WATER EXCESS DRAINAGE DURING OPERATIONS ON AGRICULTURAL LAND FITTED WITH DRAINAGE-DRAINING WORKS IN THE CATCHMENT AREA OF MOLDOVA RIVER, SUCEAVA COUNTY PUBLISHEDOprea RADU
For valorising the yield capacity of the moisture excess lands from the hydrographical basin ofthe Moldova River, Suceava County, they were performed until 1990, dry-drainage out on an area of8761 ha, of which 3059 ha with underground drainage works. Systems were designed under conditions ofland exploitation on drying sectors. Because, as concerns the property rights, they had not in view thedirection of suction drains and drying network, individual plots are situated perpendicular, parallel or ata sharp angle towards suction drains and/or drying channels. Soil tillage and especially, mouldboardploughing on individual plots have resulted with time in land modelling in ridge strips, having variablewidths, level differences and transversal slopes according to plot width, way of usage and usedequipments. This land modelling has determined the change in the depth of placing suction drains; thus,it has decreased in the ditch area and increased on the ridgeline, having influence on the functionaloutput of suction drains and the uniformity of water excess removal. In order to determine the technicalelements of the strips with ridges, accurate elevation-height topographic survey was conducted by themethod of radiation and leveling traversing combined with radiations, based on which the transversaland longitudinal profiles were drawn and in order to determine the momentary water component of thesoil, samples of soil were collected using a tubular probe, in 10 cm layers, down to 0.8 m and to 1.00 mrespectively. In case of land plots parallel to drainage lines, the best water excess drainage wasregistered when trenches were positioned over drains and the lowest water excess drainage in drainslocated below ridges. In plots perpendicular to drainage lines, we achieved a water excess drainagerelatively closet o that of drains located below ridges. Furthermore, drains located below ridges providethe uniformity of water excess drainage from the drained surface, in plots oriented parallel to absorbingdrains and absorbing drains oriented perpendicular to individual plots. Due to the slight likelihood ofgetting trenches above absorbing draining lines further to individual soil works, it results that the bestwater excess drainage is achieved on land surfaces where plots are perpendicular to absorbing drains.
excess humidity, underground drainage, individual land plots, ridge-plough land development.