Importance of growing sorghum
Sorghum is a tropical grass genetically engineered to adapt to a wide variety of environments. Under adverse conditions, it has the ability to go into a dormant stage and suspend growth until conditions become more favorable.
It is used for cattle feed as summer forage for direct grazing, or stored as high-moisture silage, whole-plant silage or concentrate.
Sorghum grains are used not only for animal feed but also for producing food and beverages, as it is fit for patients with celiac disease due to its lack of prolamins (protein forming gluten).
Sorghum improves soil coverage creating a large amount of stubble. Besides, its developed root system improves soil structure as well as physical, chemical and biological soil conditions.
It is used for cattle feed as summer forage for direct grazing, or stored as high-moisture silage, whole-plant silage or concentrate.
Sorghum grains are used not only for animal feed but also for producing food and beverages, as it is fit for patients with celiac disease due to its lack of prolamins (protein forming gluten).
Sorghum improves soil coverage creating a large amount of stubble. Besides, its developed root system improves soil structure as well as physical, chemical and biological soil conditions.
Water
Sorghum is more tolerant to droughts and excessive soil humidity than other cereals and grows well under a wide variety of soil conditions.
It has a favorable response to irrigation requiring a minimum of 250 mm during its cycle, with an optimal irrigation ranging from 400-550 mm.
Adequate soil humidity is essential at the time of seeding for a rapid and homogeneous emergence and therefore proper crop implantation.
The greatest demand for water begins about 30 days after emergence and continues until grain fill, the two most critical stages being panicle initiation and flowering, as water deficiencies at such stages may reduce crop yield.
Sorghum may also stay dormant during a drought and resume growth in favorable conditions, though such stress affects its behavior.
It has a favorable response to irrigation requiring a minimum of 250 mm during its cycle, with an optimal irrigation ranging from 400-550 mm.
Adequate soil humidity is essential at the time of seeding for a rapid and homogeneous emergence and therefore proper crop implantation.
The greatest demand for water begins about 30 days after emergence and continues until grain fill, the two most critical stages being panicle initiation and flowering, as water deficiencies at such stages may reduce crop yield.
Sorghum may also stay dormant during a drought and resume growth in favorable conditions, though such stress affects its behavior.
Temperature
Sorghum requires high temperatures for normal development, so it is more sensitive to lower temperatures than other crops.
It requires a minimum soil temperature of 15 °C, with an optimal temperature ranging from 18 and 20 °C, within 10 cm from the soil surface for a period of three days. Under these conditions, sorghum emerges between 3 and 5 days later.
Seeding at low temperatures causes uneven emergence and a lower plant stand than expected.
Plant growth is not truly active unless the temperature exceeds 15°C. The optimal temperature is around 32°C.
During flowering, it requires a minimum temperature of 16°C, as a lower temperature can cause spikelet sterility and reduce grain yield. On the contrary, it is heat resistant if the soil is dry enough.
It requires a minimum soil temperature of 15 °C, with an optimal temperature ranging from 18 and 20 °C, within 10 cm from the soil surface for a period of three days. Under these conditions, sorghum emerges between 3 and 5 days later.
Seeding at low temperatures causes uneven emergence and a lower plant stand than expected.
Plant growth is not truly active unless the temperature exceeds 15°C. The optimal temperature is around 32°C.
During flowering, it requires a minimum temperature of 16°C, as a lower temperature can cause spikelet sterility and reduce grain yield. On the contrary, it is heat resistant if the soil is dry enough.
Soil
Sorghum develops well in alkaline soils, especially in sweet soils requiring the presence of calcium carbonate, thus increasing the content of sucrose in stems and leaves.
It prefers deep soils with good drainage and fertility, a pH ranging from 6.2 to 7.8 and no excess salts or hardpans.
It is moderately tolerant to soils with a certain degree of salinity or alkalinity, so its performance is better than the performance of other crops such as peanuts, soya and corn.
