Progress of Soil Acidity Management Research in Ethiopia

FEKADU Mosissa

Greener Journal of Soil Science and Plant Nutrition, vol. 5, no. 2, pp. 009-022, 2018

Ethiopian Institute of Agricultural Research, Holeta Research Center, Ethiopia.

INTRODUCTION

Soil acidity associated to Al toxicities, soil erosion and soil nutrient depletion are the main soil related constraints to agricultural development in parts of developing countries relying on agricultural to feed their growing population (ToleraAberaet al., 2006). In Ethiopia, huge surface areas of the highlands located at almost all regional states of the country are affected by soil acidity. From current ATA report it was estimated that about 43 % of the total arable land in Ethiopia is affected by soil acidity. Soil acidity problem is significant in the north-western, south-western, southern and central regions of the country which receive precipitation high enough to leach down soluble salts and/or basic cations appreciably from the surface layers (root zone) of the soils. Some of the well-known areas severely affected by soil acidity in Ethiopia are Ghimbi, Nedjo, Hossana, Sodo, Chencha, Hagere-Mariam and Awi Zone of the Amahara Regional State (MoARD, 2007).

Nitosol/Oxisol soils are the main soil classes dominated by soil acidity. Under acidic soil conditions there has been a gradual depletion of soil bases (such as Ca, Mg and K) and soil acidity developed. Soil acidity mainly at soil pH < 5.5 affects the growth of crops due to high concentration of aluminum (Al) and manganese (Mn), and deficiency of P, nitrogen (N), sulfur (S) and other nutrients (Abreha, 2013).

Over use of agricultural by products (crop residue) and continuous crop harvest (without proper fertilization), removal of cations (Wang et al., 2006) and continues use of acid forming inorganic fertilizers (Bolan et al., 1991)make important contribution to soil acidity development in most highland areas of Ethiopia.

Continuous application of chemical fertilizers withN and/or P nutrients only in the form of DAP and urea, in the country, has adversely affected soil physical properties such as soil structure and bulk density(Brady and Weil, 2008). Besides, the practice can aggravate soil acidification and depletion of macro and micro plant nutrients to amounts below critical level needed for optimal crop growth and production (Marschner and Rengal, 2007;Sposito, 2008; Fageriaet al., 2011). Thus, in Ethiopia, acidity related soil fertility problems are major production constraints reducing the productivity of the major crops grown in the country (IFPRI, 2010).

The detrimental effect of soil acidity on plant growth and yield is mainly attributed to the deficiency of phosphorus, which is caused by adsorption of P to colloidal fractions and conversion to insoluble Al and/or Fe compounds and toxicity of aluminum, iron and manganese (Sumner, 2000; Hocking, 2001; Brady and Weil, 2008). Deficiencies of calcium, magnesium, potassium and molybdenum have also been reported to limit crop yield in acid soils (Sumner, 2000).

Soil acidity problems are commonly corrected by applying lime. Surface liming ameliorates topsoil acidity in a relatively short term, but is generally slow in ameliorating subsoil acidity (Ernani et al., 2004).

Amelioration of soil acidity by surface liming to attain a pH range which is suitable for better crop production is crucial in order to get reasonable yields in acid prone areas.In order to alleviate the soil acidity problem using agricultural lime different research activities have been done with different organizations in different parts of the country.

For a long ago, different stakeholders, Agricultural Research Institutes (both federal and regional), Universities and nongovernmental organizations used lime to reclaim acid soils. A well coordinated research activity on acid soil was started following the restructuring of EIAR in 2008. The soil acidity research project commenced its mission by identifying hot spot soil acidity benchmark sites throughout the country. Holetta Agricultural Research Center was mandated to Bedi, Emdibir and Nedjo benchmark sites that represents low, medium and highly acidic soils of the country respectively. Similarly Jima, Asosa, Pawe, Wendogenet and Tepi research centers are also conducting researches on acid soils. 

The objectives of this review were to summarize the past lime technology research achievements and recommend futureresearch direction for lime technology.

MATERIALS AND METHODS

Academic publications were searched through both electronic and hard copy literature sources. A large set of keywords were chosen to identify as many publications as possible. These include soil acidity, nitisol, lime, phosphorus, pH, exchangeable acidity.Moreover, publications in hard copies (research reports, articles in journals,chapter in books, proceedings andthesis) were obtained from different institutions such as Ethiopian Institute of Agricultural Research (EIAR), Regional Agricultural Research Institute (RARIs), NGO’s and personal communication. Only publications dealing with a progress of acid soil management research in Ethiopia were selected and arranged together for this review. Articles published only after 2000 were considered.

