Availability of soil boron fractions to M.26 apple rootstock

The availability of various boron (B) fractions in soil to M.26 apple (Malus spp.) rootstock was examined. The study was carried out in a greenhouse on soils with diverse chemical and physical properties. The following B fractions were determined: (i) B in soil solution, (ii) B non‐specifically adsorbed on soil surface, (iii) B specifically adsorbed on soil colloid surfaces, (iv) B occluded in Mn oxyhydroxides, (v) B occluded in noncrystalline aluminum (Al) and iron (Fe) oxides, (vi) B occluded in crystalline Al and Fe oxides, (vii) B fixed with soil silicates, and (viii) total soil B. In the studied soils there were: 0.07–0.17 mg kg^‐1 B in soil solution, 0.01–0.03 mg kg^‐1 B non‐specifically adsorbed on soil surface, 0.04–0.08 mg kg^‐1 B specifically adsorbed on soil colloid surfaces, 0.28–0.67 mg kg^‐1 B occluded in manganese (Mn) oxides, 4.03–17.22 mg kg^‐1 B occluded in noncrystalline Al and Fe oxides, 8.93–50.62 mg kg^‐1 B occluded in crystalline Al and Fe oxides, 12.2–42.5 mg kg^‐1 B fixed with soil silicate, and 52.9–82.2 mg kg^‐1 total B. Simple correlation analysis showed positive correlation between B contents in M.26 apple rootstocks and amounts of B in soil solution (r=0.77), B non‐specifically adsorbed on soil colloid surfaces (r=0.65), B specifically adsorbed on soil surface (r=0.76) and B occluded in Mn oxyhydroxides (r=0.77). No relation was found between plant B contents and amounts of B occluded in non‐crystalline and crystalline Al and Fe oxides, B fixed with soil silicates and total B. The results indicated that extraction of B by 0.1 M NH₂OH HCl solution adequately represented amounts of B in soil solution, B non‐specifically and specifically adsorbed on soil compound surfaces and B occluded in Mn oxyhydroxides to assess availability of B to apple trees.     

Plant Availability of Boron Adsorbed or Occulted on Goethite to Rape (Brassica napus L.) Seedling

The purpose of the study was to determine plant availability of boron (B) and relaxation of soil acid to rape seedling exhibited by B-doped goethite in acidic soil. For this purpose, two kinds of B-doped goethite were synthesized: one was goethite with adsorbed B prepared by reacting goethite with borax solution, and the other was goethite with occluded B by synthesizing goethite in the presence of boric acid. The reaction process in soil-like natural minerals of the B-doped goethite was simulated in a rhizobox culture system. Results showed that the B-doped goethite can provide available B for rape growth. Its addition on acidic soil can alleviate soil acidification by increasing soil pH and decreasing soil exchangeable acid. The observation that nutrient uptake was improved supports the view that the B-doped goethite improved soil quality, as also proved by the increase of root morphology and dry weight.     

Influence of B-permeated goethite on soil B fraction and its availability to rape seedlings (brassica napus L.)

The purpose of the study was to determine the effect of boron (B)-permeated goethite on soil B fractionation and the availability of this B fraction to rape seedlings (Brassica napus L.). For this purpose, goethite and two kinds of B-permeated goethite were synthesized and their processes in soil were simulated. Plant availability of B adsorbed or occluded on goethite was investigated with rape seedling. Results found that both ad-B-goethite and oc-B-goethite significantly increased the water soluble B (WS-B), specifically adsorbed B (SPA-B), B occluded in amorphous iron (Fe) and aluminum (A1) oxides (AMO-B) and crystalline Fe and Al oxides (CRO-B) content in the soil, compared with ordinary goethite. Also the B-permeated goethites improved B content of the rape seedling and therefore enhanced the rape shoot and root dry weight. Correlation analysis demonstrated that water soluble B (WS-B) plays the most important role in rape B uptake and accumulation, moreover the specifically adsorbed B (SPA-B), nonspecifically adsorbed B (NSA-B), amorphous Fe and A1 oxides (AMO-B) was also significant correlated with the B content or B accumulation of the rape.     

