Detailed Explanation:

Answer: Option 3 — 1 and 3 only

✅ Statement 1 – Correct: Drip irrigation delivers water directly to the root zone of plants, keeping the soil surface relatively dry. Since weeds require moist topsoil to germinate and grow, restricting surface water availability significantly reduces weed proliferation compared to flood or sprinkler irrigation methods.

❌ Statement 2 – Incorrect: Drip irrigation does not directly reduce soil salinity. In fact, because water is applied in small quantities at specific points, salts can accumulate at the edges of the wetted zone. While proper management practices (like periodic leaching) can help control salinity, drip irrigation itself is not a method for reducing existing soil salinity.

✅ Statement 3 – Correct: By releasing water slowly and directly at the root zone, drip irrigation minimizes surface runoff and water flow across the soil surface. This controlled water application prevents the washing away of topsoil, thereby reducing soil erosion and preserving soil structure and fertility.