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This study evaluated the physiological responses of subadult yellow-spotted Amazon river turtle, Podocnemis unifilis, to incremental crude protein levels (29%, 32%, 35%, and 39% CP) as extruded commercial feeds. The hematological and plasma bio-chemical parameters of P. unifilis were analyzed at 60, 120, and 180 days of the feeding trial. The increase in total thrombocyte, leukocyte, lymphocyte, heterophil, and eosinophil numbers, besides high respiratory burst activity showed an improvement in animal immune defense response to incremental protein in diets, acting together to maintain the integrity of the tissues against antigens and infectious agents. Elevated subadult P. unifilis plasma total cholesterol and triglyceride levels observed after increasing the feeding time (until 180 days) with incremented protein levels in artificial diets during captiv-ity are a nutritional warning, related to the condition of being less physically active. Based on these results, periodic physiological evaluations are particularly important to ensure the healthy and adequate nutritional conditions of captive-bred animals, such as maintaining lower stocking densities of animals to avoid stress and, if possible, providing them with fresh food in addition to extruded artificial feed. Made available in DSpace on 2022-08-09T10:20:23Z (GMT). No. of bitstreams: 1 CPAF-AP-2022-Different-dietary-protein-levels.pdf: 5041428 bytes, checksum: 87d7d363dde6db1812cf9070d387a603 (MD5) Previous issue date: 2021

The corn biomass and nutrient dynamics may be altered when it is intercropped with Brachiaria (syn. Urochloa spp.). The present study aimed to investigate the dynamics of biomass, nitrogen (N), phosphorus (P) and potassium (K) for farming systems that produce corn intercropped with Brachiaria species. Field experiments were performed during the season and off-season, in a split-plot design. The main plots were composed of Brachiaria species (B. brizantha, B. ruziziensis and B. Convert) intercropped with corn, in addition to corn monocropping. The subplots consisted of three forage sampling periods, ranging from 0 to 60 days after the corn harvest. The intercropping arrangements did not affect the corn grain yield, nutrient accumulation and partitioning, relatively to the corn monocropping. After the grain harvest, B. brizantha achieved the greater biomass accumulation rate in both the season (69 kg ha-1 day-1) and off-season (17 kg ha-1 day-1). The nutrient accumulation ranged widely between the Brachiaria species and planting seasons: 0.2-1.2 kg ha-1 day-1 for N; 0.01-0.07 kg ha-1 day-1 for P; and 0.13-0.8 kg ha-1 day-1 for K. However, the greatest nutrient accumulation was found for B. brizantha, followed by B. ruziziensis and then B. Convert. In the short-term, corn intercropped with Brachiaria in the season showed the largest effect on the nutrient cycling and biomass yield. The intercropping between corn and B. brizantha in the season was the best way to enhance the biomass yield and the N, P and K cycling. Made available in DSpace on 2019-10-04T18:06:51Z (GMT). No. of bitstreams: 1 CNPASA2019pat.pdf: 1328098 bytes, checksum: 582a1dda5fc1ebd48e2c8146836a1f9f (MD5) Previous issue date: 2019

Macrophomina phaseolina é um fungo que infecta colmos, raízes e caules de mais de quatrocentas espécies de plantas, incluindo milho, soja e feijão. A infecção de milho ocorre nos tecidos da casca e da medula, e resulta em deterioração dos tecidos do colmo e tombamento das plantas. Para avaliar as perdas causadas pelo fungo no estado de Tocantins, foi realizado um levantamento da incidência e severidade da podridão de macrophomina em regiões de cultivo do milho safrinha em 2019. Quarenta e duas amostras de colmo foram coletadas em oito cidades do estado e avaliadas quanto à incidência e severidade da doença. A quantificação de perdas foi realizada em duas propriedades, nos municípios de Paraíso do Tocantins e Porto Nacional. Foi realizada a comparação de peso de grãos em plantas sadias e doentes dispostas lado a lado na lavoura, sendo a perda calculada pela diferença porcentual entre o peso de grãos das plantas doentes em relação às plantas sadias. Ampla distribuição da podridão de macrophomina foi encontrada na região. A incidência da doença foi de 88,1% nas amostras, variando de 9,1 a 100% nos fragmentos de colmo. Alta correlação foi observada entre a porcentagem média de colmos infectados e a nota média de severidade da doença. Houve variação na redução de peso de grãos nos dois locais avaliados, sendo de 22 a 41% para o híbrido 30A37 PW em Paraíso do Tocantins, e de 19 a 47,6%, no híbrido DKB290 PRO3, em Porto Nacional.

