Top Crop Manager

Top Crop Manager
Triticale: Poised for the future

Triticale: Poised for the future

With the wrap up of the Canadian Triticale Biorefinery Initiative (CTBI), growers and industry are investigating innovative ways to move triticale forward.

Compromising borders

Compromising borders

Insect invaders and windborne diseases are common foes of the average farmer but invasive weeds usually don’t take centre stage. Expect that to change.

Dicamba-tolerant soybean moving forward

Dicamba-tolerant soybean moving forward

Soybean growers will have to wait another year or two before they have the option of using a soybean cultivar that is resistant to both glyphosate and dicamba.

Genetics of nitrogen use efficiency

Genetics of nitrogen use efficiency

Developing corn hybrids with improved nitrogen use efficiency – whether they have higher yields under normal nitrogen levels or maintain their yields despite low nitrogen levels – is a significant challenge.

Australia’s fight against herbicide resistance

Australia’s fight against herbicide resistance

In Australia, the development of multiple herbicide resistance has been the catalyst for the development of new agronomic practices.

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North American Manure Expo comes to Canada...
For the first time ever, the North American Manure Expo is being hosted within a Canadian province. The annual show is being held August 20 and 21, 2013, at the University of Guelph’s Arkell Research Station, located near Guelph, Ontario. So, what's a Manure Expo and why should you attend? This video will provide all the dirt.
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Expert Dr. Susan Watkins discusses Water Sanitatio...
Expert Dr. Susan Watkins discusses Water Sanitation
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The population explosion...
With the world's population increasing exponentially and farmland staying the same, BASF took to the streets to ask consumers if this trend is sustainable.
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Lily Tamburic...
Lily Tamburic

Seed/Chemical

Liquid or granular, the type of P fertilizer applied does not affect plant availability of P. All phosphate fertilizer forms perform the same

