Suzete Fernandes Lima

Weed suppression in the formation of brachiarias under three sowing methods

The success of conservation systems such as no-till depends on adequate soil cover throughout the year, which is possible through the use of cover crops. For this purpose the species belonging to the genus Urochloa has stood out by virtue of its hardiness and tolerance to drought. Aiming ground cover for the no-till system, the objective was to evaluate the establishment of two species of the genus Urochloa, in three sowing methods, in the weed suppression and the sensitivity of these forages to glyphosate. The study design was a randomized block with a 2 x 3 x 3 factorial arrangement, in which factor A was composed of Urochloa ruziziensis and Urochloa hybrid CIAT 36087 cv. Mulato II, factor B was formed by sowing methods: sown without embedding, sown with light embedding and sown in rows, and factor C was composed of three doses of glyphosate (0.975, 1.625 and 2.275 kg ha-1 of acid equivalent). For determination of weed suppression, assessment of biomass yield and soil cover was performed, by brachiaria and weeds, at 30, 60, 90, 120 and 258 days after sowing. Visual assessment of the desiccation efficiency at 7 and 14 days after herbicide application was performed. It is concluded that embedding Urochloa seeds stands out in relation to sowing in the soil surface. Urochloa ruziziensis is more efficient in the dry weight yield, weed suppression, in addition to being more sensitive to glyphosate herbicide.

ADUBAÇAO ANTECIPADA COM FERTILIZANTES ORGÂNICO E MINERAL ASSOCIADO À CROTALARIAS NA CULTURA DO MILHO

RESUMO- A adubacao de sistema aliada a adubacao verde pode aumentar a disponibilidade de nitrogenio no solo. Objetivou-se na pesquisa investigar se a disponibilidade antecipada de fertilizantes orgânico e mineral sobre o cultivo de Crotalaria spectabilis e Crotalaria juncea influencia nas caracteristicas de producao da cultura do milho. O delineamento experimental adotado foi o inteiramente casualizado, disposto em esquema fatorial 2 x 4, no qual o fator A foi formado por duas especies de adubos verdes (Crotalaria spectabilis e Crotalaria juncea) e o fator B foi formado por tres formas de fertilizacao (PK, NPK e orgânica) e pela ausencia de fertilizacao, com oito repeticoes. Foram realizadas avaliacoes das caracteristicas agronomicas e produtivas da cultura do milho. O numero de fileiras e numeros de graos por fileira nao diferiu entre as formas de fertilizacao. A maior altura de plantas de milho, altura de insercao de espiga e produtividade de graos foi obtida na area cultivada anteriormente com C. spectabilis. A fertilizacao com NPK e orgânica, com cama-de-aves, resultou em maior produtividade, porem com 800 kg ha-1 de NPK, valor superior ao recomendado. Conclui-se que a antecipacao de fertilizacao do solo, associado ao cultivo de adubos verdes e viavel para o cultivo da cultura do milho, a C. spectabilis proporciona maior produtividade de graos de milho em sucessao e a adubacao orgânica, com cama-de-aves, e tao eficiente quanto a adubacao mineral com NPK quando antecipada. Palavras-chave: Crotalaria spectabilis, Crotalaria juncea, cama-de-aves, adubacao verde, adubacao de sistema. PRE-FERTILIZATION WITH ORGANIC AND MINERAL FERTILIZERS ASSOCIATED WITH CROTALARIES IN MAIZE ABSTRACT- The fertilization of system combined with green manure can enhance the availability of soil nitrogen. This study aimed to research whether the anticipated availability of organic and mineral fertilizers in the cultivation of Crotalaria spectabilis and Crotalaria juncea affects the characteristics of production of corn crop. The completely randomized design (CRD) was used, with eight replications, in factorial arrangement 2 x 4, in which the factor A was formed by two species of green manure (Crotalaria spectabilis and Crotalaria juncea) and the factor B comprised three forms of fertilization (PK, NPK and organic) and the absence of fertilization. Assessments of agronomic and yield characteristics of corn crop were conducted. As conclusion,the anticipation of soil fertility, associated with green manure cultivation is viable for cultivation of corn crop, the C. spectabilis provides increased productivity of the corn crop, and the organic fertilization with bed of birds is as efficient as the mineral fertilization with NPK. Keywords: Crotalaria spectabilis, Crotalaria juncea, bed-of-birds, green manure, system fertilization.

ANÁLISE COMPARATIVA DE TÉCNICAS DE ESTIMATIVA DE FRAÇÃO DE COBERTURA VEGETAL POR Urochloa ruziziensis E Urochloa spp.

The potential of vegetation cover of soil by cover crops is an important parameter for the selection of forage species adapted to a given region. However, one of the restrictions the use this variable is associated the adoption of the estimation technique, since there are different forms of calculation. Thus, the objective was to compare the cover fractional of soil cultivated with Urochloa ruziziensis and Urochloa spp., using three measurement techniques: visual evaluation, evaluation by intercept or transect and evaluation by photographic image. For this, six experiments were conducted in the field, in randomized block design. The experiment 1, 2 and 3 was formed by the species of Urochloa ruziziensis and composed of three treatments, represented by the three measuring techniques (visual evaluation, evaluation by transect and evaluation by photographic image), with eight replications. The experiment 4, 5 and 6 had factorial arrangement 2 x 3, the factor A was formed of two species of Urochloa (Urochloa ruziziensis and Urochloa spp. cv. Mulato II) and the factor B by the three measuring techniques (visual evaluation, evaluation by transect and evaluation by photographic image), with four replications. The measures of fractional of cover soil were made at 30, 60 and 90 days after sowing. Was found that the greater the uniformity of soil cover by forage plants, closest are the values of fractional of vegetation cover obtained by the three estimation techniques. The measurement techniques of visual and to transect of the fraction of soil cover were considered similar, and the efficiency of the evaluation by photographic image depend on the individual calibration of each image.