Maize Production - Agricultural Research Council
DEPARTMENT: AGRICULTUREREPUBLIC OF SOUTH AFRICAMaize productionJéan du Plessis
2003Compiled by Directorate Agricultural Information ServicesDepartment of Agriculturein cooperation with ARC-Grain Crops InstitutePrinted and published by the Department of Agricultureand obtainable from Resource CentreDirectorate Agricultural Information ServicesPrivate Bag X144, Pretoria, 0001 South AfricaThis publication is available on the web: www.nda.agric.za/publicationsInformation provided byARC-Grain Crops InstitutePrivate Bag X1251, Potchefstroom 2520Tel. (018) 299 6100Fax (018) 294 7146
INTRODUCTIONMaize (Zea mays L.) is the most important graincrop in South Africa and is produced throughoutthe country under diverse environments.Successful maize production depends on thecorrect application of production inputs that willsustain the environment as well as agriculturalproduction. These inputs are, inter alia, adaptedcultivars, plant population, soil tillage,fertilisation, weed, insect and disease control,harvesting, marketing and financial resources.In developed countries, maize is consumed mainlyas second-cycle produce, in the form of meat,eggs and dairy products. In developing countries,maize is consumed directly and serves as staplediet for some 200 million people. Most peopleregard maize as a breakfast cereal. However, ina processed form it is also found as fuel (ethanol)and starch. Starch in turn involves enzymaticconversion into products such as sorbitol,dextrine, sorbic and lactic acid, and appears inhousehold items such as beer, ice cream, syrup,shoe polish, glue, fireworks, ink, batteries,mustard, cosmetics, aspirin and paint.Approximately 8,0 million tons of maize grain areproduced in South Africa annually on approximately3,1 million ha of land. Half of the production consistsof white maize, for human food consumption.Maize needs 450 to 600 mm of water per season,which is mainly acquired from the soil moisturereserves. About 15,0 kg of grain are produced foreach millimetre of water consumed. At maturity,each plant will have consumed 250 l of water. Thetotal leaf area at maturity may exceed onesquare metre per plant.1
The assimilation of nitrogen, phosphorus andpotassium reaches a peak during flowering. Atmaturity the total nutrient uptake of a singlemaize plant is 8,7 g of nitrogen, 5,1 g ofphosphorus, and 4,0 g of potassium. Each ton ofgrain produced removes 15,0 to 18,0 kg ofnitrogen, 2,5 to 3,0 kg of phosphorus and 3,0 to4,0 kg of potassium from the soil.No other crop utilises sunlight more effectivelythan maize, and its yield per ha is the highest ofall grain crops. At maturity, the total energyused by one plant is equivalent to that of 8 29315 W electric globes in an hour.The number of kernel rows may vary betweenfour and 40, depending on the variety. Up to1 000 kernels may be produced by a single plant.In spite of only one pollen grain being required toproduce one kernel, each tassel produces some25 000 000 pollen grains, i. e. 25 000 grains foreach kernel. As a result, up to 40 % of thetassels in a planting may be lost without affectingpollination, other factors remaining optimal.MORPHOLOGY, GROWTH AND DEVELOPMENTRoot systemThe plant has a profusely branched, fine rootsystem. Under optimal conditions, the total rootlength, excluding the root hairs, can reach 1 500 m.If root growth is not restricted, the root systemof a mature plant extends approximately 1,5 mlaterally and downwards to approximately 2,0 mor even deeper. The permanent root system hasadventitious and prop roots. Adventitious roots2
develop in a crown of roots from nodes below thesoil surface. Normally four to six adventitiousroots are formed per band. After tasselling, proproots develop into bands from the first two tothree aerial nodes. These roots are comparativelythick, pigmented and covered with a waxy substance.Prop roots have the dual function of providingsupport to the plant and taking up nutrients.Numerous root hairs occur on young plants. Roothairs increase root surface area that is exposedto the soil, and play an important role inabsorption of water and nutrients.LeavesThe eight to 20 leaves that may form are arrangedspirally on the stem, and they occur alternately intwo opposite rows on