Evaluation of Extractants for Predicting Availability of Boron to Mustard in Arid Soils of India

Abstract

Greenhouse and laboratory studies were undertaken to evaluate the suitability of extractants for determining the boron (B) status of arid soils of Rajasthan (India) using mustard (Brassica juncea L.) as a test crop. Mustard is an important oilseed crop of northern India, which is widely grown in Rajasthan. This crop is sensitive to B deficiency. For predicting response of mustard to B application, several extractants have been tried with variable results. Seven extractants, commonly used for estimating the availability of B, were evaluated and B in soil extract and in plant tissue were assayed using the azomethine-H colorimetric method. The suitability of seven extractants for ORDER REPRINTS determining available soil B was assessed by correlating the amount of extractable B in untreated soils with Bray's percent yield, plant tissue B concentration and B uptake by mustard. The results indicate that hot 0.01 M CaCl 2 and hot water extracted comparatively more B than other extractants. The amount of B extracted by these extractants was found to be in the following order: hot 0.01 M CaCl 2 > hot water > 1.0 M NH 4 OAc (pH 4.8) > sorbitol þ NH 4 OAc þ TEA ¼ mannitol þ NH 4 OAc þ TEA > mannitol þ CaCl 2 > salicylic acid þ NH 4 OAc þ TEA. Simple correlation coefficients of the amount of B extracted by different extractants and soil characteristics were calculated. Based on present studies, the suitability of extractants for mustard crop in arid soils of Rajasthan may be arranged as follows: hot 0.01 M CaCl 2 > hot water > sorbitol þ NH 4 OAc þ TEA ¼ mannitol þ NH 4 OAc þ TEA > 1.0 M NH 4 OAc (pH 4.8) > salicylic acid þ NH 4 OAc þ TEA> mannitol þ CaCl 2 soluble B. The critical values in respect to sufficiency of extractable B for mustard plants were: 0.52 for hot 0.01 M CaCl 2 , 0.33 for hot water, 0.31 for mannitol þ CaCl 2 , 0.34 for 1.0 M NH 4 OAc (pH 4.8), 0.19 for sorbitol þ NH 4 OAc þ TEA, 0.24 for mannitol þ NH 4 OAc þTEA and 0.19 mg kg À1 for salicylic acid þ NH 4 OAc þ TEA. The critical B concentration in mustard plants was 28.05 mg kg À1 on dry weight basis.

Boron Deficiency in Soils and Crops: A Review

“…There were highly significant positive correlations between the amounts of B extracted through hot water-soluble, 1:1 soil: distilled water and 1:2 soil:distilled water, ammonium acetate, calcium chloride -mannitol, and DTPA -sorbitol extractants (Goldberg et al, 2002). Latter, Chaudhary & Shukla (2004) also accentuated the advantageous features of sorbitol + NH 4 OAc + TEA and mannitol + NH 4 OAc + TEA extractants. Further, the simplicity of these extractants has also been compared to hot water and hot 0.01 M CaCl 2 methods..These extractants have the tendency to demarcate the available B status of arid soils on a routine basis where a large number of samples are to analyze.…”

“…Several extractants used for soil B extraction have been employed over time for example, hot water for plant-available B (Berger & Truog, 1939;Parker & Gardner, 1981;Mahler et al, 1984;Rahmatullah et al, 1999), 0.05 M HCl for plant-available B (Ponnamperuma et al, 1981), 0.018 M CaCl 2 for non-specifically adsorbed/readily soluble B on soil surfaces (Iyenger et al, 1981;Aitken & McCallum, 1988;Spouncer et al, 1992;Hou et al, 1996;Rahmatullah et al, 1999), 1 M NH 4 OAc for multi-element extraction (Gupta & Stewart, 1975;Chaudhary & Shukla, 2004), 0.25 M sorbitol-DTPA for bioavailable B (Goldberg, 1997;Miller et al, 2000;Gloldberg et al,, 2002;Shiffler et al, 2005), 0.05 M mannitol prepared in 0.01 M CaCl 2 for B in soil solution and its nonspecifically adsorbed forms to assess regenerative power of soil for B (Cartwright et al, 1983;Aitken et al, 1987;Jin et al, 1988;Rahmatullah et al, 1999;Vaughan & Howe, 1994), and 0.005 M AB-DTPA for multi-element extraction (Gestring & Soltanpour, 1984Matsi et al, 2000).…”

Re‐evaluation of Hot Water Extraction for Boron Availability by Use of a Boron Sorption Index

“…The data showed generally a good correlation between the values of available P after short equilibration times (2 h-7 days) and the values after longer periods (60-180 days), and regression analysis allowed corrected values of buffer indexes for short times to foresee the P-fertilizer requirements to reach the P level considered optimum. Likewise, fit indexes may be used to evaluate the suitability of extractants for determining the B requirements for crops (Chaudhary and Shukla 2004).…”

Evaluating the Absorption of Boron by Plants—A Potential Tool to Remediate Contaminated Sediments from Cecina River Basin in Italy

“…Even if no universal extractant can predict the available fraction for all plants, the used one (mannitol+CaCl 2 ) was able to distinguish the ability of each plant in reduce B available fraction. The extract obtained can be considered as the leachable portion of B and a tool to assess the potential B available for plant uptake (Chaudhary and Shukla 2004;Rhoades et al 1970), indicating a rough estimation of the time necessary to reduce B from sediment using specific plants and could be a way to select the best performing plant for subsequent pilot tests.…”