Abdul Rashid

Biofortification of wheat with zinc through zinc fertilization in seven countries

AimZinc (Zn) fertilization is an effective agronomic tool for Zn biofortification of wheat for overcoming human Zn deficiency. But it still needs to be evaluated across locations with different management practices and wheat cultivars, since grain Zn concentrations may be significantly affected by locations, cultivars and management.MaterialsField experiments were conducted over 3xa0years with the following four Zn treatments: nil Zn, soil Zn application, foliar Zn application and soil + foliar Zn application to explore the impact of Zn fertilization in Zn biofortification of wheat. The experiments were conducted at a total of 23 experimental site-years in China, India, Kazakhstan, Mexico, Pakistan, Turkey and Zambia.ResultsThe results showed that foliar Zn application alone or in combination with soil application, significantly increased grain Zn concentrations from 27xa0mgxa0kg−1 at nil Zn to 48 and 49xa0mgxa0kg−1 across all of 23 site-years, resulting in increases in grain Zn by 84xa0% and 90xa0%, respectively. Overall, soil Zn deficiency was not a growth limiting factor on the experimental sites. A significant grain yield increase in response to soil Zn fertilization was found only in Pakistan. When all locations and cropping years are combined, soil Zn fertilization resulted in about 5xa0% increase in grain yield. Foliar Zn application did not cause any adverse effect on grain yield, even slightly improved the yield. Across the 23 site-years, soil Zn application had a small effect on Zn concentration of leaves collected before foliar Zn application, and increased grain Zn concentration only by 12xa0%. The correlation between grain yield and the effectiveness of foliar Zn application on grain Zn was condition dependent, and was positive and significant at certain conditions.ConclusionFoliar Zn application resulted in successful biofortification of wheat grain with Zn without causing yield loss. This effect of Zn fertilization occurred irrespective of the soil and environmental conditions, management practices applied and cultivars used in 23 site-years. Foliar Zn fertilizer approach can be locally adopted for increasing dietary Zn intake and fighting human Zn deficiency in rural areas.

Zinc Deficiency in Rainfed Wheat in Pakistan: Magnitude, Spatial Variability, Management, and Plant Analysis Diagnostic Norms

Abstract Zinc (Zn) deficiency is a widespread micronutrient disorder in crops grown in calcareous soils; therefore, we conducted a nutrient indexing of farmer‐grown rainfed wheat (Triticum aestivum, cv. Pak‐81) in 1.82 Mha Potohar plateau of Pakistan by sampling up to 30 cm tall whole shoots and associated soils. The crop was Zn deficient in more than 80% of the sampled fields, and a good agreement existed between plant Zn concentration and surface soil AB‐DTPA Zn content (r=0.52; p≤0.01). Contour maps of the sampled areas, prepared by geostatistical analysis techniques and computer graphics, delineated areas of Zn deficiency and, thus, would help focus future research and development. In two field experiments on rainfed wheat grown in alkaline Zn‐deficient Typic Haplustalfs (AB‐DTPA Zn, 0.49–0.52 mg kg−1), soil‐applied Zn increased grain yield up to 12% over control. Fertilizer requirement for near‐maximum wheat grain yield was 2.0 kg Zn ha−1, with a VCR of 4∶1. Zinc content in mature grain was a good indicator of soil Zn availability status, and plant tissue critical Zn concentration ranges appear to be 16–20 mg kg−1 in young whole shoots, 12–16 mg kg−1 in flag leaves, and 20–24 mg Zn kg−1 in mature grains.

‘On-farm’ seed priming with zinc in chickpea and wheat in Pakistan

A series of on-station trials was implemented between 2002 and 2006 to assess the response of wheat (Triticum aestivum L.) and chickpea (Cicer arietinum) to zinc (Zn) added by soaking seeds (priming) in solutions of ZnSO4 before sowing. Wheat seed was primed for 10xa0h in 0.3% Zn and chickpea for 6xa0h in 0.05% Zn. Seed treatments increased the seed concentration in wheat from 27 to 470xa0mg/kg and in chickpea from 49 to 780xa0mg/kg. Priming wheat seeds with 0.3% Zn significantly increased the mean shoot dry mass, Zn concentration and Zn uptake of 15-day-old seedlings relative to non-primed controls and seeds primed with water alone. Using 0.4% Zn further increased shoot Zn concentration but depressed shoot dry mass to the level of the non-primed control. In seven trials, mean grain yield of wheat was significantly increased from 2.28 to 2.42xa0t/ha (6%) by priming with water alone and to 2.61xa0t/ha (14%) by priming with 0.3% Zn. Mean grain yield of chickpea in seven trials was increased significantly from 1.39 to 1.65xa0t/ha (19%) by priming seeds with 0.05% Zn. The effect of priming chickpea seeds with water was intermediate (1.49xa0t/ha) and not statistically separable from the non-primed and zinc-primed treatments. Increased grain yield due to priming in both crops was associated with increases in total biomass but there was no significant effect of priming on harvest index. In addition to increasing yield, priming seeds with Zn also significantly increased grain zinc concentration, by 12% in wheat (mean of three trials) and by 29% in chickpea (one trial) and the total amount of Zn taken up by the grain (by 27% in wheat and by 130% in chickpea). Using ZnSO4 to prime seeds was very cost-effective, with net benefit-to-cost ratios of 75 for wheat and 780 for chickpea.

