Josef Hagin

Review of interaction of ammonium-nitrate and potassium nutrition of crops

Abstract Literature review indicates that higher crop yields may be obtained with a mixture of nitrate and ammonium than with either source alone. An adequate supply of potassium enhances ammonium utilization and thus improves yields, when a mixed ammonium‐nitrate nitrogen nutrition is applied. Nitrate reduction in plant tissues consumes either chemical energy and organic acids, or competes for products of photolysis. When ammonium is applied to the roots, high concentrations of it may accumulate having a strong toxic effect. Potassium activates plant enzymes functioning in ammonium assimilation and transport of amino acids. A summary of the experiments performed by the authors indicates that a mixed ammonium, nitrate and potassium nutrition affects especially N uptake and thus production of organic nitrogen compounds.

Secondary and Micronutrients

Although a major portion of this text is devoted to the discussion of the three major fertilizer elements, nitrogen, phosphorus, and potassium, there are nine other essential plant food nutrients which are considered as fertilizer elements and Warrant some attention. These nine elements are eonveniently placed into two groups according to quantities taken up by plants. The flrst group, termed secondary nutrients, consists of calcium, magnesium, and sulfur, which are required by plants in the quantitites of the same order of magnitude as the major fertilizer elements of nitrogen, phosphorus, and potassium. The term secondary nutrient is justified only from the view of fertilizer application and is not in accordance with the importance or essentiality of these nutrients for plant growth. The secondary nutrients are, as a general rule, not as often deficient in soils as the major nutrients. In addition, they are often applied to soils along with major fertilizer elements. Elements of the second group, iron, copper, zinc, manganese, boron, and molybdenum, are required by plants in minute quantitites. Therefore, they are appropriately termed the micronutrients.

Fertilization of dryland and irrigated soils.

1 Introduction.- 1.1 Definition of Semiarid and Arid Regions.- 1.2 Major Soil Characteristics.- 1.3 Crop Production Systems.- 1.4 Irrigation.- 1.5 Changes in Fertilization Practices.- 1.6 References.- 2 Nitrogen.- 2.1 Nitrogen Fertilizers.- 2.1.1 Ammonia Fertilizers.- 2.1.1.1 Anhydrous Ammonia.- 2.1.1.2 Aqua Ammonia.- 2.1.1.3 Urea.- 2.1.1.4 Ammonium Salts.- 2.1.2 Nitrate Fertilizers.- 2.1.3 Slow-release Nitrogen Fertilizers.- 2.1.3.1 Urea Formaldehyde.- 2.1.3.2 Sulfur-coated Urea.- 2.1.3.3 Nitrification Inhibitors.- 2.2 Fate of Nitrogen Fertilizers in Soils.- 2.2.1 Oxidation of Ammonia.- 2.2.2 Volatilization of Ammonia from Soils.- 2.2.3 Denitrification of Applied Nitrogen.- 2.2.4 Nitrogen Immobilization.- 2.2.5 Nitrate Leaching.- 2.3 Crop Response to Nitrogen Fertilizers.- 2.3.1 Methods for Estimating Available Nitrogen.- 2.3.2 Nitrogen Fertilizer Requirements of Crops.- 2.3.2.1 Cotton.- 2.3.2.2 Corn.- 2.3.2.3 Grain Sorghum.- 2.3.2.4 Wheat.- 2.3.2.5 Grassland.- 2.3.2.6 Legumes.- 2.3.2.7 Sugar Beets.- 2.3.2.8 Potatoes.- 2.3.2.9 Tobacco.- 2.3.2.10 Orchards.- 2.4 Methods of Nitrogen Fertilizer Application.- 2.5 References.- 3 Phosphorus.- 3.1 Phosphate Fertilizers.- 3.1.1 Superphosphates.- 3.1.2 Phosphoric Acids.- 3.1.3 Ammonium Phosphates.- 3.1.4 Nitric Phosphates.- 3.2 Reactions of Phosphorus in Soils.- 3.3 Methods of Phosphate Fertilizer Application.- 3.4 Residual Effect of Phosphate Fertilizers.- 3.5 Phosphate Availability.- 3.5.1 Uptake of Phosphorus by Plants.- 3.5.2 Contribution of the Solid Phase to Phosphate Availability.- 3.5.3 Methods for Estimating Available Phosphorus.- 3.6 Response of Crops to Phosphate Fertilization.- 3.7 References.- 4 Potassium.- 4.1 Potassium Fertilizers.- 4.2 Reactions of Potassium Fertilizers in Soil.- 4.3 Methods for Evaluation of Plant-available Potassium.- 4.4 Potassium Movement.- 4.5 Potassium Fertilization of Crops.- 4.6 References.- 5 Secondary and Micronutrients.- 5.1 The Secondary Nutrients.- 5.1.1 Calcium.- 5.1.2 Magnesium.- 5.1.3 Sulfur.- 5.2 Micronutrients.- 5.2.1 Zinc.- 5.2.2 Iron.- 5.2.3 Manganese.- 5.2.4 Copper, Boron, and Molybdenum.- 5.3 References.- 6 Special Fertilization Practices and Multinutrient Fertilizers.- 6.1 Multinutrient Fertilizers.- 6.1.1 Solid Fertilizers.- 6.1.2 Liquid Fertilizers.- 6.2 Application of Fertilizers in Irrigation Water.- 6.3 Fertilizers for Greenhouse Cultures.- 6.4 Fertilizers for Foliar Application.- 6.5 Fertilization Under Saline and Alkaline Conditions.- 6.6 References.- 7 Determining Fertilizer Requirements.- 7.1 Determination of Nutrient Availability.- 7.1.1 Visual Deficiency Symptoms.- 7.1.2 Plant Analyses.- 7.1.3 Soil Testing.- 7.2 Field Experiments.- 7.3 Yield Equations.- 7.4 Estimating Economic Returns.- 7.5 Fertilizers Rates Recommendations.- 7.6 References.

