Changes in Soil Phosphorus Pools and Chemical Properties under Liming in Nitisols of Farawocha, South Ethiopia

Understanding the nutrient dynamics in acid soil is fundamental to carry out proper management. The study was conducted to investigate phosphorus (P) pools and selected properties under different rates of lime for acid nitisols of Farawocha, Southern Ethiopia. Four lime rates incubated for a month in three replications were tested. The lime rates were 0 t/ha (0%), 5.25 t/ha (50%), 10.5 t/ha (100%), and 15.75 t/ha (150%). Lime requirement (LR) for 100% was calculated targeting soil pH of 6.5. Data on the P pools such as soluble P (P-sol) and bounded forms of P with iron (Fe-P), aluminum (Al-P), calcium (Ca-P), organic part (Org-P), residual P (Res-P), and total of P fractions were measured. In addition, changes in soil chemical properties such as pH, exchangeable acidity, calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), boron (B), zinc (Zn), and manganese (Mn) were analyzed. The result showed that total P was 357.5 mg/kg. Compared to nontreated soil, liming at a rate of 15.75 t/ha significantly improved P-sol (34.2%, r2 = 0.88), Ca-P (61.6%, r2 = 0.92), and Res-P (195%, r2 = 0.94); however, it reduced Fe-P (58.5%, r2 = −0.83), Al-P (71%, r2 = −0.97), and Org-P (19.1%, r2 = 0.93). Overall, the P-associated fractions in the soil, regardless of the lime rates, were in the order of Org_P > Res_P > Fe_P > Ca_P > Al_P > P-sol. Liming raised soil pH by 2.1 units (4.5 to 6.6) over nonlimed soil, whereas it reduced exchangeable acidity from 4.18 to 0.23 meq/100 g soil. Available P, Ca, Mg, S, Cu, Zn, and B contents were significantly improved with lime application. However, liming reduced Fe and Mn contents. In conclusion, these findings showed that liming facilitated the release of P from various pools, modified pH and exchangeable acidity, and resulted in beneficial changes for most of the soil chemical properties.

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Amending Potassic Fertilizer with Charcoal and Sago (Metroxylon sagu) Bark Ash to Improve Potassium Availability in a Tropical Acid Soil

Agronomy ◽

10.3390/agronomy11112222 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2222

Author(s):

Puvan Paramisparam ◽

Osumanu Haruna Ahmed ◽

Latifah Omar ◽

Huck Ywih Ch’ng ◽

Ali Maru ◽

...

Keyword(s):

Soil Ph ◽

Acid Soil ◽

Chemical Properties ◽

Water Soluble ◽

Soil Chemical Properties ◽

Kaolinite Clay ◽

Exchangeable K ◽

Exchangeable Acidity ◽

Metroxylon Sagu ◽

Sago Bark

In Ultisols and Oxisols, potassium (K) in the soil solution is leached from the rhizosphere before it interacts with soil colloids, or exchanged with other cations at the exchange sites of the soils because of the abundance of kaolinite clay minerals. These soils are highly weathered, low in organic matter, and low in pH, but high aluminium (Al) and iron (Fe) ions. Hence, K becomes unavailable for plants, and this compromises crop production and farmers’ profitability. The pH neutralizing effects of sago (Metroxylon sagu) bark ash and the ability of charcoal to chelate Al and Fe could be utilized to improve soil pH, reduce soil acidity, and improve K availability. The objective of this study was to determine the effects of amending muriate of potash (MOP) with charcoal and sago bark ash on selected soil chemical properties in a tropical acid soil (Typic Paleudults) over 90 days in a laboratory incubation. The proportions of charcoal and sago bark ash were varied at 20%, 40%, 60%, 80%, and 100%, but the MOP was fixed at 100% of the recommended rate. Selected soil chemical properties before and after incubation were determined using standard procedures. Results revealed that co-application of the soil amendments with MOP increased soil-exchangeable K compared with conventional practice. Moreover, amending the acid soil with charcoal and sago bark ash positively enhanced the availability of other base cations and soil cation exchange capacity (CEC). This was possible because the amendments increased soil pH and reduced exchangeable acidity, exchangeable Al3+, and exchangeable Fe2+. However, there was no significant improvement in water-soluble K (WSK) in the soil with or without charcoal and sago bark over the 90 days laboratory study. The findings of this study suggested that increasing soil pH could potentially improve soil K sorption capacity. Thus, the optimum rates of charcoal and sago bark ash to increase K availability were found to be 80% charcoal with 80% sago bark ash, 60% charcoal with 60% sago bark ash, and 80% charcoal with 40% sago bark ash, because these rates improved soil-exchangeable K+ and CEC significantly, besides minimizing soil-exchangeable acidity.

