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Forage cactus cropping systems that include a combination of agricultural practices (cloning, irrigation, mulching and/or intercropping) can increase forage production and economic return in semi-arid environments. This study evaluated the effect on productivity, biological efficiency and economic return of combining different practices with forage cactus cropping systems in the semi-arid region of Brazil. The research was conducted in four experimental areas, in a randomised block design with four replications, and included the following practices: 1) clones – irrigation - cover, 2) different irrigation depths, 3) intercropping - mulching, and 4) different levels of mulch. The treatments in experiment I consisted of three cactus clones (‘Orelha de Elefante Mexicana’—OEM; ‘Miúda’—MIU and ‘IPA-Sertânia’—IPA), two water regimes (rainfed and irrigated), and two levels of mulch (with and without mulch). Experiment II comprised four irrigation depths (0, 40, 80 and 120% of the crop evapotranspiration) and three cactus clones. In experiment III, three crop arrangements (single cactus, cactus intercropped with millet, and single millet) were evaluated under two levels of mulching (with and without mulching). In experiment IV, four levels of mulch were used (0, 5, 10 and 15 Mg ha-1). The total number of cladodes per plant, fresh matter yield (YFM), dry matter yield (YDM), and final plant density were obtained when harvesting. Economic viability was assessed using the profitability index (PI). The rainfed systems showed greater yield. The use of mulch afforded greater productivity. The OEM clone (YFM = 310.76 Mg ha-1 and YDM = 29.87 Mg ha-1) obtained a higher yield than did the IPA and MIU clones. The highest PI values were achieved under the rainfed systems. The MIU and IPA clones exhibited lower PI values. The cactus-millet intercrop achieved the best performance with the use of mulch. Cactus systems of 15.0 Mg ha-1 showed a greater PI value. It was concluded that the integrated management of such practices as intercropping, mulching and the adoption of the OEM clone can increase the supply of forage. These practices can promote the sustainable intensification of forage input in Livestock Production Systems in semi-arid environments.

Variation in rainfall affects crops; therefore, agricultural practices become essential for forage production in semi-arid regions. This study aimed to evaluate the influence of different agricultural practices on phyllochron, structural characteristics of forage cactus and millet, and their relations with crop yield using the principal component analysis (PCA). The design was in randomized blocks, with six treatments: sole cropped cactus without straw mulching, sole cropped cactus with straw mulching, sole cropped millet without straw mulching, sole cropped millet with straw mulching, and cactus intercropping with millet, with and without straw mulching, each with four replicates. There were three cactus cycles and nine millet cycles (three cycles of cultivars BRS1501 and six of IPA Bulk-1-BF). Biometric parameters were evaluated monthly, while yield was determined after the crop harvest. Phyllochron was determined with the regression analysis. The PCA was applied to structural characteristics and yield. The systems adopted did not influence the structural characteristics of cactus and millet ( p > 0.05), except for cladode thickness, which increased with straw mulching. Phyllochron of the millet reduced when the crop was intercropped. The structural characteristics of cladode length, width, and thickness influenced crop yield, mainly in systems with straw mulching. Straw mulching and intercropping alter phyllochron of cactus and millet. The adoption of straw mulching has a more significant relationship with cactus yield, whereas biometric variables influence crop yield for millet, not the cropping system.

Clarifying cultivation techniques and making production systems more efficient are practices that have been much sought after in agricultural systems in recent decades. In this context, the forage yield, biological efficiency, and competitive ability, of different cultivation strategies for intercropping forage cactus and sorghum were determined in biosaline production systems from 2018 to 2020 in Brazil. Four experiments were carried out, comprising: 1) cropping configurations for the forage cactus-sorghum intercropping system; 2 and 3) planting densities for the forage cactus intercropped with sorghum with an east-west and north-south row orientation, respectively; and 4) planting densities for the forage cactus and sorghum. Each experiment used a randomised block design with four replications. The intercropped forage cactus and sorghum showed higher productivity than the monocropped systems. The indices of biological efficiency (LER, ATER, LEC and SPI with mean values equal to 1.6, 1.8, 0.6 and 29.0, respectively) and competitive ability (ALGY in average 870.6) show better performance under the intercropped system compared to the single crops. The increased planting density resulted in an increase in productivity under the intercropped forage cactus-sorghum system (on average an increase of 69.4% dry matter). In turn, the orientation had no influence on the productivity of the intercropping system but offered better conditions for the forage cactus when cultivation was in an east-west direction (21.7 Mg ha􀀀 1 of dry matter) compared to north-south (17.5 Mg ha􀀀 1 of dry matter). Intercropping forage cactus and sorghum using biosaline agriculture is an excellent alternative for a production system in semi-arid environments, especially at higher planting densities (50,000 and 100,000 plants ha􀀀 1). Made available in DSpace on 2022-10-05T13:05:40Z (GMT). No. of bitstreams: 1 How-to-enhance-the-agronomic-performance-of-cactus-sorghum-2022.pdf: 5591058 bytes, checksum: 0243de01975881c10b7173971fbce7dc (MD5) Previous issue date: 2022

