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 88S 886 RYAN ET AL.training courses, and a laboratory analysis manual. Continued improvement in laboratory performance is dependent upon knowledge of the capabilities of such laboratories and identification of their constraints. This presentation reports a fact-finding survey of laboratories from 16 countries of the WANA region-mainly public, from universities and ministries of agriculture, and some private or commercial ones-based on a questionnaire about analyses, facilities, methodologies, quality assurance, personnel training, and management. Future efforts to improve the quantity and quality output from of these laboratories will address such deficiencies.

Distribution of actinomycetes in different soil ecosystems and effect of media composition on extracellular phosphatase activity

“…Soil texture was determined by the Bouyoucos hydrometer method (Gee and Bauder, 1986). The pH-values of the soils were measured in saturated past (McLean, 1982), whereas electrical conductivity (EC) was determined in the extract of the water saturated past (Ryan et al, 1999). Organic Carbon (OC) was estimated by the potassium dichromate oxidation method (Nelson and Sommers, 1982).…”

Response of Wheat to NP Fertilizer Rates, Precursor Crops and Types of Vertisols in Central Highlands of Ethiopia

“…Ten years (2004Ten years ( -2013 average annual rainfall, maximum and minimum temperatures were 1219.3 mm, 21. Table 1, including interpretations (Agriculture and Fisheries of the Netherlands, 1989;Ryan, Garabet, Harmsen, & Rashid, 1996). Note.…”

Soil Characteristics Influence the Selection of Dominant Plant Genotypes Inhabiting Wadi Sudr, Egypt

“…Physical and chemical parameters of soil samples were analyzed. Soil particle size (%) was determined by the dry sieving to separate soil fractions according to Wentworth scale (American System) [27] [28]. Soil reaction (pH) was determined in the soil solution 1:1 by using a portable pH-meter (Model Ion lab pH level 1) calibrated by buffer solution; pH 4, 7 and 10 [29].…”

“…Soil reaction (pH) was determined in the soil solution 1:1 by using a portable pH-meter (Model Ion lab pH level 1) calibrated by buffer solution; pH 4, 7 and 10 [29]. Electrical conductivity (EC) of the soil extract (5:1) were determined and expressed as dS/m 29 2+ , Na + and K + ) of the soil extracts were analyzed following the method previously described [27] [29] and their values expressed as meq/L soil. Calcium carbonates content was determined volumetrically using Collin's Calcimeter [30].…”