Para estudar o comportamento agronômico de cultivares de feijoeiro-comum, de diferentes grupos comerciais, em
sistema convencional e em plantio direto sobre diferentes coberturas do solo, foram conduzidos em Lavras-MG quatro experimentos
de campo, em três safras. Nos três primeiros, estudaram-se seis cultivares (Ouro Negro, Talismã, Carioca, Pérola,
Roxão e Jalo ESAL) e quatro sistemas de plantio (plantio direto sobre as palhadas de aveia, trigo, resteva do pousio,
mais o plantio convencional). O delineamento estatÃstico foi em blocos casualizados com quatro repetições e esquema experimental
em faixas. No quarto experimento, adotaram-se o mesmo delineamento e as mesmas cultivares, mas os sistemas
foram apenas três (plantio direto sobre palhadas de aveia e resteva do pousio, mais o sistema convencional). Avaliaram-se,
em cada safra, as quantidades de palha no plantio direto, o estande final e o rendimento de grãos do feijoeiro. O comportamento
do rendimento de grão e o estande final do feijoeiro são modificados pelo sistema de plantio e principalmente pelas
safras. De modo geral, a cultivar Ouro Negro, de grãos pretos, é mais produtiva que as cultivares de grão carioca (Talismã,
Carioca e Pérola). As cultivares de grãos maiores (Jalo ESAL e Roxão) tiveram o pior comportamento. Nos ambientes
mais favoráveis, o plantio direto suplanta o sistema convencional. Em solo com pequena quantidade de palha e turnos
de irrigação espaçados entre três ou quatro dias, o plantio direto sobre resteva do pousio propicia maior rendimento de
grãos.
Four field experiments were carried out in Lavras (south region of Minas Gerais State) during three seeding seasons
whit the purpose of studying the agronomical performance of common beans cultivars from different commercial groups by
using both the conventional and no-tillage systems on different soil coats. The treatments were arranged in a split block schema.
A randomized block design was used with four replications. In the first three experiments, six cultivars (Ouro Negro, Talismã,
Carioca, Pérola, Roxão and Jalo ESAL) and four planting systems (conventional and no-tillage on oat, wheat and bare soil straw)
were used in the treatments. The same statistical design and the same cultivars were used in the fourth experiment. However,
only three planting systems (conventional and no-tillage on oat and bare soil straws) were used. The amount of straw used in notillage
system, as well as the beans plants and the grain yield, was estimated. The beans cultivars agronomical performances
were modified by the planting system, especially by the seeding seasons. In general, the black-grain Ouro Negro cultivar
has performed better than the carioca-grain ones (Talismã, Carioca, and Pérola). The cultivars with the biggest grains were
those that have had the worst performance. The highest grain yields were achieved in the winter-spring irrigated season,
followed by the rain season, and finally the dry season. At more favorable environmental conditions the no-tillage system
was found to surpass the conventional one. The no-tillage on bare soil straw promotes better grain yield at less favorable
environmental conditions.