Plants with the crassulacean acid metabolism commonly present good adaptation to arid and semi-arid environments, but it highly depends on the type of species. In this study, chlorophyll fluorescence, the concentration of inorganic and organic solutes and the productive performance were evaluated along with their relationships in different clones of the genera Opuntia and Nopalea. The experiment was conducted from 2016 to 2018. Four clones of genus Opuntia were evaluated: ‘Orelha de Elefante Mexicana’ (OEM), ‘Orelha de Elefante Africana’ (OEA), V19 and F8; and two clones of genus Nopalea: ‘IPA Sertânia’ and ‘Miuda’. The experiment was arranged in a randomised block design, with six treatments and three replications. The following parameters were measured when harvesting: initial, maximum and variable fluorescence; the quantum yield of PSII (Fv/Fm); light-induction curves of the photochemical parameters (ΔF/Fm’, qP, NPQ and ETR); the chlorophyll and carotenoid content; carbohydrates; the sodium (Na+) and potassium (K+) content; morphometry; and dry matter accumulation. The values for the effective quantum yield of PSII (ΔF/Fm’) and the alterations in photochemical quenching were higher in the OEM clone (P

O objetivo do estudo foi avaliar o potencial dos algoritmos de aprendizado de máquina k-Nearest Neighbor (kNN), Random Forest (RF), Support Vector Machine (SVM) e Artificial Neural Networks (ANN) na identificação das fitofisionomias da Caatinga a partir de imagens OLI/Landsat 8. Para tanto, foi elaborado um arquivo vetorial de treinamento com as amostras dos diferentes padrões dos usos e cobertura da terra, a fim de orientar os algoritmos no processo de classificação. A validação das classificações foi obtida por meio da validação cruzada, do tipo k-fold, com 30 repetições, sendo avaliada a qualidade da classificação a partir dos valores expressos pelo coeficiente Kappa. Para verificar a existência de diferenças significativas entre os algoritmos foi aplicado o teste estatístico de Friedman e Nemenyi. O algoritmo RF apresentou os maiores valores para o coeficiente Kappa, expressando um valor médio de 0,9841. Por outro lado, a ANN demonstrou desempenho inferior aos demais, englobando um valor médio de 0,7551, ocasionado pela confusão espectral na identificação da classe nuvem/sombra com a classe água. Apesar de todos os algoritmos testados apresentarem bons resultados, o algoritmo RF diferiu significativamente dos demais, expressando resultados superiores quando aplicado à identificação de padrões espaciais na Caatinga. Conclui-se que o uso de algoritmos de aprendizagem de máquina é eficiente na identificação de fitofisionomias da Caatinga, com destaque para o RF, o qual englobou melhor a variação dos padrões espectrais dos usos, podendo ser utilizado para estudos posteriores relacionados com a Caatinga.

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

Rainfall redistribution by forest cover has potential hydrological impacts in semi-arid regions due to continuous human intervention. Studying the process of interception loss by Caatinga vegetation and its changes due to deforestation is extremely important for local hydrology. However, such information is scarce in the literature. This study examined the partitioning of rainfall into throughfall (TF), stemflow (SF) and interception loss (I) in the Caatinga vegetation (CAA) and evaluated the influence of rainfall characteristics on this partitioning. The components of rainfall partitioning were measured from 2016 to 2017 to determine the TF and SF respectively, and their relationships with rainfall characteristics were evaluated based on linear regression models. For the Caatinga vegetation, TF and SF represent 89.2% and 0.5% of the gross rainfall, while interception loss was 10.3%, an expressive value that should be included in regional water balance models. The rainfall characteristics were able to explain the variations in water partitioning, showing that TF and SF increase for events of higher intensity and volume, whereas interception loss is mainly associated with events of longer duration. For the Caatinga, stemflow and throughfall usually occur for events of greater than 1.65 mm and 0.98 mm, while values for canopy water storage ranged from 0.88 mm to 1.16 mm. It is concluded that for semi-arid environments, these values are significant and cannot be ignored when managing local water resources.

