivo com palma forrageira visando alternativas promissoras com eficiência de cultivo. Conclui-se que o cultivo de palma forrageira com utilização de biofertilizantes alternativos orgânicos, incrementam a produção das plantas, e viabilizar técnicas de baixo custo aos produtores rurais.

Estresses ambientais podem influenciar na germinação e crescimento inicial de espécies vegetais. A compreensão destas respostas pode contribuir para o entendimento do estabelecimento das espécies no ambiente ou mesmo, subsidiar a produção de mudas. Este estudo investigou a influência da salinidade na geminação e biometria nos estádios iniciais de Cenostigma pyramidale. O estudo foi realizado na Unidade Acadêmica de Serra, Serra Talhada – Pernambuco. As sementes de Cenostigma pyramidale foram submetidas ao tratamento pré-germinativo por meio da escarificação mecânica com lixa de madeira nº 150. Em seguida as sementes tratadas foram semeadas em bandejas de células constituídas de polipropileno contendo solo e uma fina camada superficial de vermiculita para a emergência das plântulas. Mediante a semeadura, a espécie foi submetida à três níveis de salinidade: N1 - 0,18 (CONTROLE); N2 - 1,52 e N3 - 2,22 dS m-1. O delineamento adotado foi inteiramente casualizado com quatro repetições. As reposições de água foram realizadas diariamente, assim como as contagens do número de plântulas emergidas. Com estes dados obtiveram-se: porcentagem de emergência de plântulas (PE) e o índice de velocidade de emergência (IVE). Adicionalmente, foram obtidas altura (ALT), diâmetro do coleto (DC), número de folhas completamente expandidas (NFCE) e a biomassa seca total das plantas (BST). Nossos resultados mostraram que o aumento nos níveis de salinidade promoveu reduções no IVE e na PE das sementes de Cenostigma pyramidale. No entanto, não foram observadas alterações nos aspectos biométricos e no acúmulo de biomassa inicial da espécie.

No Semiárido brasileiro (SAB), a pecuária extensiva é predominante, onde alimentação dos animais é dependente da vegetação nativa, que devido a variabilidade climática não supre a necessidade dos rebanhos. Para contornar esse problema, a seleção de espécies de plantas forrageiras adaptadas ao clima Semiárido pode reduzir os impactos promovidos pelas adversidades climáticas sobre a pecuária. Nesse contexto, uma cultura que merece destaque é a palma forrageira, que devido ao seu metabolismo e características morfológicas, apresenta elevada produção de biomassa, sobretudo, em ambientes com elevadas temperaturas e déficit hídrico. De forma a incrementar a produtividade dessa cultura, face a variabilidade climática e as condições dos recursos hídricos existentes no SAB, a adoção de práticas de resiliência agrícola, como a agricultura biossalina, pode ser uma alternativa viável, proporcionando sustentabilidade ao sistema. Nesta revisão, objetivou-se fornecer uma visão geral da capacidade de produção de diferentes clones de palma forrageira cultivadas em ambiente semiárido sob agricultura biossalina, como forma de incrementar o aporte de forragem aos sistemas de produção dessa cactácea. Essa revisão baseou-se em periódicos disponíveis em plataformas digitais como ScienceDirect, Scorpus, SciELO e Google Scholar, priorizando artigos publicados nos últimos 10 anos. Concluiu-se que as mudanças climáticas devem afetar a pecuária e que sistema de produção com agricultura biossalina, associado aos melhores genótipos de palma forrageira é uma alternativa promissora para a produção de forragem no SAB.

The intercropping systems of species adapted to conditions of water deficit, such as sorghum (Sorghum spp.) and forage cacti (Nopalea spp. and Opuntia spp.), can contribute to an improvement in the biomass yield of semi-arid agricultural areas. This study aimed to evaluate the performance of intercropping cactus and sorghum as well as the biological efficiency and competitive ability of forage cactus clones and sorghum cultivars. The experiment was carried out in the Brazilian semi-arid region, in a randomised block design with 15 treatments and four replications. The treatments consisted of three forage cactus clones (‘IPA Sertânia’—IPA, ‘Miuda’—Miu and ‘Orelha de Elefante Mexicana’—OEM) and three sorghum cultivars (‘467’, ‘SF11’ and ‘2502’) under single configuration and the maximum number of combinations to comprise the intercropping systems. In terms of fresh and dry matter (221.73 and 47.04 Mg ha−1, respectively), the cactus-sorghum intercropping was 47% and 3.5 times more productive in terms of fresh and dry matter than the cactus single systems, with no effect on the quality of the forage. The forage cactus clones were dominant over the sorghum cultivars. The OEM-‘467’ configuration offered better stability (lower mortality), biological efficiency and crop competitiveness when compared to the single systems.

