In no-tillage systems, straw coverage on soil surface is the key to success, and the choice of crops for rotation is crucial to achieve the sustainability and quality that conservation agriculture requires. The objective of this study was to evaluate the agronomic performance of the common bean cultivar IAC Formoso sown in succession to three straw mulch systems (corn alone, corn/Urochloa ruziziensisintercrop and U. ruziziensisalone) and topdress nitrogen rates (0; 40; 80; 120 and 160 kg ha-1N), at the four-leaf stage, three years after the implementation of no-tillage. The experiment was arranged in a randomized block split plot design, with three replications. Common bean highest yields were achieved in succession to U. ruziziensisalone and intercropped with corn. The corn/U. ruziziensisintercrop provided both straw and seed production, allowing for quality no-tillage. Topdressed nitrogen influenced the common bean yield when in succession to corn alone, U. ruziziensisalone and corn/U. ruziziensisintercrop in no-tillage.

No abstract

O canistel é nativo do sul do México e América Central e seus frutos apresentam elevado teor de carotenoides e vitamina A. Sua propagação é feita via sementes, resultando em considerável variabilidade genética entre os indivíduos, sendo a propagação vegetativa preferível, a fim de fixar características desejáveis. Assim, o objetivo deste trabalho foi avaliar a propagação vegetativa por estaquia de ramos semi-herbáceos de canistel, em função de quatro genótipos e quatro concentrações de AIB. Foram utilizadas estacas semiherbáceas apicais, mantidas com um par de folhas, sob nebulização intermitente, por 120 dias. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 4×4 (genótipos de canistel × concentrações de AIB), com quatro repetições e dez estacas por parcela. Foram avaliados a porcentagem de sobrevivência, a retenção foliar, o enraizamento, o calejamento, o número e o comprimento médio de raízes por estaca. O genótipo PC-1 foi superior aos demais, em todas as variáveis avaliadas, com destaque para o enraizamento das estacas, superior a 60%. As concentrações de AIB (0; 1.000; 3.000 e 5.000 mg L-1) não influenciaram na sobrevivência, retenção foliar e enraizamento das estacas, mas aumentaram o número e o comprimento de raízes em relação ao tratamento-controle (sem AIB). Há diferença na capacidade de enraizamento das estacas entre os genótipos de canistel, sendo a melhor resposta obtida com PC-1. A concentração de 3.000 mg L-1 de AIB resulta em maior número e comprimento de raízes nas estacas de canistel.

Crop production in conservation systems involving intercropped cultivations mainly with corn have been proposed as a technology to promote sustainability in the Brazilian Cerrado areas. The objective of this work was to evaluate the influence of residual nitrogen fertilization applied in common bean on subsequent corn sole or intercropped with Congo grass (Urochloa ruziziensis) in no-tillage system. The experiment was carried out in randomized blocks with three replicates in a split-plot design. The treatments were composed by two cropping systems (sole and intercropped with Congo grass), and the sub-plots were five doses of nitrogen (0; 40; 80; 120 and 160 kg of N ha-1), applied in topdressing on common-bean (previous crop). There was no effect of cropping systems and residual amount of nitrogen application in the vegetative and reproductive development of corn. Corn intercropped with Congo grass leaded an adequate formation of crop residue and total land covering target at sustainability of no-tillage system.

Brazil has a great potential for the production of supersweet corn. However, this crop is lacking in technical information that assists in the management of fertilization and mineral nutrition aiming at a high crop yield, a high industrial performance, and a low environmental impact. This study aimed to quantify the growth and accumulation of nutrients by supersweet corn ‘GSS 41243’, in Guaíra, Brazil, from April to August 2013. Plant samples were collected 20 to 100 days after emergence, with 10-days intervals. At the end of the cycle, the crop accumulated 21.5 t ha-1 of dry matter, 39 % of which accumulated in the ears (8.4 t ha-1). The amount of nutrients accumulated by the crop were 306.8, 46.2, 406.3, 39.0, 33.4 and 23.1 kg ha-1 of N, P, K, Ca, Mg and S, respectively, and 213.6, 118.4, 3,360.0, 784.0 and 684.0 g ha-1 of B, Cu, Fe, Mn, and Zn, respectively. In relation to the total accumulated, the nutrient exports in the ears corresponded, in kg ha-1, to 103,0 (N); 19.0 (P); 104.5 (K); 3.4 (Ca); 9.90 (Mg); 7.3 (S) and, in g ha-1, at 64.0 (B); 33.6 (Cu); 632 (Fe); 184 (Mn) and 320 (Zn).