This study aimed to quantify forage yield, economic performance, biological efficiency and competitive ability in cactus intercropped with millet, compared with their monocrops, both with and without mulch, under irrigation. The experiment was conducted over two years in semi-arid of Brazil. The experimental design was of randomised blocks with four replications and six treatments: monocropped cactus without mulch; monocropped cactus with mulch; monocropped millet without mulch; monocropped millet with mulch and cactus intercropped with millet, with and without mulch. The individual yields of fresh (270 t ha−1) and dry (23 t ha−1) matter in the cactus were not affected by the mulch or by intercropping. Mulching improved the individual yields of fresh (69.7 t ha−1) and dry (23.4 t ha−1) matter in the monocropped millet. Total dry matter was greater in the intercropping systems, both with (32.8 t ha−1) and without (31.4 t ha−1) mulching, being the average monetary advantage index equal to 8 404 BRL ha−1. The cactus-millet configuration, irrespective of the use of mulch, but irrigated in dry environments or during dry periods of the year, is more advantageous than the monocrops, because it promotes gains in production and food diversity for meeting the demand of the herd.

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

The Brazilian semiarid region has been subjected to strong man-made actions since the 1970s, which have resulted in landscape transformation. The scientific literature presents several studies on the soil properties or microclimate of different types of landscapes; however, less attention was having been paid to the surface contrast between native vegetation and bare soil. The objective of this research was to evaluate the soil properties and microclimate of two common landscapes in the Brazilian semiarid region, a seasonally dry tropical forest (Caatinga) and a deforested area. Soil and microclimate data were obtained from two sites, both located in the State of Pernambuco, Brazil. Soil samples were collected on six dates and from layers, and microclimate variables were measured for three years. Soil properties and microclimatic data were evaluated using the MannWhitney test, as well as regression and principal component analysis. Successive years of agricultural practices affected the bulk density, promoting an increase in the total porosity of the soil in the deforested area site. In addition, changes were verified in the magnitude of many chemical properties (pH, P, K+, Mg2+, Cu2+, Fe, Mn, Zn2+ and Ca2+), indicating soil degradation. Compared with the Caatinga forest site, the minimum air temperature was 2.3 ◦C, and the maximum vapor pressure deficit was 7% higher in the deforested area site, and it is very likely that Caatinga removal there will lead to a reduction in precipitation. The results suggest that Caatinga vegetation removal followed by agricultural practices and subsequent land abandonment promotes significant changes in soil properties and the microclimate, which can contribute to advances in desertification and affects agricultural activities in the Brazilian semiarid region. Made available in DSpace on 2021-02-18T12:21:32Z (GMT). No. of bitstreams: 1 Soil-properties-and-microclimate-2021.pdf: 8423299 bytes, checksum: 87dd85ec63d373c72d7e902b8c466629 (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

It was evaluated how straw management modifies the development, growth, nutrient cycling and crop water productivity of sugarcane in the semiarid region of Brazil. The experiment was carried out using two plots with 5 ha each, being one without straw on the soil surface and one with 27.2 Mg·ha−1 covering the soil. Sugarcane growth and development and straw decomposition coefficient were evaluated, whereas the industrial yield, juice quality, dry matter partitioning, and crop water productivity were determined at harvesting. The straw decomposition coefficient was 0.0049 Mg·ha−1·day−1, and the remaining dry mass was equal to 24%. The straw affected the sugarcane growth and development until the first 100 days. The individual internode volume can be adopted as an indicator of the effect of straw on sugarcane growth because the internode volumes up to the sixth position in the with-straw treatment crop were lower than in the no-straw treatment, which was not observed in other variables of the stalks. Keeping straw on the soil surface reduced the crop lodging. Yield and juice quality were not affected, but crop water productivity was increased by keeping sugarcane straw in the field. Made available in DSpace on 2021-02-18T12:20:04Z (GMT). No. of bitstreams: 1 Straw-management-effects-on-sugarcane-growth-2020.pdf: 299525 bytes, checksum: b3d1b6af75f44912ded85e65bd2b7014 (MD5) Previous issue date: 2020

