Survival and distribution of weedy rice seedbank after twenty-two years of different rice cropping systems / Sobrevivência e distribuição do banco de sementes de arroz daninho após 22 anos de cultivo de arroz em diferentes sistemas

ABSTRACT: Weedy rice (Oryza sativa L.) is the most problematic weed in rice fields due to the few control management alternatives to control it, because of the genetic similarity with the crop. Different cropping systems (regarding soil preparation before sowing) have been used as options to control the persistence and emergence of the weed seedbank. Therefore, the objective of this study was to evaluate the longevity and vertical distribution of weedy rice seeds in the soil seedbank after 22 years of different rice cropping systems. Data was analyzed as a two-way factorial, with cropping systems carried out for 22 years [no-tillage (NT), conventional tillage (CT), wet direct-seeded (WDS)] as one factor and sampling depth (0-2, 2-5, 5-10 and 10-20 cm) as the other factor. The number of whole and deteriorated seeds per m-2 were assessed, as well as the viability (%). No effect between the systems were detected up to 5 cm, however at 5-10 cm CT and WDS showed higher amount of seeds, and WDS at 10-20 cm. As the sampling depth increased, NT showed fewer amount of seeds, while less reduction of the soil seedbank was observed in WDS. CT and WDS spread viable seeds in the soil profile from 0 to 20 cm depth. After 22 years there are viable weedy rice seeds up to 10 cm of depth in the three cropping systems and there is no difference among them up to 5 cm of depth, demonstrating the serious problem of the seedbank for this species.

RESUMO: O arroz daninho (Oryza sativa L.) é a principal planta daninha do arroz cultivado e, devido à similaridade genética com a cultura, são poucas as alternativas de controle. Uma possibilidade são os sistemas de cultivo, em razão da influência na emergência e sobrevivência da espécie no banco de sementes do solo. Diante disso, o trabalho objetivou avaliar a longevidade e a distribuição das sementes de arroz daninho no perfil do solo, após 22 anos de cultivo, sob diferentes sistemas. Os tratamentos foram arranjados em esquema fatorial, em que o fator A foi composto por três sistemas de cultivo, realizados consecutivamente durante 22 anos, sendo esses: semeadura direta (SD), sistema convencional (SC) e pré-germinado (PG); e, o fator B composto por quatro profundidades de amostragem: 0-2, 2-5, 5-10 e 10-20 cm. As variáveis avaliadas foram: o número de sementes íntegras e deterioradas m-2; e, a porcentagem de viabilidade. Não foi verificado efeito dos sistemas até 5 cm, mas a 5-10 cm SC e PG mostraram maior quantidade de sementes, e PG a 10-20 cm. A SD proporcionou diminuição de sementes íntegras conforme aumentou a profundidade de amostragem, enquanto o sistema PG elimina menos sementes do banco de sementes do solo. Os sistemas SC e PG distribuem sementes viáveis no perfil do solo de 0 a 20 cm de profundidade. Após 22 anos, nos três sistemas de cultivo há sementes de arroz daninho viáveis até 10 cm de profundidade, sendo igual a quantidade de sementes viáveis até cinco centímetros de profundidade.

Developing an algorithm to geographically estimate the available time for agricultural field spraying in the state of Mato Grosso do Sul / Desenvolvendo um algoritmo para estimar geograficamente o tempo disponível para pulverização agrícola no estado de Mato Grosso do Su

The dimensions of mechanized agricultural systems depend on the edaphoclimatic conditions, crops, and work regimes. This study aimed to geographically estimate the monthly available time and number of favorable hours for agricultural field spraying in the state of Mato Grosso do Sul, Brazil. The meteorological restrictions imposed during unfavorable hours were as follows: ambient temperature above 32 ºC, relative humidity below 50 %, wind speed above 15 km h-1, and volumetric soil humidity above 39 % (equivalent to 90 % of the available water capacity). Mathematical models were then developed considering a period of ten years, which used historical data from the ground monitoring stations of the National Institute of Meteorology within the region. The subsequent algorithm was programmed and installed in a web server to simulate the time required for agricultural field spraying. During the cropping period in the region, there were climatic restrictions on performing agricultural spraying, with relative humidity being the variable with the most significant impact. However, soil moisture conditions restricted the available time for agricultural spraying more than the wind speed, relative air humidity, or ambient temperature.

