The 2022 heatwave highlighted maize resilience. Despite difficult weather conditions, yields were quite impressive, therefore reaffirming maize relevance in crop rotation. However, the risk of scalds prompts us to reconsider our technical approach. This includes earlier sowing and selecting varieties with shorter maturation periods.
Sébastien Moureau, marketing director at Corteva Agriscience, underlines the role of genetics in providing varieties that better adapt to current water and environmental constraints. He adds, however, that seeds are just one aspect of maize competitiveness.
Jean-Luc Demars, maize market manager at KWS, agrees, stating that though genetics have made progress, they alone cannot fully enhance maize performance. While they do reveal significant varietal differences, they are not the only solution to stress management. “Seeds companies assert that to maximize crop margins, it is imperative not to solely rely on variety productivity,” argues Jean-Luc Demars.
Moving towards an earlier earliness group, from G2 to G1 or even G0, which includes ultra-early varieties, could be a good strategic move. The aim is to advance flowering, postpone water requirements and enable an earlier, drier harvest, consequently reducing drying costs.
Adapting sowing dates and earliness groups
"In regions where water scarcity cannot be offset by irrigation, advancing maize sowing dates and opting for earlier varieties offer interesting techniques for sowing under favorable conditions," Justine Sourisseau, director of the Grceta-sfa, explains.
Thomas Joly, maize sector coordinator at Arvalis, said that "this aims to achieve flowering two to three weeks earlier, ensuring that this critical stage occur under optimal circumstances. Early sowing is a good strategy to avoid hot weather and mitigate water stress during the crucial flowering phase in the maize cycle". Conversely, late sowing exposes the plant to periods of water stress earlier.
But early sowing may not be suitable for all regions. The soil might not be adequately warm, leading to slower emergence and exposing seeds to inclement weather and opportunistic pests. Joly stresses the importance of considering the environment in which the plants will grow.
It is crucial to assess the temperature requirements for each phase of the cycle in different regions. “The choice of earliness group will therefore depend on the desired sowing and harvesting date,” indicates Joly, who believes that the earlier varieties are suited to tough environments or to situations where it is difficult to make other types of crops grow.
He points out that "these early varieties require a good command of sowing techniques, to avoid taking on too much risk". Sourisseau adds: "We are increasingly considering this criterion of varietal earliness, even in areas without water problem. To maximize crop yield, we need to adapt the variety and quantify the inputs according to the potential of the plot and the variety, so that the crop remains economically profitable.”
Ensuring rapid emergence and growth
Vigor from emergence to weaning is also a criterion to consider. “We need to find the right compromise to ensure that the maize grows dynamically up to the six to eight leaf stage, a physiological period when the ear is in the process of initiation," warns Joly. This stage should not coincide with any late frost at the end of may.
Ensuring rapid, uniform emergence is vital, and localizing fertilizer before sowing can facilitate this. Properly nourished plants are more robust. Soil analyses are crucial for optimizing plant nutrition. Sourisseau advizes against sowing too densely to minimize competition for nutrients and water. "The aim is still to optimize the varietal potential by sowing at the right density, especially if conditions are limiting (hydric and/or thermal stress, light soil, low useful reserves, etc.)." Joly also points out that "the density should be adapted to the soil and climate context, striking a balance between resource availability and favorable conditions".
Early sowing reduces drying costs
Early sowing aligns with an earlier harvest date and dry conditions, reducing costs. “In the current scenario of high gas prices, this is a significant economic element,” says Sourisseau.
Without irrigation, she recommends favoring varieties with balanced yield components, capable of a lot of grains per ear. “In fact, the more the plant is subject to climatic ups and downs, the less value it will place on high Gmp. Yield is certainly a good indication of a variety performance, but it is not the only component of the crop margin. Margins vary according to the level of costs and the selling price," she explains. Joly adds: "The choice of variety also depends on the maize market price. At €150/t, it is better to grow early to reduce drying costs. At €300/t, you would be better off going later, as the last quintal will offset the drying costs."
"Whatever the case, i recommend that farmers spread the risk by staggering sowing dates and selecting varieties with different earliness indices, based on multi-year performance", Demars concludes.