Growth slowly returning
With the long-term weather forecast looking increasingly favourable and soil temperatures slowly beginning to climb it feels like time to turn our thoughts to crop nutrition. As soil temperatures approach 4-5 C we will begin to see growth return to over-wintered crops and with that a significant increase in demand for available nutrition. Most agronomists and growers will no doubt already have spent a great deal of time and effort devising detailed planning and application strategies for the seasons N, P, K, and Sulphur fertilisers but why do we fail to devote such critical consideration to the other essential nutrients? after-all the deficiency of any single nutrient has the potential to limit crop yield… this is simply and effectively demonstrated by Liebig’s barrel, his “Law of the minimum theory” states that crop growth will be limited by the essential nutrient found in least supply.
Detailed soil analysis
The balanced supply of essential nutrients is fundamental to efficient crop growth so if we wait for visual crop deficiency symptoms to show, we have already compromised potential yield. The best investment a grower can make is to carry out routine broad-spectrum soil and tissue analysis. Depending on cropping type, soil sampling may be sufficient every 3 years for an arable grower but more frequent analysis is advised where horticultural crops are included in the rotation. Saving a pound or so per hectare by opting for a basic P, K, Mg and pH soil package over the full soil plus micro-nutrient package is always false economy as the potential yield losses far outweigh the upfront savings. Berkshire agronomy offer a broad-spectrum Nutrient planning service where we incorporate a full detailed soil analysis and evaluation then construct the appropriate macro and micro nutrient application programmes for you. Knowing your soils full capabilities is essential to help make the most efficient informed agronomic decisions.
Trials show substantial yield gains from micro-nutrient inputs
Manganese is a key component in chlorophyll, essential for photosynthesis, protein synthesis and efficient nitrogen utilisation. Manganese is often deficient on calcareous, alkaline or acidic soils or in situations high in organic matter. High phosphate or loose poorly drained soils may also limit nutrient availability.
Our trials on a marginally manganese deficient site demonstrated that a programmed micro-nutrient plan applying 500g/ha Mn at the T0 timing and repeated with T1 applications increased winter wheat yields by 0.15 – 0.20 t/ha, further yield enhancement can be achieved from applying manganese seed treatments to cereals grown on deficient soils.
Zinc is required in many enzyme functions including photosynthesis, synthesis of nucleic acids, and is essential in cell division and seed production zinc levels are also critical during seedling germination. Zinc is often deficient on calcareous, alkaline or sandy soils, high phosphate and high OM may also limit availability. Min-till systems on zinc deficient soils could be particularly at risk from inadequate supply during seedling emergence.
On marginally deficient soil, winter wheat crops where zinc seed treatments were applied have consistently delivered increases of 0.4 to 0.55 t/ha over untreated from resulting increased root mass which in turn promoted greater photosynthetic activity. For winter wheat on a marginally deficient soil 80-100g/ha foliar applied zinc at an early stem extension timing (T1) can improve nutrient use efficiency during this rapid growth phase.
Green wheeling’s in cereals… a classic symptom of Manganese deficiency exacerbated by inconsistent seedbed consolidation. Often seen as a transient symptom becoming visual as soils warm up in spring however, this crop’s full potential is already being compromised due to it’s reduced photosynthetic capacity. Deficiency can be alleviated by appropriately timed foliar applications; but we must take a step back and consider the underlying problems of soil structure, cultivations and field traffic. Berkshire agronomy provide advice on soil management practices through our Soil evaluation package.
Follow up with tissue analysis
Testing leaf tissue samples in a growing crop allows us to monitor current nutrient levels in the plant. As part of our Nutrient planning service Berkshire agronomy advise taking initial tissue samples from winter cereal crops in early to mid-March which will allow us to tailor micro-nutrient applications with T1 sprays. A second sample should then be taken from the same field a couple of weeks prior to T2 this will determine how the plant has taken up the applied nutrients whilst also retaining some continuity in the analysis for comparison of results. By capturing comparable data, we can analyse and use this to our advantage to enable more efficient crop management decisions in the future.