Sunflower’s consistent yield and drought-tolerance make it an attractive crop for SA’s dryland regions. It also has a relatively long planting window. Nonetheless, care should be taken to plant at the optimal time, cautions Dr Safiah Ma’Ali, senior researcher at ARC-Grain Crops Institute.
Over the years, sunflower has come to be considered an ideal low-input crop for South Africa’s marginal cropping conditions.
It is currently the country’s third-largest grain crop after maize and wheat, and is primarily used for the manufacture of oil for human consumption and oilcake for animal feed.
Sunflower produces relatively consistent yield even under adverse weather conditions.
The plants are particularly efficient at extracting water from the soil, especially sandy loam.
This is underscored by the surprisingly high yields realised compared with those of other crops during the 2014/2015 drought.
Unlike other grain crops, sunflower has a relatively long planting window from early November to late January. But this can be misleading. It is important to choose the planting time carefully to ensure a good plant population.
The Agricultural Reseach Council’s Grain Crops Institute in Potchefstroom (ARC-GCI) has been conducting research on sunflower planting dates since 2007, which has demonstrated the importance of planting date for producing maximum yield.
Growth Stages
To better understand the effect of planting date on yield, each of the growth stages must be carefully considered: planting to floral initiation (GS1); floral initiation to bloom (GS2); and bloom to physiological maturity (GS3).
The yield components of sunflower, namely heads per hectare, number of seeds per head and weight per seed, are determined during these phases.
GS1: planting to floral initiation
This begins when the seed is planted and ends when the floral parts of the sunflower are initiated. Floral initiation cannot be observed directly; it occurs between the 10-leaf and 14-leaf stages. In GS1, sunflower is at its most delicate and is highly sensitive to stress. Fortunately, stress occurring during this period has little effect on yield. The plant must remain alive only to maintain the yield component of heads/ha.
GS2: floral initiation to bloom
Although the start of this growth stage is not readily recognisable, it determines the final yield. The floral parts, which later become the harvested seeds, are formed during this phase. After the seeds are initiated, they expand to form the visible bud and, eventually, the sunflower head, which blooms and thus completes GS2.
The head size, or the number of seeds/head, is established during this stage. Any stress that limits growth rate during GS2 will result in a reduced number of seeds/head.
Drought stress during this stage reduces yield more than at any other phase of sunflower development.
GS3: bloom to physiological maturity
The final stage of development begins when flowering is completed and the plant reaches physiological maturity.
During GS3, seed size and weight are determined. As physiological maturity approaches, the sunflower can utilise progressively lower temperatures for seed growth, while also becoming increasingly drought-tolerant.
Stress during GS3 can reduce yield, but not usually to the same extent as the reduction during GS2, as seed weight is a relatively smaller contributor to yield than seed number under most conditions.
Moisture
Ultimately, soil moisture, the most limiting yield factor, determines the planting date. Obviously, it’s difficult to predict when and how much rain will be received, so long-term averages are important (see Figure 1).
It should be pointed out, however, that such data and yield are often unrelated. Even moderate amounts of rainfall received at critical stages of growth, such as the first phase of GS2, can stimulate yield potential.
All the same, the graph clearly indicates that yield generally decreases the later the crop is planted after the period of maximum rainfall.
Another factor affecting sunflower stand is poor germination due to excessive heat at the time of planting.
Sunflower sometimes has to be planted in January or even early February, and temperatures 2017during this period often reach 32°C to 35°C.
Temperatures in this range are not ideal for sunflower seed germination. Even when seeds germinate, high temperatures may cause them to wither and die.
In addition, topsoil tends to dry out rapidly in the heat, so farmers are forced to plant the seeds slightly deeper when soil moisture content is higher. This can be risky, however; a single hard shower of rain after planting can cause a thick crust to form and the seedlings will be unlikely to emerge.
The right time
To reiterate, it’s important for producers to choose the planting time carefully and ensure a good plant population.
For the past 10 cropping seasons, seed yield from 38 national sunflower cultivar trials planted by ARC-GCI in Potchefstroom has been evaluated under three separate planting dates (1 to 30 November, 1 to 30 December and 1 to 30 January).
The results indicated that seed yield was reduced by approximately 0,21t/ ha for each 30-day delay in planting after November (see Figure 2).
The yield probability percentages for the different planting dates were subsequently calculated at different yield threshold ranges (0,5t/ha to 3t/ ha).
The results showed that the probability of obtaining higher yield under a specific yield threshold (>1,2t/ha) was lower when the crop was planted after December (see Figure 3).
