ABSTRACT Remote sensing (RS) and geographic information systems (GIS) have been used to guide the selection of suitable areas for aquaculture. This systematic review synthesizes the key suitability factors and constraints reported in the literature for establishing inland pond aquaculture. We searched for primary studies on Scopus and Web of Science according to preferred reporting items for systemic reviews and meta-analysis (PRISMA) guidelines. Between 1991 and 2020, 354 articles were published in 104 academic journals. The maximum annual number of publications occurred in 2020, with 22 publications, and there is an increasing trend in studies published over the past 30 years. From 12 selected studies, we identified 48 suitability factors, 11 related to soil suitability, 19 to socioeconomic and infrastructure suitability, and 18 to water quality and availability. The most frequently used suitability factors were road proximity, local market center distance, soil texture, soil slope, and water temperature. We listed 15 constraints that restrict or limit the selection of specific geographic locations for inland aquaculture. Urbanized areas, roads, and forests were the most frequently restricted areas. Geotechnologies provide powerful tools for spatial planning and management of aquaculture. Availability, quality, and access to spatial data are critical for the use of geotechnologies in the process of aquaculture site selection.

ABSTRACT Paricá is a native tree to the Amazon region recognized for several socioeconomic applications. However, there are few studies on the influence of irrigation regime in the seedling stage. Thus, the objective of the research was to evaluate the effect of water depths and irrigation frequency on the development of Paricá seedlings in the edaphoclimatic conditions of the Amazon region. The experiment was conducted in a greenhouse at the Federal Rural University of the Amazon (UFRA), Capitão Poço Campus, located in Capitão Poço, Pará, Brazil. The experimental design was randomized blocks, in 5x2 factorial arrangements, consisting of five irrigation depths and two irrigation frequencies, with four replications. The highest irrigation depth (725 mL) at daily frequency resulted in lowest biomass production maybe due to hypoxia in the root zone. In contrast the every three day irrigation promoted high biomass production with the highest irrigation depth (725 mL). Contrarily, 435 mL depth produces high quality seedlings at daily irrigation frequency. Regarding the rational use of water, producers may use 725 mL at 3-day frequency, given that it has promoted high seedling quality and provides savings of 580 mL compared to the best water depth on the daily irrigation (435 mL).

RESUMO Durante dois anos consecutivos, a resistência mecânica do solo à penetração (RP) foi avaliada em áreas de produção de milho segunda safra para silagem. A retirada da parte aérea do milho no processo de silagem deixa o solo exposto, sujeito à compactação, o que pode comprometer o sistema plantio direto (SPD). Neste contexto, este trabalho teve por objetivo monitorar a RP sob cultivo de plantas de cobertura, associadas à aplicação de água residuária de suinocultura (ARS), em áreas de silagem de milho sob SPD. O trabalho foi desenvolvido em Matelândia, Paraná com sete sistemas de manejo: soja/silagem/aveia e nabo (SSAN); soja/aveia e nabo (SAN); soja/silagem/escarificão + aveia e nabo (SSEAN); soja/silagem e braquiária (SSB); soja/silagem/aveia (SSA); soja e silagem (SS) e soja e milho (SM), repetidos por dois anos consecutivos. Nos tratamentos com ARS foram aplicados 100 m3 ha-1 ano-1, divididos em duas doses iguais: uma sobre o milho e outra nas plantas de cobertura. O delineamento experimental foi em blocos casualizados (DBC), com quatro repetições por tratamento, com quatro amostras por repetição. O sistema sem utilização de plantas de cobertura apresentou maior RP; a camada do solo com maior RP foi a de 0,10 a 0,15 m; a aplicação de ARS, na dose de 100 m3 ha-1 ano-1 diminuiu a RP do solo.

ABSTRACT The mechanical resistance of the soil to penetration (RP) was evaluated over two consecutive years in areas where off-season maize is produced for silage. Removal of the aerial part of the maize during the ensiling process leaves the soil exposed and subject to compaction, which may compromise a no-till system (NTS). The aim of this study therefore, was to monitor the RP of a soil under plant cover associated with the application of wastewater from pig farming (WPF) in areas of maize ensiling under NTS. The study was conducted in Matelândia, in the State of Paraná, employing seven management systems: soybean/silage/oats and turnip (SSOT); soybean/oats and turnip (SOT); soybean/silage/scarification + oats and turnip (SSSOT); soybean/silage and brachiaria (SSB); soybean/silage/oats (SSO); soybean and silage (SS) and soybean and maize (SM), repeated over two consecutive years. In the treatments that included WPF, 100 m3 ha-1 yr-1 were applied, split into two equal doses: one on the maize and the other on the cover crops. The experimental design was of randomised complete blocks (RCB), with four replications per treatment, and four samples per replication. The system with no cover crops had a higher RP; the 0.10 to 0.15 m layer of soil had the highest RP; whereas the application of WPF at a dose of 100 m3 ha-1 yr-1 decreased the RP.

