SOIL
- Have the fields been mapped - physically and chemically?
- Have the necessary adjustments been made?
- Is the yield potential of the different fields/zones known?
- Should low potential fields not be withdrawn from the cash crop production process?
- What is the soil water status of the different fields? Wetter fields can be planted first, while dryer fields can be left to receive more rain before planting. A soil drill is handy to check the soil water status of the soil profile.
PRECISION FARMING
In previous editions of Scenario, we reported extensively on precision farming and what it entails, which means we will not repeat it.
CULTIVAR CHOICE
Seed suppliers offer a large variety of cultivars - make sure that the cultivar(s) which you choose, have been adjusted for the area concerned and for yield potential. Make use of the MAIZE INFORMATION GUIDE (MIG) issued annually by the ARC Institute for Grain Crops to make an informed decision. Should “new” cultivars be considered, test it on a limited scale first. In order to limit risk, it would be good to use a cultivar package.
PLANTING DATE
Planting date is an important aspect in respect of successful crop cultivation. The soil temperature should for instance be above 15°C before maize is planted and the ideal soil temperature is 18°C. At temperatures lower than 10°C, maize will not germinate. Planting dates should, if possible, be adjusted to ensure that maize is not in the flowering stage during a possible mid-summer drought.
Sunflower germinates at 4°C, but optimal germination and development take place at soil temperatures of between 12°C and 20°C.
The possible occurrence of late frost on early plantings must also be taken into account.
Utilise optimal planting conditions and use good, tested agronomic practices.
SPACING WITHIN ROWS
Plant population and row width have an impact on spacing within rows. However, equable spacing is as important and double seeds and therefore gaps, result in yield losses. Cultivars can only compensate for gaps in the rows to some extent. The simultaneous germination and emergence of all the seeds are important and a well spaced plant stand forms part of the foundation of successful crop cultivation.
ROW SPACING
Row spacing varies between different areas and between dryland and irrigation cultivation. There is a trend to narrow row widths to decrease competition within rows. The conversion of implements is, however, expensive.
PLANTING DEPTH AND SEED-SOIL CONTACT
Equable planting depth is important to ensure equable germination and emergence of plants and unequable germination and emergence also result in yield losses.
Planting depth and gauge wheel settings have a huge impact on the germination of seed. In order for seed to take up soil moisture, the seed must be in good contact with the soil. If the pressure is high, the soil will be too dense and the seed will not emerge or will result in compacted roots.
Sources:
Gerrit Oosthuizen is a senior agronomist at Senwes. Please contact him for any enquiries at (018) 293 1968 or 084 506 8791. An e-mail can be sent to gerrit.oosthuizen@senwes.co.za