Soil Boron Research Articles

Influence of soil and foliar application of borax on fractions of boron under tomato cultivation in boron deficient soil of Typic Haplustalf

Boron (B) is a micronutrient which plays an important role in crop production. Tomato is one of the crops which respond well to B application. Blossom end rot of tomato is due to the deficiency symptom of B which affects the economic value of tomato. The present investigation was undertaken with tomato (PKM 1) as the test crop to study the effect of application of boron on boron fractions viz., readily soluble, specifically adsorbed, oxide bound, organically bound, residual and total boron in boron deficient soil of Madukkur soil series. There were twelve treatments viz., soil application of boron as borax at 0, 5, 10, 15, 20 and 25 kg ha-1and foliar application of boron as borax at 0.25 and 0.50% spray twice at 50th and 80th, 60th and 90th and 50th and 90th days after transplanting which were replicated thrice in randomized block design (RBD). The results indicated that the application of 20 kg borax ha-1 recorded the highest mean value of boron fractions viz., readily soluble (0.33 ppm), specifically adsorbed (0.27 ppm), oxide bound (0.85 ppm), organically bound (0.12 ppm), residual (34.03 ppm) and total boron (35.59 ppm). Among all five fractions, residual boron contributed nearly 96.36 to 97.83% to total boron at harvest stage of crop. The results also revealed that all the five fractions of boron were decreased with progressive growth stages of crop. Key words: Boron application, boron fractions, tomato (PKM 1).

Genetic analysis of tolerance to Boron toxicity in the legume Medicago truncatula

BackgroundMedicago truncatula Gaertn. (barrel medic) is cultivated as a pasture legume for its high protein content and ability to improve soils through nitrogen fixation. Toxic concentrations of the micronutrient Boron (B) in agricultural soils hamper the production of cereal and leguminous crops. In cereals, the genetic analysis of B tolerance has led to the development of molecular selection tools to introgress and maintain the B tolerance trait in breeding lines. There is a comparable need for selection tools in legumes that grow on these toxic soils, often in rotation with cereals.ResultsGenetic variation for B tolerance in Medicago truncatula was utilised to generate two F2 populations from crosses between tolerant and intolerant parents. Phenotyping under B stress revealed a close correlation between B tolerance and biomass production and a segregation ratio explained by a single dominant locus. M. truncatula homologues of the Arabidopsis major intrinsic protein (MIP) gene AtNIP5;1 and the efflux-type transporter gene AtBOR1, both known for B transport, were identified and nearby molecular markers screened across F2 lines to verify linkage with the B-tolerant phenotype. Most (95%) of the phenotypic variation could be explained by the SSR markers h2_6e22a and h2_21b19a, which flank a cluster of five predicted MIP genes on chromosome 4. Three CAPS markers (MtBtol-1,-2,-3) were developed to dissect the region further. Expression analysis of the five predicted MIPs indicated that only MtNIP3 was expressed when leaf tissue and roots were assessed. MtNIP3 showed low and equal expression in the roots of tolerant and intolerant lines but a 4-fold higher expression level in the leaves of B-tolerant cultivars. The expression profile correlates closely with the B concentration measured in the leaves and roots of tolerant and intolerant plants. Whereas no significant difference in B concentration exists between roots of tolerant and intolerant plants, the B concentration in the leaves of tolerant plants is less than half that of intolerant plants, which further supports MtNIP3 as the best candidate for the tolerance trait-defining gene in Medicago truncatula.ConclusionThe close linkage of the MtNIP3 locus to B toxicity tolerance provides a source of molecular selection tools to pasture breeding programs. The economical importance of the locus warrants further investigation of the individual members of the MIP gene cluster in other pasture and in grain legumes.

