Bubbler irrigation is a localized low-pressure micro-irrigation method designed specifically to apply a small, bubbling stream of water directly to individual plant or tree basins (per plant/tree basis), widely used for widely spaced orchard fruit crops.

Design criteria for furrow irrigation slopes:

• Statement (I) is incorrect: Contour furrows are constructed across the slope on lands with slopes generally up to $3\%$, beyond which erosion hazards make surface furrow irrigation unviable without bench terracing.
• Statement (II) is incorrect: A minimum furrow slope of $0.05\%$ (or $0.1\%$) is recommended to maintain uniform forward advance and avoid water ponding; a slope of $0.01\%$ is too flat to provide effective drainage in field furrows. Hence, both statements are incorrect.

Discharge measurement in pressurized pipe networks:

• In closed conduit piped irrigation systems (such as sprinkler and drip networks), water flows under positive hydrostatic pressure.
• Discharge is measured using in-line flow meters (propeller meters, turbine meters, or electromagnetic/ultrasonic meters).
• Weirs, V-notches, and Parshall flumes are used exclusively in open-channel gravity flow systems.