International Journal of Environment and Climate Change

Root growth development and nutrient distribution are important parameters for optimising the use of inputs such as water and fertiliser. This study compared drip and flood irrigation to determine their effects on tomato root development and the spatial distribution of nutrients. The study assessed the vertical and horizontal distribution of roots and the movement of nutrients in both vertical and lateral directions under drip- and flood-irrigated conditions. The number of roots under both irrigation methods decreased with increasing soil depth and extended horizontally to 30 cm along the plant and 27 cm across the plant under drip irrigation, and to 59 cm and 60 cm, respectively, under flood irrigation. Under drip irrigation, root intensity was higher at a soil depth of 0-20 cm (0.252), whereas under flood irrigation, root density was 0.197 and the number of roots declined progressively with increasing soil depth, with few roots present below 40 cm. Root distribution in the upper soil layer was greater under drip irrigation than under flood irrigation. Most available nitrates were found in the upper soil layer under drip irrigation compared with flood irrigation. Maximum nitrogen, phosphorus and potassium contents under drip irrigation were 229.6 kg ha^-1 at 20-30 cm, 201.08 kg ha^-1 at 0-10 cm and 231 kg ha^-1 at 0-10 cm, respectively. Under flood irrigation, the corresponding values were 277.9 kg ha^-1 at 40-50 cm, 209.03 kg ha^-1 at 0-10 cm and 264 kg ha^-1 at 20-30 cm, respectively. The peak nitrogen concentration of 277.9 kg ha^-1 at 40-50 cm indicated greater nitrate leaching under flood irrigation than under drip irrigation.