O dimensionamento de sistemas mecanizados agrícolas depende das condições edafoclimáticas, da cultura e do regime de trabalho. O objetivo deste trabalho foi estimar geograficamente o tempo disponível mensal e o número de horas favoráveis à pulverização agrícola no Estado de Mato Grosso do Sul, Brasil. As restrições meteorológicas impostas para o cálculo das horas desfavoráveis foram: temperatura ambiente acima de 32ºC, umidade relativa abaixo de 50%, velocidade do vento acima de 15 km h-1 e umidade volumétrica do solo acima de 39% (equivalente a 90% da capacidade hídrica disponível). Os modelos matemáticos foram elaborados considerando um período de dez anos, com base nos dados históricos das estações automáticas do Instituto Nacional de Meteorologia instaladas no Estado. O algoritmo desenvolvido e instalado em ambiente web permitiu simular o tempo disponível para pulverização agrícola no estado de Mato Grosso do Sul. Durante o período de safra na região, há restrições climáticas para a realização da atividade de pulverização agrícola, sendo a umidade relativa do ar a variável de maior impacto. A condição de umidade do solo é mais restritiva para o tempo disponível para a pulverização agrícola do que a velocidade do vento, umidade relativa do ar ou temperatura do ambiente.

Combined agricultural practices in millet and cactus: phyllochron, structural characteristics and relations with yield

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.(AU)

Impact of crop management systems on soil nematode communities in South Brazil

ABSTRACT The analysis of nematode communities allows inferring consequences of management practices on the soil food web. We studied the taxonomic structure of nematode communities in preserved areas of the Atlantic forest (native forest = NF) in Ponta Grossa, Paraná State, Brazil, and in three different agroecosystems in neighboring areas to assess the effect of agricultural land use on nematode assemblages. Agroecosystems were located in a red latosol cropped during 30 years under conventional tillage (CT), no-tillage (NT), and minimal tillage (MT). We collected ten composite soil samples in each area in the summer. Nematodes were extracted by Baermann funnel and fixed with formalin. Subsequently, individuals were classified into taxonomic groups and counted on a Peters slide to determine densities of each taxon. Plant-parasitic and free-living nematodes were classified at the genus level. Data were analyzed with the parameters abundance, Bray & Curtis, Shannon-Weaver, and Simpson indexes. We recorded 35 genera and abundance of nematodes in MT and NT areas was more similar. Higher richness was observed in NF in relation to cropped areas, especially under NT and CT. The PCA and clustering analyses from both nematode communities and soil chemical characteristics showed that MT and CT were more similar and NT was clustered near NF. The replacement of native vegetation by cropping systems caused a reduction of nematode diversity, demonstrating the influence of agricultural practices on nematode communities.

Impact of crop management systems on soil nematode communities in South Brazil

The analysis of nematode communities allows inferring consequences of management practices on the soil food web. We studied the taxonomic structure of nematode communities in preserved areas of the Atlantic forest (native forest = NF) in Ponta Grossa, Paraná State, Brazil, and in three different agroecosystems in neighboring areas to assess the effect of agricultural land use on nematode assemblages. Agroecosystems were located in a red latosol cropped during 30 years under conventional tillage (CT), no-tillage (NT), and minimal tillage (MT). We collected ten composite soil samples in each area in the summer. Nematodes were extracted by Baermann funnel and fixed with formalin. Subsequently, individuals were classified into taxonomic groups and counted on a Peters slide to determine densities of each taxon. Plant-parasitic and free-living nematodes were classified at the genus level. Data were analyzed with the parameters abundance, Bray & Curtis, Shannon-Weaver, and Simpson indexes. We recorded 35 genera and abundance of nematodes in MT and NT areas was more similar. Higher richness was observed in NF in relation to cropped areas, especially under NT and CT. The PCA and clustering analyses from both nematode communities and soil chemical characteristics showed that MT and CT were more similar and NT was clustered near NF. The replacement of native vegetation by cropping systems caused a reduction of nematode diversity, demonstrating the influence of agricultural practices on nematode communities.(AU)

Phosphorus acquisition from phosphate rock by soil cover crops, maize, and a buckwheat-maize cropping system

Alternatives to enhance the consensual low phosphorus (P) use efficiency of agriculture may include use of phosphate rock (PR) and plant species with unequal ability to get soil and rock P interplanted in cropping systems to allow plants with higher ability to facilitate access to P of plants with lower ability. This study investigated (i) the maize and three soil cover crops on their capacity to acquire P from PR and (ii) measured P acquisition of maize interplanted with the soil cover crop with the highest capacity to acquire P shown in (i). Experiments were carried out in a greenhouse, with plants grown in single and mixed cropping in pots containing a sandy, low-P soil amended with Monocalcium Phosphate (McP) or the Brazilian PR Itafós. Plant biomass production with PR, in relation to McP, was 83.7 % for buckwheat, 83.6 % for forage radish, 51.8 % for maize, and 0.3 % for pigeon pea. Buckwheat showed capacity of acquiring P from PR; nevertheless, it did not increase growth or P nutrition of maize interplanted in the soil amended with PR, showing no significant P facilitation. The soil amended with McP showed competition between the two plants in the pots. Maize had a greater growth in mixed than in single cropping and this occurred at the expenses of buckwheat. Despite the P mobilization potential of buckwheat, its simple interplanting with maize did not produce positive results.