RESUMO: O trabalho avaliou a eficiência da semeadura à taxa variada para cultura da soja em duas zonas de manejo (ZMs), as quais foram definidas com base em atributos estáveis e correlacionados com a produtividade, por meio do algoritmo de agrupamento Fuzzy C-means e o interpolador krigagem. A semeadura foi realizada nas safras 2015/2016 e 2017/2018, com variação de 20% de sementes e espaçamento entre linhas de 0,70m. Em cada ZM foram estabelecidas 8 parcelas em que variou-se maior e menor densidade de sementes. A produtividade foi medida com monitor de colheita acoplado em uma colhedora. Os dados foram filtrados e submetidos à análise descritiva, os mapas de produtividade foram gerados utilizando-se o interpolador inverso do quadrado da distância para cada densidade de semeadura. Na ZM com maior potencial produtivo (ZM 1) a produtividade foi de 3,39 e 3,18t ha-1, na ZM de menor potencial produtivo (ZM 2) foi de 3,30 e 3,11t ha-1, para os anos de 2016 e 2018, respectivamente. O interpolador estimou maior produtividade com a aplicação de 15 plantas m-1; pela análise econômica, sugere-se, dentro do estudado, a aplicação de 214.000 plantas ha-1 nas duas ZMs.

ABSTRACT: The present study aimed to assess the efficiency of sowing at variable rates for soybean cultivation in two management zones (MZs) which were defined based on stable attributes and correlated with productivity using the Fuzzy C-means clustering algorithm and the kriging interpolation.Seeding was carried out in the 2015/2016 and 2017/2018 crops with a variation of 20% of seeds and crop row spacing of 0.70m. In each MZ, 8 plots with higher and lower seed density were established. Productivity was measured using a harvest monitor connected to a harvester. Data were filtered and submitted to descriptive analysis. Productivity maps were generated using the inverse square distance interpolation for each seeding density. In the MZ with the highest productive potential (MZ 1), the productivity was 3.39 and 3.18t ha-1, and in the MZ with the lowest productive potential (MZ 2) the productivity was 3.30 and 3.11t ha-1 for the years 2016 and 2018, respectively. Interpolation estimated higher productivity with the application of 15 plants m-1. Based on the economic analysis, it is suggested in this study the application of 214,000 plants ha-1 in both MZs.

RESUMO O herbicida 2,4-D é amplamente utilizado na agricultura brasileira e mundial para o controle de plantas espontâneas, sendo potencialmente tóxico ao homem e um dos destinos finais dos herbicidas é o solo. O objetivo do trabalho foi determinar a correlação espacial do herbicida 2,4-D com os atributos do solo após 12 meses de aplicação. O experimento foi desenvolvido em área agrícola de 5,04 ha, do município de Nova Santa Rosa/PR, nos anos de 2011 e 2012. Duas coletas de solo foram realizadas: coleta 1 (03/09/2011) e coleta 2 (25/08/2012), sendo que ambas foram feitas após 12 meses da aplicação de 2,4-D. O herbicida foi aplicado em dose única de 1,5 L ha-1 em 09/2010 e em duas dosagens em 09/2011 (1,0 L ha-1 e 1,5 L ha-1 de 2,4-D). A correlação entre os atributos do solo e o 2,4-D foi determinada com a utilização de matriz de correlação espacial. O residual de 2,4-D no solo variou muito de um local para outro na mesma área, apresentando pontos sem detecção do ingrediente ativo. Não foi possível detectar diferenças entre os tratamentos 1,0 L ha-1 e 1,5 L ha-1 de 2,4-D. Diversos fatores podem ter interferido no residual do herbicida no solo, entre eles: o clima, características do produto, características físico-químicas do solo, manejo do solo, entre outros. A correlação espacial dos atributos do solo e do residual de 2,4-D no solo mostrou-se ser uma importante ferramenta para verificar a interferência de um parâmetro sobre o outro.

ABSTRACT The 2,4-D herbicide is widely used in Brazilian and global agriculture to control weeds. It is potentially toxic to mankind, and one of the herbicides final destinations is the soil. The aim of the study was to determine the spatial correlation of 2,4-D herbicide in soil attributes after 12 months of application. The experiment was conducted in an agricultural area of 5.04 ha in the municipality of Nova Santa Rosa/PR, in 2011 and 2012. Two soil samples collections were performed: collection 1 (09/03/2011) and collection 2 (08/25/2012), both of which were made 12 months after 2,4-D application. The herbicide was applied in a single dose of 1.5 L ha-1 in 09/2010 and in two doses in 09/2011 (1.0 L ha-1or 1.5 L ha-1 2,4-D). The correlation between soil attributes and 2,4-D was determined with the use of a spatial correlation matrix. The 2,4-D soil residues varied widely from one location to another in the same area, with points of no detection of the active ingredient. It was not possible to detect differences between 1.0 L ha-1 and 1.5 L ha-1 2,4-D treatments. Several factors may have interfered in the herbicide residues in the soil, including: climate, product characteristics, physical and chemical soil characteristics, soil management, among others. The spatial correlation of the soil attributes and 2,4-D residues in the soil proved to be an important tool to verify one parameter interference over another.