The intercropping of maize with forage plants is a farming technique aimed at producing grains and grazing, with beneficial results for the sustainability of production. Most of the research carried out with maize (Zea mays) intercropped with palisadegrass (Urochloa brizantha) has evaluated the agronomic performance of the crops. Therefore, there is a lack of research on the effects of this technique on the soil hydro-physical characteristics. For this reason, the objective of this study was to evaluate the effects of the cultivation of maize intercropped with U. brizantha on the soil hydro-physical characteristics. The study was conducted in an experimental area at Faculdade Católica of Tocantins, in Palmas/Tocantins, Brazil; using a randomized complete block design, in a 4x2 factorial scheme, with three repetitions. The study comprised four types of intercropping: i) maize with U. brizantha cv. Marandu sown by broadcast; ii) maize with U. brizantha cv. Marandu sown between the maize rows; (iii) maize with U. brizantha cv. Piatã sown by broadcast; iv) maize with U. brizantha cv. Piatã sown between the maize rows; and two implantation periods: v) simultaneous sowing; vi) sowing 20 days after the maize. The hydro-physical properties evaluated were soil density, total soil porosity and soil water holding capacity. There was a significant interaction between the type of intercrop and the sowing time in the soil density and total soil porosity, but no significant differences in soil water holding capacity. Results show that the intercropping of maize with U. brizantha sown simultaneously improves the physical properties of the soil such as density and porosity, in comparison to the U. brizantha implantation 20 days after sowing maize. The intercrop of i) maize with U. brizantha cv. Marandu sown between the maize row and ii) maize with U. brizantha cv. Piatã sown by broadcast between the maize row (in simultaneous sowing) improved the soil physical attributes. Made available in DSpace on 2019-05-15T00:33:02Z (GMT). No. of bitstreams: 1 CNPASA2019raes.pdf: 340569 bytes, checksum: cb9281a03dd43dc0e4714f1c2a43fd12 (MD5) Previous issue date: 2018

In flood plains, cover crops are able to alter soil properties and significantly affect rice nutrition and yield. The aims of this study were to determine soil properties, plant nutrition, and yield of tropical rice cultivated on flood plains after cover crop cultivation with conventional tillage (CT) and no-tillage system (NTS) at low and high nitrogen (N) fertilization levels. The experimental design was a randomized block in a split-split-plot scheme with four replications. In the main plots were cover crops [sunhemp (Crotalaria juncea and C. spectabilis), velvet bean (Mucuna aterrima), jackbean (Canavalia ensiformis), pigeon pea (Cajanus cajan), Japanese radish (Raphanus sativus), cowpea (Vigna unguiculata)] and a fallow field. In the subplots were the tillage systems (CT or NTS). The nitrogen fertilization levels in the sub-subplots were (10 kg N ha-1 and 45 kg N ha-1). All cover crops except Japanese radish significantly increased mineral soil nitrogen and nitrate concentrations. Sunhemp, velvet bean, and cowpea significantly increased soil ammonium content. The NTS provides higher mineral nitrogen and ammonium content than that by CT. Overall, cover crops provided higher levels of nutrients to rice plants in NTS than in CT. Cover crops provide greater yield than fallow treatments. Rice yield was higher in NTS than in CT, and greater at a higher rather than lower nitrogen fertilization level.

Corn grain yield, nitrogen (N) fertilizer efficiency and distribution to corn alone and three forms of corn and palisadegrass (Urochloa spp.) intercropping implantation was investigated. A field experiment with 15N labeling fertilizer was performed in randomized block design. No form of palisadegrass intercropping implantation affected corn grain yield, total N accumulation and N use efficiency (NUE), which were 8.7 t ha-1, 205 kg ha-1 and 37% respectively. The palisadegrass produced on average 1.9 t of dry mass, absorbing a maximum of 6 kg ha-1 or 5.5% of N fertilizer during corn growing. Furthermore, the palisadegrass did not affect N fertilizer distribution in soil-plant system, in which 28.2% was recovered in the soil and 40.4% in the plants (corn + palisadegrass). The results show that for the three intercropping implantation methods the palisadegrass did not compete with corn for N fertilizer. Made available in DSpace on 2017-10-30T09:24:17Z (GMT). No. of bitstreams: 1 CNPASA2017aabc.pdf: 497446 bytes, checksum: c639bbe3fbfea8c28c4e9333bdaece09 (MD5) Previous issue date: 2017-10-29

Exigente em nutrientes, milho requer cuidados especiais na elaboração dos programas de manejo químico e físico do solo.

Foi constatado o ataque de cupins subterrâneos em experimentos do programa de avaliação de cultivares de milho safrinha, para plantio em Tocantins. em virtude das injúrias provocadas no sistema radicular e nas galerias formadas no interior do colmo, associadas à presença de fungos saprófitas, foi observado que cerca de 10% das plantas atacadas ficaram frágeis e quebraram facilmente, pela ação de ventos ou pelo próprio peso da espiga, na base do primeiro internódio.

Sistema de plantio direto se expandiu, ajudando a elevar o cultivo de milho a cerca de 30% da área agricultada do Brasil.