Behavior of soil boron and boron uptake by M.26 apple rootstock as affected by application of different forms and nitrogen rates

Abstract

The changes in availability and uptake of boron (B) by M.26 apple rootstocks as affected by applications of different forms and rates of nitrogen (N) were examined. The study was carried out in a greenhouse using soil with low contents of organic matter, clay, calcium carbonate, NH₄‐oxalate soluble aluminum (Al) and iron (Fe), NH₂OH·HCl extractable manganese (Mn), poor cation exchange capacity and low pH. Soil N application was in the form of urea, calcium nitrate, ammonium sulphate, or ammonium nitrate at rates of 0, 17, 34, and 51 mg N kg^?1. After 1, 3, and 5 days of N application, soil B fractions were determined: B in soil solution, B specifically and non‐specifically adsorbed on soil surfaces, B occluded in Mn oxyhydroxides, and B occluded in crystalline Al and Fe oxides. The results showed that N as calcium nitrate and ammonium nitrate increased B both in soil solution and non‐specifically adsorbed on soil surface and decreased B concentration on Al and Fe oxides. This indicates that N‐NO₃ inhibited B sorption on Fe and Al oxides. Maximum B desorption from Fe and Al oxides was obtained within one day after N‐NO₃ was supplied. Nitrogen application as calcium nitrate and ammonium nitrate increased availability and uptake of B by plant roots. Thus, it was concluded that apple trees planted on coarse‐textured soils where risk of B deficiency is high, calcium nitrate or ammonium nitrates would be appropriately to apply to keep B more available.     

几种常见矿物与硼作用的红外光谱特性研究

对几种常见矿物及其与硼反应的红外光谱比较发现 ,硼在供试矿物上解吸的图谱更接近硼在矿物上吸附的图谱 ,而与无硼矿物图谱相差较大 ,故硼在几种常见矿物上都表现出不同程度的滞后性。针铁矿吸附硼后 ,在 1 40 0～ 1 44 0cm- 1 和 1 0 0 0～ 1 2 0 0cm- 1 范围处谱峰有不同程度的增强 ;水锰矿、三羟铝石和Ca 蒙脱石吸附硼后 ,此处谱峰却减弱 ,而在30 0 0～ 360 0cm- 1 处的谱峰 ,也随硼的吸附而明显减弱 ;Ca 蒙脱、三羟铝石吸附硼后 ,其图谱在 1 40 0～ 1 44 0cm- 1 和 1 62 0～ 1 670cm- 1 处的谱峰变化相似 ;水锰矿吸附硼的图谱在 1 0 0 0cm- 1 和 1 40 0～ 1 44 0cm- 1 处与三羟铝石吸附硼的图谱也有相似之处。     

不同氧化物硼负载体吸附锰离子的特性研究

以人工合成针铁矿（Goethite，简写为G），水锰矿（Manganite，简写为M），经硼砂处理的吸附态针铁矿（简写为Ad—B-G），吸附态水锰矿（简写为Ad—B-M），经硼酸处理的包被态针铁矿（简写为Oc—B—G），包被态水锰矿（简写为Oc-B—M）等6种氧化物为研究对象，在等温条件下，用吸附平衡法研究了6种硼负载体对Mn^2＋的吸附解吸行为。结果表明，吸附Mn^2＋能力：Oc—B—G〉Ad—B—G〉G；Ad—B—M和Oc—B—M吸附Mn^2＋量最大，M吸附能力最弱。6种硼负载体Mn^2＋吸附量随pH升高而增加,但铁氧化物和锰氧化物之间有差别。不同形态锰氧化物吸附Mn^2＋前后溶液pH变化不同，吸附等量Mn^2＋离子时，Ad—B—M向溶液中释放H^＋量最多，Oc—B—M最少。上述结果说明，硼的参与不仅可改变氧化物吸附Mn^2＋离子的行为，而且对反应体系的影响也不尽相同。     

EFFECT OF BORON-DOPED GOETHITE ON SOIL ACIDITY,DIFFERENT FORMS OF MANGANESE IN RED SOIL AND THE GROWTH OF RAPE (BRASSICA NAPUS L.) SEEDLINGS

