Effect of plant density on yield and quality of corn fodder.
The experiment was condunted at the Alfredo Volio Mata Experimental Station of the University of Costa Rica, located at 1542 meters above sea level. The purpose was to determine the effect of plant density on total forage mass and the nutritive value of corn. Three diferent plant distances were used: 30 x 70 cm, 50 x 70 cm and 70 x 70 cm resulting in 47619, 28600 and 20449 plants per hectare, respectively. The first sampling was taken out 42 days after establishment and every two weeks thereafter, until 126 days. Dry matter, crude protein, ashes, neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin were analyzed for different parts of the plant. The values for celulose and hemicelulose were calculated. Total forage mass (kg/ha) was greater at higher plant densities. Dry matter content of leaves was higher than in stems, all of the plant densities. No significant difference (P<0,05) was found for crude protein content in the different parts of the plant. ADF was always higher in stems than in leaves. Stage of growth considerably affects biomass yield and nutritional quality of fodder. Before 70 days the dry matter content in leaves was higher than in stems. Latter accumulation of dry matter in stems was greater than in leaves. Crude protein content in leaves was over 18% during the first 70 days, then decreases a level of 13% at the end of the period. The lowest value of ADF was found before 84 days in leaves and stems. Under the enviromental conditions of this experiment, it appears that plant densities of about 48000 plants per hectare are optimal.