Question 1: Compare the rate of required nitrogen for 1 ha area if to supply it in 1) urea form and 2) potassium nitrate form when the lab analysis result showed that it contains the total nitrogen of about 0.1455 %. The optimum recommendation rate is 170 kg N/ha for rice crop that has 30 cm root zone depth and the soil density is 1.15 g/cm. Explain why the rate of urea and KNO3 is different and in your opinion what are the factors to be considered in the selection of fertilizer type? (10 marks) PO1C5C01WP1WP3