Chapter three – Significance of Phosphorus for Agriculture and the Environment in the West Asia and North Africa Region

Abstract Fertilizers have been largely responsible for the massive increases in world food production in the past half century that permitted accelerated global population growth to current unprecedented levels. Fertilizer use not only impacts crop yields but also affects animal production. While nitrogen (N) has been the main driver of such changes, phosphorus (P) also has a major role. Like N, the use of P fertilizers can have implications beyond the farmers’ fields, if excessive amounts are applied. The past four decades have witnessed overuse of P fertilizers as well as animal manures in the intensive agricultures of some European countries and North America. Yet ironically in many areas of the world, notably Africa, agricultural output is largely constrained by low soil P in combination with little or no P fertilizer application. Rock phosphate is the global source of the raw material for P fertilizer. However, resources are finite, and therefore efficient and wise use is of paramount importance. The vast West Asia and North Africa (WANA) region is one where agricultural output is beset with major environmental constraints. Yet fertilizer use in the region is still in the incipient to early development stage, ironically in view of the fact that major deposits of exploitable rock phosphate are found in the region, mainly in Morocco and Tunisia. With the predominantly calcareous soils of the region being inherently low in available P, the main focus in the past few decades has been on promoting P use and its efficient management in rainfed and irrigated agriculture. In the 1960s and 1970s, virtually no fertilizer was used in the region, with rapid increases in N and to a lesser extent P since then. The sharp transition from low-input traditional agriculture to conventional modern agriculture has particular implications for efficient P fertilizer use from the economic and environmental standpoints. This review seeks to present a broad overview of P in countries of the WANA region, which varies considerably with respect to economic development and the level of agricultural research, education and extension. It presents the background global considerations with respect to P supplies and use, as well the agricultural context for the region, including climate and cropping systems; it draws heavily on research on soils and soil-P chemistry from Spain, which though technically excluded from WANA, has much in common with the Mediterranean region, and highlights P research from Pakistan at the eastern fringes of WANA. It highlights the discrepancy in P use between developed and developing countries such as those of WANA. The review to some extent builds on extensive research carried out in Syria by the International Center for Agricultural Research in the Dry Areas (ICARDA), with secondary emphasis on countries of the region, many of which collaborate closely with ICARDA. The review covers the past three decades, highlighting progress in field trials on fertilizer use with the regions main crops in relation to rainfall, cropping systems, soil test levels, and efforts to identify P-efficient genotypes and enhance soil P fertility with mycorrhizae. Despite the many isolated, uncoordinated, and often-overlapping, and indeed conflicting, research efforts that have taken place in the region, we have attempted to show a gradual progression in knowledge of P in relation to soils and crops. Developments with regard to P, in the overall framework of agricultural research, have contributed to increased output in the WANA region. Much of the documented research has contributed to the global information on soils of arid and semi-arid regions. Despite achievements in applied research, poorly developed technology transfer systems and weak analytical facilities remain as stumbling blocks to the widespread dissemination of the accumulated knowledge on P use to farmers.

Biofortification of wheat, rice and common bean by applying foliar zinc fertilizer along with pesticides in seven countries

AimsRice (Oryza sativa L.), wheat (Triticum aestivum L.) and common bean (Phaseolus vulgaris L.) are major staple food crops consumed worldwide. Zinc (Zn) deficiency represents a common micronutrient deficiency in human populations, especially in regions of the world where staple food crops are the main source of daily calorie intake. Foliar application of Zn fertilizer has been shown to be effective for enriching food crop grains with Zn to desirable amounts for human nutrition. For promoting adoption of this practice by growers, it is important to know whether foliar Zn fertilizers can be applied along with pesticides to wheat, rice and also common bean grown across different soil and environmental conditions.MethodsThe feasibility of foliar application of zinc sulphate (ZnSO4.7H2O) to wheat, rice and common bean in combination with commonly used five fungicides and nine insecticides was investigated under field conditions at the 31 sites-years of seven countries, i.e., China, India, Pakistan, Thailand, Turkey, Brazil and Zambia.ResultsSignificant increases in grain yields were observed with foliar Zn/foliar Znu2009+u2009pesticide (5.2–7.7xa0% of wheat and 1.6–4.2xa0% of rice) over yields with no Zn treatment. In wheat, as average of all experiments, higher grain Zn concentrations were recorded with foliar Zn alone (41.2xa0mgxa0kg−1) and foliar Znu2009+u2009pesticide (38.4xa0mgxa0kg−1) as compared to no Zn treatment (28.0xa0mgxa0kg−1). Though the magnitude of grain Zn enrichment was lesser in rice than wheat, grain Zn concentrations in brown rice were significantly higher with foliar Zn (24.1xa0mgxa0kg−1) and foliar Znu2009+u2009pesticide (23.6xa0mgxa0kg−1) than with no Zn (19.1xa0mgxa0kg−1). In case of common bean, grain Zn concentration increased from 68 to 78xa0mgxa0kg−1 with foliar Zn alone and to 77xa0mgxa0kg−1 with foliar Zn applied in combination with pesticides. Thus, grain Zn enrichment with foliar Zn, without or with pesticides, was almost similar in all the tested crops.ConclusionsThe results obtained at the 31 experimental site-years of seven countries revealed that foliar Zn fertilization can be realized in combination with commonly-applied pesticides to contribute Zn biofortification of grains in wheat, rice and common bean. This agronomic approach represents a useful practice for the farmers to alleviate Zn deficiency problem in human populations.

