The theory behind narrow row corn production is that yields of any crop will be maximized when plants are uniformly distributed across the field. To achieve this, the spacing between all plants between and within the rows must be equal. For an equidistant plant spacing with 30,000 plants per acre, both the row spacing and distance between plants within the row would be 17.4 inches. In a 15-inch row system, plants would be 13.9 inches apart in the rows.
Swallowed air. Aerophagia, or air swallowing, is a common cause of gas in the stomach. Everyone swallows small amounts of air when eating and drinking. However, eating or drinking rapidly, chewing gum, smoking, or wearing loose dentures can cause some people to take in more air. Burping, or belching, is the way most swallowed air - which contains nitrogen, oxygen, and carbon dioxide - leaves the stomach.
This method of breathing helps to keep your air sacs open longer so that air is not trapped in your lungs. It prevents the very small airways from collapsing when you breathe out. Pursed-lip breathing helps more stale air to get out of your lungs so that more fresh air with oxygen can get in (see figure below).