Which of the following practices can help improve air circulation in crop production? 

Aerated soil improves plant growth. We can incorporate air in the soil by various means like tilling, de-weeding, etc. Farmers usually practice crop rotation which helps to improve air circulation in soil apart from many other benefits. This method eventually helps increase crop production. 

Crop rotation involves planting different crops in a sequence over several years. This can help break up soil compaction, which can improve soil structure and increase air circulation. Planting crops closer together, reducing crop diversity, and using dense planting arrangements can actually reduce air circulation and may lead to problems such as disease and insect infestations.