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There is a wide application of rhizobia inoculants to legume crops in Africa, irrespective of the soil acidity, though the latter limits the effectiveness of inoculants. Two trials were conducted in a controlled environment to determine suitable soil pH and impact of liming on soybean nodulation and nitrogen fixation to inform proper application of the rhizobia-inoculant technology on acid soils. In the first trial; soil, variety and inoculation had significant influence (p < 0.05) on weighed nodule effectiveness (WNE) and N fixation. Strongly acidic soils recorded low WNE and N fixation. In the second trial, WNE and N fixation significantly increased with co-application of lime and inoculation (p < 0.05). The results showed that soybean inoculation is effective in increasing nodulation and N fixation in moderate acidic soils, contrarily to strongly acidic soils. Interestingly, co-application of lime and inoculation has potential of increasing nodulation and N fixation in strongly acidic soils. The WNE is recommended as a robust formula to report nodule effectiveness, compared to the current percentage method. [ABSTRACT FROM AUTHOR]

Good soil structure is important for achieving high productivity of agricultural land and also affects the ability of soil to withstand erosive forces. Given the importance of soil structure, efforts are commonly made to improve it, usually by application of amendments of different kinds (e.g. lime, biochar, compost, manure etc.). However, little is known about the effect of these amendments on the soil resistance to detachment. This study assessed the resistance to detachment of soil cores treated with different liming products, using a cohesive strength meter (CSM) which measures the rate of soil detachment under the action of water jets at different pressures. The amount of soil removed by the water jets was taken as an indirect measure of soil resistance to detachment, under the assumption that more resistant soils will lose less material than more susceptible soils at a given water jet pressure. The results showed that all soil amendments studied reduced detachment of particles under the action of water jets compared with unamended soil (control). [ABSTRACT FROM AUTHOR]

It has been suggested that liming can improve soil structure and thereby decrease losses of particles and associated nutrients. In this study, two types of structure lime, slaked lime (Ca(OH)2) and a mixed product of calcium carbonate (CaCO3) and slaked lime (Ca(OH)2), were applied at three different rates in field trials on clayey soils (23%–40% clay). A combination of primary tillage and structure liming was also studied, in a split-plot trial on a clayey soil (25% clay). Aggregate (2–5 mm) stability, measured as reduction in turbidity (which is strongly correlated with losses of particulate phosphorus), was significantly increased with the highest application rates of both structure lime products. Aggregate size distribution was also improved with structure lime, creating a finer tilth in the seedbed. Yield response to structure lime was not consistent, with both negative and positive responses over the four-year study period. Positive yield responses can possibly be attributed to the finer tilth preventing evaporation in two dry growing seasons. Negative yield responses were probably an effect of impaired phosphorus availability associated with limited precipitation in May-July in 2011 and 2013. Two years after liming, soil pH levels were significantly elevated in plots with the highest application rate of structure lime, whereas no significant increases were found three years after liming. However, a lingering effect of liming was still detectable, as manganese concentration in barley grain was significantly lower in plots with the highest application rates of both structure lime products in the fourth study year. These results indicate that structure liming can be used as a measure to mitigate phosphorus losses from clayey soils, thereby preventing eutrophication of nearby waters. However, the yield response was varying and unpredictable and thus further investigations are needed to determine the circumstances in which field liming can act efficiently not only to prevent phosphorus losses, but also to ensure consistent yield increases. [ABSTRACT FROM AUTHOR]

Aluminum toxicity is a major limitation to crop production on highly weathered and leached soils in Rwanda. Moreover, sulfur though widely deficient in Rwanda acidic soils has received little attention by soil fertility researchers. A field experiment on maize response and soil nutrients status to liming materials of travertines at 3.4 t ha−1, ash wood 1.2 t ha−1of CaO equivalent and sulfur at 10 kg ha−1combined with NPK at 80, 60, and 45 kg ha−1respectively was conducted in Rubona Ultisol and Nyamifumba Oxisol. Results revealed that travertine and wood ash increased the soil pH from 4.7 to 5.8 or higher and decreased exchangeable Al3+and H+to near 0 cmolc kg−1. Soil nutrients generally increased to high or medium ranges for crop production. Leaf dry biomass, plant height and maize grain yields were significantly higher in Rubona Ultisol than in Nyamifumba Oxisol. Plots that received wood ash, with NPKS or with NPK, generally had higher maize yields, followed by those which received travertines and NPKS or NPK which had maize growth response as compared to the control plots which received NPK only. Thereby, a combination of wood ash with NPKS or NPK, travertines with NPKS was found to neutralize soil aluminum toxicity, increase soil nutrients status to required levels for plant growth and increase maize yields significantly. [ABSTRACT FROM PUBLISHER]

