Zinc In Soils

Zinc has a complete 3d104s2 outer electronic configuration and, unlike the other d block micronu-trients such as such as manganese, molybdenum, copper, and iron, has only a single oxidation state and hence a single valence of II. The average concentration of zinc in the crust of the Earth, granitic, and basaltic igneous rock is approximately 70,40, and 100 mg kg1, respectively (38), whereas sedimentary rocks like limestone, sandstone, and shale contain 20, 16, and 95 mg kg1, respectively (39)....

Fertilizers For Magnesium

Magnesium-containing fertilizers are derived from the mining of natural mineral deposits or through synthetic processing. Organic magnesium sources include most manures (209). The magnesium availability to plants from different fertilizers will be dictated by the water solubility of the compounds, release rates from fertilizer coatings (where applicable), and particle size, with the finer particles solubilizing more quickly than the coarser-grade fertilizers. Magnesium concentrations and...

Diagnosis Of Boron Status In Plants

Boron deficiency in crops is more widespread than deficiency of any other micronutrient. This phenomenon is the chief reason why numerous reports are available on boron deficiency symptoms in plants. Because of its immobility in plants, boron deficiency symptoms generally appear first on the younger leaves at the top of the plants. This occurrence is also true of the other micronutrients except molybdenum, which is readily translocated. Boron toxicity symptoms are similar for most plants....

Ammonium Assimilation

The metabolism of ammonium into amino acids and amides is the main mechanism of assimilation and detoxification of ammonium. Glutamic acid formation is a port of entry of nitrogen into organic compounds and occurs in the chloroplasts or mitochondria. Ammonium assimilation in root mitochondria probably uses ammonium absorbed in high concentrations from nutrient solutions. One enzyme is involved in ammonium assimilation in mitochondria glutamic acid dehydrogenase. Ammonium assimilation in...

Amidation

Glutamate + ammonium + ATP glutamine + ADP Amides are formed by the amidation of carboxyl groups. Amides are nitrogen-rich compounds that can store or transport nitrogen. Common amides are glutamine (5C, 2N) and asparagine (4C, 2N). Glutamine is formed from amidation of glutamic acid (glutamate), and asparagine is formed by amidation of aspartic acid (aspartate). Often, when the external supply of ammonium is high, asparagine, a metabolite unique to plants, will dominate among the amides, as...

Approaches In Research

Research in plant nutrition is a continuing program. The development of new crop varieties and the introduction of new management practices to increase crop yields impart changes in nutrient requirements of plants. The increasing application of genomics is providing more understanding of the genetic basis for the efficiency with which different plants utilize nutrients. For example, a study of induction of Arabidopsis genes by nitrate confirmed that genes encoding nitrate reductase, the nitrate...

Determination Of Essentiality

Discovery of the essentiality of nitrogen is often credited to de Saussure (1-3), who in 1804 recognized that nitrogen was a vital constituent of plants, and that nitrogen was obtained mainly from the soil. De Saussure noted that plants absorb nitrates and other mineral matter from solution, but not in the proportions in which they were present in solution, and that plants absorbed substances that were not required for plant growth, even poisonous substances (2). Other scientists of the time...

Fertilizers For Boron

Modern crop production depends on addition of fertilizers to supplement natural soil fertility. Historically, crop production management has progressed to more intensive methods. Precise nutrient management has become essential for sustainable agricultural production systems. Addition of all plant nutrients must be considered for optimum crop production. With intensification of crop production, the need for micronutrient fertilization increases. Boron deficiency has been recognized as one of...

Indicator Plants

Baker (328) proposed that there are three types of plant responses to increasing heavy metal contents in soil (a) accumulators, where heavy metals are concentrated in above-ground plant parts (b) indicators, where internal concentrations reflect external levels and (c) excluders, where metal concentrations in shoots are low and constant over a wide range of soil concentrations up to a critical soil level above which unrestricted transport occurs. It might be expected that aluminum accumulators...

Functions In Plants

Calcium has several distinct functions within higher plants. Bangerth (3) suggested that these functions can be divided into four main areas (a) effects on membranes, (b) effects on enzymes, (c) effects on cell walls, and (d) interactions of calcium with phytohormones, although the effects on enzymes and the interactions with phytohormones may be the same activity. As a divalent ion, calcium is not only able to form intramolecular complexes, but it is also able to link molecules in...

