Maize cul­ti­va­tion, sow­ing and plant­i­ng den­si­ty – key factors!

Maize cul­ti­va­tion is increas­ing steadi­ly around the globe. This is due in part to ris­ing ener­gy yields and con­cen­tra­tions. As a result of cli­mate change, maize is now being sown ear­li­er and ear­li­er, in some regions as ear­ly as mid-April. It is pos­si­ble to drill maize with care in ear­ly dry peri­ods, with the resid­ual mois­ture ensur­ing a secure field emergence.

Com­pared to oth­er crops, maize has numer­ous advan­tages from a cul­ti­va­tion point of view: high self-com­pat­i­bil­i­ty and sta­bil­i­ty, good mech­a­ni­sa­tion options as well as high ener­gy yields and high tol­er­ance of fer­til­i­sa­tion cou­pled with low soil needs and low seed require­ments. There are also some dis­ad­van­tages to keep in mind: the small num­ber of plants per m³, wide row spac­ing and high heat require­ments as well as a late sow­ing time and late ground cov­er, a short veg­e­ta­tion time, late har­vest when using farm-saved seed, and weed selec­tiv­i­ty, all of which must be tak­en into con­sid­er­a­tion in the cul­ti­va­tion strategy.

Maize cul­ti­va­tion and site conditions

In maize cul­ti­va­tion, tem­per­a­ture, water sup­ply and soil are all of cru­cial impor­tance and are close­ly interlinked.

Tem­per­a­ture

The accu­mu­lat­ed tem­per­a­ture is an impor­tant fac­tor for mat­u­ra­tion and yield devel­op­ment; in maize cul­ti­va­tion, a soil tem­per­a­ture of 8–10 °C is required for ger­mi­na­tion. Tem­per­a­tures of 10 °C and above are nec­es­sary for ear­ly devel­op­ment. At the same time, dai­ly aver­age tem­per­a­tures below 10 °C can hin­der the devel­op­ment of the maize plants. This leads to chlorot­ic leaf dis­coloura­tion, fol­lowed by dimin­ished assim­i­la­tion capac­i­ty and reduced nutri­ent absorp­tion. Late frosts of below ‑3 °C can lead to a freez­ing of the leaves or even the actu­al growth points. The lat­ter would make it nec­es­sary to re-sow the crop.

Water sup­ply

As a C4 plant, maize has low water require­ments, which can be as lit­tle as 6 mm/m² per day in the sum­mer months of July and August. Thus, maize offers low tran­spi­ra­tion coef­fi­cients. How­ev­er, a lack of water inhibits growth and cob for­ma­tion. In com­bi­na­tion with heat, this leads to low pol­li­na­tion. Water defi­cien­cy after pol­li­na­tion pre­vents the assim­i­la­tion or redis­tri­b­u­tion of assim­i­lates to the cobs.

Soil

Maize has low soil require­ments, but plant growth and devel­op­ment are bet­ter in warmer cul­ti­va­tion regions. In addi­tion, humus-rich soils with a sta­ble crumb struc­ture and suf­fi­cient water and nutri­ent stor­age capac­i­ty are advan­ta­geous. Nonethe­less, good maize yields can still be achieved on sites with less favourable soil conditions.

Maize sow­ing

Maize sow­ing is all about tim­ing. Sow­ing too ear­ly can lead to poor­er and delayed ger­mi­na­tion and irreg­u­lar field emer­gence. In addi­tion, the crop pro­tec­tion can be reduced and the root growth inhib­it­ed. This then leads to a low­er nutri­ent intake. On the oth­er hand, late sow­ing can lead to a lack of mat­u­ra­tion as well as qual­i­ty loss­es and struc­tur­al dam­age. Thus, exces­sive­ly warm soil pro­motes rapid ger­mi­na­tion and ear­ly devel­op­ment. Longer days increase the length growth, which leads to a high­er ear shoot. Over­all, the veg­e­ta­tion time can­not be opti­mal­ly used. This results in insuf­fi­cient starch deposits and may lead to low­er qual­i­ty in silage maize, for example.

When it comes to till­ing, the tim­ing is also cru­cial. The soil should end up loose and crumbly. Spring till­ing mea­sures are designed to pro­mote the warm­ing of the seed bed and the removal of excess water. The most promis­ing maize sow­ing is car­ried out after soil-friend­ly manure fer­til­i­sa­tion and till­ing. In the process, the basic till­ing can be done after the pre­vi­ous crop has been har­vest­ed and pre­served through intercropping.

The qual­i­ty of the maize sow­ing has a cru­cial impact on yield. Pre­ci­sion seed­ing and sow­ing den­si­ty are key fac­tors in plant devel­op­ment, cob for­ma­tion and har­vest yields. In addi­tion to the sow­ing time, sow­ing depth is also sig­nif­i­cant for the yield, requir­ing pre­cise place­ment with­out gaps or dou­ble occu­pan­cy. Light­weight soils require a place­ment depth of up to 6 cm and heavy soils up to 4 cm, so that the seeds are locat­ed near the water-bear­ing soil lay­ers and are able to ger­mi­nate. </text4>

Maize plant­i­ng density

As well as site and sow­ing con­di­tions, suc­cess­ful maize pro­duc­tion depends on the num­ber of plants per m², accord­ing to the vari­ety. This indi­ca­tor is based on both water avail­abil­i­ty and the spe­cif­ic vari­ety. When these are per­fect­ly aligned, the genet­ic per­for­mance poten­tial of the maize vari­ety can be exploit­ed to the full. Rec­om­mend­ed plant­i­ng den­si­ties range between 6 and 12 plants/m², depend­ing on the vari­ety. Thus, a high­er plant­i­ng den­si­ty should be select­ed for ear­ly-ripen­ing vari­eties. The seed require­ment can be cal­cu­lat­ed based on the desired plant count and indi­vid­ual site fac­tors. The num­ber of seeds to be sown should be high­er than the planned stock den­si­ty in the event of unfavourable site con­di­tions, pest infes­ta­tion or bird dam­age. How­ev­er, the num­ber of seeds to be sown should be select­ed to avoid exces­sive plant­i­ng den­si­ty, where­by any lack of water could result in increas­ing com­pe­ti­tion for water and nutri­ents, reduced length growth, reduced cob devel­op­ment and rapid mat­u­ra­tion. In con­trast, exces­sive plant­i­ng den­si­ty with good water avail­abil­i­ty can lead to increased com­pe­ti­tion for light, increased veg­e­ta­tive growth, inhib­it­ed cob devel­op­ment and poor­er maturation.