Plant age, crop stage and surrounding habitats: their impact on sucking pests and predators complex in cotton (Gossypium hirsutum L. ) field plots in arid climate at district Layyah, Punjab, Pakistan / Idade da planta, estágio da cultura e habitats circundantes: seu impacto no complexo de pragas sugadoras e predadores em parcelas de algodão (Gossypium hirsutum L. ) em clima árido no distrito de Layyah, Punjab, Paquistão

Sucking pests are major threat to cotton field crop which cause unbearable losses to the crop yield. Aim of the current study was to record seasonal dynamics of major sucking insect pests including whitefly, jassid, thrips and their natural arthropod predators i.e. green lacewings and spiders in cotton field plots. The effects of surrounding field crops on pests' density and predatory efficiency of predators were also recorded. For sampling and survey of insects, the visual counting was found to be the most efficient method for recording the abundance of insects, trailed by net sweeping and tapping. Whitefly was the most dominant sucking pest found on the vegetative stage of cotton, followed by jassid and thrips. Fluctuated populations of predatory arthropods, spiders and green lacewings were also recorded during whole cropping season however, the densities of pests and predators varied with crop phenology. Spiders' population was encouraging at both vegetative and flowering stage and also the same trend of jassid and whitefly were observed at both stages of the crop. Surrounding habitats showed non-significant effect on population densities of insect pests and predators. For abiotic factors, the spiders showed strong positive correlation with humidity and temperature. However, green lacewing was only positively correlated with humidity. On the other hand, the populations of whitefly, jassid and thrips showed non-significant correlation with both temperature and humidity. Overall densities of sucking insect pests were found above economic threshold level. The plant age, crop stage and surrounding habitats effect on the population fluctuation of pests as well as the predators' abundance. The future studies are also warranted to investigate the altered habitats and multiple trap cropping to find out their impact on unattended insect predators and parasitoids in cotton crop.

As pragas sugadoras são uma grande ameaça para a cultura do algodão, causando perdas insuportáveis no rendimento da cultura. O objetivo do estudo atual foi registrar a dinâmica sazonal das principais pragas de insetos sugadores, incluindo mosca-branca, jassid, tripes e seus artrópodes predadores naturais, ou seja, crisopídeos e aranhas verdes em parcelas de algodão. Os efeitos das plantações circundantes na densidade de pragas e na eficiência predatória de predadores também foram registrados. Para amostragem e pesquisa de insetos, a contagem visual foi considerada o método mais eficiente para registrar a abundância de insetos, seguido por varredura e batida de rede. A mosca-branca foi a praga sugadora mais dominante encontrada na fase vegetativa do algodoeiro, seguida pelo jassid e tripes. Populações flutuantes de artrópodes predadores, aranhas e crisálidas também foram registradas durante toda a safra, no entanto as densidades de pragas e predadores variaram com a fenologia da cultura. A população de aranhas foi encorajadora tanto na fase vegetativa como na floração e também a mesma tendência de jassid e mosca-branca foi observada em ambas as fases da cultura. Os habitats circundantes mostraram efeito não significativo nas densidades populacionais de insetos-praga e predadores. Para os fatores abióticos, as aranhas apresentaram forte correlação positiva com umidade e temperatura. No entanto, lacewing verde foi apenas positivamente correlacionado com a umidade. Por outro lado, as populações de mosca-branca, jassid e tripes apresentaram correlação não significativa com temperatura e umidade. As densidades gerais de pragas sugadoras de insetos foram encontradas acima do nível do limiar econômico. A idade da planta, o estágio da cultura e os habitats circundantes afetam a flutuação populacional de pragas, bem como a abundância de predadores. Os estudos futuros também são necessários para investigar os habitats alterados e cultivo com armadilhas múltiplas para descobrir seu impacto sobre predadores de insetos e parasitoides desacompanhados na cultura do algodão.

Maize legume intercropping systems in southern Mexico: A review of benefits and challenges / Sistemas consorciados de milho no sul do México: uma revisão dos benefícios e desafios

Intercropping is the process of planting two or more crops simultaneously in the same field in order to provide greater ecosystem services (i.e. services related to sustainable land and water use, climate change mitigation, and ecosystem restoration). In southern Mexico, the cereal-legume intercropping is a traditional cropping practice that is declining overtime. This paper provides a literature review of the potential benefits and constraints of a maize-legume intercropping for small-scale farms in southern Mexico. This review explored and elucidated the different ecosystem services delivered by maize-legume intercropping systems. This information will help farmers know how to make a better use of cereal-legume intercropping systems to increase maize yields, improve their socioeconomic conditions, and enhance conservation agricultural practices in southern Mexico.

