Soil Water Conservation & Irrigation

In land shaping and agricultural water management:
Statement (I) is correct: In unirrigated / rainfed lands, land grading is systematically practiced to ensure uniform spreading of runoff, prevent localized ponding or scouring, increase infiltration opportunity time, and maximize in-situ soil moisture conservation.
Statement (II) is correct: Land levelling consists of rough grading (clearing and bulk earth moving using scrapers/bulldozers) followed by land smoothing (using wooden floats or land planes) as the final finishing operation to eliminate minor surface irregularities, clods, and scraper ruts.

In land preparation and leveling:
A wooden float (or land plane) is a long, sled-like wooden framework (typically 4.5 to 9 meters long) equipped with cutting blades.
As it is pulled across the field, the long wheelbase spans over depressions; high spots are sheared off and the loose soil is deposited automatically into small depressions.
This makes the float the most effective and universally recommended wooden equipment specifically for the land smoothing (finishing) operation.
Buck scrapers and U-levellers are earth-moving implements used for scraping and transporting soil over moderate distances, not fine smoothening.