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PEMANFAATAN BIOCHAR KULIT BUAH KAKAO DAN SEKAM PADI UNTUK MENINGKATKAN PRODUKTIVITAS PADI SAWAH DI ULTISOL LAMPUNG

Jurnal Pengkajian dan Pengembangan Teknologi Pertanian ◽

10.21082/jpptp.v20n1.2017.p69-80 ◽

2017 ◽

Vol 20 (1) ◽

pp. 69 ◽

Cited By ~ 1

Author(s):

Neneng Laela Nurida ◽

Sutono , ◽

Muchtar ,

Keyword(s):

Rice Husk ◽

Soil Ph ◽

Rice Yield ◽

Acid Soil ◽

Chemical Properties ◽

Soil Chemical Properties ◽

Growth And Yield ◽

Cocoa Shell ◽

Rice Husk Biochar ◽

Planting Season

Utilization of Biochar of Cocoa Shell and Rice Husk to Increase Rice Productivity in Ultisol Lampung. Biochar application as soil amendment is technology for soil and crop productivity improvement in acid soil. The main problem of acid soil including in paddy field is high concentration of Al3+ that inhibit crops growth causing low crop production. The objective of this study was to evaluate the effects of cocoa shell and rice husk biochar on paddy field productivity and soil chemical properties. The study was conducted at Agricultural Research Station of Tamanbogo, East Lampung on June-September 2012 (planting season 1), January-April 2013 (planting season 2) and December 2013-March 2014 (planting season 3). The experimental design was split plot design, which the main plots were two types of biochar (cacao shell and rice husk), the sub plots were biochar rates 0.5 t/ha (control), 5 t/ha and 15 t/ha with five replications. The parameters measured were paddy growth, yield and soil chemical properties (soil pH,C organic, N total, available P, K total, and Al3+ ). The result showed that biochar could affect weight of rice straw and rice yield at the second and third planting season, while biochar rates could affect crop growth and yield of rice at three planting. The effect of cacao shell and rice husk biochar application with the rate of 15 t/ha could up to three planting seasons without any biochar addition in following two consecutives year, whereas addition biochar 5 t/ha was less effective. The cacao shell biochar was more effective in increasing crop growth and yield than rice husk biochar,as seen on dry grain rice yield, i.e. 3.58 t/ha (PS1) and 5.06 t/ha (PS III). During two planting seasons, both biochar at the rate of 15 t/ha were sufficient to improve soil chemical properties. Cacao shell biochar with the rate of 15 t/ha had better effect in improving soil chemical properties significantly in term of soil pH, available P, and total K content and decreasing aluminum content than rice husk biochar especially at second planting season. Keywords: lowland, biochar, rice, Ultisol, LampungABSTRAKAplikasi biochar sebagai pembenah tanah merupakan salah satu teknologi untuk memperbaiki produktivitas tanah dan tanaman pada lahan masam. Permasalahan utama pada lahan masam adalah tingginya konsentrasi Fe3+ yang dapat menghambat pertumbuhan tanaman sehingga menyebabkan rendahnya produksi. Tujuan penelitian ini adalah untuk mempelajari pengaruh pemberian biochar kulit buah kakao dan sekam padi serta takarannya terhadap peningkatan sifat kimia tanah dan produktivitas padi sawah di Ultisol Lampung. Penelitian dilaksanakan pada lahan sawah di Kebun Percobaan Taman Bogo, Lampung selama tiga musim tanam yaitu bulan Juni-September 2012 (musim tanam pertama), bulan Januari-April 2013 (musim tanam kedua) dan Desember 2013 - Maret 2014 (musim tanam ketiga). Percobaan disusun dalam rancangan kelompok petak terpisah, sebagai petak utama terdiri dari biochar kulit buah kakao dan biochar sekam padi, sedangkan sebagai anak petak adalah takaran biochar yaitu tanpa biochar (kontrol 0 t/ha), 5 t/ha dan 15 t/ha, dengan 5 kali ulangan. Parameter yang diamati meliputi pertumbuhan dan hasil padi, sifat kimia tanah (pH, C-organik, N-total, P-tersedia, K-total dan Al3+ ). Hasil penelitian menunjukkan bahwa jenis biochar hanya berpengaruh nyata terhadap berat jerami kering dan hasil gabah pada musim tanaman kedua dan ketiga, sedangkan takaran biochar berpengaruh nyata terhadap pertumbuhan dan hasil padi pada ke tiga musim tanam. Pengaruh pemberian biochar kulit buah kakao dan sekam padi 15 t/ha mampu bertahan sampai tiga musim tanam dilihat dari pertumbuhan dan hasil padi sawah, sedangkan pemberian biochar 5 t/ha bertahan satu musim saja. Efektivitas biochar kulit buah kakao dalam mendukung pertumbuhan dan hasil tanaman lebih tinggi dibandingkan sekam padi terlihat dari hasil gabah kering panen sebesar 3,58 t/ha (MT II) dan 5,06 t/ha (MT III). Selama dua musim tanam pemberian biochar kulit buah kakao sebanyak 15 t/ha juga mampu meningkatkan pH tanah, P tersedia, dan kandungan K tetapi menurunkan kandungan aluminium melebihi biochar sekam padi terutama pada musim tanam kedua.Kata kunci: produktivitas, padi sawah, biochar, Ultisol

