here are majorly 12 factors influence Soil fertility
Infiltration of water.
Soil structure.
Active Soil life.
Content of organic matter.
Minerals present in the soil.
Acidity or Soil pH.
Water Retention capacity of soil.
Water draining ability of the soil.
(google)
Pandas only blink sometimes because they are looking out for danger most of the time. Like other mammals, they have an upper and lower eyelid, so yes they do blink, but not as much as humans.