Consórcio é o processo de plantar duas ou mais safras simultaneamente no mesmo campo, a fim de fornecer maiores serviços de ecossistema (ou seja, serviços relacionados ao uso sustentável da terra e da água, mitigação das mudanças climáticas e restauração do ecossistema) para as lavouras. No sul do México, o consórcio cereal-leguminosa é uma prática tradicional de cultivo que está diminuindo com o tempo. Este artigo fornece uma revisão da literatura sobre os benefícios e limitações potenciais do consórcio milho-leguminosa para fazendas de pequena escala no sul do México. Esta revisão foi escrita para explorar e elucidar os diferentes serviços ecossistêmicos fornecidos por sistemas consorciados de milho e leguminosa. Essas informações ajudarão os agricultores a saber como fazer um melhor uso dos sistemas consorciados de cereais e leguminosas para aumentar a produtividade do milho, melhorar sua subsistência socioeconômica e melhorar as práticas agrícolas de conservação no sul do México.

Resistance of sorghum hybrids to sorghum aphid / Resistência de híbridos de sorgo ao pulgão do sorgo

The aphid Melanaphis sorghi (Theobald) (Hemiptera: Aphididae), which infest the sorghum crop, has been an economically important pest which have been causing severe damage to sorghum crops in Brazil since 2019. These species have been observed mainly at the end of vegetative stage and beginning of reproductive stage of plants. Their high reproductive rate on sorghum raises concerns about these pests. Therefore, the present study aimed to estimate the life expectancy and fertility tables of Melanaphis sorghi fed on 15 hybrids of grain sorghum, in order to know the resistance characteristics of these materials and understand how plant resistance can help manage this insect. This study was carried out in a laboratory at 26±2 ºC and 60±10% R.H (relative humidity). Fifty insects were kept in each hybrid, each insect was considered one repetition. According to biological parameters and fertility life table, hybrids BRS373, DKB590 and 50A10 were less suitable for the sugarcane aphid multiplication. Thus, these hybrids could be useful to manage this pest, since the population growth speed is one of the worst problems for the implementation of cropping systems. Genotypes AG1090, MSK327 and XGN1305 favored the development of this pest and, when chosen within a cropping system, other management strategies should be considered.

O pulgão Melanaphis sorghi (Theobald) (Hemiptera: Aphididae), que infesta a cultura do sorgo, tem sido uma praga economicamente importante que vem causando sérios danos às lavouras de sorgo no Brasil desde 2019. As infestações têm sido observadas principalmente no final do estádio vegetativo e início do período reprodutivo das plantas. A alta taxa de reprodução destes insetos no sorgo aumenta a preocupação com a praga. Nesse sentido, o presente estudo teve por objetivo estimar as tabelas de esperança de vida e fertilidade para Melanaphis sorghi, alimentados com quinze híbridos de sorgo granífero, afim de conhecer as características de resistência desses materiais e entender como a resistência de plantas pode ajudar no manejo do inseto. O estudo foi conduzido em laboratório com temperatura de 26±2ºC e UR (Umidade Relativa) de 60±10%, foram mantidos 50 insetos em cada hibrido, cada inseto, considerado uma repetição. Com as estimativas dos parâmetros biológicos e mediante tabela de vida de fertilidade, verificamos que os híbridos BRS373, DKB590 e 50A10 foram menos adequados para a multiplicação da praga o que poderia ser considerado melhor para uso em sistemas de manejo da praga, uma vez que a velocidade de crescimento populacional pode ser vista como um dos piores problemas para implementação do sistema de manejo. Os genótipos AG1090, MSK327 e XGN1305 favoreceram o desenvolvimento da praga e, ao ser escolhido dentro do sistema de produção devem ser considerados outras estratégias de manejo.

Impact of crop management systems on soil nematode communities in South Brazil

The analysis of nematode communities allows inferring consequences of management practices on the soil food web. We studied the taxonomic structure of nematode communities in preserved areas of the Atlantic forest (native forest = NF) in Ponta Grossa, Paraná State, Brazil, and in three different agroecosystems in neighboring areas to assess the effect of agricultural land use on nematode assemblages. Agroecosystems were located in a red latosol cropped during 30 years under conventional tillage (CT), no-tillage (NT), and minimal tillage (MT). We collected ten composite soil samples in each area in the summer. Nematodes were extracted by Baermann funnel and fixed with formalin. Subsequently, individuals were classified into taxonomic groups and counted on a Peters slide to determine densities of each taxon. Plant-parasitic and free-living nematodes were classified at the genus level. Data were analyzed with the parameters abundance, Bray & Curtis, Shannon-Weaver, and Simpson indexes. We recorded 35 genera and abundance of nematodes in MT and NT areas was more similar. Higher richness was observed in NF in relation to cropped areas, especially under NT and CT. The PCA and clustering analyses from both nematode communities and soil chemical characteristics showed that MT and CT were more similar and NT was clustered near NF. The replacement of native vegetation by cropping systems caused a reduction of nematode diversity, demonstrating the influence of agricultural practices on nematode communities.