Release kinetics and distribution of boron in different fractions in some calcareous soils

The aim of this study was to evaluate the release kinetics, speciation, and fractionation of boron (B) in some calcareous soils of western Iran. Ten surface soil samples were incubated with 100 mg B kg−1 for a week at field capacity moisture. After air drying of samples, the trend of B release was experimented using sequential extraction with 10 mM CaCl2. B speciation in soil solution was calculated for the first and the last steps of extraction by the visual MINTEQ program. The distribution of B among five fractions including exchangeable (F1), specially adsorbed (F2), bound by Fe–Mn oxides (F3), organically bound (F4) and residual (F5), was determined in control and spiked soils. The results indicated that the release rates were initially rapid followed by a slower reaction and the main proportion of the added B was extracted by CaCl2. The release kinetics of B was described well with Elovich, parabolic diffusion, power function, and first-order equations. The speciation results revealed that the uncharged boric acid (H3BO30) was the dominant species in soil solutions. In control soils, B concentration in different fractions decreased in the following order: F5 > F1 > F2 > F3 > F4. In spiked soils, however, the largest and the smallest fractions were exchangeable and residual, respectively. This implies that B transformation from soluble to less mobile and non-labile forms is not a rapid process and requires more than a week. The significant relationship observed between kinetic parameters of power and parabolic equations and organically bound B fraction and OM content indicated that organic matter played an important role in B adsorption and release in calcareous soils.

Phenological Response of Rice Plants to Different Micronutrients Application under Water Saving Paddy Fields on Calcareous Soil

Due to a reduction of world water resources, rice cultivation has shifted from flooded to aerobic condition. This shift may alter soil physico-chemical conditions and cause reduced availability and uptake of nutrients, especially boron and zinc in calcareous soils, and may ultimately reduce yield. Thus a field experiment in a calcareous soil was conducted in which basal application of boron & zinc alone, or in combination, was undertaken in rice grown aerobically (T1), flooded for the entire growth period (T2) or flooded for two weeks after transplanting, given supplemental irrigation up to panicle initiation and then flooded from panicle initiation to physiological maturity (T3). The study showed that rice crop was significantly reduced growth in term of Leaf Area Index (LAI), Leaf Area Duration (LAD), Crop Growth Rate (CGR), Total Dry Matter accumulation (TDM) and Net Assimilation Rate (NAR) when it was grown in aerobic condition. However, the crop was not affected significantly different from normal flooded rice (T2) when it was grown in modified rice culture (T3). Application of zinc alone or in combination with boron enhanced chlorophyll contents in T2similar to T3 while the crop grown in aerobic condition (T1) had significantly lower chlorophyll content

Effect of boron fertilization of apple trees (Malus domestica Borkh.) on uptake and distribution of mineral elements

The aim of this study was to examine effect of boron (B) fertilization of 'Šampion' apple trees (Malus domestica Borkh.) grafted on M.26 rootstock on uptake and distribution of mineral elements. The trees were planted at a distance of 4,0 x 2,5 m on sandy-loam soil with low hot-water extractable B content. The study was carried out in 1994-1996 in Dąbrowice Experimental Station located near Skierniewice. The following treatments were applied: (i) soil B application at a rate of 2g B tree<sup>-1</sup> as Bortrac fertilizer (16% B in form of boric acid); (ii) three times leaf B applications before full bloom at a rate of0,67g B tree' at the stage: green and pink bud and beginning of flowering; (iii) three times leaf B applications after bloom at a rate of0,67g B tree<sup>-1</sup>. First spraying was applied at petal fall and next two ones at 2-weeks interval; (iv) control-trees unfer tilized with B. The measurements included: soil chemical analysis (contents of available phosphorus (P) and boron (B) and exchange potassium (K), magnesium (Mg), and calcium (Ca) and plant analysis (concentrations of N,P,K,Mg,Ca and B in the spur leaves, the leaves from oneyear-old shoots and the apple flesh). It was shown that B fertilization had not effect on N uptake and its distribution within apple tree. It was found that soil B application stimulated P uptake which increased concentration of this element in the spur leaves, the leaves from current shoots and the apple flesh. Boron sprayings after bloom increased Ca uptake which rised Ca concentration in studied plant parts. Additionally, leaf B application after bloom reduced plant Mg uptake. As a result of B sprayings after bloom, K concentration was increased in the spur leaves and decreased in the apple flesh. Boron spraying before bloom was less effective in increasing this microelement in plant than leaf B applications after bloom and soil B application.

