The correct option is "1 and 3 only." Micro-irrigation techniques, such as drip and sprinkler systems, help minimize fertilizer and nutrient loss by delivering water directly to the plant roots, thereby increasing nutrient use efficiency and reducing runoff. Additionally, in regions facing over-extraction of groundwater, micro-irrigation can support sustainable practices that help recharge aquifers and stabilize groundwater tables. However, it is not the only means of irrigation in dryland farming, as other traditional methods are also prevalent, making the second statement incorrect.