Geographical Areas

1. Humid summers of six months or more and mild winters.

2. Precipitation varies from 850 mm to 180 mm/year.

3. Precipitation is mostly well distributed throughout the year.

4. Droughts occur, but widespread droughts are infrequent.

5. Most of zone between 25 degrees and 35 degrees latitude.

6. World distribution of zone:

• Southeastern U. S.
• Argentina
• South Africa
• Southeastern Coastal Australia
• N. new Zealand
• S. Japan and China

Soils

1. Primarily ultisols and alfisols.

2. Soils can be very productive under intensive management.

3. Attention must be given to fertilization, liming, and protection from water and wind erosion.

Current Crop Production Systems

1. Most crops of major importance in North America are grown to some extent in this zone.

2. Nearly all the rice, peanuts, tobacco, and sugar cane, 2/3 of cotton crop grown in this zone in the U. S.

3. Less than 25% of zones total land resources in crop land except for MS Delta where 75% in crop land.
 
4. Rice is China?s most important grain crop.

5. Soybeans, corn and wheat grown in this zone in China (but not major production areas in country).

6. Multiple cropping is practiced extensively in China.

• Three grain crops/year common, wheat or barley followed by Indica rice followed by photo period-sensitive Japonica rice
• Second pattern is barley, cotton, and rice
• Vegetable crops are grown extensively, as many as 12 crops in a single season

• Still an important crop in U. S.
• Semi-arid of U. S. expanding cotton production
• Boll-weevil hastened this movement

• Leading cash crop in this area of U. S.
• Requires 700 worker hours of labor to grow and harvest one ha (10 hr for corn)
• U. S. share of world market dropped from 60% in 1959 to 33% at present
• U. S. growers produce 25% of world market of burley tobacco
• Tobacco grown in sandy loams with good drainage
• Adequate soil moisture must be available or irrigation needed for top yields
• Strict government control over annual marketing practiced in U. S.

• Grown primarily in MS Delta, AR, TN, MS, LA, and Gulf Coast state of TX.
• Fine textured soils with impeded drainage
• Grown 2 or more years in succession
• After rice, levees are destroyed and alternate crops grown
• Soybeans most often in rotation

• 1/3 of U. S. soybeans grown in S. E.
• Minimum frost-free of 120 days and mean summer temp. above 21 degrees C favorable

• Long growing season in zone makes forage production popular and generally profitable
• Forage crops can provide direct feed for livestock over a high proportion of the year
• Forages provide protection to soil against erosion by water and wind
• Small grain grown as a grain crop may be grazed in the south for a high proportion of the winter
• Bermudagrass is well adapted to this zone

• Peanuts are an important crop
• Frost-free period of 200 days
• Mean annual temperature above 7 degrees C is required
• Mean mid-summer temperature over 24 degrees C
• Light, well drained loam soils
• Grown in rotation with cotton, corn, tobacco, and pasture
• Zone in U. S. produces 10% of U. S. corn crop
• Is of lesser importance than other crops mentioned

• Can be practiced with higher degree of success than in humid cool temperate zone
• Schemes involve two crops in one year (double cropping)
• Three crops in two years
• Improved tillage practices particularly no-till has encouraged double cropping
• Improved weed control and earlier maturing cultivars also encourage double cropping
• 10% of all U. S. soybean acreage planted as second crop on land following winter wheat or other small grain

1. Pests.

• Mild winters, higher mean annual temperature, and humidity cause more serious pest problems than cool temperate region
• Insects, disease organisms and weeds better able to survive from one year to next
• Control measures must be timely and effective

• Are generally more highly leached
• Lower in OM
• A more limited rooting zone
• More rolling topography
• Soil and water management practices to provide nutrients as needed and control loss of water, soil and nutrients essential for high levels of crop production
• Drought can be a serious constraint to high crop production, especially in sandy or shallow soils

1. Multiple cropping.

• Earlier maturing cultivars of wheat and soybeans which have yield potential equal to full season cultivars will encourage multiple cropping
• No-till planting; pest control will also hasten adaptation
• Narrow row plantings of soybeans generally increase yields
• Late planted soybeans will not produce exceptionally large plants, narrow rows allow greater interception of sunlight, greater photosynthesis, larger yields
• Total forage production per year may be increased by multiple cropping
• Small grain may be grown for silage followed by corn or sorghum for silage
• Triple cropping reported in Georgia
• Barley-corn (relay-intercropped in barley) - soybeans
• Barley-corn -snapbeans

• No-tillage crop production may be most revolutionary and effective soil conservation practiced adopted in this country
• Especially adapted to this zone where erosion can be a serious hazard, and no-tillage can help ensure successful multiple cropping
• Advantages of no-till
• Less delay in planting second crop
• Higher soil moisture content
• Slower drying by evaporation
• Lowering maximum soil temperature
• Improved soil structure
• Disadvantages of no-till
• High moisture, reduced soil temperature in early spring
• Poor soil/seed contact
• Pest control more difficult

• Crop acreage under irrigation in this zone has increased appreciably in last decade
• Relatively high/ha investment
• Justified in sandy soils in zone
• Droughts can be disastrous to crop production - irrigation insures high production
• Land shaping to improve surface runoff during excess rainfall permits timely field operations
• Conservation tillage using crop residues
• Improves infiltration
• Recharges soil moisture
• Minimizes soil erosion from intense rainstorms
• Contour planting and strip cropping especially in Piedmont and upper Coastal Plains
• Winter cover crops
• Small grains for grazing and/or harvested for grain replacing crops strictly used for covers

• Methods include pesticides, resistant varieties, biocontrol, and cultural control
• No one method used at exclusion of others
• Pests do not remain static
• Integrated pest management used to denote combinations of chemical, cultural, biological, or mechanical control techniques