Effect of boron fertilization of apple trees (Malus domestica Borth.) on yield and fruit quality

Aim of this work was to examine effect of boron fertilization on yield of apple trees and fruit quality. The experiment was carried out during 1994-1996 in Dąbrowice Experimental Orchard belonging to Research Institute of Pomology and Floriculture in Skiemiewice, on Š a m p i o n cultivar, grafted on M26 rootstock. Trees were planted in the autumn of 1991 at the distance 4 x 2,5 m, on sandy-loam soil. Before starting and during carrying out the study there were not visual symptoms of boron deficiency. In the experiment applied boron fertilization to the soil at the dose 2 g B per tree or three times boron sprays before or after bloom at the dose 0,67 g B per tree. Apple trees without any boron fertilization were served as a control. Results of experiment showed that only boron sprays after bloom increased fruit set and yield. There were no significant differences between treatments in fruit maturity at harvest, fruit weight losses dunng storage, apple number infected by <em>Penicillium, Monilina</em> and <em>Botrytis cinerea</em>. Boron sprays after bloom increased firmness of apples after storage and decreased sensibility to bitter pit, internal breakdown and <em>Gloeosporium</em>-rot. All boron treatments increased boron concentration in apples in comparison with control ones. However, the highest increase of boron concentration in apples was observed when boron sprays were done after bloom and soil boron application. Only boron sprays applied after bloom increased calcium concentration in apples.

Development of effective methods for determination of boron in soils and soil solutions

Development of effective methods for determination of boron in soils and soil solutions

Investigation and mapping of risk areas for harmful boron content and the relationship to salt and sodium content in soils of Soke Plain, Aydin, Turkey

In the Great Meandros Basin, the boron content of irrigation water is considerable, up to 21.1 mg L−1. This results in boron accumulation in soils of Soke Plain over an area of ∼25 000 ha. This study aimed to determine soil boron levels and map risk areas in Soke Plain for boron content. Large-scale soil maps were used. Soil sampling points were determined by visual interpretation of LANDSAT5-TM satellite views. One hundred soil samples were taken from a depth of 0–30 cm. Analysis showed that soil boron content ranged between 1.92 and 31.04 mg kg−1. Soil boron contents were interpolated to create risk distribution maps for soil boron levels in Soke Plain. Furthermore, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite views were used to monitor restrictions in plant growth due to the high boron contents. A geographic information system (GIS) database of the area was established. Ninety-six percent of the study area had high to toxic boron levels. Positive correlations between soil boron content and salt and sodium contents indicate that soil management needs to consider the strong influence of the Mediterranean climate and irrigation water quality on the decline in soil fertility due to high soil boron content.

Effects of boron fertilization of spring cereals depending on application methods

The study is a comparison of effects produced by boron fertilization applied to spring barley and oats, grown on light soil, low in available boron, in relation to the application method (pre-sowing, top dressing, foliar applications) and rates of the element. The study was carried out as a three-year series of one-year, two-factor strict field trials (the splitplot design). It has been demonstrated that top dressing with boron applied to soil at the tillering stage as well as foliar fertilization during the stem elongation stage can significantly improve yields. Grain of both cereals from the control plots showed symptoms of insufficient boron nutrition, which were absent when boron fertilization had been applied. Presowing fertilization, although not affecting the yields, improved the supply of grain with boron. Differences between the cereal species were found in terms of boron concentrations in vegetative organs of the cereals and in their response to higher availability of this nutrient. Compared to spring barley, oats was characterised by a much higher content of boron in vegetative parts and was more responsive to increased concentrations of boron in soil.

Evaluation of Soil Degradation Impact on Wheat Yield by Geographical Information System

Soil degradation and its relation to wheat yield were analyzed in a 1041.2-ha catchment in Ustic soil moisture regime in north-central Anatolia, Turkey. The soils in the study area were sampled based on a randomized sampling scheme, using 142 samples from topsoil and 115 samples from subsoil. All the soil samples were analyzed for sand, silt, clay, coarse material (material with a diameter of >2 mm), soil organic matter, phosphorous, nitrogen, boron, zinc, iron, electrical conductivity, pH, hydraulic conductivity, and cation exchange capacity. Wheat yield was measured at 115 sampling locations. Data were evaluated by global information system (GIS) will and variable reduction (factor analysis) techniques. The majority of the soil properties exhibited high variation with a skewed distribution. Low organic-matter content, high penetration resistance, low water-holding capacity, and deficiency in some macro- and microelements were the most important factors limiting wheat yield.