Monoammonium phosphate (MAP), ammonium polyphosphate (APF) and orthophosphate (OP).  These commonly used inorganic phosphate fertilizers are used to meet nutrient demand for crop growth, but are there differences in soil solubility and plant availability? Not according to research from the University of Manitoba (U of M). “In the experiment, what we saw was that within a few days, differences in solubility and plant available P became insignificant,” says soil scientist Rigas Karamanos at Calgary who collaborated on the research with Tee Boon Goh with the department of soil science at the U of M, and John Lee with Agvise Laboratories at Northwood, N.D. Phosphorus (P) is absorbed by plants largely as the primary and secondary orthophosphate ions, H2PO4- and HPO42-, which are present in soil solution. The orthophosphate forms are soluble in the pH range found in agricultural soils from pH 5.0 to pH 9. The concentration of these ions in soil solution, and the ongoing concentration in soil solution are of the greatest importance for plant uptake of P. Granular phosphate fertilizer dissolves slowly in soil solution and converts to orthophosphate forms, but the latter react quickly in soils to form secondary phosphate compounds with calcium (Ca), iron (Fe) and aluminum (Al), becoming insoluble over time. Liquid P fertilizer formulations that combine sparingly soluble orthophosphates and more soluble phosphates such as P2O74-, were theorized to be more available because they do not require dissolving in soil solution. However, P2O74- must still convert to orthophosphate for plant uptake. To address this theory, the researchers investigated the impact of fertilizer formulation on short-term solubility and plant availability. Three soils, four fertilizers and one unfertilized controlThree soils of similar texture, organic matter and “available” P level were selected for use in the greenhouse trial. One was acidic and two were alkaline (one non-calcareous and one calcareous).  Four fertilizer formulations were applied; a MAP (11-52-0), an ammonium polyphosphate (10-34-0) and two ammonium orthophosphates (6-24-6 and 9-18-9), at a rate of 100 ppm. All treatments were replicated four times. The fertilizer was physically injected into the soils. The soil water was kept at nearly field capacity throughout the experiment. Samples were assayed for water soluble (orthophosphate) and “available” P (Olsen method) immediately after application (zero days) and at one, two, four, eight, 16 and 32 days after application. No differences after two to four daysKaramanos says that the trends for all three soils were similar. Water soluble and available P levels were significantly different immediately following application of the fertilizer products. However, the differences were not significant after two to four days. Specifically, the three liquid fertilizers had significantly higher (P<0.05) water solubility than the granular 11-52-0 fertilizer in the acid soil until day 2; the 9-19-9 liquid fertilizer had significantly higher water solubility than all the other fertilizers until day 2. In alkaline soils, Karamanos explains that the P converted to less soluble Ca and Mg compounds producing the same trends, except that the 9-18-9 maintained higher water soluble P values until day 4 in the non-calcareous soils. Looking at plant available P using the bicarbonate extractable P method, the trends were the same, with higher plant available P from the liquid fertilizers in the first two to four days, and then non-significant differences after that. Differences in the first few days were widest in the non-calcareous soils and narrower for the slightly acidic soil, reflecting the limitation of the bicarbonate extractable P method in acidic soils. When phosphate fertilizer is applied at time of seeding, either side-banded or seed-placed, the differences in short term P availability observed by the researchers would not make a difference to P uptake by a crop. Plants would not start to take up P from the soil until well after the two to four day period after planting when the fertilizer formulations differences become insignificant. Time of emergence after seeding depends on the crop and soil temperatures. Generally, research in Western Canada has shown that even under optimum conditions, the earliest a crop typically emerges is in four days, but for most crops under cool soil conditions, emergence is typically more in the six- to 10-day range. Additionally, research has shown that P uptake by plant roots does not start until approximately 10 days after seeding. Other research in Western Canada has confirmed that P uptake and accumulation in cereals happens at the tillering to stem elongation stage between approximately 22 and 36 days after seeding. In canola, Karamanos did a study monitoring nutrient uptake in hybrid canola and found that measurable biomass and nutrient accumulation did not start until the third week after seeding. He says the biomass accumulation in the third week averaged one pound per acre per day, and the P uptake was 0.0 to 0.1 pounds P per acre per day. “What the research is telling us is that the type of phosphate fertilizer formulation applied does not have any impact on long term solubility or plant availability and uptake of P. The soil-P interactions control P uptake and not the formulation of fertilizer applied,” says Karamanos. Further, Karamanos cautions that no matter the formulation applied, phosphate fertilizer needs to be applied at rates that will ensure the long-term sustainability of P fertility in the soil. Cutting P fertilizer rates because a fertilizer is thought to have better solubility and plant availability will lead to nutrient deficiencies over the long term. “Soil test using a recognized and calibrated soil test for your area, and apply adequate amounts of phosphate to maintain soil fertility,” he advises.      

Agronomy

Solid seeded bean trial at Bow Island, Alta., comparing nitrogen fertilizer application with and without rhizobium inoculation. Fertilizing irrigated dry beans

