RESPONSES OF CORN SILAGE TO SOWING PATTERN UNDER SUBSURFACE DRIP IRRIGATION IN A SANDY SOIL

The subsurface drip irrigation technique is introduced in many agricultural areas of Morocco, particularly in the forage production systems. This study aims to determine the optimal sowing pattern of forage corn equipped with a subsurface drip irrigation system. A field experiment was carried out on sandy soil. Five rows spacing were evaluated: 40 cm, 55 cm, 70 cm, 85 cm, and 100 cm. The sowing rate was around 120000 plants ha-1. The subsurface irrigation system consisted of drip lines buried at 30 cm and separated by 100 cm with 1 L h-1 emitters and 50 cm as emitters spacing. The results revealed that the fraction of PARi and the accumulated PARi were not influenced by the sowing pattern. The highest corn dry biomass was recorded at 40 cm, 70 cm, and 85 cm row spacing. The biomass increase was mainly attributed to grain yield. The lowest irrigation water use efficiency was recorded at 100 cm row spacing (4.3 kg m-3). Concerning the forage quality, the sowing pattern did not influence the net energy for lactation and other forage quality parameters.