Mineralogical and geochemical studies of boron-rich bauxite ore deposits in the Songqi region, SW Henan, China

The Songqi region, SW Henan, is an important bauxite province in China. The bauxite ore deposits occur unconformably on the top of Middle Ordovician argillaceous carbonates. The bauxite ores from the Songqi region are characterized by unusually high boron contents. In this paper, we report the mineralogical and chemical compositions of selected bauxite ores from the region. These new data, together with existing geochemical data of soils in the region, are used to evaluate the origin of boron enrichment in the bauxite ores. The compositional characteristics of tourmaline in the bauxite ores suggests that this mineral was likely derived from a meta-sedimentary protolith. Mass balance calculation reveals that tourmaline only accounts for a small portion of boron in the bauxite ores; the majority of boron in the ores must occur in other forms, possibly by ion absorption on the surfaces of diaspore and clay minerals. In the Songqi region, the Precambrian meta-sedimentary rocks are known to contain abundant tourmalines whereas the Cambrian–Ordovician argillaceous carbonates and the Upper Proterozoic shales are all enriched in boron in free ion state. We suggest that these rocks provided tourmaline and boron ion to the bauxite deposits in the region. Most known bauxite deposits in the Songqi region occur at the margins of boron-rich soil domains, suggesting that boron in soils is a potential exploration indicator for unknown bauxite deposits in this region.

Boron in soils and plants of the West Transbaikal region

Some particularities of the distribution of boron in the main types of soils were studied. A close dependency between the boron content in the soils and its concentration in the soil-forming rocks (r = 0.85) was established, as well as the absence of a correlation between the content of boron and that of humus. It was found that boron is an element with an average intensity of accumulation in plants: the coefficient of its biological absorption from the soil of the steppe, meadow, and agrocenoses varied from 1.2 to 3.2. A correlation between the bulk content of boron in the soils and its accumulation in plants was absent (r = −0.07–0.11). The vegetation of a significant part of the steppe, dry-steppe, and forest-steppe landscapes had a boron deficiency (30–75%).

Comparative Evaluation of Inductively Coupled Plasma–Atomic Emission Spectroscopy and Colorimetric Methods for Determining Hot-Water-Extractable Boron in Soils

Frequency of boron (B) deficiency is increasing in rainfed systems, and hence there is a need to diagnose the deficiency. Colorimetric methods are still widely used in soil-testing laboratories in India for measuring B. Little information is available on the comparative evaluation of the colorimetric and inductively coupled plasma (ICP) methods for determining extractable B in soils. We describe results of the comparative evaluation of these methods for measuring extractable B in 57 soil samples with pH values ranging from 5.3 to 9.5. There was a significant correlation between B values determined by the two methods, and the correlation coefficient was greater for soil samples with pH in the neutral to alkaline range. Interaction between soil samples and methods (ICP or colorimetric) was significant except for soil samples in the pH range of 8.0 to 9.5. Precision for B determination was greater with the ICP than with the colorimetric method.

Evaluation of Extractants for Boron under the Influence of Organic Matter and Applied Boron in Rhizosphere and Nonrhizosphere Soils Growing Rape (Brassica campestris L.)

Field experiments during 2006–07 and 2007–08 were conducted in an Aeric Endoaquept to evaluate extractants suitable for boron (B) under the influence of organic matter and B in both rhizosphere (R) and nonrhizosphere (NR) soils with rape (Brassica campestris L.) as a test crop. The results reveal that the average B content in Mehlich 3 (MH-3) B was greatest (0.791 mg kg−1) in NR soil, while that of the same in R soil was greatest (0.785 mg kg−1) with Mannitol–calcium chloride (CaCl2) (MCC) followed by hot -CaCl2 (HCC, 0.750 mg kg−1) in the treatment T4 where NPK (80:40:40), B at 0.5 kg ha−1, and farmyard manure (FYM) at 5 t ha−1 were applied together. Based on linear regressions and correlations between different extractants and yield responses, the MH-3 extractant gave the greatest value of co-efficient of determination (R2 = 0.36**, r = 0.598**) and has proved to be a superior extracting solution for B in NR in an Aeric Endoaquept. The results further suggested that the extractability of B with these three extractants did not have any control over rhizosphere soil zone.