the stem. The maize leaf isa typical grass leaf and consists of a sheath,ligules, auricles and a blade. The leaf blade islong, narrow, undulating and tapers towards thetip and is glabrous to hairy. The leaf is supportedby a prominent mid-rib along its entire length.Stomata occur in rows along the entire of the leafsurface. More stomata occur on the underside ofthe leaf than on the upper surface. On the uppersurface motor cells are present. These large,wedge-shaped cells occur in rows, parallel to andbetween the rows of stomata. During moistconditions, these cells rapidly absorb water,become turgid and unfold the leaf. During warm,dry weather, the cells quickly lose their turgorwith the result that leaves curl inwards exposinga smaller leaf surface to evaporation.3
StemThe maize stem varies in height from less than 0,6 min some genotypes to more than 5,0 m (in extremecases) in others. The stem is cylindrical, solid andis clearly divided into nodes and internodes. Itmay have eight to 21 internodes. The internodesdirectly below the first four leaves do notlengthen, whereas those below the sixth, seventhand eighth leaves lengthen to approximately 25,50 and 90 mm, respectively. Tillers may developfrom nodes below the soil surface.The lateral shoot bearing the main ear developsmore or less from the bud on the eighth nodeabove the soil surface. The five or six budsdirectly below the bud give rise to rudimentarylateral shoots of which one or two develop toproduce ears.InflorescenceMale and female flowers are borne on the sameplant as separate inflorescences. Male flowers areborne in the tassel and female flowers on the ear.Maize earThe maize ear (the female inflorescence)terminates one or more lateral branches, usuallyhalfway up the stem. Bracts enclose the ear. Thesilk of the flowers at the bottom appear first andthereafter those on the upper part of the ear.It remains receptive to pollen for approximatelythree weeks but after the tenth day, receptivitydecreases.4
Maize kernelEndospermGermPericarpTip capFIG. 1. Maize kernelThe maize kernel consists of an endosperm,embryo, a pericarp and tip cap (Fig. 1). Theendosperm contains the main carbohydrates. Theembryo contains the parts that give rise to thenext generation, while the pericarp and tip capenclose the entire kernel.The endosperm contains approximately 80 % ofthe carbohydrates, 20 % of the fat and 25 % ofthe minerals, while the embryo contains about80 % of the fat, 75 % of the minerals and 20 %of the protein found in the kernel.The starch part of the kernel is used in foodsand many other products such as adhesives,clothing, and pharmaceutical tablets and in paperproduction. The starch can be converted intosweeteners and used in products such as softdrinks, sweets, bakery products and jams, toname but a few.MaizeThe oil from the embryo is used in cooking oils,margarine and salad dressings. The protein, hullsand soluble part of the maize kernel are used inanimal and poultry feed.5
TABLE 1. Composition of maize kernelsComponentsDent kernels%Flint p and tip capTABLE 2. Chemical composition of the maize 5Minerals1,3Kernels can be of the dent or flint (round) types.Dent kernels have a dented crown, which is formedduring drying when the softer starch in the middleof the kernel shrinks faster than the outer moretranslucent sides. The dent kernel has two flat sidesopposite each other and the one side contains theembryo.The embryo contains all the parts that give rise tothe next generation.Flint kernels can be round or flat in appearance andcontain mainly translucent starch, with only a smallpart of soft starch in the middle, hence the name.The pericarp and tip cap enclose the entire kernel.Maize with a high percentage of translucent ofhard endosperm is preferred by the dry millingindustry, because it produces more of the popularhigh-quality and high-value products sought afterthan does soft maize.6
TasselEarLeavesStemBrace rootsRootsFIG. 2. Mature maize plant7
