DURING summer such as our current rain season in Zimbabwe, planting sorghums, sorghum-Sudan hybrids, and pearl millet may be done in wide rows, drilled or broadcast. 

Row plantings may be undertaken to allow for cultivation if necessary. 

Tall-growing forage sorghums should be planted in rows to facilitate harvest. 

Match row width of planter with row width of the forage-chopper head – these are standard farm implements. Forage sorghums can be drilled or broadcast if the harvester has an all-crop harvest head. 

Sorghums and pearl millet are particularly warm-weather crops and should not be planted until the soil is warm in the spring and all danger of frost is past. 

In most farming areas of Zimbabwe, new plantings can be made into the summer until about 120 days prior to the end of the growing season or to the date of the first frost. 

Plantings made after this will have lower yields than earlier plantings and will suffer more from diseases and insects. 

Plantings made without irrigation may suffer from drought stress. 

In such situations, sorghum may be the better crop choice compared to corn since sorghum is drought tolerant. 

Early-planted grain or silage sorghums may make a second crop, but yields of such crops are often less than half of the original harvest.

Seeding rate for the sorghums, sorghum-Sudan hybrids, and pearl millet is 4-5kg/acre of seed when planted in rows of a 70 to 107cm width. 

For broadcast or drilled plantings, the seeding rate should be increased by 25 percent or more for sorghums and more than doubled for sorghum-Sudan grass.

When planted for cattle silage, the forage sorghums should be planted in rows unless an all-crop harvest head is available on the silage harvester. 

Regardless of seeding method, seeds should be planted in moist soil at a depth of 2,5-5cm and covered.

To produce a higher protein silage or haylage, sorghum-Sudan grass and pearl millet can be harvested when they reach a height of about one metre. 

However, harvesting at this young stage of growth reduces overall yield. 

Also, in some instances, regrowth has been very poor when plants were harvested at a height of one metre, compared to regrowth following harvest at the boot or early-flower stage.

A stubble of 15cm-20cm should be left if a second crop is planned. 

The cut should be made in such a way that shattering of the stubble is avoided and equipment does not run over the stubble.

Soil tests should be made well in advance of planting and used as a guide to nutrient management. 

Lime should be applied three to five months in advance of planting when possible. 

All the phosphorus (P2O5), a third of the potassium (K2O), and about 14kg/nitrogen (N) should be applied at planting. 

The remainder of the N(nitrogen) and K(potassium) may be applied in split applications, but should be completed by six-to-seven weeks after planting. 

A good schedule for applying the remaining nitrogen (N), is a third at three, five, and seven weeks after emergence.

Calcium and magnesium are usually available in adequate amounts when the pH is corrected to 6.0 or higher with dolomitic limestone. 

Sulphur should be applied at the rate of 7-9kg/acre. 

Minor elements should be applied with the starter fertiliser as needed following recommendations from the soil-test report. 

Sandy soils usually need boron at ½ kg/acre applied with later applications of nitrogen through the irrigation system. 

All nutrients should be applied according to soil-test values.

Pest control recommendations change from year to year; extension offices should keep updated information with the most current recommendations for farmers.

Cultivation and herbicides must be used to control weeds. 

Foliage-feeding worms can cause serious damage, especially on late-planted corn. 

For recommended control measures for worms and other insects, see your county agricultural agent or agro-supply store/hardware.

Soils tests for liming and fertilisation should be carried out during autumn or winter to determine the kinds and amounts of lime and fertilisers needed. 

Sorghums perform best in soils with a pH of 5.5–6.5. 

If lime is needed, it should be broadcast and incorporated into the soil during the land-preparation process.

Apply all of the soil-test-recommended P205, 30 percent of the recommended K2O, and 13,6kgnitrogen /acre in a preplant or at planting application. 

Top-dress fertilisers or side dress the remaining 70 percent of the K2O and nitrogen (N). 

Side-dress before plants are too tall to cultivate or approximately four weeks after planting.

If a second crop is to be attempted, it should be fertilised at about half of the original rate. 

The fertiliser should be applied immediately after the first harvest.

Sorghum is attacked by many of the insects commonly associated with corn. 

Corn ear-worms, army worms and aphids are very common in sorghum. 

Sorghum midge and sorghum webworm may also attack sorghum.

Sorghum midge usually appear at the flowering stage.

Corn ear worms and army worms may be present from the seedling stage through to maturity.  

While plantings of the first crop may escape severe infestations, late summer crops can be subjected to heavy infestations that result in serious damage to the crop. 

An infestation of one larva per spikelet is sufficient to cause a loss of grain. 

Corn ear worms, army worms and sorghum web worms can also destroy the ripening grain.

The dry-matter yield of forage sorghum may equal or exceed that of corn. 

Forage sorghums also have the advantage of producing one or more ratoon crops. 

However, while the nutritive value of forage-sorghum silage is typically less than that of corn silage, the nutritive value of grain-sorghum silage is usually equal to that of corn silage. 

As a general rule, the lower the grain content, the lower the nutritive value.

Cattle grazing certain sorghum hybrids after frosts or droughts can suffer or die from prussic acid poisoning. 

So diligently feed your livestock with only safe recommended mixes.

Dr Tony Monda holds a PhD in Art Theory and Philosophy and a DBA (Doctorate in Business Administration) and Post-Colonial Heritage Studies. He is a writer, lecturer and a specialist post-colonial scholar, Zimbabwean socio-economic analyst and researcher. 

For views and comments, email:  MONDA@gmail.com