FOCUS
Fertiliser
Special
Fertigation for irrigated crops
Product information
JACQUESMILLEN,
technical advisor, Agriplas
T
he optimum performance of a crop
can be achieved partially by ef-
fectively supplying the nutrients
required at every stage of the crop
cycle. The traditional mechanical applica-
tion of solid fertiliser is not that effective,
requiresmanpower andmachineryandcan-
not be automated.
Fertigation (the addition of liquid fertilis-
ers to irrigation water) makes dissolved
nutrients immediately available for the
plants and this improves the fertiliser ef-
ficiency. The cost of each addition of ferti-
liser through fertigation is minimal, which
makes it possible to increase the frequency
of the additions and therefore improving
the crop’s efficiency. The two systems com-
monly used are venturi injectors or positive
displacement dosing pumps. The venturi
systemsdependonvariables suchasdensi-
tyandviscosityof theproduct tobe injected
and the water velocity through the devic .
The venturi also requires a pressure drop
to function, normally created by a booster
pump that leads to energy expenditure.
ITCDostec-40 piston
dosing pump
Piston dosing pumps are an excellent alter-
native to venturis, because their flow is not
affected by the physical characteristics of
the network or the product. The flow is reg-
ulatedwith high precision by regulating the
stroke length of the pump or pump speed.
Thesedosingpumpsalsohavegoodenergy
efficiency.
An ITCDostec-40pistondosingpump.
kan voorsien nie en indien groter toedienings gemaak wil word,
kandit diegewas beskadig (brand).
Hoewel blare hoofsaaklik die proses van fotosintese ondersteun,
is daar alreeds meer as ‘n eeu en ‘n half gelede gevind
dat voedingstowwe deur ‘n blaar geabsorbeer kan word.
Blaarvoedings word aanvullend tot grondtoegediende bemesting
gebruik wanneer die wortels nie in die gewas se behoefte
kan voorsien nie óf wanneer daar ‘n behoefte na ‘n spesifieke
voedingstof is óf wanneer spesifieke toestande, soos stres of
ongunstige grondtoestande, dit noodsaak. Blaarvoeding het die
verdere voordeel dat dit ‘n baie vinnige reaksie gee ommoontlike
strestoestande (klimaat en voeding) teoorkom.
Geen twee gewasse het presies dieselfde voedingsbehoefte nie
en die belangrikheid van verskillende voedingstowwe verskil
gedurendeverskillendegroeistadiums vandiegewas. Eenproduk
kan nie aan al die gewasse se behoeftes in al die verskillende
groeistadiums voldoen nie. Blaarvoedings behoort om hierdie
redes gewasspesifiek asook groeistadiumspesifiek te wees om
verbeterdedoeltreffendheid tebewerkstellig.
Opsommend kan gesê word dat die doeltreffendheid van
bemestingverhoogkanworddeurdiegewas, klimaat, plasing, tyd
van toediening asook produkkeuse gelyktydig in aanmerking te
neem.Dit gaannieoordiegebruikvan “wondermiddels”nie,maar
om die regte kombinasies te selekteer wat die doeltreffendheid
van bemesting kan verhoog. Vir verder navrae, kontak gerus jou
bemestingsadviseur enmaak homdeel van jouboerdery.
Pasopvir té slim raak
55
July2014