RESULTS AND DISCUSION

Phosphorus status of the reddish-brown soils of Ethiopian highlands

The reddish-brown soils of the Ethiopian highlands are highly deficient in phosphorus. For instance, soil analytical results have indicated that most of the soils in the Walmera area are low in pH and deficient in available P (Table 1).

Table 1: Initial soil chemical properties of the experimental field of Holeta Agricultural Research Centre, 2001 – 2003

Notes: P determined by Olsen method; CEC = cation - exchange capacity; OC= Organic carbon.

Source: Getachew Agegnehu and Taye Bekele, 2005b.

Table 2: Chemical characteristics of soils of two sites in Walmera area, 2003 – 2004

Notes: CEC = cation - exchange capacity; Source: Getachew Agegnehu and Taye Bekele, 2005a.

Thus, the amount of available P in the soil is, by and large, insufficient to meet the requirements of barley production.  Soil analytical results were found to be suboptimal for the production of crops. Similar to Marschner, 1995 finding, soils with pH values less than 5.5 are deficient in Ca and/or Mg, and also P. As presented in Table 1 and 2, the soil pH, available P and exchangeable cations were found to be far below the optimum.

Management of Acid Soils with Lime application

Due to increasing scope and magnitude of soil acidity problem in Ethiopia, reclamation program focusing on liming has been under taken in seriously affected part of the country. Some of the achievements obtained are presented as follows.

Table 3: Effect of lime on the grain yield (t/ha) of maize at Nedjo

________________________________________________________________

Lime                            NP₂O₅ (kg/ha)                          Mean Yield

t/ha                  _____________________________                     (t/ha)

0-0                   35-35               70-70

________________________________________________________________

0                      5.40                 4.95                 4.22                     4.86

3                      3.95                 6.14                 5.49                     5.19

________________________________________________________________

Mean               4.67                 5.55                 4.85

­________________________________________________________________

Source: Holeta  Agricultural  Research  Center (HARC), 2010

Table 4: Effect of Lime and P application on grain yield (kg ha^-1) of Barley at Bedi

Source: Holeta  Agricultural  Research  Center (HARC), 2010

As indicated in tables 3 and 4, increased rate of lime application from 0 - 3 t/ha resulted in increased yield of Maize when applied with 35-35 N P₂O₅ (kg/ha) and Barely yield also increased with increasing lime (0-1.5 t/ha) and P application (0-30 P₂O₅ kg/ha). This clearly indicated that, application of lime coupled with fertilizer improve the productivity of crops in acid affected soils. This might be related with poor fertility of acid soils prevalent in high rainfall areas where leaching of nutrients is expected to be high.

An experiment was conducted at Nedjotesting site to evaluate the interaction effects of different lime rates and phosphorus levels on yield of teff and finger millet.The lime level which gave best yield of finger millet was 5 t ha^-1 with69 kg ha ^-1 of phosphorus(1346.2kg ha ^-1).The second best yield of finger millet was recorded by 20t ha^-1 lime with 46 kg ha ^-1 of phosphorus (Table 5).

Similarly, the best yield of teff was obtained by 5 t ha^-1 with 69 kg ha ^-1 of phosphorus (1635.5 kgha ^-1). The second best yield of teff (1365.8 kg ha ^-1)was recorded by 10t ha^-1 lime with 46 kg ha ^-1 of phosphorus (Table 6). Both teff and finger millet grown on extremely acidic soils (Nedjo site) were more responsive to inorganic fertilizer phosphorus rate than lime levels. This might be because of temporary saturation of phosphorus fixation around the plant root zone.

Table 5: Influence of lime & Phosphorus on Finger millet grain yield (kg ha ^-1), Nedjo 2013

                 Source: HARC Progress Report (2015)

Table 6: Influence of lime & Phosphorus on teff grain yield (kg ha ^-1), Nedjo 2013

                          Source: HARC Progress Report (2015)

Research work has been done on integrated soil fertility management (i.e., organic fertilizer sources combined with inorganic fertilizers)under limed /unlimedcondition on teff yield at Nedjo testing site. The experiment was conducted for two consecutive years without changing plots that received the organic fertilizer sources farmyard manure (FYM) and compost only in the first year but received the inorganic fertilizers every year. TSP and Urea were used as source of phosphorus and nitrogen.

