Nitrogen balance of cabagge at different soil conservation techniques in talun berasap, Indonesia

Usually, the use of nitrogen fertilizer in vegetables growing area by farmers is too high. Study on nitrogen balance of cabbage at different soil conservation techniques was conducted in Talun Berasap, a vegetables growing area in Kerinci District, Indonesia in 2011. The aimed of this study were to determine the nitrogen recommendation application rate at different soil conservation techniques and to estimate the nitrogen fertilizer at Kerinci district. Four treatments were tested including control, a farmers practices with the direction of planting in line with slop (KTA-1), modification of farmer practice by adding ridge terrace every 5 m of slope length (KTA-2), modification of farmer practice by adding ridge terrace and hill side ditch every 5 m of slope length (KTA-3), and (4) planting in line with contour (KTA-4). Nitrogen balance was calculated according to the differences between nitrogen gains and losses. To quantify total nitrogen input, nitrogen content in urea, dosage of urea, rate of compost, nitrogen concentration in compost, and nitrogen concentrations in rainfall were collected. Output parameters were cabbage yield, crop residues production, nitrogen concentrations in cabbage and crop residues as well as erosion. The results indicated that negative nitrogen balances were taken place in planting in line with slop (KTA-1) and planting in line with contour (KTA-4) treatments. Concerning the environmental, agronomical and economic point of views as well as to get higher cabbage yield and stabile, recommended urea application rate should be from 400 to 500 kg ha-1 season-1 with adding more compost to 20 - 30 tons ha-1 season-1.