Growth and developmentDifferent growth stages are numbered 0 to 10.Growth stage 0 lasts from planting of the seed upto when the seedling is just visible above the soilsurface. Growth stage 10 is reached when theplant is biologically mature (Fig. 2).Growth stage 0: from planting to seedemergenceDuring germination, the growth point and theentire stem are about 25 to 40 mm below the soilsurface. Under warm, moist conditions seedlingsemerge after about six to 10 days, but under coolor dry conditions this may take two weeks orlonger. The optimum temperature range forgermination is between 20 and 30 ºC, whileoptimum moisture content of the soil should beapproximately 60 % of soil capacity.Growth stage 1: four leaves completelyunfoldedThe maximum number of leaves and lateral shootsis predetermined and a new leaf unfolds more orless every third day. The growth point at thisstage is still below the soil surface and aerialparts are limited to the leaf sheath and blades.Initiation of tasselling also occurs at this stage.Growth stage 2: eight leaves completelyunfoldedDuring this period, leaf area increases five to 10times, while stem mass increases 50 to 100 times.Growthstage 18
Ear initiation has already commenced. Tillers beginto develop from nodes below the soil surface. Thegrowth point at this stage is approximately 5,0 to7,5 cm above the soil surface.Growth stage 3: twelve leaves completelyunfoldedThe tassel in the growth point begins to developrapidly. Lateral shoots bearing cobs developrapidly from the sixth to eighth nodes above thesoil surface and the potential number of seedbuds of the ear has already been determined.Growthstage 3Growth stage 4: sixteen leaves completelyunfoldedThe stem lengthens rapidly and the tassel is almostfully developed. Silks begin to develop and lengthenfrom the base of the upper ear.Growth stage 5: silk appearance andpollen sheddingAll leaves are completely unfolded and the tasselhas been visible for two to three days. The lateralshoot bearing the main ear as well as bracts hasalmost reached maturity. At this point demand fornutrients and water is high.Growth stage 6: green mealie stageThe ear, lateral shoot and bracts are fullydeveloped and starch begins to accumulate inthe endosperm.Growthstage 59
Growth stage 7: soft dough stageGrain mass continues to increase and sugars areconverted into starch.Growth stage 8: hard dough stageSugars in the kernel disappear rapidly. Starchaccumulates in the crown of the kernel andextends downwards.Growth stage 9: physiological maturityWhen the kernel has reached its maximum drymass, a layer of black cells develops at the kernelbase. Grains are physiologically mature and onlythe moisture content must be reduced.Growth stage 10: drying of kernels(biological maturity)Although grains have reached physiological maturity,they must dry out before reaching biologicalmaturity. Under favourable conditions, dryingtakes place at approximately 5 % per week up tothe 20 % level, after which there is a slowdown.ADAPTATION AND PRODUCTION POTENTIALTotal yield on any farm is the product of climateand soil that can be regarded as the yieldpotential of that area.10
Climatic requirementsTemperatureMaize is a warm weather crop and is not grown inareas where the mean daily temperature is less than19 ºC or where the mean of the summer months isless than 23 ºC. Although the minimum temperaturefor germination is 10 ºC, germination will be fasterand less variable at soil temperatures of 16 to 18 ºC.At 20 ºC, maize should emerge within five to sixdays. The critical temperature detrimentally affecting yield is approximately 32 ºC. Frost can damagemaize at all growth stages and a frost-free periodof 120 to 140 days is required to prevent damage.While the growth point is below the soil surface,new leaves will form and frost damage will not betoo serious. Leaves of mature plants are easilydamaged by frost and grain filling can be adverselyaffected.WaterApproximately 10 to 16 kg of grain are produced forevery millimetre of water used. A yield of 3 152 kg/harequires between 350 and 450 mm of rain perannum. At maturity, each plant will have used 250 lof water in the absence of moisture stress.Soil requirementsThe most suitable soil for maize is one with agood effective depth, favourable morphologicalproperties, good internal drainage, an optimalmoisture regime, sufficient and balanced quantitiesof plant nutrients and chemical properties thatare favourable specifically for maize production.11