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Coapplication of Chicken Litter Biochar and Urea Only to Improve Nutrients Use Efficiency and Yield ofOryza sativaL. Cultivation on a Tropical Acid Soil

The Scientific World JOURNAL ◽

10.1155/2015/943853 ◽

2015 ◽

Vol 2015 ◽

pp. 1-12 ◽

Cited By ~ 6

Author(s):

Ali Maru ◽

Osumanu Ahmed Haruna ◽

Walter Charles Primus

Keyword(s):

Acid Soil ◽

Nutrient Use Efficiency ◽

Chemical Properties ◽

Acid Soils ◽

Field Trials ◽

Soil Chemical Properties ◽

Nutrient Use ◽

Chicken Litter ◽

Rice Yields ◽

Use Efficiency

The excessive use of nitrogen (N) fertilizers in sustaining high rice yields due to N dynamics in tropical acid soils not only is economically unsustainable but also causes environmental pollution. The objective of this study was to coapply biochar and urea to improve soil chemical properties and productivity of rice. Biochar (5 t ha−1) and different rates of urea (100%, 75%, 50%, 25%, and 0% of recommended N application) were evaluated in both pot and field trials. Selected soil chemical properties, rice plants growth variables, nutrient use efficiency, and yield were determined using standard procedures. Coapplication of biochar with 100% and 75% urea recommendation rates significantly increased nutrients availability (especially P and K) and their use efficiency in both pot and field trials. These treatments also significantly increased rice growth variables and grain yield. Coapplication of biochar and urea application at 75% of the recommended rate can be used to improve soil chemical properties and productivity and reduce urea use by 25%.

