Drip Irrigation And Fertigation Of Potato Under Light- Textured Soils Of Cappadocia Region

Abstract

In order to evaluate potato response to drip irrigation and N fertigation; and also to improve nitrogen and water use efficiencies of potato and eventually to obtain less nitrogen polluted surface and water, 10 field experiments were carried out at three different locations in Cappadocia Region of Turkey in 1997, 1998, 1999 and 2000 growing seasons Nitrogen as ammonium sulphate ((NH4)2So4), was supplied by drip irrigation water (fertigation) at rates of 0, 30, 60 and 90 kg N/da Also, soil N application treatment equivalent to the fertigation treatment of 60kg N/da was included These five treatments were investigated in a completely randomized block design with four replicants Agria potato variety was used in all experiments and potato was planted in mid May and harvested at the end of October''1''5N-labelled ammonium sulphate fertilizer were applied in isotope-sub plots within the macroplots for each treatment, in order to determine the amount of nitrogen taken up by the plant, nitrogen use efficiency and the distribution of residual nitrogen at different depths in the soil profile Each year, during the growth period, total 12 irrigations were done and 50 mm of water was applied at each irrigation At harvest, plant samples (tuber and leaf+vein) and soil samples were taken from each plot and N%, ''1''5N% atom excess (''1''5N% ae) and Ndff% determinations were done Soil water contents at differrent soil depths were determined by soil moisture neutron probe at plantingand at harvest period so that water contents at different soil layers and water use efficiencies were calculated for each treatment The results obtained showed that 3350 kg/da mean total marketable tuber yield was obtained with application of 600 mm irrigation water Also,it was found that water did not move below 90 cm of soil layer in drip irrigation-fertigation system, which showed clearly that no nitrogen movement occured beyond 90 cm soil depth Tuber yields and %Ndff increased when nitrogen is applied with drip irrigation-fertigation system in comparison to the application to the soil and then drip irrigation At harvest, more nitrogen was accumulated at shallower depths with fertigation treatments