Step 1: Understanding the Question:
This question tests knowledge of techniques to reduce shading in agroforestry.
Step 2: Detailed Explanation:
Canopy manipulation (pruning, thinning) minimizes the shading effect of trees.
It allows more light to reach understory crops.
Root management (A): Reduces root competition.
Irrigation (B): Provides water but does not reduce shading.
Fertigation (C): Provides nutrients but does not reduce shading.
Thus, the correct answer is canopy manipulation.
Step 3: Final Answer:
Thus, shading can be minimized by canopy manipulation, which corresponds to option (D).
[0.5cm]