Efficiency in land utilization, yield and yield components of crops in association

Abstract

Continuing research initiated in the previous growing season, a field experiment was conducted during 1982/83 involving the sole crops of dry beans (Phaseolus vulgaris L.), com (Zea mays L.), and sunflower (Helianthus annuus L.) and the associations of these species two by two. The research was located at the Estação Experimental Agronômica of Universidade Federal do Rio Grande do Sul, at Guaíba, RS, Brazil. The main objectives were to compare monocultures and intercrops in land utilization efficiency and to evaluate the individual behaviour of crop species when grown in association. All the crop systems, established at the same date, were submitted to two nitrogen side dressing levels (0 and 80 kg/ha) and to two weed control practices (with and without hoeing). The intercrops showed greater efficiency in land utilization than the correspondent sale crops. Sunflower and corn presented equivalent competition abilities and exerted high competition effect on beans. The utilization of high management level was mainly canalized by the tallest crops, in detriment of the associated dry beans. Under low disposable nitrogen, corn was more competitive to beans than sunflower; however, under high disposable nitrogen, the oposite occurred. For sunflower and corn under environmental stress, it is recommended to utilize lower plant populations than those normally used.