Although large-scale maize production takesplace on soils with a clay content of less than10 % (sandy soils) or in excess of 30 % (clay andclay-loam soils), the texture classes between10 and 30 % have air and moisture regimes thatare optimal for healthy maize production.Production potentialSeveral methods can be used to determine yieldpotential, each with its own limitations. One ofthe most reliable methods is long-term yield datacollected by each individual producer, as thisreflects inherent yield of the specific environment,as well as the effect of agronomic practices suchas fertilisation, soil cultivation and plant populationand managerial abilities of the producer.CULTURAL PRACTICESSoil tillageSoil tillage, particularly primary tillage, is thefoundation of any crop production system and isthe biggest cost factor in maize production.Effect of tillage practices on soilphysical propertiesSoil tillage in a farming system refers to thephysical soil cultivation practices, changing thesoil’s structure, hydraulic properties and stabilityto such an extent that plants will grow and produceoptimally.12
Soil physical properties affectedby tillageTexture and structureTexture refers to size of mineral soil particlesand is the single most important physical propertyof soil. It involves a ratio of sand, silt and clay ina specific soil. This ratio determines the capacityand strength of structures that are formed, aswell as ability to store water.The objective of soil tillage is to maintain theexisting structure of soil or to improve thestructure of poorly structured soil.Effect of tillage on soilInfiltration and evaporationThe most important processes affected by soiltillage include infiltration and evaporation ofwater. Because water availability during thegrowing season is the single most importantfactor in crop production in South Africa, it isessential that soil tillage be aimed at optimisinginfiltration and minimising evaporation.Germination and root growthGermination and root growth are affected bytillage methods in that the soil temperature canbe manipulated and evaporation reduced.ErosionThe type of tillage affects vulnerability of the soilto either wind or water erosion. Finely-structuredtopsoil is susceptible to both types of erosion,while a coarse structure limits erosion.13
Implements and soil tillageThe aims of soil tillage are weed control, incorporation of residue, reducing wind and water erosionand improving soil structure.Secondary tillage is applied to control weeds andprepare a seedbed.Primary implements are basic implements used toloosen the soil with the object of improvingstructure and countering compaction. Theseinclude mouldboard ploughs, disc ploughs, chiselploughs and rippers.Primary tillage implementsMouldboard ploughsThis implement is used to turn sods up to 300 mmdepth and is particularly useful on heavierwell-structured soils. Turning the soilalso has the advantage that weedseeds and unwanted crop residuescan be buried deeply. Mouldboardploughs are not recommended onsandy soils, because poorly-structuredunits which may exist, can be destroyedand wind erosion be promoted.Disc ploughs and discsThe disc plough has a slicing action with the mainadvantage that better penetration is obtained underdry, hard conditions, with an additional advantagethat wear is lower than in the case of a mouldboardplough. The implement is useful on hard, dry soilswhere loss of structure is not too critical. It is onno account recommended for sandy soils.14
Chisel ploughsChisel ploughs are used mainly to loosen the soilto a limited depth of 250 mm. Best results areobtained if the soil is relatively dry, because thechisels break the soil, creating structural units.If conditions are too dry, however, big clods areformed, restricting plant development.RippersRippers are used when deep cultivation is necessaryand turning of the soil is undesirable. If soils aretilled annually to the same depth, a plough-soledevelops. This confined layer prevents infiltrationand root development. To ensure better drainage,conservation and utilisation of water, it is essentialto break this layer regularly. Under wet, clayconditions, the main disadvantage of the ripper isthat it compacts the soil laterally and inwards,which can limit lateral root development.Secondary tillage implementsRotary tillerUnder ideal conditions, on moist clay soils, thisuseful implement can prepare the seedbed in oneoperation. On dry, sandy soils it can, however,destroy the structure within a very short period.15