Agricultural production in semi-arid regions is limited due to water availability. In addition, the water quality available for irrigation is often compromised due to the high salt content present. Millet is a forage species considered tolerant to water deficit and moderately salt tolerant. In view of the above, the objective was to evaluate the growth of millet under water and saline stress associates. The experiment was carried out in a randomized block design, in a 4x3 factorial scheme, composed of four levels of water replacement, based on crop evapotranspiration (ETc): 25%.ETc, 50%.ETc, 75%.ETc and 100%.ETc and three levels of water salinity (0.03, 2.0 and 4.0 dS m-1). With 25%.ETc independent of salinity, all morphological characteristics of millet were affected, occurring death of plants in the initial growth phase. In the absence of salt and greater availability of water, greater plant growth occurred. With respect to salinity, there was a reduction in the increment of all variables evaluated, with the highest reduction at the highest saline level (4.0 dS m-1). Water and salt stresses, when associated, reduce the growth of millet, since concentrations above 2.0 dS m-1 and less than 50%.ETc compromise its full development, providing declines in yield. Agricultural production in semi-arid regions is limited due to water availability. In addition, the water quality available for irrigation is often compromised due to the high salt content present. Millet is a forage species considered tolerant to water deficit and moderately salt tolerant. In view of the above, the objective was to evaluate the growth of millet under water and saline stress associates. The experiment was carried out in a randomized block design, in a 4x3 factorial scheme, composed of four levels of water replacement, based on crop evapotranspiration (ETc): 25%.ETc, 50%.ETc, 75%.ETc and 100%.ETc and three levels of water salinity (0.03, 2.0 and 4.0 dS m-1). With 25%.ETc independent of salinity, all morphological characteristics of millet were affected, occurring death of plants in the initial growth phase. In the absence of salt and greater availability of water, greater plant growth occurred. With respect to salinity, there was a reduction in the increment of all variables evaluated, with the highest reduction at the highest saline level (4.0 dS m-1). Water and salt stresses, when associated, reduce the growth of millet, since concentrations above 2.0 dS m-1 and less than 50%.ETc compromise its full development, providing declines in yield.

RESUMO: Objetivou-se determinar a necessidade de água e o coeficiente de cultura para as diferentes fases fenológicas do milho ( Zea mays L) e do feijão-caupi ( Vigna unguiculata (L) Walp) em sistemas de plantio exclusivo e consorciado sob as condições climáticas do Semiárido brasileiro. O experimento foi conduzido no município de Petrolina, PE. Foram monitorados o rendimento de matéria seca total da parte aérea e a radiação fotossinteticamente ativa interceptada para ambas as culturas. Além disso, obteve-se a evapotranspiração da cultura (ETc) por meio do método do balanço de água no solo. Com estes dados e a evapotranspiração de referência foi obtido o coeficiente de cultura (Kc), os quais foram utilizados, posteriormente, para ajustar modelos em função dos graus dias acumulados. Com os resultados, constatou-se que o requerimento hídrico do milho e feijão-caupi no sistema de plantio consorciado foi maior que no sistema exclusivo. Os valores de Kc no consórcio foram de 0,90, 1,30, 1,20 e 0,72 para o milho, e 0,86; 1,30, 1,21 e 0,91 para o feijão-caupi, respectivamente, para as fases vegetativa, floração, enchimento de grãos e maturação. No sistema exclusivo esses valores foram de, 0,86, 1,23, 0,97 e 0,52 para o milho e de 0,68; 1,02, 1,06 e 0,63 para o feijão-caupi, nesta ordem. As variações dos valores de Kc para ambos os sistemas e culturas estiveram associadas ao incremento de biomassa e a interceptação da radiação. O modelo Gaussiano ajustado descreveu adequadamente a relação entre os valores de Kc e dos graus dias acumulados. ABSTRACT: In order to determine the water requirement and crop coefficient for the different phenological stages on corn plants ( Zea mays L.) and cowpea plants ( Vigna unguiculata (L.) Walp) in intercropping and sole cropping systems under the climatic conditions of the Brazilian semiarid. The experiment was conducted in the city of Petrolina, PE. Shoots total dry mass and photosynthetically active radiation intercepted for both crops were monitored. Furthermore, it was obtained the evapotranspiration (ETc) by the soil water balance method. With these data and reference evapotranspiration it was obtained crop coefficient (Kc), which were subsequently used to adjust models as a function of accumulated degree days. With the results, it was found the water requirements from maize and cowpea intercropped system were greater than the sole system. Kc in the intercropped system was 0.90, 1.30, 1.20 and 0.72 for maize and 0.86, 1.30, 1.21 and 0.91 for cowpea, respectively, for the vegetative, flowering, grain filling and ripening stages. In the sole system, these values were, 0.86, 1.23, 0.97 and 0.52 for maize and 0.68, 1.02, 1.06 and 0.63 for cowpea in those phases mentioned. The variations of the Kc values for both systems and cultures have been associated to the increase of biomass and light interception. The Gaussian model adjusted properly described the relationship between Kc and accumulated degree days.

