Utilization of industrial waste aqueous ammonia for irrigated forage sorghum production

Sorghum is one of the water- and nutrient-use efficient crops raised in dry regions worldwide. A 3 × 3 split-plot experiment in randomized complete block design was conducted to study the effects of petroleum refinery waste aqueous ammonia (NH3) on irrigated fodder sorghum for two consecutive growing seasons. The main plots consisted of 0 (control), 40, and 80 kg N ha-1, respectively, and the injection depths (surface 15 cm, and 20 cm depth) were assigned to sub-plots. A significant effect of NH3 on both fresh and dry biomass production was observed where the highest yield was recorded from the 80 kg N ha-1 than the control and 40 kg N ha-1, respectively. Sorghum biomass yield increased most when NH3 was injected at 20 cm depth as compared to other depths. Biomass nutrient content and nitrogen-use efficiency were increased when 80 kg N ha-1 was applied as compared to the control. The critical limit of K:(Ca+Mg), above which the tetany risk increases, did not exceed in sorghum biomass by NH3 fertilization. Results suggested that industrial waste NH3 equivalent to 80 kg N ha-1 injected at 20 cm depth can be a sustainable approach to fertilize irrigated sorghum growing as a forage crop. © 2015 Taylor & Francis

Micronutrient constraints to crop production in the middle east-west Asia region: Significance, research, and management

In addition to nine major nutrients, eight micronutrients [i.e., boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), and zinc (Zn)] are also essential for healthy growth and reproduction of higher plants. Globally, crop production is largely dependent on chemical fertilizer use, especially in developed countries. While fertilizer use, particularly nitrogen (N) and phosphorus (P), has increased substantially in the past four decades in developing countries, such as Pakistan and India, fertilizer use is limited in many areas of the world where agriculture is constrained by harsh climatic conditions, especially low rainfall. The disparity between developed and developing countries is particularly acute with respect to micronutrient awareness and use.One area of the world that is characterized by major climatic and soil constraints, often exacerbated by unfavorable socioeconomic conditions, is the Middle East-West Asia region. This review provides a current perspective on that region of the world where crop yields are invariably low due to drought, with limited inputs and inherent soil nutrient deficiencies. With a high population, there is an urgent need to sustainably expand output. However, there is generally limited awareness of the potential significance of micronutrients in agriculture as factors in crop production, as well as limited research on micronutrients in most countries of the region. The long history of cultivated agriculture in the Middle East-West Asia region and the peculiar characteristics of its soils and climate predispose it toward problems of micronutrient deficiencies.Over three decades ago, a global study on micronutrients indicated widespread deficiencies of iron (Fe) and zinc (Zn), in contrast to copper (Cu) and manganese (Mn), but suggested the likelihood of excess levels of boron (B) in some countries of the region. This overview primarily addresses three focal points in the region, Pakistan in the east, Syria/Lebanon/Turkey in the center, and Spain on the western fringes, reflecting the zones of activity of the respective authors; the latter focal point is a developed region, where, because of soil and climatic similarities, the research is relevant to the whole Middle East-West Asia region.While providing some international context, this article brings together and summarizes published work in the areas of crop and soil micronutrient availability, their behavior in soils in relation to crop growth, and strategies to deal with either deficiency or toxicity, including crop selection for tolerance and subsequent genetic manipulation. Considerable strides have been made in elucidating the significance of both Zn and Fe in the region's mainly calcareous soils, through soil and plant analysis, with the resulting knowledge providing a sound basis for management interventions through validated field research. While B deficiency is common in some countries such as Pakistan, the problem of B toxicity (BT), where it exists, is only handled by crop adaptation.The review also highlights the implications of micronutrient constraints in the soil-plant-human-animal continuum. Intensification of agricultural production as a result of overall macronutrient use, expansion of irrigation, and introduction of new or "niche" crops is likely to accentuate micronutrient deficiencies in the region, but developments such as conservation agriculture may counteract this trend. As the trend for land-use intensification increases because of higher yields due to fertilizer use and irrigation and the introduction of new crops, and as other nutrient constraints are eliminated, micronutrients will inevitably assume greater significance in the future agriculture of the Middle East-West Asia region together with improvements in plant breeding and crop management. © 2013 Elsevier Inc

Iron acquisition by phytosiderophores contributes to cadmium tolerance

PubMedID: 17337530Based on the ability of phytosiderophores to chelate other heavy metals besides iron (Fe), phytosiderophores were suggested to prevent graminaceous plants from cadmium (Cd) toxicity. To assess interactions between Cd and phytosiderophore-mediated Fe acquisition, maize (Zea mays) plants were grown hydroponically under limiting Fe supply. Exposure to Cd decreased uptake rates of 59Fe(III)-phytosiderophores and enhanced the expression of the Fe-phytosiderophore transporter gene ZmYS1 in roots as well as the release of the phytosiderophore 2'-deoxymugineic acid (DMA) from roots under Fe deficiency. However, DMA hardly mobilized Cd from soil or from a Cd-loaded resin in comparison to the synthetic chelators diaminetriaminepentaacetic acid and HEDTA. While nano-electrospray-high resolution mass spectrometry revealed the formation of an intact Cd(II)-DMA complex in aqueous solutions, competition studies with Fe(III) and zinc(II) showed that the formed Cd(II)-DMA complex was weak. Unlike HEDTA, DMA did not protect yeast (Saccharomyces cerevisiae) cells from Cd toxicity but improved yeast growth in the presence of Cd when yeast cells expressed ZmYS1. When supplied with Fe-DMA as a Fe source, transgenic Arabidopsis (Arabidopsis thaliana) plants expressing a cauliflower mosaic virus 35S-ZmYS1 gene construct showed less growth depression than wild-type plants in response to Cd. These results indicate that inhibition of ZmYS1-mediated Fe-DMA transport by Cd is not related to Cd-DMA complex formation and that Cd-induced phytosiderophore release cannot protect maize plants from Cd toxicity. Instead, phytosiderophore-mediated Fe acquisition can improve Fe uptake in the presence of Cd and thereby provides an advantage under Cd stress relative to Fe acquisition via ferrous Fe. © 2007 American Society of Plant Biologists