The question below consists of a set of labelled sentences. These sentences, when properly sequenced form a coherent paragraph. Select the most logical order of sentences from among the options. P: The depletion of organic nutrients in the soil has reached alarming proportions, thanks to indiscriminate use of chemical fertiliser in Green Revolution areas. Q: As against an acceptable level of ?soil organic carbon? of well over 5 percent, soils in Punjab are said to have levels far below 1 percent. R: Besides, 5.3 billion tonnes of soil is eroded annually, at a rate of 16.4 tonnes/hectare. S: The nutrient imbalance has been skewed by the overuse of urea (N) vis-a-vis phosphatic (P in chemical parlance) and potassic (K) fertiliser.