An experiment was conducted to develop a model of vegetative growth based on the nitrate concentrations in nutrient solutions using the nutrient film technique and to determine the best cultivar for each concentration. The chicory cultivars ("Pão de Aç ucar," "Folha Larga," "Precoce de Trieste" and "Catalonha") and the subplots corresponded to different nitrate concentrations (6.68, 10.0, 13.32 and 16.64 mmol L ¡1 ). There was an interaction between the evaluated factors, such that there was no similarity in the response of the chicory cultivars to the N concentrations in the nutrient solution. The most productive chicory cultivar was "Pão de Aç ucar," which exhibited 10.5% higher productivity than the average, and the least productive was "Folha Larga," which showed approximately 8.5% lower productivity than the average.

RESUMONesse trabalho, o objetivo foi avaliar a reação de oito porta-enxertos de videira aos nematoides das lesões radiculares. As estacas dos porta-enxertos Kober, SO4, 101-14, R99, 420-A, Rupestris du Lot, Riparia do Traviú e Telek 5C, cedidas pelo Centro APTA de Frutas/IAC, foram plantadas em vasos contendo mistura de solo:areia na proporção 2:1 (v:v) e mantidas em casa de vegetação. Após quatro meses, os porta-enxertos foram inoculados com 1.200 espécimes de Pratylenchus brachyurus ou P. zeae, e o milho foi usado para comprovar a viabilidade do inóculo. Aos 180 dias após a inoculação, avaliou-se o número de nematoides por sistema radicular e em 100 cm 3 de solo. O milho foi avaliado aos 90 dias após a inoculação e cada vaso recebeu uma nova planta, que foi avaliada juntamente com os porta-enxertos. No milho, as populações finais de P. brachyurus e P. zeae foram respectivamente iguais a 8.040 e 6.940 indivíduos. Todos os porta-enxertos comportaram-se como imunes a P. brachyurus e P. zeae, isto é, a população final dos nematoides e o fator de reprodução foram iguais a zero. Recuperaram-se seis e 11 espécimes de P. zeae nas amostras de solo cultivadas com os porta-enxertos Kober e 420-A, respectivamente. Conclui-se que os porta-enxertos estudados apresentam potencial para serem usados em áreas infestadas com esses nematoides das lesões. Palavras-chave: Vitis spp., nematoides das lesões radiculares, resistência. ABSTRACT Reaction of grapevine rootstocks to Pratylenchus brachyurus and Pratylenchus zeaeThe aim of this study was to evaluate the reaction of eight grapevine rootstocks to root-lesion nematodes. Cuttings of the rootstocks Kober, SO4, 101-14, R99, 420-A, Rupestris du Lot, Riparia do Traviú and Telek 5C, provided by the Centro APTA de Frutas/IAC, were planted in 5-L pots containing a 2:1 (v:v) soil and sand mixture, and kept in greenhouse. After four months, they were inoculated with 1,200 specimens of Pratylenchus brachyurus or P. zeae. Maize was used for detecting the inoculum viability. After 180 days of the inoculation, the root systems of the plants were collected along with 100 cm 3 soil for evaluating the number of nematodes. Maize plants were evaluated 90 days after inoculation and each pot received a new seedling, which was evaluated along with the rootstocks. All rootstocks exhibited immunity to P. brachyurus and P. zeae, because the final populations in the root systems and the reproduction factor were zero. It was recovered six and 11 specimens of P. zeae in samples from cultivated soil with Kober and 420-A rootstock, respectively. In the maize, the respective average populations of P. brachyurus and P. zeae were 8,040 and 6,940. The rootstocks are potentially valuable for infested areas.