Micronutrient deficiencies in rainfed calcareous soils of Pakistan. I. Iron chlorosis in the peanut plant

Abstract Peanut (Arachis hypogaea L.) is susceptible to iron (Fe) chlorosis, however, plant analysis diagnostic criteria are lacking for determining the intensity of chlorosis in this crop. As total Fe content is a misleading index of Fe nutritional status of plants, determination of physiologically active Fe fraction (Fe2+) is suggested for the purpose. In a nutrient indexing survey of the chlorosis‐affected peanut crop grown in the rainfed Potohar plateau of Pakistan, o‐phenanthroline extractable Fe2+ concentration in plants decreased with increasing severity of chlorosis and thus proved an effective technique for determining the intensity of Fe chlorosis. Green plants contained 40.1 to 67.3 mg Fe2+/kg, mildly chlorotic 32.1 to 40.0 mg Fe2+/kg, moderately chlorotic 28.0 to 32.0 mg Fe2+/kg, and severely chlorotic <28.0 mg Fe2+/kg. The minimum Fe2+ requirement in green plants was estimated to be 40 mg/kg on dry weight basis. In rainfed field experiments on a calcareous Typic Hapludalfs soil, foliar sprays...

Micronutrient constraints to crop production in the Middle East-West Asia region: significance, research, and management

Abstract 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 regions 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.

Micronutrient Constraints to Crop Production in the Near East

This review focuses on the Near East, a region of the world where there is a dearth of information on micronutrients in soils and plants. The long history of cultivated agriculture in the region and the peculiar characteristics of the soils and the climate predispose towards problems with micronutrient deficiencies. Over 2 decades ago, a global study on micronutrients indicated deficiencies of iron (Fe) and zinc (Zn), and the likelihood of excess levels of boron (B), in some countries of the Near East. This review primarily addresses two focal points in the region, Pakistan on one side and the Syria/Lebanon/Turkey region on the other, reflecting the zones of activity of the two authors. It brings together and summarises published work in the areas of crop and soil micronutrient availability, their behaviour 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. The review highlights the implications of micronutrient constraints in the soil– plant–human–animal continuum. While intensification of agricultural production is likely to accentuate micronutrient deficiencies in the region, other developments may counteract this trend. Nevertheless, as the trend for land use intensification increases, and as other nutrient constraints are eliminated, micronutrients will inevitably assume greater significance in future agriculture of the Near East.

Assessment of soil and plant analysis laboratories in the West Asia‐North Africa Region

Abstract Although limited amount of water is the primary constraint to agricultural productivity in the rainfed area of West Asia and North Africa (WANA), yields are also low because of the poor mineral nutrient status of soils. Yields can, therefore, be considerably increased by judicious fertilizer use. Laboratories for soil and plant analysis are essential for identifying nutrient constraints and providing a basis for efficient fertilizer use, through correlation studies to establish suitable soil testing extractants and calibration studies with crop responses. The Soils Laboratory at the International Center for Agricultural Research in the Dry Areas (ICARDA) has initiated a quality control program among the national agricultural research systems (NARS) in the countries of the WANA region. The efforts include linkages with the Wageningen International Soil Analytical Exchange Program, in‐country training courses, and a laboratory analysis manual. Continued improvement in laboratory performance is depe...

Zinc Fertilization Impact on Irrigated Cotton Grown in an Aridisol: Growth, Productivity, Fiber Quality, and Oil Quality

Zinc (Zn) deficiency is widespread in calcareous soils. Therefore, we conducted a 2-year field experiment to investigate the impact of graded Zn levels on growth, yield, and fiber and oil quality of cotton (Gossypium hirsutum L., cv. CIM-473) grown in a calcareous Aridisol having 0.54 mg diethylenetriaminepentaacetic acid (DTPA)-extractable Zn kg−1 soil. Zinc use increased boll bearing, boll weight, seed index, and seed cotton yield (P ≤ 0.05). Maximum yield increase was 15%, with 7.5 kg Zn ha−1; however, greater Zn levels depressed yield. Leaf chlorophyll, membrane permeability, seed protein, and oil content and quality improved (P ≤ 0.05), and fiber quality remained unaffected with Zn use. Critical Zn concentration in cotton leaves was 36 mg kg−1. Positive relationships of leaf Zn concentration were observed with boll weight, protein content, total unsaturated fatty acids, and fiber characteristics. Thus, Zn fertilization of low-Zn Aridisols is suggested for improving cotton productivity and seed quality.