Explanation:

System of Rice Intensification (SRI) was first developed in Madagascar in the 1980s and since then several countries in the world have been practising it, including India. It promises to save 15 to 20% ground water, improves rice productivity.

Option 1 is correct: Under SRI 2kg seed is required to grow a nursery for one acre against 5kg seed required in the traditional method.

Option 2 is correct: SRI is a holistic approach to sustainable rice cultivation. By minimizing water use and alternating wet and dry conditions, it minimizes methane production.

Option 3 is correct: With less consumption of water, adoption of SRI saves total energy inputs. A study found in Vietnam has also proved that applying SRI methods can save around 23% of energy inputs, while increasing energy outputs by 11%.