31. But it can also damage soil fertility and increase erosion. 32. In addition to improving soil fertility , annelids serve humans as food and as bait. 33. Good drainage is considered more important than soil fertility ; poor drainage can stunt growth. 34. Management of soil fertility has been the preoccupation of farmers for thousands of years. 35. It only occurs in areas where rainfall is high and soil fertility is good. 36. The most influential factors in stabilizing soil fertility are the soil colloids, clay and humus. 37. The hay, available in bales at nurseries, decomposes with time and adds to soil fertility . 38. Research in community ecology might measure species diversity in grasslands in relation to soil fertility . 39. Manure deposited on pastures by grazing animals themselves is applied efficiently for maintaining soil fertility . 40. An application of a balanced fertilizer in June is beneficial when soil fertility is low.
