Agrii Events News
February 15, 2013
Intensive Nutritional Care for Struggling Crops
Thin crops of small plants in cold, waterlogged soils will need intensive nutritional care this spring to help them recover from one of the most challenging establishment seasons in recent memory, Bishop Burton conference goers were warned.
Speaking at well-attended morning and afternoon crop management clinics at the event, senior Yorkshire-based Agrii agronomist, Philip Marr stressed that experience from similarly difficult seasons like 2000/1 shows that backward winter cereals and oilseed rape can deliver handsomely with the right agronomy. However, he pointed out that the difference between the best managed crops and the average is invariably much greater under these conditions.
“The natural near-surface compaction of soils we’ve experienced under the sheer weight of this season’s rainfall has been unbelievable,” he observed. “This and very cold soil temperatures from late September have meant slow crop development and generally poor rooting.
“So we’re coming into the spring with far fewer roots at depth than we’d like and poorly drained soils with little air or biological activity in the root zone. Interestingly, though, our early N-Min readings are surprisingly high – presumably because water flow and nutrient leaching through the profile have been restricted by the natural soil compaction. So the nitrogen is sitting there. We just have to get the roots to it.”
Under these circumstances, Philip Marr insists that the first priority this spring must be to get early nutrients into both cereals and OSR from the top. This will stimulate root proliferation which will assist in opening-up soils as well as allowing crops to access soil-applied fertilisers.
“The limited mobility of key nutrients in the soil – especially under cold, wet conditions – means they are only accessible to crop root hairs within a very restricted range,” he explained. “The phosphate that is critical to support both root development and early spring growth, for instance, can, at best, only be accessed from within a few millimetres. And under waterlogged conditions it can be completely unavailable.
“This means early dressings of nitrogen and sulphur will be of limited value unless you can get sufficient phosphate into your crops. Which is why an early foliar application of Nutriphite PGA will be so important this season. Our studies show it can markedly increase rooting and early crop growth, providing just the kick start backward crops in waterlogged soils need to enable them to make the most of soil-applied fertilisers.
“Once you’ve got your crop away, little and often N+S will be the order of the day,” continued Philip Marr. “Large amounts of early fertiliser will be a waste with thin crops and cold, wet ground. So in many cases I’d be limiting the first application to around 50kg N/ha and going back with the same again in 10 days and then again 10 days later.
“Where phosphate availability is a problem Avail fertiliser treatment is also well worth considering. It protects the applied phosphate from being locked-up and has been shown to give a major boost to rooting and crop performance.
“Pay particular attention to micro-nutrition too this spring, “Philip Marr added. “Making the most of backward crops depends on doing everything possible to avoid any limitation to their growth and development. Maintaining the right balance of manganese, magnesium, copper and zinc in cereals and manganese, magnesium, boron and molybdenum in oilseed rape will be especially critical.
“And don’t forget plant growth regulation either. Early applications of Adjust or Meteor can work wonders for root development and tillering in cereals. Equally, it will be crucial to manage both cereal and OSR canopies to minimise the strain placed on seriously limited root systems.”