Rape (Brassica napus L.) seedling pot experiments were performed with a red soil treated with goethite which had boron (B) either adsorbed (ad-B-goethite) or occluded (oc-B-goethite). Soil acidity, different forms of manganese in the soils and different elements content of the rape seedlings were determined. It was found that the addition of boron-containing goethite to the soils resulted in increased rape growth, elevated soil pH and decreased exchangeable acidity. Compared with the control, boron-containing goethite elevated the content of exchangeable manganese (Mn) (EXC-Mn), organic matter bound Mn (OM-Mn), reducible oxide Mn (RO-Mn) and residual Mn (RES-Mn) which were difficult to use for plant. Low labile organic matter was significantly correlated with easily reducible oxide Mn (ERO-Mn) (P < 0.01) and RO-Mn (P < 0.05). Middle organic matter and soil pH was significantly (P < 0.05) correlated with RES-Mn. Stepwise regression was used to select the combination of variables that best estimates shoot and root dry weight of rape seedling. Among them, soil pH, EXC-Mn, OM-Mn, RO-Mn and RES-Mn significantly influenced the dry weight of rape seedlings. The addition of boron-containing goethite improved the uptake of iron (Fe), calcium (Ca), magnesium (Mg), and copper (Cu) element and decreased the uptake of Mn and zinc (Zn) element in rape seedling. The results suggested that boron-containing goethite could provide a better soil acidity environment for plant growth; it was also an important agent increasing a part of manganese difficult to use for plant and reducing the activity of soil manganese, which was beneficial to altering rape seedling growth.     

The relationship between boron soil test results and boron uptake by bean plants

Abstract

Boron sensitive crops, kidney beans and soybeans, were grown in pots containing soil collected from a beet field and a nearby pasture. Two soil extraction procedures were used to measure boron concentrations in the soils. Dilute acid was used to extract what is believed to be readily available boron. A modified‐Soxhlet apparatus, which employed continuous leaching with hot water, measured what is believed to be slowly available boron. Plant boron status was determined by analyzing the above ground portion of the plants grown in two soils. The amount of boron in the plant tops provides an indication of biologically available boron or that boron actually available to plants. Although kidney beans and soybeans extracted more boron from the beet soil, both soil extraction procedures indicated that the concentration of boron was higher in the pasture soil. Neither extraction procedure proved reliable in predicting plant response.     

Influence of soil applied boron on yield of berseem (Trifolium alexandrium L.) and soil boron fractions in calcareous soils

A greenhouse experiment was conducted in North-west India to study the effect of soil applied boron on yield of berseem (Trifolium alexandrium L.) and soil boron fractions in boron deficient calcareous soils. Three soils with varying calcium carbonate content viz. 0.75% (Soil I), 2.6% (Soil II), and 5.7% (Soil III) were collected from different sites of Ludhiana, Bathinda, and Shri Muktsar Sahib districts, Punjab, India. The treatments consisted of six levels of soil applied boron viz. 0.5, 0.75, 1.0, 1.25, 1.5, and 2.0 mg B kg^?1 along with control. The green fodder yield and dry matter yield increased significantly at 0.75 mg B kg^?1 soil treatment level in the first cutting, while these were significant at 1.0 mg B kg^?1 soil treatment level in all soils at second, third, and fourth cuttings. Among all three calcareous soils, Soil I with lower calcium carbonate was the best soil in respect of mean yield in comparison to Soil II and Soil III. Combined effect of boron level and soils had significant effect on yield of berseem. There was a significant increase in mean dry root biomass at 1.0 mg B kg^?1 soil level over control and then remained non-significant with further high levels of soil applied boron. The mean dry root biomass decreased significantly for the soils having 0.75%, 2.6%, and 5.7% calcium carbonate levels. Readily soluble fraction is considered to be easily available fraction of B for plant uptake and consisted of 0.47–0.62% in Soil I, 0.31–0.43% in Soil II, and 0.24–0.34% in Soil III of the total boron. Among all B fractions, mean readily soluble, specifically adsorbed, and oxide-bound fractions got increased significantly with increase in B levels. Readily soluble and organically bound B fractions were more in Soil I as compared to Soil II and Soil III. Specifically adsorbed boron, oxide bound fraction, residual and total boron were more in Soil III in comparison to Soil I and Soil II. Among all fractions, residual fraction accounted for the major portion of the total B. It comprised of 92.71–93.90% in Soil I, 94.51–95.40% in Soil II, and 94.91–95.25% in Soil III of the total boron.     