            Result obtained from two years data and the over years aggregate (Table 7, 8 and 9) clearly showed that superior grain yield, biomass weight and plant height were recorded with treatment  50% FYM + 50% NP + 50% lime. The second best result was obtained withtreatment 50% compost + 50% NP + 50% lime.Similar result was obtained by Chilimba et al., (2004) evaluated the response of maize grain yield to applied compost and farmyard manure in combination with inorganic fertilizer materials.Both organic fertilizer sources (FYM & Compost) combined with equal amount of NP inorganic fertilizers in the absence of a soil conditioner lime gave statistically similar teff grain yield, biomass and plant height.This might be probably happened due to the inorganic fertilizers thus increase the above ground and root biomass due to immediate supply of plant nutrients in sufficient quantities as stated by Sarkar et al., 2003; Bostick et al., 2007

The obtained results clearly assured that proper knowledge and enhanced use of integrated soil fertility management technologies such as combined use of organic and inorganic fertilizers in the presence oflime are vital in improving and sustaining crop production.

Table 7:  Effect of organic fertilizer sources on teff grain yield and yield components(kg ha ^–1) on acidic soil at Nedjo 2014

PLHT = plant height (cm), Pnkln = panicle length (cm), BM = Biomass( kg ha ^{– 1}),GY = grain yield(kg ha ^{– 1})

Source: HARC Progress Report (2015)

Table 8:  Effect of organic fertilizer sources on teff grain yield (kg ha ^-1) on acidic soil at Nedjo 2015

    Source: HARC Progress Report (2015)

Table 9: Over year aggregate effect of organic fertilizer sources on teff grain yield(kg ha ^-1) on acidic soil at Nedjo  (2014 – 2015)

          Source: HARC Progress Report (2015)

An experiment was conducted to observe the interaction of Lime and P on seed yield of faba bean at Bedi and Emdibir. The results of these experiments are presented in tables below. The highest significant (P≤ 0.05) yield of faba bean was obtained by applications of 1.65 (t ha^-1) and 13(t ha^-1) of lime along with 30 kg ha^-1 P fertilizer at Bedi and Emdibir respectively (Table 10 and 11).  Application of 1.65 t ha ^-1 lime with 30 P (kg ha ^-1 ) gave 212% yield increment  over the control that has no lime but 30 P  (kg ha ^-1 ).

                             Source: HARC Progress Report (2015)

To discern the effects of liming on root nodulation and grain yield of soybeanan experiment was conducted at Bako area, western Ethiopia. The finding from the experiment with regard to growth and yield attributes revealed that liming acid soil in soybean production had significantly influenced the number and dry weight of nodule, the plant height, the above ground biomass and grain yield (Table 15, 16). The nodule number and nodule dry weight increased linearly with increase of liming rate until it reached the recommended level (DeribKifile, 2014). The optimum value of nodule number and weight obtained is 113 and 963.3 mg /plant which were improved remarkably by73.84% and 71.04% respectively due to liming (Table 12).

Table 12: Nodulation of soybean as influenced by liming, Bako Agricultural Research Center, western Ethiopia (DeribKifile, 2014)

Table 13. Yield and Yield Related Traits as influenced by Liming, Bako Agricultural Research

Center, westernEthiopia. (DeribKifile ,2014)

A field experiments were conducted at the two locations on acidic soil to study the effect of lime and phosphorus application on haricot bean varities at Dolla and Gununo in Wolaita Zone, Southern Ethiopia. The research work was initiated to evaluate the response of haricot bean varieties to liming on acid soils. The experiment was laid out in factorial randomized complete block design with three replications. Hawasadume and Omo-95 were treated by 0 and 0.4 t ha^-1 of lime.There was a significant increase on growth parameters of the two varieties as rates of lime increased both at Dolla and Gununo sites. Maximum values of plant height, leaves and branches number were recorded at application rates at both location with liming in year 1 and 2. Similarly, the highest grain yield and yield components were obtained at 20 kg P ha^-1 with lime (0.4 t ha^-1) on both varieties at two locations. Furthermore, application of lime improved soil conditions and in turns varieties performance at both locations (Table 14).