Increasing salt tolerance of wheat by mixed ammonium nitrate nutrition

Abstract In a greenhouse experiment with wheat, sandy loam or clay soils were salinized by additions of 0, 3. or 8 g NaCl/3L pot. Ammonium and nitrate nitrogen mixtures in ratios of 0/100, 25/75 and 50/50 together with DCD, a nitrification inhibitor, were applied with irrigation water. Salinity significantly reduced dry matter yields, and N and P content in grain and stover. In accordance with previous reports, a mixed ammonium and nitrate N source produced larger dry matter and protein yields than nitrate alone, particularly in grains. The relative increases in yields and N and P accumulation, due to mixed N nutrition, were significantly higher in salinized soils and increased with increasing proportions of ammonium. Grain dry matter and N yields at medium salinity with a 50/50 N mixture, were equal to, or higher than those in non‐salinized soil fertilized with nitrate only. Chloride concentrations in stover increased with salinity and proportion of ammonium in the mixed source indicating that the advant...

Nitrification inhibitors ‐ Interaction with applied ammonium concentration

Abstract Soil samples of 50 g clay, clay loam and sandy loam were amended with ammonium sulphate giving 25, 50, 100, 200, and 400 mg nitrogen (N)/kg and with two nitrification inhibitors, Dicyandiamide (DCD) and N‐Serve (N‐S) each at two levels calculated relative to the N applied, 1 and 5%, and 0.5 and 1%, respectively. Water was added to moisture field capacity and the samples were incubated at 30°C for 7, 14, 28, and 56 days, each treatment and timing in three replicates. The lower level of application of nitrification inhibitors was not effective. Nitrate‐N (NO3‐N) recovery peaked at 28 days and did not change appreciably later, except the 1% N‐S treatments where a flush of NO3 appeared at the 56th sampling day. The nitrification inhibitory effects of the two inhibitors were enhanced at the 200 and 400 mg/kg ammonium‐N (NH4‐N) application in all three soils. Nitrification inhibition was not related to salt concentrations as measured by electrical conductivity.

Determining Fertilizer Requirements

The practice of crop fertilization has become a necessity in most agricultural areas to maximize crop yields and increase net profits. Fertilizers are used to Supplement the innate available supply of plant nutrients from the soil. The amounts of nutrients taken up by previous crops are not a good indication of fertilizer requirements of the current crop because such an approach ignores the nutrient-supplying power of the soil. The potential of a given soil to supply nutrients to a crop is a result of previous fertilization, nutrient fixation, leaching, and crop uptake. The decision of kinds and amounts of fertilizer to apply, therefore, is a function of total crop requirement and available nutrients expected from the soil during the growing season. Economics plays a key role because fertilizer application must be profitable.

Special Fertilization Practices and Multinutrient Fertilizers

Semiarid and arid climates may generate conditions that Warrant specific ways of fertilizer application, or specific Compounds for maximalization of fertilizer effectiveness. Such conditions may be inherent to soils developed under these climates, as for example excessive soil salinity and soil alkalinity, or they may be formed by agrotechnical practices suitable to the area. Application of fertilizers through irrigation water or fertigation is one example of an agrotechnique characteristic of semiarid and arid climates. Another one is a very intensive protected plant cultivation possible because of the relatively high intensity and length of sunshine light during the cooler period of the year. Another practice, although not specific to semiarid and arid climates, that of foliar application of fertilizers will be discussed. This practice seems promising in raising yields above those that may be attained by conventional fertilizer application.