This paper presents the results of experiments carried out at the Vezaiciai Branch of the Lithuanian Institute of Agriculture during the period 1996-2004. The effects of long-term liming (at × 0.5 rate=3.8 t ha-1 CaCO3 every 7 years and × 2.0 rate=15.0 t ha-1 CaCO3 every 3-4 years) on soil chemical properties, aggregate composition and population distribution of micro-organisms and activity of two enzymes across different size classes of soil aggregates (<0.25, 0.25-0.5, 0.5-1.0, 1.0-2.0, 2.0-3.0 and 3.0-5.0 mm) were investigated. The soil of the experimental site is a Dystric Albeluvisol and textural class is sandy loam (sand (2.0-0.05 mm) 51%; silt (0.05-0.002 mm) 34%; clay (<0.002 mm) 15%). Moderate periodical liming at×0.5 rate every 7 years enabled us to maintain soil reaction at a low acidity level (pH in KCl 5.5), whereas when the soil was limed intensively at × 2.0 rate every 3-4 years topsoil reaction was slightly alkaline: pH in KCl 7.2. Moderate liming (×0.5 rate every 7 years) affects an increase in the amount of agronomically-valuable mesoaggregates (especially of 1.0-2.0 and 1.0-0.5 mm size class). Microbe distribution in different aggregate fractions in acid and moderately limed soil were not significantly different. In intensively limed soil, there was an observed tendency of microbe displacement from the smallest aggregate-size classes to the largest (1.0-2.0 mm). [ABSTRACT FROM AUTHOR]

The aim of this study was to critically assess the accumulation and depletion in total contents of trace elements from non-point pollution areas, specifically agricultural fields. Enrichment or depletion of trace elements was assessed using Al, Fe and V (control topsoil and B horizon) as reference elements. We found that various reference elements and selecting reference horizons could give contradictory results and lead to different assessments of the effects of various agricultural practices in Lithuanian soils. Cultivation on naturally acid soils in east and west Lithuania led to enrichment in some trace elements, predominantly Ag, Mn and Sr in sandy loams or loams of west Lithuania and B, Cu and Sr in sandy loams of east Lithuania. Differential fertilization led to Sr accumulation in calcareous silt loams of central Lithuania. Many experiments revealed Sr accumulation, which means that Sr concentrations have profoundly changed during decades of soil fertilization and liming in Lithuanian soils. Subsoil reference indicated a greater number of affected elements in almost all the cases. It is probable that other regional factors (such as atmospheric pollution and precipitation chemistry) influence differences in enrichment factors (EFs) between topsoils and subsoils. Research findings accord with earlier published results on changes of mobile element forms after liming and adds knowledge on the total amounts of affected elements. We suggest that assessment protocols using a few reference elements and soil layers allow filtering of datasets and indicate reliable changes in enrichment factors (EFs). However, changes occurred in other specific elements in specific circumstances, and these reference elements merit special attention. Reference selection procedures also merit further investigation and discussion. [ABSTRACT FROM AUTHOR]

A field experiment investigating amendments of organic material including farmyard manure, paper factory sludge and crop residues combined with fly ash, lime and chemical fertilizer in a rice-peanut cropping system was conducted during 1997-98 and 1998-99 at the Indian Institute of Technology, Kharagpur, India. The soil was an acid lateritic (Halustaf) sandy loam. For rice, an N:P:K level of 90:26.2:33.3 kg ha-1 was supplied through the organic materials and chemical fertilizer to all the treatments except control and fly ash alone. The required quantities of organic materials were added to supply 30 kg N ha-1 and the balance amount of N, P and K was supplied through chemical fertilizer. Amendment materials as per fertilization treatments were incorporated to individual plots 15 days before planting of rice during the rainy season. The residual effects were studied on the following peanut crop with application of N:P:K at 30:26.2:33.3 kg ha-1 through chemical fertilizer alone in all treatments, apart from the control. An application of fly ash at 10 t ha-1 in combination with chemical fertilizer and organic materials increased the grain yield of rice by 11% compared to chemical fertilizer alone. The residual effect of both lime and fly ash applications combined with direct application of chemical fertilizer increased peanut yields by 30% and 24%, respectively, compared to chemical fertilizer alone. Treatments with fly ash or lime increased P and K uptake in both the crops and oil content in peanut kernel compared to those without the amendments. Alkaline coal fly ash proved to be a better amendment than lime for improving productivity of an acid lateritic soil and enriching the soil with P and K. [ABSTRACT FROM AUTHOR]