A adoção de práticas de manejo pode afetar a fenologia e, consequentemente, o momento de colheita e o nível produtivo de palma forrageira. Objetivou-se avaliar o efeito de lâminas de irrigação e sistemas de cultivo sobre as fenofases e o momento de corte da palma forrageira Opuntia stricta (Haw.) Haw. O delineamento foi em blocos ao acaso com parcelas subdivididas e quatro repetições. Lâminas de irrigação, com base na evapotranspiração de referência (8,75 %; 17,5 %; 26,25 %; e 35 % ETo), mais uma testemunha (0 % ETo) compuseram as parcelas, e os sistemas de cultivo as subparcelas (cultivo exclusivo, cultivo exclusivo com cobertura morta e consórcio palma-sorgo). Com a morfogênese de emissão de cladódios foram delimitadas as fases fenológicas, e com a extrapolação da taxa de acúmulo mensal de matéria seca de forragem definiu-se o momento de corte. A aplicação de lâminas de irrigação aumentou a fenofase II (maior emissão de cladódios de segunda ordem), em detrimento à fenofase III, associada a cladódios de terceira ordem. A fenofase III foi mais reduzida nos sistemas de cultivo exclusivo com cobertura morta e consórcio palma-sorgo, quando comparada ao sistema cultivo exclusivo. O momento de corte ideal para a palma irrigada é de 19 meses, independentemente do sistema de cultivo. Os sistemas de cultivo exclusivo com cobertura morta e consórcio palma-sorgo incrementaram expressivamente a taxa de acúmulo mensal de matéria seca de forragem, com maior antecipação do momento de corte para o sistema consórcio palma-sorgo (17 meses). Management practices can affect the phenology and, consequently, the harvest time and crop production level of forage cactus. This study aimed at evaluating the effect of irrigation depths and cropping systems on the phenophases and cutting time of the forage cactus Opuntia stricta (Haw.) Haw. The experimental design was a randomized block with split plots and four replications. Irrigation depths based on reference evapotranspiration (8.75 %, 17.5 %, 26.25 % and 35 % ETo) and a control (0 % ETo) made up the plots, while cropping systems (exclusive cropping, exclusive cropping on mulch and forage cactus-sorghum intercropping) were distributed in the subplots. Cladode emission morphogenesis was used to define the phenological phases, while the extrapolation of the monthly dry matter accumulation rate was applied to obtain the cutting time. The use of irrigation depths significantly increased the phenophase II (higher emission of second-order daughter cladodes), decreasing the phenophase III, associated with third-order daughter cladodes. The phenophase III was lower in the exclusive cropping on mulch and forage cactus-sorghum intercropping systems, when compared to the exclusive cropping system. The ideal cutting time for irrigated forage cactus is 19 months, regardless of the cropping system. The exclusive cropping on mulch and forage cactus-sorghum intercropping systems significantly increased the monthly forage dry matter accumulation rate, with an earlier cutting time for the forage cactus-sorghum intercropping system (17 months).

A pecuária leiteira é uma atividade de grande importância no nordeste brasileiro, podendo ser afetada de forma direta e indireta, caso as atuais previsões climáticas sejam confirmadas até o final do século. O objetivo deste trabalho foi estimar os impactos das mudanças climáticas sobre a produção leiteira nos estados de Alagoas, Bahia e Sergipe. Os valores do índice de temperatura e umidade (ITU), do declínio da produção de leite (DPL) e da redução do consumo alimentar (RCA) de vacas leiteiras foram calculados para os cenários climáticos B1 e A1F1 do IPCC. Utilizou-se um modelo multiplicativo para estimar o efeito das alterações de temperatura sobre os valores normais da umidade relativa do ar. Com base em ambos os cenários do IPCC, as regiões produtoras, situadas no norte e litoral do estado da Bahia e áreas litorâneas dos estados de Alagoas e Sergipe, serão afetadas expressivamente em decorrência do aumento do estresse térmico, com reduções marcantes na produção de leite e no consumo alimentar, especialmente de animais com alto potencial genético de produção. Este cenário pode afetar as atuais regiões produtoras dos estados nordestinos, de forma que a exploração leiteira seja limitada aos animais com baixo desempenho produtivo.

Understanding the effect of the cropping system on the morpho-yield relationship of plants is crucial for success in the agricultural activity, mainly in arid and semi-arid regions, where there are major challenges for food production. In this study, the objective was to apply multivariate statistics in the morpho-yield evaluation of forage cactus clones in cropping systems as sole crop and intercropped with sorghum cultivars. The experiment was conducted in Serra Talhada, PE, Brazil, between March 18, 2017 and June 16, 2018. The design adopted was in randomized blocks with 12 treatments composed of three forage cactus clones in sole-crop system (IPA Sertânia, Miúda and Orelha de Elefante Mexicana) and nine forage cactus-sorghum intercropping systems with the cultivars 467, SF11 and 2502. Morphometric and phytomass measurements of forage cactus clones were performed throughout the cycle. The relationship between the morpho-yield traits of the clones was evaluated by means of principal component analysis. Cladode width, length, perimeter, and area are morphometric variables that determine phytomass accumulation in clones. The cropping systems did not influence the association of morpho-yield traits, but it depends on the genus of forage cactus. Negative correlations between cladode dimensions and phytomass of the clones of the genus Nopalea explained their lower phytomass accumulations. Principal components analysis makes it possible to elucidate associations between morpho-yield variables of forage cactus.