The impact of pipe spacing on drainage of surplus soil water

Abstract

Agricultural production is very risky on such developed agricultural areas, especially when surplus and/or deficit of precipitation occurs before or during the growing season. Such conditions make production planning very difficult and/or almost impossible, because production, and thereby also yield, depends on weather conditions, making yields of field crops and their quality highly variable. If soil water surplus persists during a long period of time and being the zone of plant roots in a part of the growing period, then the hydro-amelioration measure of drainage should be applied. Drainage of surplus water is an ameliorative procedure that involves the collection and removal of surplus water from soils intended for cropping or some other activity. The goal of three-year investigations was to determine the influence of precipitation upon drainage discharge (runoff) in two different climatic regions (Croatia and Lithuania) at two different pipe drainage spacings in each region; 15 m and 20 m drainage spacing in the first region and 12 m and 18 m drainage spacing in the second region. The researchers calculated soil water balance according Thornthwaite's method, compared the measured drainage discharge and calculated the surplus of water in the soil. The investigations were carried out at the experimental amelioration site in the central Sava Valley (Croatia) and the middle part of Lithuania, in the period 2009- 2011, on hydro-ameliorated Gleyic Podzoluvisol soil and hydro-ameliorated Hypogleyic Luvisol soil. The results show that the drainage discharge and its duration depended on the amount and distribution of precipitation during the study period.