Consider the following statements and choose the correct answer:
1. Control of land loss can be attempted through restoring forest and grass cover to check erosion and floods
2. Shifting cultivation can be replaced by crop rotation, mixed cropping or developing piantation crops which would improve fertility and support a large population
3. Salinity can be prevented by covering the area with appropriate plant species and by raising trees as wind breaks
4. Shifting sand can be controlled by mulching