Home › MCQs › Agronomy › Question #2053
Back to Questions
Agronomy QUESTION #2053
Question 1
The 'source–sink' relationship in crop physiology as applied to agronomic management refers to:
  • The relationship between irrigation source and water sink capacity of soil
  • The balance between photosynthetic capacity (source: leaves producing assimilates) and the capacity of storage organs (sink: grain, tuber) to accumulate dry matter, which determines yield potential✔️
  • The nutrient flow between organic matter source (manure) and plant nutrient sink (roots)
  • The relationship between rainfall source and soil water deficit (sink)
Correct Answer Explanation
In crop physiology, source = photosynthetic organs producing assimilates; sink = organs storing assimilates (grain, tubers). Yield is co-limited by both: a large source with small sink (poor grain set) wastes photosynthate; a large sink with small source (poor canopy) starves grain fill. Agronomic practices (planting density, nutrition, irrigation) manage both.