This section is from the book "Vegetable Gardening", by Ralph L. Watts. Also available from Amazon: Vegetable Gardening.
So far as soil management is concerned, tillage is the most important operation in vegetable gardening. Both yield and quality are largely determined by the character of the tillage operations. The objects of tillage are as follows: (1) To modify the physical conditions; (2) to regulate the soil moisture content; (3) to modify soil temperatures; (4) to aerate the soil; (5) to provide proper conditions for the action of friendly bacteria; (6) to destroy weeds; (7) to prevent surface erosion; (8) to cover humus-producing materials, \ as manure and green crops.
The value or efficiency of tillage depends upon character, thoroughness, and timeliness. Both the character and the thoroughness of tillage count for much in vegetable gardening, for in growing crops of high cash value gardeners should be certain that tillage operations should be of the right kind and be fully completed before work is discontinued. Timeliness is of primary importance, for to plow, harrow, cultivate, hoe and weed at just the right time may make the difference between profit and loss. Conditions may be satisfactory for plowing today, while rain tomorrow may fill the soil with too much moisture for the most effectual plowing, and so much rain may fall that plowing, harrowing and planting may be delayed a week or more. Such delays often result in reaching the market too late for the best prices. The failure to cultivate a field at the right time frequently results in the weeds taking possession, a situation causing unnecessary expense in hoeing and hand weeding, and in addition producing later maturing crops and reduced yields. There is a proper time in vegetable gardening for every tillage operation and fortunate is the man who not only knows when to till but who usually does the work when most advantageous.
 
Continue to:
plants, crops, gardening, cultivated, harvesting, food ,greenhouses, fertiliser, vegitables