The Aspidosperma pyrifolium Mart. & Zucc. is one of the main species of Caatinga biome, a seasonally dry tropical forest in Brazilian Semi-arid, very prominsing for the restoration of degraded or desertified areas. The combined effects of salt and water stress on morphological dynamics, biomass accumulation and gas exchange in A. pyrifolium were investigated. The experiment was conducted in state of Pernambuco, Brazil. A completely randomised design was adopted, where the plants were submitted to four water regimes based on a percentage of the reference evapotranspiration (ET0): 25%, 50%, 75% and 100%.ET0, and four salinity levels, using NaCl: 0.2 (control), 1.8, 2.82 and 3.93 dS m−1. Biometric, biomass and gas exchange data were obtained, and water use efficiency, momentary and intrinsic water use efficiency were calculated. The water deficit affected stem diameter, and stem and root biomass. Gas exchange showed a reduction for an increase in salt and water stress. Momentary and intrinsic efficiency were maximized under a water regime of 65%.ET0 and an electrical conductivity of 1.51 dS m−1, and 67%.ET0 and 1.75 dS m−1, respectively. It is concluded that the species A. pyrifolium changes the biomass partitioning between the plant structures to compensate the salt and water stress.

Estima-se que metade da superfície da Caatinga já foi modificada. A remoção da vegetação aumenta a fragilidade das terras e intensifica o processo de desertificação. Sob condições de aporte hídrico variado, a adoção de tecnologias hídricas é indicada. As características morfofisiológicas e biofísicas da palma forrageira foram investigadas neste estudo como indicativo à adequação do manejo da cultura sob diferentes tecnologias hídricas (clones, irrigação e cobertura morta). O experimento foi conduzido em blocos casualizados, com três repetições, e sob três ambientes de crescimento com uma ou mais tecnologias hídricas: RH(-) - clones sob regime hídrico inferior à normal climatológica (sequeiro); RH(+) - clones sob regime hídrico superior à normal climatológica (irrigado); e, RH(+C) - clones sob regime hídrico superior à normal climatológica (irrigado) e adoção de cobertura morta. Os clones avaliados foram: IPA Sertânia e Miúda, e Orelha de Elefante Mexicana. Medidas biométricas foram obtidas ao longo do tempo e a matéria seca na ocasião da colheita, a partir dos quais, calculou-se índices morfofisiológicos e biofísicos. Os ambientes de crescimento e sua interação com os clones afetaram apenas a magnitude do índice de distribuição dos cladódios de 5ª ordem (p < 0,05), mas foram decisivos na sazonalidade do acúmulo de matéria seca pelos clones. A maioria dos índices morfofisiológicos e biofísicos foi influenciada pelo tipo de clone (p < 0,05). Os índices biofísicos se mostram ótimas opções de substituição ou complementação dos índices morfofisiológicos quando se dispõem apenas de dados biométricos e de matéria seca da ocasião da colheita da palma forrageira.

Em regiões áridas e semiáridas as condições climáticas e salinização do solo e da água proporcionam declínios na produção de forragem e comprometem o rendimento dos rebanhos. Logo, o uso de espécies forrageiras adaptadas e de alto valor nutricional, torna-se uma alternativa para manter a disponibilidade de alimentos em períodos sazonais. Dentre estas espécies, a palma forrageira é um alimento recomendado para os ruminantes, devido ao alto teor de água em suas estruturas, boa aceitabilidade e baixo custo de produção. A cultura do sorgo, também apresenta elevado potencial forrageiro, alta produção de matéria seca, baixa exigência hídrica, e adaptabilidade à consorciação, auxiliando em melhores produções em ambientes áridos e semiáridos. A utilização de sistemas consorciados acrescidos com a irrigação é de grande relevância para o manejo sustentável da pecuária local, uma vez que esse tipo de sistema maximiza o rendimento de forragem das áreas produtivas. Assim, objetivou-se com a presente revisão ressaltar a importância de estudos relacionados ao consórcio palma-sorgo em condições irrigadas no semiárido para subsidiar políticas de produção contínua de forragem. Os achados dessa revisão encorajam pesquisas no planejamento agrícola de área em ambientes negligenciados sob condições semiáridas com o consórcio de palma-sorgo para produção de forragem.

