Concentraciones de nitrógeno en un suelo con diferentes espaciamientos de drenaje subterráneo en la Chontalpa, Tabasco

subsurface drainage systems are needed for crop production in soils in tropical areas. however, these systems have had an impact on the concentration and the state of nitrogen (n) in the soil. an experiment was carried out in sorghum plots in order to evaluate the effect of the subsurface drainage spacing (eds) at 10, 20 and 40 m and crop types (tc) with irrigation and rainfall, on the concentration of nitrate (n-no-3), ammonium (n-nh+4), nitrate plus ammonium (n-no-3 + n-nh+4) and total nitrogen (nt) in the soil. the concentrations of n-no-3 , n-nh+4 and nt were estimated at depths of 15, 30, 60, 90 and 120 cm, at time intervals of 15 days in each eds and tc. the amount of irrigation water, daily precipitation, gravimetric humidity (gh) at depths of 30, 60, 90 and 120 cm, and depth of the water table (ni) were quantified. data were analysed with a 3 x 2 factorial treatment design. the first factor was eds with spacing levels of 10, 20 and 40 m between drains and the second factor was the tc with two levels, one of irrigation and the other of rainfall. the eds had no effect on the mean concentrations of n-no-3, n-nh+4, (n-no-3+ n-nh+4) and nt at the five depths. n-nh+4 was the predominant form of n in eds and tc. the tc impacted on the nt, as its highest concentration was recorded in the tc with rainfall.