Improving irrigation, crop, and soil management for sustainable soybean production in Southern Brazilian lowlands

Lowlands have been cultivated with irrigated rice (Oryza sativa) in a monoculture cropping system for more than a century in southern Brazil. Shallow topsoil with high bulk density and deficient water infiltration favors the of production paddy rice; however, this condition does not favor species non-tolerant to flooding or oxygen restriction. Thus, soil and irrigation management may be necessary to raise the rice-soybean (Glycine max) rotation systems to sustainable levels. We carried out a two-year field experiment to assess the effects of irrigation treatments and soil management on soil physical properties, soybean growth, and grain yield in lowland systems. The experiment comprised a randomized block design with two factors and three replications. The main factor comprised the following irrigation treatments: sprinkler; surface, and rainfed. Four soil managements composed the second factor: conventional tillage (CT), no-tillage (NT), conventional tillage with raised-seedbed, and no-tillage with raised-seedbed. Soil physical properties, soil penetration resistance, crop parameters, grain yield and water productivity were evaluated. CT increased the soil penetration resistance near the soil surface layer. The highest soil bulk density at the 0.05-0.10 m layer in the CT reduces grain yield in rainfed soybean compared to NT. Supplementary irrigation increased soybean yield of about 36 % in years of uneven rainfall distribution. Sprinkler irrigation resulted in higher irrigated water productivity (90 %) compared to surface irrigation, contributing to a more sustainable increase in grain yield. Crop rotation in a no-tillage cropping scheme could improve the sustainability of diversified agriculture in lowlands.

Increasing soybean productivity by plant equidistant arrangements and modification of technology levels of cropping systems / Incrementos produtivos na cultura da soja pelo uso de arranjos equidistantes e níveis tecnológicos nos sistemas de cultivo

The arrangement of soybean plants defines their ability to recognize the environment and improve their abiotic and biotic interactions with it. This study aimed to evaluate the effect of planting arrangements associated to two distinct crop systems (high technological level or conventional crop level) for the soybean varieties 8473 RSF and AS 3730, to evaluate the plant performance and productivity in the field. A double factorial scheme was used with two varieties and six spatial arrangements. Two experiments were conducted during the 2017­2018 crop season: the first was based on standard cultivation of the Brazilian Cerrado (without irrigation systems and adequate fertilizer), whereas the second utilized high technology (irrigation systems and increased fertilizer). The morphophysiological parameters, normalized difference vegetation index (NDVI), leaf pigment content and crop yield parameters were evaluated. Our study pointed out the positive responses for both cultivated varieties and two technological levels adopted cultivated under equidistant arrangement and high density. The leaf area index, leaf pigment content, NDVI, and crop production showed substantial responses under different equidistant arrangements. Therefore, this procedure requires adjustments in the level of cultivation technology and identification of the most suitable soybean variety.

O arranjo das plantas de soja define sua habilidade em reconhecer o ambiente e aprimorar suas interações bióticas e abióticas com este. Este estudo objetivou avaliar o efeito de diferentes arranjos de plantio associados com dois distintos sistemas de cultivo (alto nível tecnológico ou nível tecnológico convencional), nas variedades 8473 RSF e AS 3730, para avaliar a performance e produtividades das plantas à campo. O esquema fatorial duplo foi adotado, sendo: duas variedades e seis arranjos espaciais. Dois experimentos foram conduzidos durante o ano agrícola 2017-2018; no primeiro experimento considerou-se o padrão de cultivo da soja no Cerrado Brasileiro (sem sistema de irrigação a nível adequado de adubação), enquanto no segundo experimento foi adotado alto nível tecnológico (com sistema de irrigação e adubação superior aos padrões convencionados para o Cerrado). Foram avaliados parâmetros morfofisiológicos, índice de vegetação por diferença normalizada (IVDN), conteúdo de pigmentos foliares e parâmetros de produção da cultura. Nosso estudo apontou respostas positivas de ambos genótipos cultivados e sob os dois níveis tecnológicos sob os arranjos equidistantes e submetidos a alta densidade de plantio. Significativas respostas foram observadas para índice de área foliar, conteúdo de pigmentos foliares, IVDN e produção de soja, quando submetida aos diferentes arranjos equidistantes. Entretanto, este procedimento requer ajustes dentro dos níveis tecnológicos e identificação das variedades mais adequada a este modelo de cultivo.