Exogenous nitric oxide donor protects Artemisia annua from oxidative stress generated by boron and aluminium toxicity

Nitric oxide (NO) is an important signal molecule modulating the response of plants to environmental stress. Here we report the effects of boron (B) and aluminium (Al) contamination in soil, carried out with or without application of exogenous SNP (NO donor), on various plant processes in Artemisia annua, including changes in artemisinin content. The addition of B or Al to soil medium significantly reduced the yield and growth of plants and lowered the values of net photosynthetic rate, stomatal conductance, internal CO2 concentration and total chlorophyll content. The follow-up treatment of NO donor favoured growth and improved the photosynthetic efficiency in stressed as well as non-stressed plants. Artemisinin content was enhanced by 24.6% and 43.8% at 1mmole of soil-applied B or Al. When SNP was applied at 2mmole concentration together with either 1mmole of B and/or Al, it further stimulated artemisinin biosynthesis compared to the control. Application of B+Al+SNP proved to be the best treatment combination for the artemisinin content in Artemisia annua leaves.

Biophysical Correlates with the Distribution of the Invasive Annual Red Brome (Bromus rubens) on a Mojave Desert Landscape

AbstractBecause of its ability to transform ecosystems by increasing the prevalence of fire, the invasive annual red brome is a priority exotic species for management in arid lands of the southwestern United States. By sampling red brome presence and 97 environmental (climatic, topographic, and soil) and native vegetation (e.g., perennial species richness) variables on 126 sites, we assessed biophysical correlates with red brome distribution on a 755,000-ha (1.9 million ac) Mojave Desert landscape. Brome occupied 55 of 126 (44%) 0.09-ha plots. The simplest models (i.e., those containing the fewest or most easily obtained variables) in multivariate (classification trees and nonparametric multiplicative regression) and univariate (χ2) models often portrayed red brome distribution as well, or nearly as well, as more complicated models containing more variables harder to obtain. The models varied, however, in their abilities for describing brome presence compared with absence. For example, a simple classification tree using only elevation, soil great group, parent material, and vegetation type improved estimates of brome presence for 55% of sites, absences for 87%, and overall for 73% of sites compared with a naïve model containing the observed frequency of brome in the data. Conversely, a more complicated model, including soil boron and sulfur, performed better for presences (96%) than for absences (73%; 83% overall). Results also showed variable support for two general postulates in invasive species science. Red brome distribution was not correlated with soil N, which is inconsistent with the supposition that nutrient-rich soils are more prone to invasion. Brome was correlated with native perennial species richness to support the postulate that exotic species abundance is correlated with species-rich habitats, but the correlation was weak (r= 0.38) and similar in strength to correlations with many other environmental variables. On this relatively low-elevation landscape, the areas currently most invaded by red brome include the higher elevations (> 777 m [2,549 ft]), limestone–sandstone soils, and burrobush and mixed perennial communities. Areas least inhabited by brome are the lowest elevations (< 491 m), gypsum soils, and creosotebush and saltbush communities.

Determination of Available Boron in soil with a water quality analysis kit and hand-made colorimeter using LED

Determination of Available Boron in soil with a water quality analysis kit and hand-made colorimeter using LED

Boron in humus and inorganic components of Hamra and Grumosol soils irrigated with reclaimed wastewater

