Summary:

The aim of the study was to determine the effect of drip irrigation and microsprinkler irrigation on the content of starch, total sugars (including reducing sugars) in tubers of chosen potato cultivars after harvest and after storage during 6 months. Experiments were carried out in 2001–2003 at Kruszyn Krajeński near Bydgoszcz on the soil include to VI – quality class and 7 – complex of agricultural suitability (very weak rye complex). The soil was characterized by the very low silt and clay fraction content in topsoil (7%) and subsoil horizon (3–5%). The value of pH in 1n KCl was slightly acidic, and the abundance of basic macroelements was on the average level. The experiment included three factors: A – irrigation (with-out irrigation – control plots, drip irrigation, micro-sprinkler irrigation), B – cuti-var (‘Barycz’, ‘Mors’, ‘Triada’), C – storage (after harvest – control, after storage during 6 months). Three replications were applied. Drip irrigation was applied using ‘T-Tape’ drip lines (in-line emitters spaced 20 cm apart). The single drip line was located between two neighbouring rows of potatoes. The single emitter’s output amounted on average 0,6 l h^-1. Micro-jet irrigation was done with the use of micro-jets ‘Hadar’ (diameter of nozzle 1,3 mm and output 30 l.h^-1). Terms of ir-rigation were established according to soil water potential indicated by tensiome-ters. Irrigation was started when the soil water potential achieved -0,03 MPa. The starch content in tubers of potatoes grown on non-irrigated plots amounted, on average for years and cultivars, on the level 16,1%. Investigated irrigation systems did not influence on the content of the studied component in tubers of the tested cultivars, directly after harvest as well as after storage during 6 months. After storage of potato tubers during 6 months, the starch content was decreased and contents of reducing sugars and total sugars were increased.