Sequential cold and hot water extract of boron from soils and re‐extraction after adsorption by bentonite,kaolinite, iron,and aluminum hydrous oxides over a range of pH values

Abstract

The relative amounts of boron re‐extracted by cold and hot water sequentially after adsorption, over a range of pH values, onto bentonite, kaolinite, precipitated iron, and aluminum (AI) hydrous oxides have been examined, in an attempt to understand why hot water especially is successful as an extractant to indicate plant availability of boron (B). The relative ability of cold and hot water to extract boron was also tested on some Scottish soils. The recovery of boron adsorbed by bentonite, by extraction with cold water compared with that extracted by hot water, was related to pH, but this was not the case for kaolinite. Comparison of the results for the minerals and soil systems indicates that mineral composition and pH in combination probably regulate the relative extraction power of cold and hot water for soil B. It may be assumed, therefore, that hot water better reflects the capability of plant roots to access B from different adsorption sites than cold water does.     

Hydrolysis of cellobiose by β-glucosidase in the presence of soil minerals - Interactions at solid-liquid interfaces and effects on enzyme activity levels

Extracellular enzymatic activities in soils are essential for the cycling of organic matter. These activities take place in multiphase environments where solid phases profoundly affect biocatalytic activities. Aspergillus niger is ubiquitous in soils; its β-glucosidase plays an important role in the degradation of cellulose, and therefore in the global carbon cycle and in the turnover of soil organic matter. However, the information on the interactions of this protein with soil minerals is very limited, and even less is known about their consequences for the hydrolysis of the natural substrate cellobiose. We therefore characterised the sorptive interactions of this enzyme with the soil minerals montmorillonite, kaolinite and goethite and quantified the resulting changes in the hydrolysis rate of cellobiose. Fractions of adsorbed protein, and the resulting catalytic activity loss, were lower for montmorillonite than for kaolinite and goethite at given experimental conditions; adsorption was 9.7 ± 7.3% for montmorillonite, 70.3 ± 3.1% for kaolinite and 71.4 ± 1.8% for goethite, respectively. Adsorption of the protein to the minerals caused a total decrease in the catalytic activity of 18.8 ± 3.4% for kaolinite and 17.9 ± 4.7% for goethite whereas it was not significant for montmorillonite. The average catalytic activity lost by the pool of adsorbed molecules was 26.8% for kaolinite and 25.0% for goethite. Both the amount of adsorbed protein and the resulting loss of catalytic activity were found to be independent of the specific surface areas yet were influenced by the electrical properties of the mineral surfaces. Under the experimental conditions, montmorillonite and kaolinite are negatively charged whereas goethite is positively charged. However, because of the adsorption of phosphate anions from the buffer, a charge reversal took place at the surface of goethite. This was confirmed by zeta (ζ)-potential measurements in phosphate buffer, revealing negative values for all the tested minerals. Indeed goethite interacted with the enzyme as a negatively charged surface: the amount of adsorbed protein and the resulting catalytic activity loss were very similar to those of kaolinite. Our results show that, even if an important fraction of β-glucosidase is adsorbed to the minerals, the catalytic activity is largely retained. We suggest that this strong activity retention in presence of soil minerals results from a selective pressure on A. niger, which benefits from the activity of the adsorbed, and thus stabilized, enzyme pool.     

Methods of assessing boron availability to kiwifruit plants growing on high boron soils

Abstract

Five soil boron (B) extraction methods were evaluated for their ability to predict available B to kiwifruit plants in soils with high B concentration. The methods were hot water soluble (Hws‐B), 0.05M mannitol in 0.01M calcium chloride (CaCl₂ extractable (Man‐B), 0.05M hydrochloride acid (HCl) soluble (HC1‐B), resin extractable (Resin‐B), and saturation extract (Sat‐B). The amounts of B recovered by the first four methods investigated were strongly correlated with each other, the highest correlation obtained being between Hws‐B and HC1‐B. Plant B was highly correlated to the B recovered by the first four extractants and poorly correlated to the B determined by the saturation method. Soil B concentrations corresponding with B toxicity in kiwifruit are 0.51, 0.80, 0.18, and 2.0 μg‐g^‐1 soil for Hws‐B, Man‐B, HC1‐B, and Res‐B, respectively. The coefficients of determination in some cases were improved when in the regression equations, soil pH and clay content were included.     

