Measurement of in situ Phosphorus Availability in Acidified Soils using Iron-Infused Resin

A hybrid anion resin was tested for in situ phosphorus (P) availability measurement in soils of two stands recovering from acidification and having different P-sorption characteristics. The phosphate (P-PO₄) sorption capacity of the resin (before saturation) was 48 µmol g^?1. Sorption and elution were tested under P-PO₄ concentrations common in acidic soils (0–0.42 mmol l^?1) either with or without the presence of sulfate (0.2 mmol l^?1). The efficiency of P-PO₄ sorption was independent of the sulfate and was 100 ± 0.2% (n = 56, ± SD). The P-PO₄ recovery stabilized after six elution steps (each: 50 ml of 0.5 M sodium hydroxide, resin/solution 5:1). The efficiency of P-PO₄ recovery was 80 ± 7% and was used to evaluate field measurements. We determined the amount of P-PO₄ in the field using resin bags in three consecutive years. The results indicate that bioavailable P is negatively related to the soil ability to retain P.     

水温对磷化铝片剂产生磷化氢的影响

在实验室内用排集气法测定国产磷化铝片剂与水反应释放磷化氢进行实验。分别测定了10℃、20℃、30℃、40℃和50℃的水温下单片磷化铝片剂的产气量，并对不同水温下的产气量和产气速率进行了分析。结果表明，在30℃以下的水温条件下磷化铝片剂与水反应完全放出磷化氢需要比较长的时间，水温高于40℃时反应速率明显加快，水温高于50℃以后，在2小时左右片剂在水中基本上可以完全将磷化氢释放出来。     

Changes in the chemical properties of acid soil and aggregate stability in the whole profile under long-term management history

ABSTRACT

The effects of long-term (1959–2005) liming in combination with cattle manure application on the chemical properties and aggregate stability of acid soil were investigated in the whole soil profile to a 100 cm depth. Investigations were performed in a long-term liming and fertilizing field trial at Vezaiciai Branch of Lithuanian Research Centre for Agriculture and Forestry situated in West Lithuania. The soil of the study site is Bathygleyic Distric Glossic Retisol (WRB 2014) with a texture of moraine loam. Acid soil had been periodically limed and manured at different intensity for 47 years. The experiment involved the following treatments: (1) unlimed and unfertilized (control); (2) unlimed and 60 t ha^?1 manure; (3) limed and unfertilized; and (4) limed and 60 t ha^?1 manure. During the 47-year period, liming was performed using pulverized limestone at a rate 1.0 (by hydrolytic soil acidity) every 7 years. During the whole study period, the soil received 38.7–36.5 t ha^?1 CaCO₃; 840 t ha^?1 cattle manure, 2740 kg ha^?1 mineral nitrogen; 3030 kg ha^?1 phosphorus and 3810?kg?ha^?1 potassium. The data showed that long-term (47 years) periodic liming of different intensities in combination with cattle manure application significantly changed the chemical properties of the whole soil profile. The soil acidification was neutralized in the topsoil and subsoil to the 60?cm depth when the soil had been systematically limed with 1.0 rate every 7 years in combination with 60?t?ha^?1 manure application every 3–4 years. Periodic long-term liming in combination with manuring had a positive effect on the improvement of chemical properties of acid soil profile in the ElB₁ and ElB₂ horizons. The data of the soil structure in the topsoil and subsoil showed that such liming practice together with manuring had a positive effect on soil aggregate stability.     

Extraordinary high aluminium tolerance of the acidophilic thermophilic alga,Cyanidium caldarium

A strain of an acidophilic, thermophilic alga, Cyanidium caldarium, was cultured in a medium containing various metal ions (A1, Cd, Cr, Cu, Mn, Ni, Zn). Among these metals, the alga tolerates especially high levels of AI: it can grow in a medium containing 200 mM AI, although the growth rate was reduced to 58%. The cellular Al concentration was kept at a considerably lower level as compared to the medium Al concentration. This may account for the Al tolerance of the alga. Treatment of the algal cells with carbonylcyanide m-chlorophenylhydrazone in the presence of Al increased the cellular Al concentration. It was suggested that energy-coupled Al exclusion mechanisms can operate in the alga.     

