Concept:Thinning out is the agricultural practice of removing excess seedlings from a stand to reduce overcrowding and promote healthy growth.
Explanation:When seeds are sown, more seedlings may germinate than required in each stand.
These crowded seedlings compete for sunlight, water, nutrients, and space.
To ensure better growth and higher yield, some seedlings are carefully removed or uprooted.
This process of reducing the number of seedlings per stand is called thinning out.
Earthing up means mounding soil around the base of a plant, so option
A is incorrect.
Filling in, or gap filling, means sowing seeds in empty spaces, so option
B is incorrect.
Pricking out means transplanting seedlings from a nursery bed to another location, so option
C is incorrect.
Only thinning out directly reduces the number of seedlings per stand for better growth.
Answer:D. Thinning out.