Angelo Vieira dos Reis

Efeito da escarificação sobre alguns parâmetros físicos de um planossolo

Face the planosols (Albaqualf) importance to the agricultural activities in the South Region of the State of Rio Grande do Sul, Brazil, the effect of chiselling on physical parameters of this soil was studied. Experiments were carried out at the Agricultural Machines Experimental Area of EMBRAPA - CPACT, in Capao do Leao, RS, November, 1994. It was analysed the effect of chiselling at three operating speeds (4.76; 3.63 and 2.58 km h-1), in two levels of soil moisture content (119.6 and 71.7 g kg-1), on bulk density, porosity and soil aggregation. No significant effects due to interaction between moisture content and operating speed were observed. Except for bulk density and macroporosity, which were not affected by water content, physical conditions were improved when the soil was prepared with the highest moisture level. Geometric mean diameter and aggregate stability showed the best results at the lowest operating speed, but no effects of chisel speed were observed on other physical parameters.

UTILIZAÇÃO DE FERRO FUNDIDO NODULAR AUSTEMPERADO EM PONTEIRAS SULCADORAS DE ADUBO DE SEMEADORAS DE PLANTIO DIRETO

RESUMEN Na semeadura direta em funcao da nao mobilizacao do solo e da ocorrencia de compactacao, devido ao trafego de maquinas, sao empregados mecanismos de hastes como sulcadores para a deposicao de fertilizantes. Entretanto, um problema preocupa fabricantes e consumidores, o qual diz respeito ao rapido desgaste sofrido pelas ponteiras das hastes sulcadoras , provocando modificacao na sua configuracao geometrica, comprometendo assim sua eficiencia de trabalho. O estudo dos mecanismos de desgaste referentes aos materiais utilizados em maquinas agricolas e fundamental para a otimizacao da escolha dos mesmos e para a previsao da sua durabilidade. Pesquisas tem demonstrado que os solos arenosos sao os que apresentam maior abrasividade, entretanto, ate o momento, existem raros estudos que quantificam como ocorre o desgaste nestas ferramentas. O objetivo deste trabalho foi quantificar e estimar a vida util das ponteiras de sulcadores de uma semeadora de plantio direto, trabalhando em solo arenoso, utilizando como material alternativo o Ferro Fundido Nodular Austemperado (ADI). Os resultados demonstraram que as ponteiras confeccionadas em ADI apresentaram um acrescimo na sua vida util em torno de 27% quando compradas as ponteiras comerciais confeccionadas em Aco SAE1060-forjado. Palavras chave: abrasao, planossolo , maquina agricola ABSTRACT In no-till seeding in function of the absence of internal soil movement and the occurrence of compaction, due to machinery traffic the use of chisels as fertilizers furrow openers became usual. However, a problem worries manufacturers and consumers, which is the fast wearing of the tips in the chisel furrow openers, causing changes in its geometric design, thus compromising its working efficiency. The study of the mechanisms of wear of the materials used in agricultural machines is a basic issue for material selection and for the forecast of their durability. Reports have described that sand soils present great abrasiveness, however, up to now, little is known about quantifying the way the wear occurs in these tools. The objective of this work was to quantify and estimate the useful life of the no-till chisel type furrow openners , working in sand soils, using as alternative material the Austempered Ductile Iron (ADI). The results demonstrated that the tips made of ADI present longer useful life (27% more) when compared with those made of forged SAE1060 steel . Key words: abrasion, albaqualf , agricultural machinery