scholarly journals Extent and distribution of surface soil acidity in the rainfed areas of Ethiopia

Author(s):  
Gizaw Desta ◽  
Tibebu Kassawmar ◽  
Matebu Tadesse ◽  
Gete Zeleke

The soil acidity level is a key soil characteristic that determines soil nutrient availability, soil microbial activities and crop growth. However, studies on distribution and extent of soil acidity in Ethiopia are not available. This study was carried out to predict the extent and severity of soil acidity. The study used 88,265 soil pH samples collected from soil laboratories and 21,439 samples compiled from studies. Rainfall, altitude, slope gradient, soil, and land cover were considered to generate spatial autocorrelation and integrated into geospatial analysis to predict the soil pH. The performance of the kriging model was found to be satisfactory with a standard error of 0.77, RMSE of 0.51, and R2 of 0.74. The model estimates showed that 47% and 30.2% of the country’s total area and rainfed areas were acidic (pH<6.5), respectively. Out of the total area of the country, 3.7% is found to be extremely to strongly acidic (pH<5.5), 20.7% is moderately acidic (5.6

BUANA SAINS ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 109
Author(s):  
Bambang Siswanto

Soil nutrient availability maps are needed to be used as a basis for managing fertilizer use, as well as soil acidity (pH) values. If the nutrient status of N, P, K and soil acidity is known, it is expected that the dosage of fertilization of each land can be done in accordance with thenutrient status. It can also reduce the cost of fertilization. This study aims to determine the factors of land affecting the distribution of nutrients N P K and soil pH. The research was conducted in Gugut Village, Rambipuji District, Jember from June to August 2016. The research was conducted by using free grid survey method with semi-detailed survey rate of 1: 25.000 scale. The distribution pattern of each nutrient status was analyzed by matrix method approach to find out the factors that most influence the distribution of nutrients N, P, K and pH.  From the result of research, map of nutrient distribution of N, P, K is almost similar to the result of geological map overlay, landform, land use and altitude. According to Wilding and Drees (1983), the diversity of nutrient status can be due to differences in lithology / parent material, climate, erosion, biological influences, and hydrology. The N, P, K soil availability map only meets 32.76% of the elevation map section. Therefore, the temporal nutrient status mapping can not be generated based on existing land map units so it is advisable to use the rigid grid method. While soil pH maps are almost similar to overlays between geological maps, landforms, land use and climate.


1977 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
W. A. RICE ◽  
D. C. PENNEY ◽  
M. NYBORG

The effects of soil acidity on nitrogen fixation by alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) were investigated in field experiments at 28 locations, and in greenhouse experiments using soils from these locations. The pH of the soils (limed and unlimed) varied from 4.5 to 7.2. Rhizobia populations in the soil, nodulation, and relative forage yields (yield without N/yield with N) were measured in both the field and greenhouse experiments. Rhizobium meliloti numbers, nodulation scores, and relative yields of alfalfa decreased sharply as the pH of the soils decreased below 6.0. For soils with pH 6.0 or greater, there was very little effect of pH on any of the above factors for alfalfa. Soil pH in the range studied had no effect on nodulation scores and relative yields of red clover. However, R. trifolii numbers were reduced when the pH of the soil was less than 4.9. These results demonstrate that hydrogen ion concentration is an important factor limiting alfalfa growth on acid soils of Alberta and northeastern British Columbia, but it is less important for red clover. This supports the continued use of measurements of soil pH, as well as plant-available Al and Mn for predicting crop response to lime.


2021 ◽  
Vol 97 (4) ◽  
Author(s):  
Lucas Dantas Lopes ◽  
Jingjie Hao ◽  
Daniel P Schachtman

ABSTRACT Soil pH is a major factor shaping bulk soil microbial communities. However, it is unclear whether the belowground microbial habitats shaped by plants (e.g. rhizosphere and root endosphere) are also affected by soil pH. We investigated this question by comparing the microbial communities associated with plants growing in neutral and strongly alkaline soils in the Sandhills, which is the largest sand dune complex in the northern hemisphere. Bulk soil, rhizosphere and root endosphere DNA were extracted from multiple plant species and analyzed using 16S rRNA amplicon sequencing. Results showed that rhizosphere, root endosphere and bulk soil microbiomes were different in the contrasting soil pH ranges. The strongest impact of plant species on the belowground microbiomes was in alkaline soils, suggesting a greater selective effect under alkali stress. Evaluation of soil chemical components showed that in addition to soil pH, cation exchange capacity also had a strong impact on shaping bulk soil microbial communities. This study extends our knowledge regarding the importance of pH to microbial ecology showing that root endosphere and rhizosphere microbial communities were also influenced by this soil component, and highlights the important role that plants play particularly in shaping the belowground microbiomes in alkaline soils.