It prefers deep soils with good drainage and fertility, a pH ranging from 6.2 to 7.8 and no excess salts or hardpans.
It is moderately tolerant to soils with a certain degree of salinity or alkalinity, so its performance is better than the performance of other crops such as peanuts, soya and corn.
Seeding
As a general rule, sorghum seeding must begin from fifteen to thirty days later than corn seeding in each region.
In order to schedule seeding one must keep mind the cycle of the type of sorghum, as it is of utmost importance that between the pre-flowering and the flowering stages there is no water deficit or extreme temperatures.
Seed density will depend on the quality, size and weight of the seed, the seeding system used, the cycle of the hybrid chosen, irrigation availability and the type of soil.
In general, it is advisable to use lower plant densities in long cycle crops with low water availability and use larger densities in short or intermediate cycles.
Irrespective of the seeding system used, it must be taken into account that the sorghum seed is quite small and contains less reserves than other cereals such as soya or corn; for this reason, it must be placed in wet soil and in direct contact with it for a rapid germination and emergence, both of which are the key requirements for a successful crop.
It is essential not to bury the seed too deep into the soil, only 3-4 cm deep, and to ensure that all seeds are planted at the same depth thus allowing for proper seed spacing in the seed row and, as a result, a homogeneous crop.
Generally, 150,000-250,000 grain and silage sorghum plants are obtained while 350,000 to 600,000 forage sorghum plants are obtained.
The normal spacing of grain sorghum seeds ranges from 42 to 52 cm, though it is advisable to place seeds at a distance of 35 cm between rows in short/ultra-short cycles.
The recommended seed spacing for whole-plant silage sorghum ranges from 42 and 52 cm between rows with a density of 18-20 plants/m2 when cutting (dual purpose sweet hybrids).
In the case of forage sorghum for direct grazing, seed spacing should be 20 cm between rows for the purpose of increasing the leaf/stem ratio for an increased nutritional quality.
Sorghum-on-sorghum and sorghum-on-corn seeding are not advisable due to any potential diseases depending on the seeding area, such as Fusarium, Anthracnosis, Helminthosporium and Cercospora. Another point to consider is the potential incidence of Diatraea, a stem borer, especially when seeding on corn.
Neither is it advisable to seed on sorghum near a BT-corn, as caterpillars might feed on the sorghum and cause plant tipping.
It is important to perform regular controls of greenbugs and once detected to take proper action; otherwise, it can damage plants infecting them with toxic saliva and allowing for the presence of fungus, thus causing plant tipping and losses.
In order to schedule seeding one must keep mind the cycle of the type of sorghum, as it is of utmost importance that between the pre-flowering and the flowering stages there is no water deficit or extreme temperatures.
Seed density will depend on the quality, size and weight of the seed, the seeding system used, the cycle of the hybrid chosen, irrigation availability and the type of soil.
In general, it is advisable to use lower plant densities in long cycle crops with low water availability and use larger densities in short or intermediate cycles.
Irrespective of the seeding system used, it must be taken into account that the sorghum seed is quite small and contains less reserves than other cereals such as soya or corn; for this reason, it must be placed in wet soil and in direct contact with it for a rapid germination and emergence, both of which are the key requirements for a successful crop.
It is essential not to bury the seed too deep into the soil, only 3-4 cm deep, and to ensure that all seeds are planted at the same depth thus allowing for proper seed spacing in the seed row and, as a result, a homogeneous crop.
Generally, 150,000-250,000 grain and silage sorghum plants are obtained while 350,000 to 600,000 forage sorghum plants are obtained.
The normal spacing of grain sorghum seeds ranges from 42 to 52 cm, though it is advisable to place seeds at a distance of 35 cm between rows in short/ultra-short cycles.
The recommended seed spacing for whole-plant silage sorghum ranges from 42 and 52 cm between rows with a density of 18-20 plants/m2 when cutting (dual purpose sweet hybrids).
