Cereal growers are being encouraged to review their crop nutrition programs to ensure they include sufficient calcium. Dr Katharina Koetting, Director Innovation and Technical Marketing Agriculture for Omya, says “calcium is a vital nutrient for high yielding cereal crops, ensuring sufficient calcium in cereal crop for productivity and guaranteeing a calcium rich cereal relevant for both growers and consumers”.
“Calcium is a key component of plant cell walls and membranes,” she explains. “Proper calcium nutrition in crops helps plants maintain cell wall integrity, which gives it structural strength. Cereal crops must be able to support their own weight, especially during grain fill when heads become heavy. Lack of calcium in cereals causes weakening of plant stems increasing the risk of lodging, making harvest difficult and contributing to lower yields. Calcium improves grain fill and seed development which results in higher yields and better grain quality. A continuous supply of calcium throughout the growing season helps plants to withstand adverse weather conditions as well as making them more resilient to pests and disease.”
Calcium plays a crucial role in the growth, development, and overall health of cereal crops. As growers focus on maximizing yield and improving crop quality, understanding the importance of calcium in cereal cultivation can provide a significant edge.
The role of calcium in plant growth
Calcium is not just essential for structural integrity. It is responsible for critical functions in the plant, including activating enzymes in metabolic processes for nutrient uptake, photosynthesis and energy transfer. Calcium controls the elongation of cells, which is necessary for the development of long roots to ensure plants can access sufficient nutrients. It also balances negative charges in the cell and acts as a messenger molecule, facilitating communication between plant cells.
“The other area in which calcium plays an important role,” says Dr Koetting,” is in the plant’s stress response. Abiotic stress presents a significant challenge to growers, whether from heat, drought or excess water. Maintaining optimal calcium levels in plants allows crops to better respond to abiotic stress and enables plants to recover from damage more quickly.”
Calcium deficiency in cereal crops
Calcium is taken up by the roots from the soil and transported with the transpiration stream to the plant’s growing tips. Once incorporated in a cell, calcium is immobile which means it cannot be easily relocated to other parts of the plant. For this reason, calcium deficiency is typically noticed first in new growth and young tissues, which are more vulnerable to nutrient shortfalls. Sufficient calcium nutrition is essential for promoting plant health and resilience. Crops deficient in calcium are more likely to release exudates which attract pathogens and are more susceptible to diseases. Dr Koetting says calcium deficiency is sometimes hard to identify until it is too late. “Whilst deficiency may cause stunted growth, especially in younger plants, you won’t necessarily notice the effect on the crop until you start seeing lodging or increased susceptibility to fungal diseases. Lack of calcium causes poor root development and therefore reduced nutrient uptake, which has a significant impact on yields at harvest.”
Soil factors affecting calcium availability
The soil’s capacity to retain calcium depends on the soil type and the cation exchange capacity (CEC). Sandy soils, which are coarse textured and have low organic matter, with a low CEC are more likely to leach calcium, reducing the supply to the crop. In contrast, clay soils, which are fine textured, retain more calcium but may release it more slowly. Soils rich in organic matter with a high CEC are less likely to leach calcium because of their higher water holding capacity. Another factor that significantly impacts calcium availability is soil pH. In acidic soils, soils with a low pH, calcium ions are easily leached away due to rainfall or irrigation, leaving plants deficient of this nutrient. In cases of alkaline soils calcium is abundant but is less available to the crop because it is insoluble, which limits its uptake by plants. Correcting and managing soil pH is important and growers are advised to maintain their soil pH at optimal levels.
The impact of calcium on soil health
In addition to its direct impact on plant health, calcium is essential for maintaining a healthy soil structure. Calcium ions which bind to the clay humic complex help to improve soil flocculation, promoting better aeration, water infiltration, and root penetration. Healthy soil structure also helps reduce soil compaction, a common issue in intensive farming practices.
Calcium sources for cereal crops
Whilst there are several options for growers wishing to add calcium to their crop nutrition programs, Dr Koetting says the choice of calcium source depends on the specific needs of the soil, crop and growing conditions. “Before applying calcium, it is recommended to conduct a soil testing to determine the soil pH and the current levels of calcium. This will help identify what type of amendment and or fertilizer needs to be used for calcium nutrition. If soil pH is low, then the acidity needs to be corrected to enable the crops to make best use of nutrients including calcium nutrition. In this instance calcium carbonate would be the most appropriate recommendation. However, if your soil does not need pH adjustment, then calcium sulfate or gypsum would be a more suitable solution for calcium nutrition.”
Omya has developed a range of granulated products which are ideal for cereal growers wishing to boost their calcium nutrition. Where soil pH amendment together with calcium nutrition are required, applying Omya Calciprill is ideal. Omya Calciprill are granules made from micronized calcium carbonate, which dissolve and disperse rapidly into the soil when exposed to moisture. The carbonate reacts with the soil acidity to improve pH within a short time, whilst the calcium ions bind to the CEC to provide readily available calcium for the crop.
In situations where no pH soil adjustment is required, Omya Sulfoprill can be applied. Omya Sulfoprill is a micronized calcium sulfate material which is a source of calcium and in addition contains sulfur which is also important for crop health and support nitrogen plant uptake. As Dr Koetting concludes, calcium is a critical yet often underappreciated nutrient for cereal crops. “It is vital to provide sufficient calcium for high yielding cereal crops. The advantage of using Omya Calciprill or Omya Sulfoprill is that growers can apply the granules using their standard equipment, applications can be done before or during plant growth. Calcium together with other nutrients should be part of every crop program to raise cereal productivity.”