Question

what is a factor contributing to the falling land productivity​

Answer 1

Acid rain is greatly responsible for falling land productivity. It makes the soil acidic thus not suitable for cultivation.

Next important factor is soil erosion. The fertile upper layer of soil is washed away by wind and water thus the land Becomes unsuitable for cultivation.

Deforestation is also responsible for fall in land productivity as it causes soil erosion.

Other reasons are increased use of fertilisers and pesticides.

Answer 2

Acid rain, soil erosion, deforestation, pesticides etc.