Guandu [Cajanus cajan (L.) Millsp.] management with two types of pruning in coffee (Coffea arabica L.) fields

Abstract

This study was carried out to determine the maximum production period of organic matter from guandu [Cajanus cajan (L.) Millsp] and the effect of regular pruning, used to anticipate green manure management, in order to reduce competition with the coffee crop. The experiment was carried out in Venda Nova do Imigrante city, ES. Coffee seedlings were planted in April 1998 in a 2x1 m row spacing. C. cajan was seeded on October 5th, 2000, between the coffee plants, with ten guandu plants per meter. A randomized block design with a 2 x 4 factorial arrangement and six replications was used (each replication consisted of a 5m long row of guandu). The first factor was type of pruning, “decote” (pruning at 1 meter) and “esqueletamento” (pruning only of the lateral branches). The second factor was time of initiation of pruning (pruning initiated at 120, 150, 180 and 210 days after seeding, corresponding to February, March, April and May 2001), and subsequent prunings every 60 days afterwards. C. cajan maximum plant development was 17.77 t ha-1 of fresh matter on February 28th, 6.20 t ha-1 of dry matter on March 7th and 196.88 kg ha-1 of nitrogen on March 6th. The greatest concentration of nitrogen observed was 37.6 g kg-1 on March 20th. The best period for pruning C. cajan was between February 28th and March 20th (after this period the guandu did not accumulate biomass). The prunings done every 60 days after the initial pruning at 150 days allowed for the same production rate as one pruning at 180 and 210 days. In the production of green mass, dry mass and nitrogen the “decote” type of pruning was better than the “esqueletamento”.