Tined cultivatorsTined cultivators include a variety of hoeingimplements, which are used mainly for controllingyoung weeds, but also utilised for breaking surfacecrusts. These implements are only effective onmoist soils. They are completely ineffective on dry,clay soils. These implements are often used forseedbed preparation.HarrowsHarrows include a variety of implements. The tinedharrow is primarily used to level the seedbed onceit is in a fine condition. The primary objective ofthe disc harrow is to break surface crusts, but itcan be used to break clods to obtain a fineseedbed.Tillage systemsNo-tillWith this system, soil is left undisturbed fromplanting to harvesting. A prerequisite for thistype of cultivation is that 30 % of the soil mustbe covered with plant residue after planting toreduce water erosion effectively.Stubble-mulch tillageIn this case, soil is disturbed before plantingwithout burying or destroying. For this actionchisel ploughs, discs, spring-tooth implements orV-type blades are used. Weeds are controlledchemically and/or mechanically.16
TABLE 3. Major advantages and disadvantages of different No-till Lowest fuel consumption Higher application ofherbicide and intensiveherbicide managementnecessary Requires:– management inputs– special or adaptedplanters– more expensiveequipment Possible compaction ofsoil and accumulationof nutrients in topsoil Earlier occurrence ofleaf diseases Possible insect populations Quicker adaptation tooptimum planting date Lower machinery costs Best control of windand water erosionStubblemulching Fuel saving (comparedto ploughing) Good control/bettermanagement of:– wind and water erosion– soil compaction– weed control Soil preparation dependantpendent on spring rains Greater possibility ofleaf diseasesReducedtillage Greater fuel economy(than e.g. ploughing) Control of:– Wind erosion– Insect population Accumulation of nutrientsnot a problem Poor management ofwater erosion Better weed managementConventional Good weed andtillageinsect control Lowest management inputs17 Highest:– fuel consumption– machinery costs Waiting period for suitablesoil water No control of water andwind erosion
Reduced tillageThis could be any type of tillage practice whichleaves 15 to 30 % of the soil surface coveredwith stubble. Weeds are controlled chemically ormechanically.Conventional tillageThis includes tillage that leaves less than 15 % ofthe soil surface covered wit
DEPARTMENT: AGRICULTURE REPUBLIC OF SOUTH AFRICA. 2003 Compiled by Directorate Agricultural Information Services Department of Agriculture in cooperation with ARC-Grain Crops Institute Printed and published by the Department of Agriculture and obtainable from Resource Centre
Maize Farming Techniques Manual PART II: 5. Basic 5.1 V (C) Tasseling stage TECHNICAL Know ledge for Maize C arious stages of Maize plant (A) Seedling stage It is the initial stage of maize plant with 2-4 leaves after the emergence. It takes 1 plantation (B) Growth stage of maize
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Directorate Marketing Tel: 012 319 8456 Private Bag X 15 Fax: 012 319 8131 . Yellow maize is mostly used for animal feed production while white maize is primarily produced for human consumption. Maize is the second largest produced crop in South Africa after sugar cane. The maize industry is important to the economy both
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The Current Status of Maize Diseases in Brazil Fernando T. Fernandes1 EMBRAPA - Centro Nacional De Pesquisa, De Milho E Sorgo Caixa Postal 151 35701-970 Sete Lagoas, MG, Brazil 1 Fernandes, F.T. 1998. The Current Status of Maize Diseases in Brazil. In Diagnosing Maize Diseases in Latin America (Eds. C. Casela, R. Renfro and A.F. Krattiger).
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within the global context, we recommend the formulation of a maize sector export strategy that focuses on increasing the competitiveness of maize exports, and market development. Keywords: growth-share matrix, trade potential, strategic markets 1 International Trade and Investment Manager: The Agricultural Business Chamber. PO Box 76297, Lynnwood