Intercropping sorghum and grasses during off-season in Brazilian Cerrado

Sorghum (Sorghum bicolor (L.) Moench) may be harmlessly intercropped with Urochloa species during the off-season in the Brazilian Cerrado. At the end of the sorghum cycle, forages can be used for straw production for soybean (Glycine max L.) as the summer crop. This study aimed to evaluate sorghum cultivated during the off-season, intercropped with palisade grass (Urochloa brizantha cv. 'Marandu' (Hochst. ex A. Rich). R. D. Webster) and Congo grass (Urochloa ruziziensis (R. Germ. and Evrard) Crins) in two row spacings (0.5 and 0.7 m) for their effect on plant growth, dry mass production, sorghum yield and soybean grain yield. The experiment was a randomized block design: a 3 × 2 factorial scheme, with three levels of intercropping (palisade grass, Congo grass or sole cropping) and two levels of row spacing (0.5 or 0.7 m) with four replicates. Several physiological growth indexes were estimated from 10 to 60 days after emergence (DAE), including dry matter production and sorghum agronomic performance. Sorghum accumulated 0.22 g of dry matter d-¹ at 10 to 60 DAE, and was not affected by intercropping. The dry mass gain of forages (0.04 g d-¹ on average) was not affected by sorghum either. Higher sorghum grain yield (2,922 kg ha-¹) was observed under the 0.5-m row spacing when compared to the 0.7-m spacing. The results indicate that palisade or Congo grass may be used as companion crops for sorghum with no grain yield loss, be it to improve soybean grain yield, soil cover or integrated crop systems, aiming at sustainable intensification.

Crop rotation and tillage system on the Italian ryegrass seed bank after long-term field management

Italian ryegrass (Lolium multiflorum Lam.) is a troublesome weed widely found in temperate Brazilian fields with several herbicide-resistant populations. Soil seed bank is the main source of future infestations and can be strongly affected by agricultural practices, such as crop rotation and tillage system. Therefore, this study evaluated the long-term effects of different crop rotation and tillage systems on the seed bank of Italian ryegrass. Data were collected in 2012 and 2013 in a field managed since 1985 under conventional-tillage and no-tillage and subjected to three cropping systems (monoculture, total, and partial rotation) compared to the control plot. The samples were collected at three soil depths (0-5, 5-10, and 10-20 cm) using a cylindrical soil sampler, and infestations in the field were evaluated with a sample frame of 1 m². All cropping systems reduced the soil seed bank of Italian ryegrass, regardless of soil management and sampling depths comparing to the control plot. Total and partial rotation were more effective than soil tillage to reduce the seed bank. A larger number of seeds was observed on the surface layer (0-5 cm) for all cropping systems with more uniform distribution in the soil profile in conventional-tillage. Infestation of Italian ryegrass was greater for monoculture under no-tillage in both years, whereas in total and partial rotation, regardless of soil tillage, infestations remained below 40 seedlings m². Thus, strategies to reduce the soil seed bank and infestations of Italian ryegrass should focus on cropping systems with crop rotation and no-tillage.(AU)

Crop rotation and tillage system on the Italian ryegrass seed bank after long-term field management

Italian ryegrass (Lolium multiflorum Lam.) is a troublesome weed widely found in temperate Brazilian fields with several herbicide-resistant populations. Soil seed bank is the main source of future infestations and can be strongly affected by agricultural practices, such as crop rotation and tillage system. Therefore, this study evaluated the long-term effects of different crop rotation and tillage systems on the seed bank of Italian ryegrass. Data were collected in 2012 and 2013 in a field managed since 1985 under conventional-tillage and no-tillage and subjected to three cropping systems (monoculture, total, and partial rotation) compared to the control plot. The samples were collected at three soil depths (0-5, 5-10, and 10-20 cm) using a cylindrical soil sampler, and infestations in the field were evaluated with a sample frame of 1 m². All cropping systems reduced the soil seed bank of Italian ryegrass, regardless of soil management and sampling depths comparing to the control plot. Total and partial rotation were more effective than soil tillage to reduce the seed bank. A larger number of seeds was observed on the surface layer (0-5 cm) for all cropping systems with more uniform distribution in the soil profile in conventional-tillage. Infestation of Italian ryegrass was greater for monoculture under no-tillage in both years, whereas in total and partial rotation, regardless of soil tillage, infestations remained below 40 seedlings m². Thus, strategies to reduce the soil seed bank and infestations of Italian ryegrass should focus on cropping systems with crop rotation and no-tillage.

Reconnecting nature and agricultural production: mixed cropping systems as a way forward sustainable intensification

In the last decades, population growth worldwide boosts agricultural demand for food production. This huge driver rendered global food production more and more specialized, so agricultural landscapes became uniform and monotonic. The loss of diversity is a strong evidence of how modern agricultural landscapes have been disconnecting from nature. Evidence of environmental side-effects from this pathway are abundant in literature. Now, society is pressing towards changing practices aiming for healthy diets and sustainable food production systems. This raises the question: how to reconnect nature and agriculture in the context of future food production? In this review we propose a reconnection process based on the principles of ecological intensification or sustainable intensification. The integrated crop-livestock systems (ICLS) are the most consolidated technological pathway to reconcile crop production with natural processes. These systems are diverse and can partially mimic natural ecosystems exploring the synergies of natural biological processes, while achieving high levels of food production. ICLS promote soil improvements and mitigate greenhouse gas (GHG) emissions, reducing the agricultural share of global warming and climate change. Besides, these systems are more efficient in the use of nutrients and can optimize the use of other inputs such as pesticides. We present evidence of soil health and biogeochemical cycle restoration in addition to system stability improvement, and assume those symptoms as evidence of mixing crops and livestock fostering reconnection with natural processes.