Put another way, sunflower planted later in the season, especially during January, will have a lower yield potential. A farmer planning to plant sunflower as a main crop should consider planting during November and no later than the end of December in order to reach the target yield of more than 2t/ha.
over the counter viagra substitute walmart how long before sex do you take viagra how much does the military spend on viagra
cialis paypal accepted cialis professional review cialis alcohol
ivermectin price in india azelaic acid metronidazole ivermectin ivermectin 3
generic ivermectin cream ivermectin 1.87 dosage for cats ivermectin pigeon
cialis patent expiration cialis viagara original cialis low price
buy cialis through paypal cialis without a doctor prescription canada overnighted cialis for men
price of doxycycline doxycycline online singapore doxycycline 100mg capsules buy
doxycycline 100mg best buy doxycycline cream buy doxycycline united states
buy generic doxycycline 500 mg doxycycline pill can you buy doxycycline over the counter canada
prednisone 5 50mg tablet price buying prednisone without prescription can i purchase prednisone without a prescription
amoxicillin 500 mg without a prescription amoxicillin 500mg capsules price medicine amoxicillin 500mg
clomid steroid clomid 50mg tablets cost clomid online pharmacy uk
doxycycline 120mg doxycycline 100 mg tablets where can you buy doxycycline online
ed doctor erectile dysfunction cure ed meds online
prescription drugs online without male enhancement products ed vacuum pumps
best ed pills ed treatments that really work cialis without doctor prescription
natural remedies for ed ed medicine online ed pills comparison
erectial disfunction ed supplements ed cures
can you buy prednisone over the counter in canada prednisone 10mg tablet cost how much is prednisone 10 mg
erectile dysfunction medication medicines for ed male erection
cialis efectos secundarios cialis online doctor cialis for enlarged prostate
stromectol usa ivermectin contraindications in humans ivermectin for rabbit ear mites
ivermectin wiki cost of ivermectin for humans ivermectin contraindications in humans
ivermectin for snakes ivermectin poultry
which is better cialis or levitra cialis online purchase canada generic cialis?
cheap generic prednisone cheap prednisone prednisone 250 mg
ivermectin pour-on tractor supply ivermectin for dogs dosage in mg stromectol ebay
cialis lion where can i get cialis european cialis
cialis over the counter at walmart cialis usa prescription cheaper alternative to cialis
buy ivermectin canada is ivermectin safe for cats ivermectin paste for scabies
prescription drugs without prior prescription shots for ed prices of viagra at walmart
propecia prescription online generic propecia canada propecia order
amoxicillin without a doctor’s prescription canadian drugs pain medications without a prescription
erectile dysfunction medicines top erection pills buying ed pills online
how to cure ed generic ed pills best ed pills at gnc
best medication for ed best pill for ed online ed medications
treatments for ed new ed pills ed pills comparison
non prescription erection pills prescription drugs without prior prescription best online canadian pharmacy
provigil 200mg brand
provigil 200mg without prescription buy modafinil 100mg without prescription
erythromycin eye ointment for newborns erythromycin ophthalmic ointment for cats
price for viagra sildenafil citrate tablets 100 mg viagra tablets for men
cost modafinil 100mg buy provigil 200mg generic
order provigil 200mg sale buy provigil online
provigil 200mg canada
provigil order online buy provigil 100mg
buy provigil 200mg for sale purchase modafinil generic
buy clomid 50mg buy clomid 50mg online clomid for sale
buy provigil pill
price of cialis 20 mg where to buy liquid cialis tadalafil without a doctor’s prescription
modafinil 200mg ca
stromectol for sale stromectol tablets for humans ivermectin cream side effects
stromectol for sale stromectol tablets for humans stromectol 12 mg tablets
erythromycin for dogs erythromycin allergy
generic viagra walmart pfizer viagra 100mg price where can i buy viagra over the counter
mexican viagra viagra viagra from india
where to buy viagra online viagra tablets for men buy viagra online usa
cialis 2.5 mg generic tadalafil 20mg india what does cialis do
https://erythromycin1m.com/# clindamycin vs erythromycin
cialis super active for cheap tadalafil without a doctor’s prescription cialis 20mg shopping
where can i buy cialis online in canada tadalafil 20mg best price cialis low dose
buy cialis online australia pay with paypal generic tadalafil 20mg india cialis generic 20 mg 30 pills
liquid cialis tadalafil without a doctor’s prescription what happens when you mix cialis with grapefruit?