Rainfall partitioning by trees is an important hydrological process in the contexts of water resource management and climate change. It becomes even more complex where vegetation is sparse and in vulnerable natural systems, such as the Caatinga domain. Rainfall interception modelling allows extrapolating experimental results both in time and space, helping to better understand this hydrological process and contributing as a prediction tool for forest managers. In this work, the Gash model was applied in two ways of parameterization. One was the parameterization on a daily basis and another on a seasonal basis. They were validated, improving the description of rainfall partitioning by tree species of Caatinga dry tropical forest already reported in the scientific literature and allowing a detailed evaluation of the influence of rainfall depth and event intensity on rainfall partitioning associated with these species. Very small (0.0–5.0 mm) and low-intensity (0–2.5 mm h−1) events were significantly more frequent during the dry season. Both model approaches resulted in good predictions, with absence of constant and systematic errors during simulations. The sparse Gash model parametrized on a daily basis performed slightly better, reaching maximum cumulative mean error of 9.8%, while, for the seasonal parametrization, this value was 11.5%. Seasonal model predictions were also the most sensitive to canopy and climatic parameters.

Extreme weather events assume great socioeconomic relevance, especially in regions climatically sensitive such as semi-arid climate. The analysis of the rainfall regime of a given region can be made by the Rainfall Anomaly Index (RAI), which allows classifying the rainfall regime as to the annual anomalies of precipitation, inferring on the dry and humid cycles. Therefore, the objective was to study the spatial-temporal variability of precipitations of an area inserted in the Semiarid region of Brazil. For this, the RAI was used for the climatological normal 1987-2017 of 11 rainfall stations inserted in the mesoregion of the Sertao of the state of Pernambuco. The annual and interannual precipitations were analyzed, determined the negative and positive anomalies along the climatological normal, and, through the spatial interpolation of precipitation by the Method of inverse of the Square of Distance, elaborated spatial distribution maps of rainfall in different annual anomalies. The results showed that in 90.9% of the stations studied the rainy block occurs between the months of January to April, and that the accumulated of these months corresponds to more than 50% of the precipitated annual volume, thus demonstrating the irregularity in the annual distribution of rainfall. It was found that in 55% of the years there were negative anomalies in the mesoregion of the Sertao of Pernambuco. Moreover, it was spatially verified a greater homogeneity in the spatial distribution of negative anomalies in relation to positive anomalies, that is, drought events, when they occurred, tended to reach the entire studied area.

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.

Atividades agropecuárias no semiárido brasileiro são de grande importância, no entanto, as mudanças do clima e da vegetação vêm ameaçando a segurança alimentar dos rebanhos. Visto que, geralmente os animais são criados de forma extensiva, se alimentando da vegetação nativa da Caatinga. A palma forrageira, por ser uma planta adaptada às condições climáticas dessa região, tornando-se uma alternativa de cultivo, e podendo ter sua produtividade aumentada de forma sustentável com um manejo adequado, além de sofrer alterações nos indicadores agrometeorológicos. A adubação orgânica, por exemplo, pode proporcionar alterações na qualidade, produtividade e estrutura espacial dessa cultura, no entanto, estudos avaliando a interação de clones de palma forrageira com bioestimulates são escassos na literatura, logo, a aplicação de indicadores agrometeorológicos no cultivo sustentável dessa cultura, torna-se uma ferramenta com grande potencial para avaliação da eficiência dos cultivos e melhorar o planejamento e tomada de decisão dos produtores. O objetivo desse estudo foi apresentar uma revisão sobre a intensificação sustentável da palma forrageira por meio de biofertilizantes e o uso de indicadores agrometeorológicos, sugerindo estudos futuros para avanço técnico e cientifico e melhoramento na governança agropecuária das propriedades em ambientes semiáridos.Palavras-chave: bioestimulantes; forragem; pecuária; semiárido; Opuntia. Biofertilizer use for sustainable intensification of irrigated forage cactus production and use agrometeorological indicators for evaluation A B S T R A C TAgricultural activities in the Brazilian semi-arid region are of great importance, however, climate and vegetation changes have been threatening the food security of livestock. Since, generally the animals are raised extensively, feeding on the native vegetation of the Caatinga. The forage cactus, being a plant adapted to the climatic conditions of this region, becomes an alternative for cultivation, and its productivity can be increased in a sustainable way with an adequate management, in addition to undergoing changes in agrometeorological indicators. Organic fertilization, for example, can provide changes in the quality, productivity and spatial structure of this crop, however, studies evaluating the interaction of forage cactus clones with biostimulates are scarce in the literature, therefore, the application of agrometeorological indicators in the sustainable cultivation of this crop, becomes a tool with great potential for evaluating the efficiency of crops and improving the planning and decision-making of producers. The aim of this study was to present a review on the sustainable intensification of forage cactus through biofertilizers and the use of agrometeorological indicators, suggesting future studies for technical and scientific advancement and improvement in the agricultural governance of properties in semi-arid environments.Keywords: biostimulants; forage; livestock; semi-arid; Opuntia.