Dry beans yield very well under irrigation, providing excellent economic returns when grown in the Brown soil zone of southern Alberta. Benefits to including beans in a crop rotation include reduced nitrogen fertilizer requirements compared to cereal and oilseed crops, greater residual soil nitrogen levels for subsequent crops and more diverse crop rotations. To achieve optimum bean production specific fertilizer management is required. Soil sampling and testing: This gives a good inventory of soil nutrient levels and provides the basis for recommending additional nutrients on an individual field basis. Ideally, samples should be taken at zero- to six- and six- to 12-inch depths from at least 20 locations within a uniform field and then bulked into composite samples. Inoculant: Beans are a legume crop but only fix about 30 to 50 per cent of their total nitrogen (N) requirements. The remaining N comes from mineralization of soil N and from N fertilizer. When beans are properly inoculated with Rhizobium phaseoli bacteria, the bacteria infect bean roots and form nodules on the roots which fix N from the air. Inoculants come in powdered, granular or liquid form. It takes three to five weeks after seeding for the bacteria to infect plant roots, form nodules and start fixing N. Nodules that are reddish or pink inside indicate the bacteria are functioning and fixing N. Nodules are likely not fixing N when they appear white, grey or greenish when cut in half. Alberta research has shown that response to inoculant is not consistent in increasing bean yield. Generally, yield benefit of inoculation will range from two to 12 per cent. The benefit of inoculation tends to be reduced when fields that have had a history of inoculant use from past bean production results in a build-up of rhizobia bacteria in the soil. Nitrogen (N): When growing beans in soil testing less than 80 to 100 lbs. of N/ac in the zero- to 12-inch depth, additional N fertilizer is often beneficial to achieve optimum yield. In a cool spring, when nodules are slow to develop, plants may not be able to obtain sufficient N from the soil, resulting in deficiency and delayed crop growth. Therefore, in soils deficient in soil N, a modest application of N fertilizer can be a good investment. Alberta research shows that optimum bean production is generally achieved when the soil N in the zero- to 12-inch depth plus fertilizer N total is between 80 to 100 lbs. N/ac, when beans are grown as a row crop. There has recently been increased interest in growing beans as a solid seeded crop. When beans are solid seeded, the yield potential is generally slightly higher. For solid seeded beans, it is recommended that soil N in the zero- to 12-inch depth plus fertilizer N, should total between 100 to 120 lbs. N/ac (Table 1). It should be noted the N fertilizer recommendations for solid seeded beans is preliminary and field research by Alberta Agriculture and Rural Development (AARD) is ongoing to finalize these recommendations. Excess N fertilizer may reduce the amount of N fixed by beans and could delay crop maturity. To date, ARD research has not shown a benefit of in-crop N fertilizer application. However, ESN (polymer coated slow release nitrogen) fertilizer has sometimes shown benefit over using only 46-0-0 urea fertilizer. Farmers growing beans, particularly on sandy soils, may find benefit of using a portion of N fertilizer as ESN. Phosphate (P2O5): Table 2 provides recommendations for phosphate fertilizer based on soil test analysis using the modified Kelowna method. The recommendations are based on banded phosphate fertilizer near the seed. Broadcast incorporated rates should be increased by 1.5 to two times to be equally effective on low P soils. Potassium (K): Beans tend to have a higher requirement for K and often require almost as much potassium as nitrogen. Only 20 to 25 per cent of K taken up by a bean plant is contained in the seed at harvest. The remaining K is in the leaves and stems, which is returned to the soil after harvest. Many southern Alberta soils are medium to high in exchangeable potassium, often ranging from 400 to 1000 lbs of K/ac in the zero- to six-inch depth of soil. Generally, K deficiencies are most likely to occur on intensively cropped sandy soils. Table 3 provides general recommendations for potassium fertilizer requirements when soils are less than 300 lbs. K/ac. It is best to either band K before seeding or sideband at the time of seeding. Broadcast incorporated K should be increased by 1.5 times to be as effective as banded K application on deficient soils. Sulphur (S): Deficiencies of S are normally not a problem on irrigated soils in southern Alberta. Irrigation water generally contains enough sulphate-sulphur (SO4-S) to meet crop requirements. If soil S levels are less than 20 lbs/ac in the top 12 inches (30 cm), Table 4 can be used as a guide to decide if S fertilizer is required and what rates to use. If sulphur is required, apply a sulphate containing fertilizer such as ammonium sulphate (21-0-0-24) to correct the deficiency. There are times when S deficient areas are found on sandy soils or in a small percentage of a field in the surface soil. Sulphur deficiency may occur on sandy soil after heavy precipitation events leach the sulphate from the surface soil into the subsoil. This can result in the surface soil being deficient in sulphate, yet there may be adequate sulphate in the subsoil. Micronutrients: Beans require all the essential micronutrients. Micronutrient research with beans in Alberta has only identified zinc (Zn) as occasionally being deficient and usually only on sandy soils. From limited Zn response research data, Zn fertilizer recommendations have been developed (Table 5). Recommendations are based on soil texture and soil Zn analysis of a 0 to 6 inch soil sample depth using the DTPA extractable zinc method. Banding zinc before or at the time of seeding is the preferred method of application. However, soil applied zinc sulphate could be substituted with one or two early foliar applications in June. Zinc deficiency can be induced by cool, wet soil conditions in spring, which may reduce soil zinc availability to the crop. Beans grown in soils that have soil test Zn levels above the critical level may still show visual symptoms of Zn deficiency during wet, cool conditions in June. Beans will often grow out of the deficiency as the weather warms up. However, if cool weather conditions are prolonged, a foliar application may result in some benefit.