How is the permaculture farming different from conventional chemical farming?<br/>1. Permaculture farming discourages monocultural practices but in conventional chemical farming, monoculture practices are predominant.<br/>2. Conventional chemical farming can cause increase in soil salinity but the occurrence of such phenomenon is not observed in permaculture farming.<br/>3. Conventional chemical farming is easily possible in semi-arid regions but permaculture farming is not so easily possible in such regions.<br/>4. Practice of mulching is very important in permaculture farming but not necessarily so in conventional chemical farming.<br/><br/>Select the correct answer using the code given below.

1. Correct. Permaculture emphasizes diversity, mixed cropping and ecological design; conventional chemical farming often relies on monoculture for scale and input efficiency.

2. Correct. Chemical-intensive farming, especially with improper irrigation/fertilizer use, can contribute to soil salinity. Permaculture builds soil organic matter and water balance, so such salinity problems are generally not characteristic of it.

3. Incorrect. Permaculture is possible in semi-arid regions too, using water harvesting, mulching, drought-resilient species and soil-moisture conservation. So it is not true that it is "not so easily possible."

4. Correct. Mulching is a core practice in permaculture for moisture retention, weed control and soil health; in conventional chemical farming it is not an essential or defining practice.

Hence, statements 1, 2 and 4 are correct.