Em regiões suscetíveis a desertificação, como é o caso do Semiárido, o uso de tecnologias hídricas pode servir como ferramenta para mitigar os impactos ambientais, aumentar a eficiência no uso da água e garantir uma menor estacionalidade da produção. Nesta revisão, buscamos abordar as principais estratégias que podem contribuir para a sustentabilidade, intensificação e planejamento da atividade agrícola nas regiões com riscos de desertificação. Para isso, discutiu-se os problemas e as principais características ambientais das áreas suscetíveis a esse processo; abordou-se o uso de tecnologias hídricas (e.g. adoção de espécies vegetais resistentes ao estresse hídrico, uso de clones/cultivares mais adaptados à condições estressantes, intensidade de corte, cultivo, uso de cobertura morta), práticas que visam aumentar a eficiência do uso da água na agricultura; destacou-se o modelo AquaCrop da FAO como ferramenta para inferir sobre o impacto de possíveis cenários ambientais na agricultura, bem como simular as melhores estratégias de resiliência; e, por fim, frisou-se outros conceitos relacionados a sustentabilidade da agricultura como: eficiência no uso da água, agricultura verde, e caracterizadores de um sistema agrícola. Nossos achados reforçam a necessidade de uma visão holística dos agroecossistemas para integrar as tecnologias hídricas a outras estratégias de aumento da eficiência no uso dos recursos e de redução a liberação de gases de efeito estufa (GEE), de modo a contribuir com a sustentabilidade da atividade e a mitigação dos impactos no meio ambiente. Outrossim, com a utilização da modelagem é possível prever os impactos que as condições climáticas futura proporcionarão ao planeta, de modo a planejar estratégias mais eficazes para a convivência da agricultura com as mudanças do clima.Palavras-chave: AquaCrop; eficiência no uso da água; estratégias de resiliência agrícola. Water technologies and modeling: strategies in the search for sustainability and intensification of agriculture in susceptible environments to desertification A B S T R A C TIn regions susceptible to desertification, such as the semi-arid region, the use of water technologies can serve as tool to mitigate environmental impacts, increase water efficiency, and ensure a lower state of production. In this review, we seek to address the main strategies that can contribute to the sustainability, intensification and planning of agricultural activity in regions with desertification risks. To this end, the problems and main environmental characteristics of the areas susceptible to this process were discussed; the use of water technologies (e.g. adoption of plant species resistant to water stress, use of clones/cultivars more adapted to stressful conditions, cutting intensity, cultivation, use of mulch), practices aimed at increasing the efficiency of water use in agriculture; the FAO AquaCrop model was highlighted as a tool to infer about the impact of possible environmental scenarios on agriculture, as well as to simulate the best resilience strategies; and, finally, other concepts related to the sustainability of agriculture were emphasized, such as: efficiency in the use of water, green agriculture, and characterizations of an agricultural system. Our findings reinforce the need for a holistic view of agroecosystems to integrate water technologies with other strategies to increase resource efficiency and reduce the release of greenhouse gases (GHG), to contribute to the sustainability of the activity and the mitigation of impacts on the environment. Moreover, with the use of modeling it is possible to predict the impacts that future weather conditions will bring to the planet, to plan more effective strategies for the coexistence of agriculture with climate change.Keywords: AquaCrop; efficiency in water use; agricultural resilience strategies