An experiment was also carried out on acid soils of Jima and Ilubabore zones of south-western Ethiopia to know the effect of split application of lime on the basis of maize-soybean rotation system in two sets. Treatments of split lime applications were control, full dose of recommended lime applied at one time during the cropping season, two splits in which 50% of the dose applied in the first year and the rest 50% in the second year, three splits in which 33% of the dose applied in the first year, 33% in the second year and the rest 33% in the third year and four splits in which 25% of the dose applied in the first year, 25% in thesecond year, 25% in the third year and the rest 25% in the fourth year. Recommended rate of N, 46 kg ha ^-1 and 92 kg ha ^-1 were uniformly applied for soybean and maize, respectively. However, 20P kg ha^-1was uniformly applied for all treatments and for both test crops.

Over years mean showed that split application of lime significantly affected maize and soybean yield at Doyo (Jima). In this line, splitting into two and applying in two consecutive years as well as splitting of lime into three and applying in three consecutive years gave similar yield with full rate application of lime for maize. Splitting into four was even gave similar maize grain yield with splitting lime into two and three(TesfuKebede et al., 2010).  This might be due to less acidity of Doyo area. Result of this experiment revealed that splitting the required amount of lime into 33%and 50% is possible if maize to be grown on this soil(Table 15).

Table15: Effect of Split Application of Lime on Maize Yield (kg ha^-1) at Doyoin 2009-2013 growing seasons(TesfuKebede et al., 2010)

              Means with in a column with the same letter(s) are not significantly different at 0.05 probability level.

                ns =Not significantly different at 0.05 probability level

Split application and full rate application gave almost similar soybean yield at the testing site (Table 16). However, resource poor farmers who cannot afford the price of full dose lime can split in to two, three and four and apply every year without significant yield loss for both crops compared to one time application of full dose.

Table 16: Effect of split application of lime on soybean seed yield (kg ha^-1) at Doyo

in2009-2013 growing seasons(TesfuKebede et al., 2010)

            Means with in a column with the same letter(s) are not significantly different at 0.05 probability level.

            ns =Not significantly different at 0.05 probability level

Similar to Doyo soil, Hurumu’s soil was also responsive to split lime application. Splitting into two and three gave similar maize and soybean yield with full rate application of lime at once (Tables 17 and 18). Depending on the availability of lime and affordability of maize and soybean growers, it is possible to use either of the above frequencies.

Table 17: Effect of split application of lime on maize grain yield (kg ha^-1) at Hurumu

in 2009-2013 growing seasons(TesfuKebede et al., 2010)

            Means with in a column with the same letter(s) are not significantly different at 0.05 probability level.

            ns =Not significantly different at 0.05 probability level.

Table18: Effect of Split Application of Lime on Soybean seed Yield (kg ha^-1) at Hurumu in 2009-2013 Growing seasons(TesfuKebede et al., 2010)

            Means with in a column with the same letter(s) are not significantly different at 0.05 probability level.

            ns =Not significantly different at 0.05 probability level

Another study was conducted at Megele-33 kebele, Assosa area of north western Ethiopia   from 2012 – 2015 on the basis of cereal food legume/oil crops rotation system in two sets.Treatment with 50% lime in split application gave the highest mean grain yield (3143.3kg/ha) of sorghum (Table 19), and as clearly observed from Table 19 the ANOVA result showed a significant difference of grain yield between treatments (DessalegnTamene and BekeleAnbesa, 2015).

Table 19: Effect of Split Application of Lime on Soybean seed Yield (kg ha^-1) at Asosa

To evaluate different agricultural lime materials produced in Ethiopia for their agronomic effectiveness on acid soils an experiment was conducted at Holeta agricultural research centre for three years. The agricultural lime materials were brought fromSenkele (Oromia), Dejen (Amhara) and both Awash Dolomite and Awash calcite from Awash 7 kilo. Statistically no yield difference was observed among different agricultural limes produced in Ethiopia, and this implies that both limes produced at Senkele (Oromia) and Dejen (Amhara) can successfully answer their regional lime needs. When Senkele lime, Dejen lime and Ca(OH)₂ from Ghion gas factory were compared with Awash calcite and Awash dolomite, these two Awash products were greatly preferred (Table 20 and 21). The reason might be mainly from the material they were processed and as well the technology under which they were crushed.