cialis 20 mg dosage cialis pills how can i get cialis fast
erythromycin oint erythromycin eye
erythromycin fish side effects of erythromycin ophthalmic ointment
svi4u
g0rhr
ngtx
b96au
f7z1n
[url=http://novrazbb.com/#]yjvp[/url]
erythromycin ophthalmic ointment usp erythromycin oint
hiyle
kb26z
hw93
erythromycin ophthalmic solution https://erythromycinn.com/#
hydroxychloroquine generic plaquenil 200mg friends program
neurontin liquid [url=https://neurontin.site/#]gabapentin cost of [/url] what dose does neurontin come in what is a gabapentin
azithromycin for acne zithromax 250 mg mechanism of action of azithromycin how long does it take for azithromycin to work
buy plaquenil pills
dapoxetine and cialis [url=http://priligy.site/#]where to buy priligy in canada [/url] dapoxetine dosage for premature ejaculation how does dapoxetine work
types of viagra cialis free trial side effects of cialis and viagra what does the viagra pill do
Accused in the past of embezzling players' funds, OddsPoker is still operating through its Antigua license, but that doesn't make it a safe place to play. To comply with anti-money laundering legislation, legal US poker sites are not allowed to accept new players unless they provide Personal Identifiable Information (PII). Playing poker can sometimes take hours and hours. Some games can be quick when played online, but land casino games are very rarely fast. Imagine this…You get stuck into a game at noon and, suddenly, it’s 8pm in the evening. Where did the time go? It is easy to get lost while playing poker, and along with lost time, you will probably feel exhaustion. The poker sites we recommend offer a particularly large selection of game variants and tournament formats, and you can usually play all the games that are available for real money with play money. Here you can not only play Texas Hold’em for free, but also engage in many other lesser-known games such as Omaha, Stud, Triple Draw 2-7, Razz, and HORSE. Even action-packed, turbo variants of poker like Snap or Zoom are also available as free games. https://ruskillfish.ru/forum/profile/teradoll2146680/ In 2011, Tilman Fertitta bought the run-down Trump Marina casino in Atlantic City for $38 million, renamed it the Golden Nugget and put $150 million into renovations. Gaming revenue is up 50% from a year ago. Mars Casino Dracula Fun bitcoin casino london So, the BestCryptoCasino.today platform based on AI determines how gambling sites meet certain parameters with an accuracy of up to 92%. Based on its assessment, we have compiled a list of the TOP representatives of bitcoin casinos: Bitcoin casino reviews represent an indispensible guide that can help you explore the world of bitcoin gambling safely. Benefit from the experiences of others who play on bitcoin casinos and choose the one that suits your needs and preferences. The first casino on our list is the Dragonara Casino found in the heart of the Mediterranean, on the island of Malta. Owned and operated by Dragonara Gaming Limited, it features 300 slot machine games, 15 dice tables, a VIP lounge for high rollers and a poker room. The casino’s exterior speaks luxury and class, while the interior gives you the Mediterranean view when you step into it.
dapoxetine premature ejaculation where can i buy dapoxetine in singapore priligy dapoxetine 60mg pills how does dapoxetine work
kamagra cenforce 100 [url=https://kamagraaustralia.quest/#]what is super kamagra [/url] can you buy kamagra at walgreens how long kamagra last
plaquenil pharmacy
Right here on Onlineroulette.org! Just find a roulette game you want to try, like European roulette or American roulette and give it a go. When you’re ready to play for real money, one of our top-rated roulette sites will offer you the best bonuses & most exciting roulette games. Some online roulette casinos, like Bovada and CafeCasino, offer free practice roulette games. You won’t be eligible to win real money when playing practice roulette, but these virtual games do offer a way to learn the rules of the game. Even more important, free roulette games allow you to try out a casino’s gaming software before you commit to the platform. It is a Federal offense for persons physically located outside of Michigan to engage in Internet wagering through this website. Our Free Roulette game serves to virtually transport you to land-based casinos that are found in some of the world’s most well-known gambling meccas across the world. The online casino game found on this particular page is none other than European Roulette – one of the world’s most popular variants of the game. Much of its popularity stems from the fact that this game not only has simple rules to implement but also that this version of Online Roulette has a much lower house edge than its American cousin. https://islam.ng/community/profile/felicitashague2/ That just about wraps everything up in this review of the best casino apps for iPhone. As an Apple user, you have a lot of great options available to you. Furthermore, as a British player, you can enjoy some of the best and most well-regulated operators worldwide on iPhones. Whether you’re looking to bet from an iPhone, Android, or Google phone, there will be mobile sports betting available to you on any operating systems. If you’re wondering what the best gambling sites for 18 and up bettors are that feature mobile capabilities, look no further. Read our mobile sports betting guide and discover the ways 18+ bettors can wager on their favorite sports. What Causes an Addiction to Gambling? Many factors can contribute to a gambling addiction, including desperation for money, the desire to experience thrills and highs, the social status associated with being a successful gambler, and the entertaining atmosphere of the mainstream gambling scene.
can you get hydroxychloroquine otc make hydroxychloroquine over the counter
lasix tablets [url=http://lasix.site/#]90 furosemide [/url] does lasix raise blood sugar to which of the following pharmacologic classes does furosemide belong
propecia results timeline can you buy propecia over the counter in canada can you buy propecia over the counter when does propecia cause ed