O sucesso do agronegócio no setor pecuário, depende da oferta de forragem para os animais, especialmente em zonas semiáridas, onde as características climáticas e a baixa disponibilidade de alimento podem dificultar a atividade. Diante disso, o uso de práticas agrícolas que melhorem a resiliência agrícola dos cultivos e possibilitem a oferta de forragem durante todo o ano para os animais torna-se imprescindível. Dentre tais práticas, destacam-se: o uso de espécies adaptadas as condições climáticas, escolha da configuração de cultivo, a densidade de plantio e orientação de cultivo. Nesse contexto, duas culturas que merecem destaque em ambientes quentes e secos são palma forrageira e sorgo forrageiro, ambas apresentam elevada eficiência no uso dos recursos, com produtividade satisfatória, além da existência de trabalhos que evidenciam os benefícios na associação dessas culturas na dieta alimentar dos animais. Dessa forma, na presente revisão, objetivou-se analisar as melhorias produtivas e estruturais das culturas da palma e sorgo sob adoção de práticas de resiliência agrícola. Os achados desta revisão, podem servir como subsídios para o planejamento da produção de forragem, ao tempo em que sugerem que a adoção de práticas adequadas (i.e. irrigação, consorciação, orientação de cultivo e densidade) e suas combinações no sistema de produção permitem um melhor aproveitamento dos recursos naturais e, com isso, maiores acúmulos de biomassa, constituindo-se em fatores determinantes para o êxito na produção.Palavras-chave: configuração de cultivo, densidade e orientação de plantio, Opuntia stricta, Nopalea cochenillifera, Sorghum bicolor. Agricultural resilience in intercropped forage cactus-sorghum cultivation in a semi-arid environment: A review A B S T R A C TThe success of agribusiness in the livestock sector depends on the supply of fodder for animals, especially in semi-arid areas, where climatic characteristics and low food availability can hamper activity. Therefore, the use of agricultural practices that improve the agricultural resilience of crops and make it possible to offer fodder throughout the year for animals becomes essential. Among such practices, the following stand out: the use of species adapted to climatic conditions, choice of cultivation configuration, planting density and cultivation orientation. In this context, two crops that deserve to be highlighted in hot and dry environments are forage cactus and forage sorghum, both have high efficiency in the use of resources, with satisfactory productivity, in addition to the existence of studies that show the benefits in the association of these cultures in the diet animal feed. Thus, in this review, the objective was to analyze the productive and structural improvements of palm and sorghum crops under the adoption of agricultural resilience practices. The findings of this review may serve as inputs for the planning of forage production, while suggesting that the adoption of appropriate practices (i.e. irrigation, intercropping, cultivation and density guidance) and their combinations in the production system allow for a better use of natural resources and, with this, greater accumulations of biomass, constituting determining factors for success in production.Keywords: cultivation setting, density and orientation planting, Opuntia stricta, Nopalea cochenillifera, Sorghum bicolor.

A palma forrageira (Nopalea e Opuntia) é uma cultura de fundamental importância para o Semiárido brasileiro (SAB), principalmente como fonte de alimento para os animais. Devido ao seu Metabolismo Ácido das Crassuláceas (MAC) e traços morfofisiológicos. Essa cactácea apresenta fácil adaptação à ambientes com altas temperaturas do ar e déficit hídrico, exibindo elevada eficiência no uso da água e produção satisfatória de biomassa, sobretudo em épocas de longa estiagem. Contudo, ainda é necessário o emprego de práticas de manejo que possam melhorar ainda mais as respostas da palma às condições ambientais dessa região. Nesta revisão, objetivou-se discorrer sobre a utilização do manejo de corte baseado na relação fonte-dreno (FonDren) e o uso de irrigação complementar no cultivo da palma forrageira, de modo a melhorar o aporte forrageiro da agricultura familiar no Semiárido brasileiro. O manejo FonDren consiste na retirada de cladódios que não estejam participando ativamente no processo de fotossíntese (i.e., com injúrias e/ou sombreados), de forma a possibilitar maior emissão de novos, com incremento no desenvolvimento e acúmulo de biomassa da cultura. Por sua vez, a irrigação complementar à chuva, melhora o aproveitamento dos recursos hídricos locais, favorecendo o aumento do uso da água pela palma. A utilização dessas práticas em conjunto, pode incrementar o rendimento dos clones de palma forrageira, e promover maior aporte forrageiro aos sistemas produtivos de agricultura familiar do Semiárido brasileiro.Palavras-chave: Intensidade de corte, Nopalea, Opuntia, relação fonte-dreno, semiárido Sustainable management techniques for the fodder supply of family agriculture in the brazilian semiarid: forage cactus, irrigation and fondren A B S T R A C T The forage cactus (Nopalea and Opuntia) is a crop of fundamental importance for the Brazilian Semiarid Region (BSR), mainly as a source of food for animals. Due to its Crassulaceous Acid Metabolism (CAM) and morphophysiological traits. This cactus is easily adapted to environments with high air temperatures and water deficit, showing high efficiency in the use of water and satisfactory production of biomass, especially in times of long drought. However, it is still necessary to use management practices that can further improve cactus responses to environmental conditions in that region. In this review, the objective was to discuss the use of cut management based on the source-drain ratio (FonDren) and the use of complementary irrigation in the cultivation of forage cactus, in order to improve the forage contribution of family agriculture in the Brazilian Semiarid. FonDren management consists of removing cladodes that are not actively participating in the photosynthesis process (i.e., with injuries and/or shading), in order to enable greater emission of new cladodes, with an increase in the development and accumulation of biomass in the culture. In turn, irrigation complementary to rainfall improves the use of local water resources, favoring the increased use of water by the forage cactus. The use of these practices together, can increase the yield of forage cactus clones, and promote greater forage input to the productive systems of family agriculture in the Brazilian Semiarid.Keywords: Cutting intensity, Nopalea, Opuntia, source-drain ratio, semiarid

