Components of the water balance in soil with sugarcane crops

摘要: Abstract The objective of this study was to analyze the components water balance in an Ultisol, located municipality Jaboticabal, SP, Brazil (21°20′20″S, 48°18′35″W), that cultivated with sugarcane. monitoring performed during agricultural cycle first ratoon between 11/16/2006 and 7/9/2007. Three treatments were established four blocks doses ammonium sulfate, as follows: Treatment 1 (T1), without fertilizer; 2 (T2), 100 kg ha−1 nitrogen (N) 114 kg ha−1 sulfur (S); 3 (T3), 150 kg ha−1 N 172 kg ha−1 S. Rainy precipitation (P) area measured a rain gauge. soil storage (H) variations (ΔH) determined by gravimetric method, internal drainage (D)/capillary rise (CR) at depth 0.9 m quantified flux density using Darcy–Buckingham equation. actual evapotranspiration (ETa) calculated ETa = P − D + CR ± ΔH. During period, amount rainfall 1406 mm, 121 mm greater than historic average for region (1285 mm), notable peak month January 402 mm (historic average: 251 mm). 300 mm under T1, 352 mm T2, 199 mm T3, relevant times elevated P, when H field capacity H. (T1: −897.7 mm, T2: −847.5 mm, T3: −970.8 mm) use efficiency −131.3 kg mm−1, −146.6 kg mm−1, −127.5 kg mm−1) did not differ among treatments. dispersion D other balance, especially period errors process propagated estimation ETa. Despite standard deviation ETa, it accounted less 15% total showing method may be conveniently used studies sugarcane crops.