Theory question 104
Soil Fertility and Plant Nutrition(a) State four functions of each of the following macro-nutrients in plant nutrition: (i) nitrogen; (ii) phosphorus; (iii) potassium
(b) List four factors that affect the availability of nutrients to crops.
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(a)(i) Nitrogen (any four): forms proteins and protoplasm; part of chlorophyll; promotes leafy growth; gives dark green colour; increases protein in grain; helps use of other nutrients
(ii) Phosphorus (any four): root development; flowering, fruiting and seed formation; early maturity; energy transfer (ATP); cell division; strengthens straw
(iii) Potassium (any four): formation and movement of sugars and starch; strengthens stems against lodging; disease resistance; controls opening of stomata/water balance; improves fruit quality; activates enzymes
(b) Any four: soil pH; soil texture; organic matter content; soil moisture; leaching; soil temperature and aeration; activity of micro-organisms; cation exchange capacity; nutrient fixation
Four functions under each nutrient.