Reconnecting nature and agricultural production: mixed cropping systems as a way forward sustainable intensification

In the last decades, population growth worldwide boosts agricultural demand for food production. This huge driver rendered global food production more and more specialized, so agricultural landscapes became uniform and monotonic. The loss of diversity is a strong evidence of how modern agricultural landscapes have been disconnecting from nature. Evidence of environmental side-effects from this pathway are abundant in literature. Now, society is pressing towards changing practices aiming for healthy diets and sustainable food production systems. This raises the question: how to reconnect nature and agriculture in the context of future food production? In this review we propose a reconnection process based on the principles of ecological intensification or sustainable intensification. The integrated crop-livestock systems (ICLS) are the most consolidated technological pathway to reconcile crop production with natural processes. These systems are diverse and can partially mimic natural ecosystems exploring the synergies of natural biological processes, while achieving high levels of food production. ICLS promote soil improvements and mitigate greenhouse gas (GHG) emissions, reducing the agricultural share of global warming and climate change. Besides, these systems are more efficient in the use of nutrients and can optimize the use of other inputs such as pesticides. We present evidence of soil health and biogeochemical cycle restoration in addition to system stability improvement, and assume those symptoms as evidence of mixing crops and livestock fostering reconnection with natural processes.(AU)

Epigeal fauna and soil attributes in a cover-cropped organic vegetable system / Fauna epígea e atributos do solo sob manejo com plantas de cobertura em cultivo orgânico

ABSTRACT: This study assessed the effect of cover crop biomass on the epigeal fauna of an organic eggplant (Solanum melongena L.) cropping system. A randomized block design was used, with four cover crop treatments: brachiaria, crotalaria, millet, and cocktail (brachiaria, crotalaria and millet). The epigeal faunal indices were determined at each plot. The epigeal fauna of a secondary forest site was also assessed for comparison. Epigeal individuals were collected using pitfall traps at two sampling periods (110 and 180 days after mowing cover crops). Soil samples were collected for determination of physical and chemic properties. 2032 individuals were captured in the first sampling and 3806 individuals in the second. The highest values of wealth in the first collection were observed in the millet and cocktail areas. Cluster analysis showed similarity of epigeal faunal groups between millet and brachiaria plots at the first sampling and between cocktail and crotalaria sites at the second sampling. Co-inertia analysis showed a significant covariance between epigeal fauna at the second sampling and soil properties. The cover crops management had a beneficial influence on the activity, wealth and ecological indexes, in both sampling periods. The positive association observed between epigeal faunal groups and soil physical and chemical properties demonstrates the efficiency of cover crops in improving soil quality in organic cropping systems.

RESUMO: O objetivo deste estudo foi avaliar o efeito da fitomassa de diferentes plantas de cobertura no desenvolvimento da comunidade da fauna epígea em área de cultivo orgânico de berinjela (Solanum melongena, L.). Foi adotado delineamento em blocos ao acaso, com quatro tratamentos de plantas de cobertura: braquiária, crotalária, milheto e coquetel (crotalária, braquiária e milheto), além de uma área de floresta secundária (FR). A fauna epígea avaliada por meio de armadilhas do tipo "pitfall traps" em dois períodos de coletas, aos 110 dias e aos 180 dias, após o corte das plantas de coberturas. Foram coletadas amostras de solo para análise de atributos físicos e químicos. Foram capturados 2032 indivíduos na primeira coleta e 3806 indivíduos na segunda coleta. Os maiores valores de riqueza na primeira coleta foram observados nas áreas milheto e coquetel. A análise de agrupamento mostrou similaridade dos grupos da fauna epígea entre o milheto e braquiária na primeira amostragem e entre o coquetel e crotalária na segunda amostragem. A co-inércia evidenciou covariância significativa entre a fauna epígea da segunda coleta e os atributos do solo. O manejo com plantas de coberturas influenciou de forma benéfica a atividade, riqueza e índices ecológicos, em ambos os períodos de amostragens. A associação positiva entre grupos da fauna e os atributos físicos e químicos mostram a eficiência das plantas de coberturas em cultivo orgânico na promoção de melhorias da qualidade do solo.