Table 20: Effects of different agricultural limes on yield & yield components of barley,combined analysis (Year I) -2014

           Source:  HARC Progress Report 2016

Trt. 1= control, 2= Dejen lime, 3= Awash Dolomite, 4= Awash Calcite, 5= Senkele lime, 6= Ca (OH)₂,    PLHT=plant height, Spkln = Spike length, Spkpsp = No of Spikelet per Spike, BM=Biomass (kg ha^-1) , GY= Grain yield (kg ha^-1), HLW=hectolitre weight, TSW= Thousand seed weight.

Table 21:Effects of different agricultural limes on yield & yield components of barley,Rob Gebeya  (Kifile) -2016

           Source:  HARC Progress Report 2016

Trt. 1= control, 2= Dejen lime, 3= Awash Dolomite, 4= Awash Calcite, 5= Senkele lime,  6= Ca (OH)₂,    PLHT=plant height, Spkln = Spike length, Spkpsp = No of Spikelet per Spike, BM=Biomass (kg ha^-1) , GY= Grain yield (kg ha^-1), HLW=hectoliter weight, TSW= Thousand seed weight.

The Capacity building for scaling up of evidence–based best practices in agricultural production in Ethiopia (CASCAPE) project conducted research in selected woreda’s in the Southern and Amhara regions with the aim of reclaiming acid soils for crop production. In both regions different treatments with varying quantities of lime per hectare were tested. In the South region six  treatments used were, (i) 900 kg ha^-1  lime  (ii) 900 kg ha^-1 lime plus the recommended fertilizer rate  (iii) 1800 kg ha^-1 lime  (iv) 1800 kg ha^-1 lime plus the recommended fertilizer rate (v) application of recommended fertilizer (100 kg DAP and Urea  per ha) only; (vi) control (no treatment); where as in  CASCAPE Amhara  (i) 1925 kg ha^-1  lime  (ii) 2050 kg ha^-1 lime  and (iii) control (no lime application ) were used. All three treatment plots followed the recommended fertilizer dosage.  Barley was the experimental crop used. Grain yield was measured on each treatment and was analyzed using SAS software.

Grain yield of barley increased with lime application. The highest grain yield of 1367 kg ha^-1 was obtained with application of 1800 kg lime and recommended fertilizer, as opposed to application of 900 kg lime and recommended fertilizer (1283.5 kg ha^-1) (Table 22). These yield levels were significantly higher than the control (554.0 kg ha^-1).  Barley grain yield in Dera & JabiTehnan woredas of Amhara region showed significant differences between lime treated plots and non treated plots. Lime rates based on the buffer method (1925 kg ha^-1 on average of four sites) and the exchangeable acidity method (2050 kg ha^-1 ) on average of four sites) gave grain yields of 3648 and 3643 kg ha^-1   of barley, respectively and the difference were not significant (Table 23). The non – treated (control) plot gave a grain yield of 2452 kg ha^-1, and this was significantly lower than the other treatments. Biomass (straw) yield of barley was highest (10058 kg ha^-1 ) for a lime rate of 2050 kg, but the difference between the treatments was not significant.

Table 22: Mean grain yield of barley across different liming treatments in Buleworeda, Southern Ethiopia(WondwosenBekele et al., 2014)

           RFR: recommended fertilizer rate (100 kg DAP & 100 kg Urea)

Table 23: Grain yield of barley across liming treatments following buffer and exchangeable acidityin Amhara region  (Wondwosen Bekele et al., 2014)

*As the trial in CASCAPE  Amhara were conducted at two districts, Dera and Jabi: the data on the table combined over the two woredas.

Comparison of soil pH level changes before planting and after harvest at CASCAPE south showed that after harvest the pH levels consistently increased from 4.68 in the control (T₁) to 5.33 (T₅) due to the treatment with 1800 kg ha^-1 lime plus no fertilizer. For the control, pH after harvest showed a reduction by 0.03 compared to the pH level before planting, which might be associated with the macronutrient mining of test crops from the native soil.

