American author/consultant, Gary Zimmer, has made an important contribution to high-production agriculture with his book “The Biological Farmer”. The book summarises thirty years of research and practical experience and includes several new findings not previously considered in this arena. Perhaps the most significant of these relates to the efficiency and performance of calcium – the king of all nutrients.
Calcium often considered a mere pH modifier in conventional agronomy is in fact the key to nutrient uptake. Calcium is the trucker of all minerals and it is not possible to achieve maximum yield and quality in the absence of this keystone nutrient. Calcium sources like lime are generally evaluated in terms of three criteria: neutralising value, calcium content and particle size. The higher the neutralising value and calcium content and the finer the particle size, the better the product.
Gary Zimmer’s background as a dairy nutritionist has predisposed him toward intense scrutiny of plant analysis data in relation to soil inputs. Gary has fervently sought the best techniques to build the nutrient value of forage as he is convinced that this should be the primary livestock food source instead of the cereal grains currently dominating livestock cuisine. In the process he has cross-referenced tens of thousands of leaf analysis with soil nutrition inputs. This research has consistently confirmed the king-pin role of calcium in the nutrient equation.While working in the potato industry and utilising these same cross-referencing skills, Gary identified a tremendous variation in overall nutrient uptake based upon the type of calcium input involved. He found when comparing ag-lime, gypsum and calcium nitrate that 100 kg of calcium nitrate provided a far more pronounced calcium response than 1 tonne of lime or a similar amount of gypsum. One tonne of lime contained 400 kg of calcium, the gypsum 200 kg, and the calcium nitrate contained just 20 kg. He reasoned that the difference in performance may be based upon the solubility of calcium. Lime and gypsum had never previously been evaluated in terms of solubility. Utilising industrial tests from the cement industry, Gary was able to test the calcium solubility of these materials for the first time. The findings were something of a revelation. Gypsum contained just 15 kg of soluble calcium per tonne, and ag-lime a paltry 5 kg per tonne. Obviously the insoluble calcium content in both products would slowly solublise over time, but if you need calcium in your soil then you need it now and not in two years time. Gary Zimmer saw the opportunity to manage calcium nutrition with a combination of slow-release and soluble inputs in much the same way that his company, Mid-Western BioAg manages all other nutrients.
Calcium nitrate was simply too expensive for a major soluble boost (although it has an important role to play in fine-tuning via fertigation and foliar feeding). A lime source with much higher solubility was required. Two hundred and twenty years previously, President George Washington had kickstarted American agricultural production with wide-scale application of lime. However, his great successes were not based upon limestone (calcium carbonate) but burnt lime (calcium hydroxide). The carbon in calcium carbonate is the material which fuels the burning process. Burnt lime or calcium hydroxide is 30 times more soluble than calcium carbonate (limestone) but there is an application problem with the harsh alkalinity of the material.
Mid-Western BioAg have developed a dry hydroxide based soluble calcium fertiliser called Bio-Cal, which is buffered by sulfur and boosted with boron. This product has been tremendously successful for the company in the US and during his recent Australian tour Gary showed several leaf analysis comparisons illustrating the improved nutrient uptake associated with Bio-Cal vs lime or gypsum. Phosphate showed the most dramatic level increased. In one example involving a 30,000-acre potato farm, dry soluble calcium substantially outperformed heavy phosphorus inputs in terms of lifting phosphate in the leaf.
Nutri-Cal™ – Soluble Calcium
With a host of ‘fast food’ extras
Nutri-Tech Solutions market a calcium hydroxide based dry fertiliser which is very similar to Gary Zimmer’s Bio-Cal. Nutri-Cal Dry Soluble is a treated ash-based concentrate comprising calcium, boron, magnesium, sulfur, silica, iron and humates. One tonne of Nutri-Cal Dry Soluble is produced from the firing of twenty tonnes of humates. Calcium borate and humates are added during the curing process. The ‘fast food’ calcium content comprises around 19%, magnesium 7.5%, sulfur 5%, silica 12% and humic acid 6%. There has been a growing international focus upon silica in recent years following impressive results with this element in the Cuban sugarcane industry.
The Silica Surprise Package
Very few agronomists would consider the addition of silica in a soil and plant nutrition program, and yet soluble silica (monsilicic acid) is a proven essential for maximum yield of several crops. Silica is an essential nutrient for rice, for example, where the straw contains up to 15% SiO2. Pasture grasses, sugarcane, wheat, barley, sorghum, oats, sunflower, tomatoes, cucurbits and several root crops have been the focus of research reporting improved growth and yield, and the research continues.
Silica has a surprisingly large number of functions in plants, including the following:
** 1.** The strengthening of epidermal cells in leaves and stems.
** 2.** It is an important constituent of DNA and RNA, ie. Silica deficiency decreases the synthesis of proteins and chlorophyll.
** 3.** Decreasing toxicity. Silica regulates the plants uptake or iron, manganese and aluminium. The infamous toxicity of these elements in acid soils can be counteracted with soluble silica.
** 4.** Water balance. Low silica content increases the transpiration rate (water loss through leaves) creating poor water-use efficiency.
** 5.** Improved plant growth and yield. Published research catalogues increased root growth in grasses, spectacular yield increases for cucumbers (1500% in one study), 30% to 50% increases in cane ??, and substantial increased yield in beets.
** 6.** Increased rates of photosynthesis partially due to stronger stems producing more erect leaves, which capture more sunlight.
** 7.** Improved reproduction. Studies have found enhanced pollination in tomatoes and better pllen fertility in cucurbits.
Nutri-Cal Dry Soluble contains 120 kgs of highly available silicate in every tonne. NTS also produce a liquid silica foliar fertiliser based upon potassium silicate called Photo-Finish™, which can offer many of the above benefits including improved photosynthesis.