Relationships between the Ratio of Plant-Available Phosphorus (P-AL) to Total Phosphorus and Soil Properties

Abstract

The relationships between the ratio of plant-available phosphorus (P-AL) to total P and soil properties were examined in 52 samples of mineral soils collected from different parts of Norway. The ratio P-AL/total P in the soils was used as a measurement of a soil's capacity to bind P in sparsely soluble forms and of the possibility for plants to utilize added P. Simple regression analysis showed that the ratio P-AL/total P was correlated with clay (r= ?0.60???, significant at the 0.1% probability level), Tamm acid oxalate extractable Fe (r= ?0.63???), and Tamm acid oxalate extractable Al (r-= ?0.44???), but not with organic C and pH. Variation of Fe, Al and clay content could explain 50% of the variation of the ratio of P-Al/total P. Partial correlation coefficients showed that Fe was the most important factor explaining the variation of the ratio of P-AL/total P.     

Extraction methods for aluminium and iron in relation to phosphate adsorption

Abstract

Three extraction methods for aluminium and two for iron were compared with phosphate sorptivity (Bache and Williams index) for 40 tropical and 40 British soil samples. Extractable aluminium was well correlated with phosphate sorptivity in both groups, but extractable iron was well correlated only in British soils. In general methods which extracted more sesquioxides gave higher correlation coefficients. With aluminium, N ammonium acetate (pH 4.8) or 0.1N HCl gave better correlation than N KCl, while with iron dithionitecitrate was better than 0.1N HCl.     

Aiuminium tolerance of durum wheat germplasm

Summary Aluminium tolerance of Macedonian durum wheat (Triticum turgidum L. conv. durum (Desf.) MacKey) germplasm was evaluated in nutrient solutions containing 0, 74 or 148 M of total Al. Relative root length (148 M Al/0 Al) of various genotypes ranged from 41 to 72% (from moderately sensitive to moderately tolerant to Al). No genotype with Al tolerance close to that of very tolerant T. aestivum cultivar Atlas-66 was found. Seed Ca concentration was positively (r=0.64, P0.05) and seed Fe concentration negatively (r=–0.71, P0.05) related to the relative root growth. Such a significant correlation was not obtained for seed concentrations of other nutrients or seed protein content.Abbreviations HSD Tukey's Honestly Significant Difference - RRL-2 relative root length, in % (74 M total Al/0 M Al) - RRL-4 relative root length, in % (148 M total Al0 M Al)     

Soil base saturation affects root growth of European beech seedlings§

To assess the potential effects of Al toxicity on the roots of young European beech (Fagus sylvatica L.), seeds were sown in soil monoliths taken from the Ah and B horizons of forest soils with very low base saturation (BS) and placed in the greenhouse. The Ah horizons offered a larger supply of exchangeable cation nutrients than the B horizons. After 8 weeks of growth under optimal moisture conditions, the seedlings were further grown for 14 d under drought conditions. Root‐growth dynamics were observed in rhizoboxes containing soils from the Ah and B horizons. The concentrations of Al³⁺, base cations, and nitrate in the soil solution and element concentrations in the root tissue were compared with above‐ and belowground growth parameters and root physiological parameters. There was no strong evidence that seedling roots suffered from high soil‐solution Al³⁺ concentrations. Within the tested range of BS (1.2%–6.5%) our results indicated that root physiological parameters such as O₂ consumption decreased and callose concentration increased in soils with a BS < 3%. In contrast to the B horizons, seedlings in the Ah horizons had higher relative shoot‐growth rates, specific root lengths, and lengths and branching increments, but a lower root‐to‐shoot ratio and root‐branching frequency. In conclusion, these differences in growth patterns were most likely due to differences in nutrient availability and to the drought application and not attributable to differences in Al³⁺ concentrations in the soil solution.     

A rapid method for screening barley for aluminium tolerance

Summary A method for rapid screening of large numbers of barley genotypes for aluminium tolerance is described, and the results of a small scale screening of composite cross CC XXX-C given.     

Sand culture of mycorrhizal plants

In this work, a sand culture system for ecto- or arbuscular mycorrhizal plants was developed. Nutrients were added into the sand at a constant rate using solutions with similar concentrations of nutrients as those found in forest soil solutions. Plants grew well in the system and inoculated plants developed abundant ecto- or arbuscular mycorrhizas. To test the suitability of the culture system for studies on metal toxicity, aluminium was added to the nutrient solutions of non-mycorrhizal and mycorrhizal spruce seedlings. Measurments of labile Al in the solution draining from the sand revealed that Al was mainly present as phytotoxic monomeric Al. In addition, concentrations of Ca²⁺, Mg²⁺ and SO₄^2— ions which have the potential to alleviate Al toxicity, were similar in the draining as in the nutrient solutions. After 10 weeks of exposure to 400 μM Al, taproot growth as well as Ca and Mg uptake of the seedlings were impaired by Al. Mycorrhizal colonization had no effect on the degree of inhibition of these processes. We conclude that this culture system is suitable for investigations on effects of Al and other toxic metals on mycorrhizal tree seedlings.