Similarly, from an experiment conducted at Chencha and Hagerselam areas of southern Ethiopia application of lime together with other macro-nutrients (nitrogen, phosphorus and potassium) significantly increased yield of barley. It is clearly observed that the relative barley yield increased due to application of 0.85 and 1.75Mg lime alone or with different combinations of NPK in 2007 was promisingly high. Application of 0.85 and 1.75Mg lime gave 64 and 100% higher yield, respectively than absolute control; whereas 7 and 64%, 52 and 37%, 116 and 100% and 24 and 22% higher yields were observed by combining with NP, NK, PK and NPK, respectively as compared to application of respective fertilizer alone. Application of half and full doses of lime alone or with NPK gave statistically similar barley yield both at Chencha and Hagerselam. These results suggested that lime application increased the effect of fertilizer on barley yield at both sites, the highest being on NP in Chencha soils and on PK in Hagerselam soils (Table 24).

Table 24: The effect of lime and NPK fertilizer application on the grain yield of Barley (kg ha^-1) in acidic soils of Chencha and Hagerselam(WondwosenBekele et al., 2014)

         Lime rate for barley at Hagerselam --- L₁ = 0 lime, L₂ = 0.85 Mg ha^-1 lime, L₃ = 1.75 Mg ha^-1 lime,

         Lime rate for barley at Chencha --- L1= 0 lime, L₂ = 3.84 Mg ha^-1 lime, L₃ = 7.68 Mg ha^-1 lime

CONCLUSION

Crop development and potential yield depend on different environmental and soil factors. Soil acidity problems are increasing in the highland areas of Ethiopia. Different experiments confirmed that and suggested that lime is essential but must be complimented with balanced plant nutrients in order to get adequate crop yield in acid prone areas. In Nedjo condition, lime level 5 t ha^-1 with 69 kg ha ^-1 phosphorus gave best yield (1346.2 kg ha ^-1)and (1635.5 kgha ^-1) of finger millet and teff respectively.Similarly, yield of faba bean was obtained by applications of 1.65 (t ha^-1) and 13(t ha^-1) of lime along with 30 kg ha^-1 P fertilizer at Bedi and Emdibir respectively.  

Around Bakoarea liming significantly influenced the number and dry weight of nodule, plant height, above ground biomass and grain yield of soybean. The nodule number and nodule dry weight increased linearly with increase of liming rate until it reached the recommended level.

The study of lime and phosphorus application on haricot bean varieties at Dolla and Gununo in Wolaita Zone, Southern Ethiopia showed that the highest grain yield and yield components were obtained at 20 kg P ha^-1 with lime (0.4 t ha^-1) at two locations.

Split application of lime on the basis of maize-soybean rotation system in two sets on acid soils of Jima and Ilubabore zones of south-western Ethiopia has showed that splitting into two and three parts gave similar maize and soybean yield with full rate application of lime at once. However, resource poor farmers who cannot afford the price of full dose lime can split in to two, three and four parts and apply every year without significant yield loss for both crops compared to one time application of full dose. Similarly, from an experiment conducted at Megele-33 kebele, Assosa area of north western Ethiopia on the basis of cereal food legume/oil crops rotation system showed that splitting full dose of lime into two parts gave the highest mean grain yield of sorghum without significant yield loss.

From research work done on integrated soil fertility management (i.e., organic fertilizer sources combined with inorganic fertilizers) under limed /unlimed condition on teff yield at Nedjo testing site, two years data and the over years aggregate clearly showed that superior grain yield, biomass weight and plant height were recorded with treatment  50% FYM + 50% NP + 50% lime.

Similarly, an experiment was conducted at Holeta station and on-farm to evaluate different agricultural lime materials produced in Ethiopia for their agronomic effectiveness on acid soils. Statistically no yield difference was observed among different agricultural limes produced in Ethiopia, and this implies that both limes produced at Senkele (Oromia) and Dejen (Amhara) can successfully answer their regional lime needs. When Senkele lime, Dejen lime and Ca(OH)₂ from Ghion gas factory were compared with Awash calcite and Awash dolomite, these two Awash products were greatly preferred. The reason might be mainly from the material they were processed and as well the technology under which they were crushed.

Soil acidity limits crop production in many tropical soils. Lime and inorganic phosphate fertilizers are used to remedy these problems. However, due to increasing costs and unavailability when needed, their use among our farmers in our country is not widespread. Thus the government should give an attention to the supply of lime where it is prudently needed.

ACKNOWLEDGEMENTS

I would like to acknowledge all researchers contributed for soil acid management to fetch a solution to minimize its adverse impact and foster its contribution to the country’s food security.

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