2021 ◽  
Vol 13 (4) ◽  
pp. 2226
Author(s):  
Joisman Fachini ◽  
Thais Rodrigues Coser ◽  
Alyson Silva de Araujo ◽  
Ailton Teixeira do Vale ◽  
Keiji Jindo ◽  
...  

The thermochemical transformation of sewage sludge (SS) to biochar (SSB) allows exploring the advantages of SS and reduces possible environmental risks associated with its use. Recent studies have shown that SSB is nutrient-rich and may replace mineral fertilizers. However, there are still some questions to be answered about the residual effect of SSB on soil nutrient availability. In addition, most of the previous studies were conducted in pots or soil incubations. Therefore, the residual effect of SSB on soil properties in field conditions remains unclear. This study shows the results of nutrient availability and uptake as well as maize yield the third cropping of a three-year consecutive corn cropping system. The following treatments were compared: (1) control: without mineral fertilizer and biochar; (2) NPK: with mineral fertilizer; (3) SSB300: with biochar produced at 300 °C; (4) SSB300+NPK; (5) SSB500: with biochar produced at 500 °C; and (6) SSB500+NPK. The results show that SSB has one-year residual effects on soil nutrient availability and nutrient uptake by maize, especially phosphorus. Available soil P contents in plots that received SSB were around five times higher than the control and the NPK treatments. Pyrolysis temperature influenced the SSB residual effect on corn yield. One year after suspending the SSB application, SSB300 increased corn yield at the same level as the application of NPK. SSB300 stood out and promoted higher grain yield in the residual period (8524 kg ha−1) than SSB500 (6886 kg ha−1). Regardless of pyrolysis temperature, biochar boosted the mineral fertilizer effect resulting in higher grain yield than the exclusive application of NPK. Additional long-term studies should be focused on SSB as a slow-release phosphate fertilizer.


2021 ◽  
Author(s):  
Amanda E. Knauf ◽  
Creighton M. Litton ◽  
Rebecca J. Cole ◽  
Jed P. Sparks ◽  
Christian P. Giardina ◽  
...  

Pedosphere ◽  
2016 ◽  
Vol 26 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Adel Rabie A. USMAN ◽  
Mohammad I. AL-WABEL ◽  
Yong S. OK ◽  
Abdulaziz AL-HARBI ◽  
Mahmoud WAHB-ALLAH ◽  
...  

1977 ◽  
Vol 57 (2) ◽  
pp. 157-164 ◽  
Author(s):  
D. C. PENNEY ◽  
M. NYBORG ◽  
P. B. HOYT ◽  
W. A. RICE ◽  
B. SIEMENS ◽  
...  

The amount of cultivated acid soil in Alberta and northeastern British Columbia was estimated from pH values of farm samples analyzed by the Alberta Soil Testing Laboratory, and the effect of soil acidity on crops was assessed from field experiments on 28 typical acid soils. The field experiments consisted of two cultivars of barley (Hordeum vulgare L.) and one cultivar each of rapeseed (Brassica campestris L.), red clover (Trifolium pratense L.) and alfalfa (Medicago sativa L.) grown with and without lime for 2 yr. There are about 30,000 ha of soils with a pH of 5.0 or less where soil acidity seriously restricts yields of all four crop species. There are approximately 300,000 ha with a soil pH of 5.1–5.5 where liming will on the average increase yields of alfalfa by 100%, yields of barley by 10–15%, and yields of rapeseed and red clover by 5–10%. There are a further 1,600,000 ha where soil pH ranges from 5.6 to 6.0 and liming will increase yields of alfalfa by approximately 50% and yields of barley, rapeseed and red clover by at least 4–5%.


1998 ◽  
Vol 78 (3) ◽  
pp. 477-479 ◽  
Author(s):  
C. J. Westman ◽  
S. Jauhiainen

Forest soil pH in southwest Finland was measured with identical sampling and analysing methods in 1970 and 1989. The acidity of the organic humus layer increased significantly as pH values measured on water and on salt suspensions decreased between the two sampling dates. For the mineral soil layers, no unambiguous trend was found. pH values measured on salt suspension tended to be unchanged or lower, while pH on water suspension in some soil layers were even higher in 1989 than in 1970. Key words: pH, repeated sampling


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