Inorganic Nitrogen in Soil

Soil inorganic nitrogen is commonly less than 2 of the total nitrogen of surface soils and undergoes rapid changes in composition and quantity. Inorganic nitrogen varies widely among soils, with climate, and with weather. In humid, temperate zones, soil inorganic nitrogen in surface soil is expected to be low in winter, to increase in spring and summer, and to decrease with fall rains, which move the soluble nitrogen into the depths of the soil (105). Despite being small in magnitude, the...

Nitrogen Fertilizers

Soils have little capacity to retain oxidized forms of nitrogen, and ammonium accumulation in soils is small consequently, most of the soil nitrogen is associated with organic matter. Release of nitrogen from organic matter is slow and unpredictable. If soil organic matter is depleted, as occurs in cultivated soils, nitrogen for plant growth is limited. Nitrogen is usually the most deficient nutrient in cultivated soils of the world, and fertilization of these soils with nitrogen is required....

Soil Analysis

A close relationship between the plant-available sulfur content of the soil and yield is a prerequisite for a reliable soil method. Such a significant correlation was verified in pot trials under controlled growth conditions (103,175-178). Several investigations have shown, however, that the relationship between inorganic soil sulfate and crop yield is only weak, or even nonexistent, under field conditions (103,179-181). Such missing or poor correlations are the major reason for the large...

Sulfur Fertilization

The optimum timing, dose, and sulfur form used depends on the specific sulfur demand of a crop and application technique. Under humid conditions, the sulfur dose should be split in such a way that sulfur fertilization in autumn is applied to satisfy the sulfur demand on light, sandy soils before winter and to promote the natural resistance against diseases. At the start of the main vegetative growth, sulfur should be applied together with nitrogen. With farmyard manure, on an average 0.07 kg...

Info

With Whole Plant Nutrition Davidian, J.-C., Grill, D., De Kok, L.J., Stulen, I., Hawkesford, M.J., Schnug, E., Rennenberg, H., Eds. Backhuys Publishers Leiden, 2003 pp. 45-46. Heinz, E. Recent investigations on the biosynthesis of the plant sulfolipid. In Sulfur Nutrition and Sulfur Assimilation in Higher Plants Regulatory, Agricultural and Environmental Aspects De Kok, L.J., Stulen, I., Rennenberg, H., Brunold, C., Rauser, W.E., Eds. SPB Academic Publishing The Hague, 1993 pp. 163-178. De Kok,...

References

The essentiality of certain elements in minute quantity for plants with special reference to copper. Plant Physiol. 14 371-375, 1939. 2. H. Marschner. Mineral Nutrition of Higher Plants, 2nd ed. London Academic Press, 1995, p. 889. 3. E. Epstein, A.J. Bloom. Mineral Nutrition of Plants Principles and Perspectives, 2nd ed. Sunderland, Mass. Sinauer, 2005, p. 400. 4. J.B. Jones, Jr. Hydroponics. A Practical Guide for the Soilless Grower. Boca Raton, Fla. St. Lucie, 2000,...

Plant Mechanisms Of Aluminum Avoidance Or Tolerance

There are two types of mechanisms whereby a plant can avoid or tolerate aluminum toxicity (a) exclusion of aluminum from the symplasm, or (b) internal tolerance of aluminum in the sym-plasm. Good reviews on this subject are in Taylor (186,187), Matsumoto (99), Kochian et al. (179, 188), and Barcelo and Poschenrieder (96). 16.8.1 Plant Mechanisms of Aluminum Avoidance Based on chemical analysis of aluminum in root sections, Horst et al. (189) showed that the root tips of an aluminum-tolerant...

Fertilizers For Chlorine

Chlorine is added to soil from a wide variety of sources that include chloride from rainwater, irrigation waters, animal manures, plant residues, fertilizers, and some crop protection chemicals. The amount of chloride deposited annually from the atmosphere varies from 18 to 36 kg1 ha1 year1 for continental areas to more than 100 kg1 ha1 year1 for coastal areas (4). Most of the chloride applied as animal manures or plant residues is soluble and readily available for crop uptake. Because most of...

