Statement (i) and (ii) are correct because manure is prepared from the breakdown of plant and animal waste products. Hence it is rich in organic matter. Manures contribute to the fertility of the soil by adding organic matter and some essential nutrients like N, P and K which helps in enhancing growth of plants.

It helps in increasing soil structure by keeping the soil intact and this also decreases soil erosion. It helps in regulating water holding capacity of soil so that water is not lost from the plant soil early by evaporation.

Manures make the clayey soil aerated because of their small pores and increase the water holding capacity of the sandy soil due to their large pore size. Hence statement (iii) is false and (ii) is correct.

Since manure is made from animal excretory waste its is completely organic and replenish the soil with its nutrient content, Hence statement (iv) is wrong.