In the case of forage sorghum for direct grazing, seed spacing should be 20 cm between rows for the purpose of increasing the leaf/stem ratio for an increased nutritional quality.
Sorghum-on-sorghum and sorghum-on-corn seeding are not advisable due to any potential diseases depending on the seeding area, such as Fusarium, Anthracnosis, Helminthosporium and Cercospora. Another point to consider is the potential incidence of Diatraea, a stem borer, especially when seeding on corn.
Neither is it advisable to seed on sorghum near a BT-corn, as caterpillars might feed on the sorghum and cause plant tipping.
It is important to perform regular controls of greenbugs and once detected to take proper action; otherwise, it can damage plants infecting them with toxic saliva and allowing for the presence of fungus, thus causing plant tipping and losses.
Weed control
A weed free crop is advisable within the first 30 days, in order to prevent a significant decrease in production.
Some of the weed management practices used to protect crops against weeds are the following: increased seed density, decreased seed spacing between rows, scheduling a date for seeding on the basis of weed emergence, using fertilizers in the row as a starter.
Pre-seeding: Round Up should be used to control highly complex weeds such as Cynodon dactylon (L), Sorghum halepense (L) and Cyperus rotundus (L).
A good fallow increases the chances for successful implantation.
Pre-emergence: For seeds treated with Concep III, S-metolachlor and Atrazine should be used to prevent annual grass weeds and broadleaf weeds.
Post-emergence: For weeds with up to four leaves, hormonal herbicides, 2, 4-D and picloram should be used as well as dicamba for broadleaf control.
Some of the weed management practices used to protect crops against weeds are the following: increased seed density, decreased seed spacing between rows, scheduling a date for seeding on the basis of weed emergence, using fertilizers in the row as a starter.
Pre-seeding: Round Up should be used to control highly complex weeds such as Cynodon dactylon (L), Sorghum halepense (L) and Cyperus rotundus (L).
A good fallow increases the chances for successful implantation.
Pre-emergence: For seeds treated with Concep III, S-metolachlor and Atrazine should be used to prevent annual grass weeds and broadleaf weeds.
Post-emergence: For weeds with up to four leaves, hormonal herbicides, 2, 4-D and picloram should be used as well as dicamba for broadleaf control.
Pest control
Sorghum midge: Controlled when one insect per panicle is detected while 20 - 30 % of panicles are flowering. Insecticides based on pyrethroids (Cypermethrin 25 % – Deltamethrin 5% - Chlorpyrifos 50 % + Cypermethrin 5%) are used.
Spodoptera: Chemical control is applied when detecting damages in leaf parenchymas and larvae are in their early stages of development. IGR type or Diamides insecticides are used. Their effectiveness depends on the development stage of larvae.
Diatraea: Chemical control based on pyrethroids when a 10% of plants have orange egg clusters.
Greenbugs: When small colonies of light green greenbugs are found in the underside of lower leaves. Heat and droughts accelerate infestation causing it to spread all over the lot. Chemical control based on Chlorpyrifos 48 % – Dimethoate 50% – Pirimicarb 50%.
Dosage in chemical pest controls varies depending on insect population and their development stage, as well as weather conditions and the phenological stages of crops, so we recommend that you seek advice from a professional in each case in particular.
Spodoptera: Chemical control is applied when detecting damages in leaf parenchymas and larvae are in their early stages of development. IGR type or Diamides insecticides are used. Their effectiveness depends on the development stage of larvae.
Diatraea: Chemical control based on pyrethroids when a 10% of plants have orange egg clusters.
Greenbugs: When small colonies of light green greenbugs are found in the underside of lower leaves. Heat and droughts accelerate infestation causing it to spread all over the lot. Chemical control based on Chlorpyrifos 48 % – Dimethoate 50% – Pirimicarb 50%.
Dosage in chemical pest controls varies depending on insect population and their development stage, as well as weather conditions and the phenological stages of crops, so we recommend that you seek advice from a professional in each case in particular.