Considering the lack of technical information on the water depth and nitrogen fertilization via fertigation in protected cultivation for bell pepper production in northern Brazil, this paper aimed to study the soil water tensions under different nitrogen doses for the cultivation of bell pepper in protected environment. The experiment was conducted in a greenhouse at the Igarapé-Açu School Farm of the Federal Rural University of the Amazon, at 1.0 x 0.50 m spacing, using the experimental design of randomized blocks in a 5x4 factorial scheme, with three replicates. The treatments consisted of five soil water tensions (15, 25, 35, 45 and 65 kPa) and four nitrogen doses (0, 135, 265 and 395 kg ha-1). There was interaction between soil water tension and nitrogen doses only for nitrogen use efficiency, and the best value was obtained with the combination between soil water tension of 15 kPa and nitrogen dose of 135 kg ha-1. Total number of fruits, fruit length and fruit diameter showed significant differences only as a function of soil water tensions. Production per plant, total yield and water use efficiency were statistically significant for soil water tensions and nitrogen doses. Therefore, for the conditions in which this study was carried out, it is recommended to apply a soil water tension of 15 kPa and nitrogen dose of 265 kg ha-1 for bell pepper cultivation in protected environment.

Water availability is a crucial factor in the final productivity of cowpea. The objective of this work was to evaluate the production and productivity components of cowpea under different irrigation depths in Amazonian conditions. The experiment was carried out at the School Farm of the Federal Rural University of Amazonia, in the municipality of Castanhal-PA, using the cultivar BR3 Tracuateua, from September to November 2014, 2015, and 2016. The experimental design was conducted on six blocks and four treatments, where the four irrigation depths of 0, 25, 50, and 100% of crop evapotranspiration were tested. The productivity analysis was performed when 90% of the plants were in the phenological stage R9. The evaluated production components were pod length, number of pods per plant, number of grains per pod, mass of one hundred grains, and harvest index. There was a statistical difference among all treatments for the components of production and among productivities. An average reduction of 827 kg ha⁻¹ in cowpea productivity was observed during the three years of study, when the treatment without irrigation was compared with the treatment irrigated with 100% of the crop’s water demand. It was found in this research that the simple fulfillment of the nutritional and phytosanitary demands of the crop, associated with an adequate planning of when to plant in the region, would already help in the improvement of local production when choosing times where the water deficit in the reproductive phase is less than 33 mm.

The tomato cultivation in the Amazon is not feasible mainly due to the natural infestation of Ralstonia solanacearum in the soil. Preventive control through grafting has been one of the main alternatives to manage this problem. This study aimed to evaluate the compatibility of Solanaceae genotypes as rootstocks for 'Santa Clara' tomato, aiming to control the bacterial wilt. Five rootstocks were evaluated: cubiu; red jurubeba; jurubebão; commercial hybrid tomato rootstock Guardião; and 'Santa Clara' tomato (self-grafting). In the seedling phase, characteristics of rootstock survival rate and compatibility were evaluated; while, in the field, that happened for survival rate, compatibility and fruit yield. In the seedling phase, Guardião and red jurubeba showed the best performances. In the field, red jurubeba presented a low compatibility, although it obtained the best productive performance among the wild rootstocks. Guardião obtained the best compatibility and yield among the studied rootstocks. Grafting is a viable technique for tomato production under soil-borne disease conditions.

Objetivou-se avaliar o crescimento de mudas de Khaya ivorensis A. Chev. (Mogno africano) cultivadas com e sem calagem em amostras de solo submetido à adubação fosfatada. O estudo foi conduzido em casa de vegetação na Universidade Federal Rural da Amazônia (UFRA) – Campus Capitão Poço/PA e o solo utilizado para compor o substrato foi um Latossolo Amarelo proveniente da camada de 0–20 cm de profundidade. Os tratamentos constituíram-se de cinco doses de fósforo, tendo como fonte o fosfato natural reativo de Arad. O experimento foi montado em delineamento inteiramente casualizado (DIC) em esquema fatorial, sendo duas doses de calcário (0 e 5 g vaso-1) e cinco doses de fósforo (0, 10, 20, 40 e 80 g vaso-1 de P2O5) com 6 repetições, totalizando 60 parcelas experimentais. Cada parcela foi formada por uma muda, cultivada em vasos com capacidade de 12 quilos de solo durante 210 dias. Ao final do experimento foram realizadas avaliações de altura da planta (H), diâmetro do coleto (DC), número de folhas (NF), massa seca da parte aérea (MSPA), massa seca da raiz (MSR) e do índice de qualidade de Dickson (IQD). As mudas responderam positivamente às doses de P2O5 em todas as variáveis avaliadas e não há necessidade de correção do solo ao se utilizar como fonte de P2O5 o Arad. Para a obtenção de mudas de qualidade em condições semelhantes a este experimento, deve ser utilizada a dose 40 g vaso-1 de P2O5.

Com objetivo de fornecer informações técnicas sobre a produção da couve-flor irrigada em casa de vegetação no nordeste paraense, instalou-se um experimento na Fazenda Experimental da UFRA, no município de Igarapé-Açu, com a cultivar híbrida Desert, que apresenta adaptabilidade para o clima da região. O delineamento utilizado foi em blocos casualizados em esquema fatorial 4 x 3, com 12 tratamentos e 3 repetições. Os tratamentos foram constituídos por quatros tensões de água no solo (15, 30, 45 e 60 kPa), com indicativo no momento de irrigar e três doses de boro (0, 3 e 6 kg ha-1) aplicadas via foliar. O método de irrigação utilizado foi o gotejamento e o manejo de irrigação foi via tensiometria. As parcelas experimentais apresentaram 3,6 m2 constituídas de 8 plantas, com espaçamento de 0,8 m entre linhas e 0,5 m entre plantas. Em cada parcela, foram avaliadas 4 plantas centrais, totalizando 288 plantas. De acordo com os dados obtidos, a cultivar híbrida Desert mostrou-se promissora para o cultivo nas condições edafoclimáticas da região nordeste do Pará. A tensão que apresentou melhores resultados foi a de 37 kPa, obtendo produtividade de cabeça de 11,3 t ha-1, massa fresca de 450 g, massa seca de 31,48 g, diâmetro de 15,6 cm, circunferência de 50,99 cm e altura de 9,87 cm. As doses de boro não apresentaram diferença significativa.

Capsicum chinense Jacq. presents great prominence in the cuisine of Pará. This crop was cultivated with low technological level in its production chain, however, in the last years, there has been an increase in the size of the planted area, in view of the national and international recognition of the vegetable as a substitute for pepper. The objective of this work was to evaluate the effect of different irrigation depths on the yield of Capsicum chinense Jacq. cv. Lupita. The experiment was carried out at the Experimental Farm of the Federal Rural University of Amazonia (UFRA), located in the municipality of Igarapé-Açu-PA. The experimental design was a randomized block with five treatments and four replications. The treatments corresponded to five irrigation depths based on the evaporation of the Class ‘A’ pan (ECA) (30, 60, 90, 120 and 150% ECA). The results showed that the maxi­mum commercial yield was 14.0 t ha-1, reached at 101% ECA, which corresponds to a 724.50 mm depth, and the highest water use efficiency (22.78 kg ha-1 mm-1) was obtained with the 458.64 mm total water depth at 56% ECA.