Este trabalho utilizou uma serie de dados de precipitacao referente ao periodo de 1973 a 2010 para o municipio de Castanhal-PA com a finalidade de investigar: 1) os padroes de precipitacao; 2) as mudancas de tendencia; 3) a ocorrencia dos eventos de deficit e excesso de agua pelo uso do Indice Padronizado de Precipitacao (SPI) e suas relacoes com fenomenos atmosfericos como El Nino e La Nina; 4) a associacao entre a probabilidade de ocorrencia das chuvas e o tempo de retorno (TR). Para tanto, utilizaram-se dados de chuva obtidos em uma estacao pluviometrica da Agencia Nacional de Aguas e Saneamento Basico (ANA). Os dados foram analisados por periodos, tendo sido considerados os intervalos: mensais, trimestrais, anuais ou decadais realizando estatistica descritiva, para entendimento da variacao sazonal, valores medios, analise da tendencia por meio do teste nao parametrico de Mann-Kendall e da ocorrencia de valores extremos associados a probabilidade de ocorrencia e tempo de retorno. Nossos resultados demonstraram que: a media anual de precipitacao para o periodo estudado foi de 2573,15mm; o intervalo de 2003-2010 foi aquele de menor variacao nos valores de precipitacao anual. Nao foram observadas tendencias nos valores de precipitacao durante o periodo analisado. O SPI-1 mostrou boa adequabilidade a ocorrencia dos valores extremos de precipitacao no local em alguns casos associado aos fenomenos El Nino e La Nina. O maior (4.709,4 mm) e menor (1.379,6 mm) volume de chuva foram observados nos anos de 1994 e 1981, respectivamente, com probabilidade de ocorrencia de 3% e TR = 39 anos. Understanding the Characteristics Associated with Precipitation for a Northeastern Region of Para: An Analysis of Behavior, Tendency, Extreme Events and Time of Return for the 1973-2010 period A B S T R A C T This work used a series of precipitation data for the period 1973 to 2010 for the municipality of Castanhal-PA in order to investigate: 1) precipitation patterns; 2) changes in trend; 3) the occurrence of deficit and excess water events using the Standardized Precipitation Index (SPI) and its relationship with atmospheric phenomena such as El Nino and La Nina; 4) the association between the probability of rain occurrence and the return time (TR). For this purpose, rainfall data obtained from a rainfall station of the National Water and Basic Sanitation Agency (ANA) were used. Data were analyzed by periods, considering the intervals: monthly, quarterly, annual or decadal performing descriptive statistics, to understand seasonal variation, mean values, trend analysis using the nonparametric Mann-Kendall test and the occurrence of extreme values associated with the probability of occurrence and turnaround time. Our results showed that: the mean annual rainfall for the period studied was 2573.15mm; the 2003-2010 interval was the one with the smallest variation in annual precipitation values. There were no trends in precipitation values during the analyzed period. SPI-1 showed good suitability for the occurrence of extreme precipitation values at the site in some cases associated with the El Nino and La Nina phenomena. The highest (4,709.4 mm) and lowest (1,379.6 mm) volume of rainfall were observed in 1994 and 1981, respectively, with a probability of occurrence of 3% and TR = 39 years. Keywords: Rainfall; Droughts; Floods; Atmospheric phenomena.

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.