Determination of critical pH and Al concentration of acidic Ultisols for wheat and canola crops

Abstract

Abstract. Soil acidity has become a serious constraint in dry land crop production systems of acidic Ultisols in tropical and subtropical regions of southern China, where winter wheat and canola are cultivated as important rotational crops. Regardless of other common existing concerns in acidic Ultisols of southern China, it needs to be investigated whether soil acidity has any effect on wheat and canola growth. There is little information on the determination of critical soil pH as well as aluminium (Al) concentration for wheat and canola crops. The objective of this study was to determine the critical soil pH and exchangeable aluminium concentration (AlKCl) for wheat and canola production. Two pot cultures with two Ultisols from Hunan and Anhui were conducted for wheat and canola crops in a controlled growth chamber, with a completely randomized design. A soil pH gradient ranging from 3.7 (Hunan) and 3.97 (Anhui) to 6.5, with three replications, was used as a treatment. Aluminium sulfate (Al2(SO4)3) and hydrated lime (Ca(OH)2) were used to obtain the target soil pH levels. Plant height, shoot dry weight, root dry weight, and chlorophyll content (SPAD value) of wheat and canola were adversely affected by soil acidity in both locations. The critical soil pH and AlKCl of the Ultisol from Hunan for wheat were 5.29 and 0.56 cmol kg−1, respectively. At Anhui, the threshold soil pH and AlKCl for wheat were 4.66 and 2.36 cmol kg−1, respectively. On the other hand, the critical soil pH for canola was 5.65 and 4.87 for the Ultisols from Hunan and Anhui, respectively. The critical soil exchangeable Al for canola cannot be determined from the experiment of this study. The results suggested that the critical soil pH and AlKCl varied between different locations for the same variety of crop, due to the different soil types and their other soil chemical properties. The critical soil pH for canola was higher than that for wheat for both Ultisols, thus canola was more sensitive to soil acidity. Therefore, we recommend that liming should be undertaken to increase soil pH if it falls below these critical soil pH levels for wheat and canola production.

Evaluation of plant growth promotion properties and induction of antioxidative defense mechanism by tea rhizobacteria of Darjeeling, India

“…In the slightly acidic soils of Darjeeling district (4.2 < pH < 7.0), base cations such as calcium (Ca), magnesium (Mg), potassium (K) and sodium (Na) are replaced by protons and subsequently leached from the rhizosphere zone of the crops and thereby become unavailable 22 . Previous studies have shown that the lower soil availability of Ca, Mg, K, and P can be detrimental towards crop growth and development in acidic soils 46 , 47 . Moreover, crop production is shown to be already limiting at pH values below 5.5–6.5 48 .…”

Biochar physicochemical properties: pyrolysis temperature and feedstock kind effects

“…The increases in pH and the corresponding reduction in exchangeable Al could also have improved the chemical environment (e.g. soil pH, soil organic matter, phosphorus (P) or potassium (K) contents) of the biocharamended soils for radish plants (Abdulaha-Al Baquy et al 2017). Chan et al (2007) reported that the pH increases were accompanied by a significant reduction in exchangeable Al by [ 50.0% at the higher rates of biochar application, i.e., 50.0 and 100.0 t/ha.…”

Performance assessment of nanoparticulate lime to accelerate the downward movement of calcium in acid soil

“…The nanoparticulate liming effect was interpreted in terms of the critical limits of soil pH and Ca ex for plant growth and yield: pH < 5.0 is very low, 5.1–5.4 is low, 5.5–5.9 is medium, and > 6.0 is high; Ca ex < 2.0 cmol c kg −1 is low, 2.1–4.0 cmol c kg −1 is medium, and > 4.0 cmol c kg −1 is high (Rheinheimer, Tiecher, Gonzatto, Zafar, & Brunetto, ). The critical Al ex of the Ultisol for sensitive crops such as wheat is 0.56 cmol c kg −1 (Al Baquy, Li, Xu, Mehmood, & Xu, ).…”