Nickel Fertilizers

Essentially under all normal field conditions, it is unlikely that application of nickel fertilizer will be required. Exceptions to this concept occur when urea is the primary source of nitrogen supply, in species in which ureides play an important physiological role (2), when excessive applications of Zn, Cu, Mn, Fe, Ca, or Mg have been made over many years (2) and perhaps also in nitrogen-fixing crops grown on mineral-poor or highly nickel-fixing (high pH, high lime) soils. In experiments...

Introduction

The determination of manganese (Mn) essentiality in plant growth by McHargue (1914-1922) focused the attention of plant nutritionists on this nutrient, and led the way for further groundbreaking studies. Since then, research into the concentrations of manganese that confer deficiency or toxicity, and the variation between- and within-plant species in their tolerance or susceptibility to these afflictions has proliferated. The symptoms of toxicity and deficiency have also received much attention...

Physical And Chemical Properties Of Nickel And Its Role In Animal And Bacterial Systems

Nickel is a first-row transition metal with chemical and physical characteristics ideally suited to biological activity (18). Divalent nickel is the only oxidation state of nickel that is likely to be of any importance to higher plants. Nevertheless, Ni2+ forms a bewildering array of complexes with a variety of coordination numbers and geometries (19). Nickel readily binds, complexes, and chelates a number of substances of biological interest and is ubiquitous in all biological systems. Nickel...

Molybdenum Fertilizers

Several molybdenum sources can be used to prevent or alleviate molybdenum deficiency in crop plants (Table 13.4). These sources vary considerably in their solubility and in molybdenum content, and their effectiveness often depends primarily on the method of application, plant requirements, and on various soil factors (87). The relative solubilities of some molybdenum fertilizers are as follows sodium molyb-date > ammonium molybdate > molybdic acid > molybdenum trioxide > molybdenum...

Table 111

Fe Deficiency Chlorosis-Inducing Factors That Are Often Observed, and Synonyms for These Chlorosis Symptoms Lime-induced chlorosis Bicarbonate-induced chlorosis High ethylene concentration Ethylene-induced chlorosis High soil compaction High heavy metal content Management factors Soil compaction High P fertilization High application of Cu-containing fungicides Inadequate assimilate delivery and late vintage (harvest) Plant factors Low root growth High shoot root dry matter ratio Low Fe...

Copper Toxicity In Plants

Prior to the identification of copper as a micronutrient, it was regarded as a plant poison 7 . Therefore, no discussion of copper toxicity can rightfully begin without mention of its use as a fungicide. In 1882, botanist Pierre-Marie-Alexis Millardet developed a copper-based formulation that saved the disease-ravaged French wine industry 68 . Millardet's observation of the prophylactic effects against downy mildew of grapes by a copper sulfate-lime mixture led to the discovery and development...

Soil Testing For Boron

8.6.1 Sampling of Soils for Analysis Agricultural soils can be sampled by removing subsamples from uniform land areas to a depth of 15 to 20 cm. Uniform areas generally have similar soils and slopes, and do not include washed-out areas, bottomlands, or other dissimilar areas. Soil subsamples should be placed in a plastic container to avoid contamination and mixed together thoroughly. Generally, 25 to 50 subsamples per hectare are sufficient to obtain a representation of the soil. 8.6.2...

Soil Testing For Detecting Plant Nutritional Needs

Growth and function as criteria in determining the essential nature of inorganic nutrients. In E. Truog, ed. Mineral Nutrition of Plants. Madison, Wis. University of Wisconsin, Press, 1951, pp. 313-341. R.D. Munson, W.L. Nelson. Principles and practices in plant analysis. In L.M. Walsh, J.D. Beaton, eds. Soil Testing and Plant Analysis. Madison, Wis. Soil Science Society of America, Inc., 1973, pp. 223-248. A Ulrich. Critical nitrate levels of sugar beets estimated from analysis of...

Diagnostic Criteria 121 Visual Diagnosis

Careful observations of the growth of plants can furnish direct evidence of their nutritional conditions. Metabolic disruptions resulting from nutrient deficiencies provide links between the function of an element and the appearance of a specific visible abnormality. Symptoms of disorders, therefore, provide a guide to identify nutritional deficiencies in plants. Careful experimental work and observations are needed to characterize symptoms. For example, nitrogen is needed for protein synthesis...