Improvement of boron soil test

Abstract

Boron soil tests often do not adequately reflect B plant uptake or deficiency levels in the Eastern United States. In an attempt to develop a better test, the following systems were studied: Silicic acid replacement of boron; B soil buffering power; and the addition of small quantities of boron (0.175 ugB/g‐soil) to each soil sample to overcome some of the stronger boron fixing sites prior to hot water extraction.

Boron extracted with B spiked hot water (r=0.80 for plant tissue B vs. extractable B, opposed to r=0.76 for nonspiked hot water) was the only new test that showed promise.

The results appear to explain why hot water extractable B correlates well with plant uptake for soils previously treated with boron fertilizer (e.g. alfalfa fields); but why, on the other hand, hot water extractable B fails to correlate well with plant boron uptake for soils not having a recent history of boron fertilization. . . in which some fixing sites apparently have to be satisfied before the hot water test will work well.     

Impact of boron fertilization on boron fractions at different crop growth stages in cauliflower_cowpea_okra sequence in an inceptisols of North East India

Abstract

A field experiment was conducted at Horticultural Experimental Farm, Assam Agricultural University, Jorhat during the year 2015–17 to assess the impact of boron fertilization on dynamics of boron fractions in soil and crop yields in cauliflower–cowpea–okra cropping sequence. Five levels of boron (0, 0.5, 1.0, 1.5 and 2.0?kg ha^?1) along with the recommended dose of NPK fertilizer were applied in soil in cauliflower once in each 2 years (2015–17) of experimentation to assess the direct effect of boron fertilization, while cowpea and okra were grown as a suceeding test crop to study the residual effects of boron fertilization in the cropping sequence. Among the different levels of boron, the highest content of all the boron fractions in soil was recorded at rate of 2?kg B ha^?1 at different crop growth stages for all the three crops. Progressive decrease in content of all the boron fractions with crop ageing was noticed. The content of different boron fractions in soil follows the order readily soluble boron (RSB)<oxide bound boron (OXB)<organic bound boron (ORBB)<specifically adsorbed boron (SAB) <residual boron, respectively. The boron level of 2?kg B ha^?1 was found to prominent in increasing the yield in all the crops. In respect of contributions of different boron fractions to yield of crops, oxide bound boron(2.10) was found to be the highest contributor of cauliflower yield, while the residual boron (1.10), contributed the highest to cowpea yield and organic bound boron fraction (1.24) was found to be most prominent contributor of boron in leveraging okra yield.     

Fractionation and colorimetric determination of boron in soils

We attempted to modify and evaluate existing sequential fractionation schemes for B involving the use of chemicals, which subsequently do not interfere with the measurement of B by colorimetry. Also evaluated was the contribution of various soil B fractions to the amount of B extracted by hot CaCl₂, CaCl₂‐mannitol, salicylic acid, ammonium acetate, HCl, and tartaric acid. For this purpose, 17 soils with diverse properties were used. The extraction scheme proposed here partitioned B into five pools, (i) readily soluble, (ii) specifically adsorbed, (iii) oxide bound, (iv) organically bound, and (v) residual boron, respectively extracted with 0.01 M CaCl₂, 0.05 M KH₂PO₄, 0.175 M NH4‐oxalate (pH 3.25), 0.5 M NaOH, and HF + H₂SO₄ + HClO₄. The procedure of elimination of color from extracts of oxide bound, organically bound, and residual B fractions was also evolved. Relationships of individual B fractions with physicochemical properties of the experimental soils confirmed the general validity of the proposed fractionation scheme. The relationships of different B fractions with extractable B in soils suggest that hot CaCl₂ and salicylic acid may be better extractants for available B in soils.     

