Soil and crop management aspects of water table control practices

Excerpt

HIGH average annual rainfall, high solar radiation, and warm temperatures could make the Southeast Coastal Plain of the United States an ideal dace to vcrow crotx. I but, other “geographic areas consistently outproduce it. A fundamental problem in the region is variable rainfall during the growing season (24). At times, flooding and aeration problems occur; at other times there is drought, and crops cannot thrive because the sandy soils have a low water-holding capacity (7). These factors are worse in soils with shallow rooting zones caused by subsurface hardpans.

These problems are not confined to the Southeast Coastal Plain. However, the regional climate and soil characteristics combine to require unique solutions. One such solution, water table management by controlled drainage-subirrigation, can ameliorate variability of crop water supply (9, 14, 33, 39).

Climatic effects

The Southeast Coastal Plain is known for high humidity, heat, and a long growing season. Humidity, represented as dewpoint temperature, has a mean annual value in excess of 52°F. Average daily extreme temperatures for July, the hottest month of the year, range from 70° to 91°F. Similar values for January, the coldest month of the year, range from 34 O …