Cytokinin induces the development of gabirobeira root cuttings / Citocininas induzem o desenvolvimento de estacas de raiz de gabirobeira

The gabirobeira is a species native to the Brazilian Cerrado with potential for use in cropping systems. This study evaluated the effect of the cytokinin 6-benzylaminopurine (BAP) on root cuttings of gabirobeira (Campomanesia adamantium). The plant material was obtained from gabirobeira progenies of one and two-years-old. The cuttings were segmented in 5 cm length and 1.90 to 3.22 mm diameter, immersed in the following BAP concentrations: 0.0; 1.0; 2.0 and 4.0 mg L-1 for 15 seconds and planted in trays containing the substrate Bioplant®. A complete randomized experimental design was adopted in a factorial scheme 2x4, (cuttings age x BAP concentrations) with fifteen replicates per treatment. After 140 days the number of cuttings with shoots, number of shoots, number of leaves, and diameter of the main root were evaluated. The better development of the cuttings was observed on progenies of two-years-old. The lowest cytokinin concentrations promoted the better emission and number of shoots of the progenies from both ages.(AU)

A gabirobeira é uma espécie nativa do Cerrado brasileiro com potencial para uso em sistemas de cultivo. O objetivo deste estudo foi avaliar o efeito da 6-benzilaminopurina (BAP) em estacas radiculares de progênies de Gabirobeira (Campomanesia adamantium). As estacas radiculares foram obtidas de progênies de Gabirobeira de um e dois anos de idade. Estes foram segmentados em 5 cm de comprimento e apresentavam entre 1,90 a 3,22 mm de diâmetro, imersos nas concentrações: 0.0; 1.0; 2.0 e 4.0 mg L-1 de BAP por 15 segundos e plantados em bandejas contendo Bioplant®. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 2x4 (idades das estacas x concentrações de BAP), com quinze repetições por tratamento. Após 140 dias, foram avaliados o número de estacas com brotações, número de brotações, número de folhas e diâmetro da raiz principal. Estacas de raízes de progênies de dois anos de idade apresentaram melhor desenvolvimento. Menores concentrações de citocinina trouxeram melhores resultados de emissão e número de brotações das progênies de ambas as idades.(AU)

Epigeal fauna and soil attributes in a cover-cropped organic vegetable system / Fauna epígea e atributos do solo sob manejo com plantas de cobertura em cultivo orgânico

This study assessed the effect of cover crop biomass on the epigeal fauna of an organic eggplant (Solanum melongena L.) cropping system. A randomized block design was used, with four cover crop treatments: brachiaria, crotalaria, millet, and cocktail (brachiaria, crotalaria and millet). The epigeal faunal indices were determined at each plot. The epigeal fauna of a secondary forest site was also assessed for comparison. Epigeal individuals were collected using pitfall traps at two sampling periods (110 and 180 days after mowing cover crops). Soil samples were collected for determination of physical and chemic properties. 2032 individuals were captured in the first sampling and 3806 individuals in the second. The highest values of wealth in the first collection were observed in the millet and cocktail areas. Cluster analysis showed similarity of epigeal faunal groups between millet and brachiaria plots at the first sampling and between cocktail and crotalaria sites at the second sampling. Co-inertia analysis showed a significant covariance between epigeal fauna at the second sampling and soil properties. The cover crops management had a beneficial influence on the activity, wealth and ecological indexes, in both sampling periods. The positive association observed between epigeal faunal groups and soil physical and chemical properties demonstrates the efficiency of cover crops in improving soil quality in organic cropping systems.

O objetivo deste estudo foi avaliar o efeito da fitomassa de diferentes plantas de cobertura no desenvolvimento da comunidade da fauna epígea em área de cultivo orgânico de berinjela (Solanum melongena, L.). Foi adotado delineamento em blocos ao acaso, com quatro tratamentos de plantas de cobertura: braquiária, crotalária, milheto e coquetel (crotalária, braquiária e milheto), além de uma área de floresta secundária (FR). A fauna epígea avaliada por meio de armadilhas do tipo "pitfall traps" em dois períodos de coletas, aos 110 dias e aos 180 dias, após o corte das plantas de coberturas. Foram coletadas amostras de solo para análise de atributos físicos e químicos. Foram capturados 2032 indivíduos na primeira coleta e 3806 indivíduos na segunda coleta. Os maiores valores de riqueza na primeira coleta foram observados nas áreas milheto e coquetel. A análise de agrupamento mostrou similaridade dos grupos da fauna epígea entre o milheto e braquiária na primeira amostragem e entre o coquetel e crotalária na segunda amostragem. A co-inércia evidenciou covariância significativa entre a fauna epígea da segunda coleta e os atributos do solo. O manejo com plantas de coberturas influenciou de forma benéfica a atividade, riqueza e índices ecológicos, em ambos os períodos de amostragens. A associação positiva entre grupos da fauna e os atributos físicos e químicos mostram a eficiência das plantas de coberturas em cultivo orgânico na promoção de melhorias da qualidade do solo.