The role of organic matter in soil boron (B) turnover and availability is not well understood. The forms and mobility of B are of special concern in soils irrigated with reclaimed wastewaters (RWW). We studied B distribution and binding in major components of two irrigated Mediterranean soils, with special emphasis on humus and water-mobile phases. The results showed that most B in the sandy loam Hamra soil and a large part in the clayey calcareous Grumosol was bound to extractable humus fractions and, in the Grumosol, to organic/mineral refractory residue, along with fractions of free (non-silicate) iron/aluminium (Fe/Al) minerals and aluminosilicates. Among humus fractions, the major B carriers were humin, Fe/Al-humates (complexed firmly, presumably through polyvalent Fe/Al cations), and calcium/magnesium (Ca/Mg)-humates (bridged to soil particles through divalent cations), and to a much lesser extent fulvic-Fe/Al (Hamra) and fulvic-Ca/Mg (Grumosol) complexes. The mode of B preferential binding indicates an origin of the soil humus from lignin of plant cell walls and membranes. In water extract, B was bound firmly (non-exchangeable) to coarse colloids >0.20 μm, presumably of organic/bacterial origin. Boron was not detected in the exchangeable fraction. This raises the question of the forms of bioavailable B in the soils. It can be assumed that the bulk of B in the soil–plant system circulates among plants (lignin) and the inherited soil organic matter/humified material. It is noteworthy that irrigation with RWW resulted in a slight increase of mannitol-extractable B and a redistribution of humus-B in favour of firmly bound Fe/Al-humate complexes.

Practical Salinity Management for Leachate Irrigation to Poplar Trees

Landfill leachate can be beneficially reused for irrigation of fiber crops with appropriate attention to nutrient and salinity management. The Riverbend Landfill in Western Oregon has been effectively practicing irrigation of landfill leachate to poplar trees since 1993. Over that time, the site has been adaptively managed to control salinity impacts to the tree crop while beneficially utilizing the applied water and nutrients during each growing season. Representative leachate irrigation water has ranged in concentration of total dissolved solids from 777 to 6,940 mg/L, chloride from 180 to 1,760 mg/L and boron from 3.2 to 7.3 mg/L. Annual leachate irrigation applications have also ranged between 102 and 812 mm/yr. Important conclusions from this site have included: 1) Appropriate tree clone selection and tree stand spacing, thinning, and harvest rotations are critical to maintaining a productive tree stand that is resilient and resistant to salt stress. The most effective combinations have included clones DN-34, OP-367, 184–411, 49–177, and 15–29 planted at spacing of 3.7-m · 1.8-m to 3.7-m · 3.7-m; 2) Leaf tissue boron levels are closely correlated to soil boron levels and can be managed with leaching. When leaf tissue boron levels exceed 200 to 250 mg/kg, signs of salt stress may emerge and should be monitored closely; 3) Salinity from leachate irrigation can be managed to sustain a healthy tree crop by controlling mass loading rates and providing appropriate irrigation blending if necessary. Providing freshwater irrigation following each leachate irrigation and targeting freshwater irrigation as 30 percent of total irrigation water applied has successfully controlled salt impacts to vegetation; and 4) Drip irrigation generally requires more careful attention to long-term soil salinity management than spray irrigation. Moving drip irrigation tubes periodically to prevent the formation of highly saline zones within the soil profile is important. In this paper, a fifteen year record of monitoring and operational data are presented that can be used by others in managing irrigation of saline water to poplar trees. When salinity is carefully managed, tree systems can help to provide sustainable leachate management solutions for landfills.

Influence of Integrated Nutrient Management on Soil Properties of Old Alluvial Soil under Mustard Cropping System

Field experiments were conducted at the fields of Crop Research and Seed Multiplication Farm of Burdwan University, Burdwan, West Bengal, India during the winter seasons of 2005–2006, 2006–2007, and 2007–2008 in old alluvial soil (pH-6-7) to evaluate the influence of integrated nutrient management on soil physicochemical and biological properties under mustard (Brassica campestris cv. ‘B9’) cropping system. In the first year (2005–2006), seven varieties of mustard were cultivated under recommended dose of chemical fertilizer (100:50:50). In the second year of the experiment (2006–2007), six different doses of biofertilizer and chemical fertilizer were applied. In the third year (2007–2008), six different level of compost along with a combined dose of biofertilizer and chemical fertilizer (T3-3/4 Chemical fertilizer: 1/4 biofertilizer) were applied. The results indicated significant improvement in the soil quality by increasing soil porosity and water holding capacity significantly, as well as gradual build-up of soil macronutrient status after harvesting of the crop. Applications of biofertilizers have contributed significantly toward higher soil organic matter, nitrogen (N), available phosphorus (P), and potassium (K). The use of biofertilizers and compost have mediated higher availability of iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), and boron (B) in soil. The use of biofertilizers and compost significantly improved soil bacterial and fungal population count in the soil, thereby increasing the soil health.