甘蓝型油菜硼营养高效的遗传分析

利用土壤有效硼缺乏的田间小区试验 ,研究甘蓝型油菜硼营养高效品种和低效品种间 2个杂交二代群体及其回交一代硼营养性状的分离规律。结果发现 ,硼营养高效受一对主效基因控制。在缺硼胁迫下 ,硼高效性状与抽薹天数和生育天数之间紧密连锁 ,生育期 (抽薹天数和生育天数 )可作为甘蓝型油菜硼高效种质筛选及其杂种后代硼效率鉴定和选育的参考指标。     

Field studies with boron on muscadine grapes

Abstract

A 2‐year study failed to show a significant yield response from soil applications of boron to eight‐year‐old muscadine grape vines; however, a definite trend toward yield response was evident from linear regression models. No difference in B levels of tissue occurred the initial year but in the second year, the tissue from the highest B rate was significantly higher than other treatments. Boron content of the soil correlated well with B treatment levels (r = .88). Fruit soluble solids were not related to B treatments.     

Boron toxicity of strawberry

Abstract

Radlands Crimson strawberries were grown in a glasshouse with 7 rates of applied boron. Wood shavings mulches with different boron concentrations were also applied as separate treatments. Boron toxicity symptoms were produced in leaves by boron rates of 0.32 kg ha^‐1 and greater on a soil containing 1.6 ug B g^‐1 of hot water extractable boron. Concentrations greater than 123 μg B g^‐1 in old leaves were associated with boron toxicity symptoms.

In the B rate experiment, soil boron concentrations greater than 1.9 μg B g^‐1 soil were associated with leaf toxicity symptoms which increased in severity with increasing soil boron concentrations up to 4.1 μg B g^‐1 soil. Wood shavings mulch containing 17 μg B g^‐1 caused boron toxicity symptoms in older leaves whereas mulches containing less than 6 μg B g^‐1 did not produce toxicity symptoms.     

Is occluded phosphate plant‐available?

Background: The phosphate concentration of the soil solution is generally low, allowing sufficient plant nutrition only for a few days. Therefore, supply from various fractions of bound phosphate is essential to meet plant demand. It is known that plants have developed strategies to acquire phosphorus (P) from phosphates adsorbed on clay minerals or oxides, from organically bound phosphates, and from calcium phosphates. However, it is generally assumed that occluded phosphate is not plant‐available. Results: In a pot experiment, two plant species, namely maize (Zea mays L.) and white lupin (Lupinus albus L.), differing in acquisition efficiency, were used to investigate whether Al oxide‐occluded and Fe oxide‐occluded phosphates can be acquired. Artificially prepared Al oxide‐occluded phosphate or Fe oxide‐occluded phosphate, respectively, was added to a subsoil low in available phosphates. It is shown that both plant species were not able to acquire P from Al oxide‐occluded phosphate. Also, maize was incapable of using Fe oxide‐occluded phosphate. In contrast, white lupin took up significant amounts of P from Fe oxide‐occluded phosphate. Conclusion: It is concluded that the strategy to form cluster roots together with their reducing power may allow white lupin to destabilize Fe oxides that occlude phosphates and to mine the soil for this additional phosphate fraction.     

Effect of boron and farmyard manure application on growth,yields, and boron nutrition of sunflower

To examine the role of organic manure on boron (B) availability, a greenhouse experiment was conducted to study the effect of B and farmyard manure (FYM) levels on growth, yields, and B accumulation of sunflower (Helianthus annuus L.). Application of B or FYM individually increased the plant height, capitulum diameter, dry matter yields of seed and stalk and their B concentration and accumulation. The interaction of B and FYM levels had a significant influence only on B concentration of stalk and total B accumulation of sunflower. In the absence of B application, use of highest level of FYM (10 g kg^‐1 soil) significantly increased B concentration of stalk and total B accumulation by the crop while with B application, use of FYM at lower rates was effective. Application of B or FYM, especially at higher rates of the latter (5 and 10 g FYM kg^‐1 soil) increased the content of hot‐water soluble soil B in the soil after crop harvest. The interaction of B and FYM levels had no significant effect on the content of hot‐water soluble soil B. Application of FYM increased apparent availability of native and added B from soil to sunflower crops.