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Liming Effects of Sawdust Ash and Lime on Sunflower (Helianthus annuus L.) Yield in Acidic Soil of Southeastern Nigeria

International Journal of Plant & Soil Science ◽

10.9734/ijpss/2019/v28i530121 ◽

2019 ◽

pp. 1-11

Author(s):

C. V. Ogbenna ◽

V. E. Osodeke

Keyword(s):

Soil Ph ◽

Chemical Properties ◽

Exchange Capacity ◽

Acidic Soil ◽

Soil Chemical Properties ◽

Growth And Yield ◽

Available Phosphorus ◽

Yield Data ◽

Southeastern Nigeria ◽

Head Weight

Aim: A pot experiment was carried out to determine the effect of sawdust ash and lime (Ca(OH)2) on soil characteristics and yield of sunflower in acidic soil of southeastern Nigeria. Study Design: The experiment was laid out in split-plot design, using sawdust ash (0, 1, 2, 3, 4 t ha-1) as the sub plot and lime (0, 0.5, 1.0, 1.5 t ha-1) as the main plot. Place and Duration of Study: Study was conducted outdoors at Michael Okpara University of Agriculture Umudike, Nigeria, during the 2010 planting season. Materials and Methods: Treatment combinations were applied to the 60 buckets containing soil, mixed thoroughly and watered adequately. After 1 week of treatment application, two sunflower seeds were planted and later thinned to one seedling per bucket. Plant growth and yield data were collected. Pre planting and post-harvest soil samples were collected and analyzed for soil properties. Results: Results showed that with the exception of organic carbon there was significant effect of treatments on all soil chemical properties. Lime and sawdust ash (SDA) as single and combined treatments significantly increased total nitrogen (P=0.05), available phosphorus (P<0.010), and base saturation (P<0.012). The interaction between SDA and lime significantly (P=0.05) increased total exchangeable bases and effective cation exchange capacity, while soil pH was significantly increased (P=0.05) by single applications. The increases in soil chemical properties led to significant positive response of the sunflower. With the exception of number of leaves, other plant parameters (Plant height, stem diameter, head weight, 50 seed weight, head diameter) had significant increases for sawdust ash alone at P=0.05. Correlation studies showed positive significant relationship between soil pH and sunflower yield. Conclusion: The study showed that sunflower performed best at the combination of 3 tha-1 SDA and 1.5 t ha-1 lime producing a mean head weight of 45.4 g.

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Effects of biochars generated from crop residues on chemical properties of acid soils from tropical and subtropical China

Soil Research ◽

10.1071/sr12118 ◽

2012 ◽

Vol 50 (7) ◽

pp. 570 ◽

Cited By ~ 51

Author(s):

Jin-Hua Yuan ◽

Ren-Kou Xu

Keyword(s):

Soil Ph ◽

Crop Residues ◽

Chemical Properties ◽

Acid Soils ◽

Base Cations ◽

Exchange Capacity ◽

Chemical Compositions ◽

Subtropical China ◽

Exchangeable Base Cations ◽

Exchangeable Acidity

The chemical compositions of biochars from ten crop residues generated at 350°C and their effects on chemical properties of acid soils from tropical and subtropical China were investigated. There was greater alkalinity and contents of base cations in the biochars from legume residues than from non-legume residues. Carbonates and organic anions of carboxyl and phenolic groups were the main forms of alkalis in the biochars, and their relative contributions to biochar alkalinity varied with crop residues. Incubation experiments indicated that biochar incorporation increased soil pH and soil exchangeable base cations and decreased soil exchangeable acidity. There were greater increases in soil pH and soil exchangeable base cations, and a greater decrease in soil exchangeable acidity, for biochars from legume than from non-legume residues. The biochars did not increase the cation exchange capacity (CEC) of soils with relatively high initial CEC but did increase the CEC of soils with relatively low initial CEC at an addition level of 1%. The incorporation of biochars from crop residues not only corrected soil acidity but also increased contents of potassium, magnesium, and calcium in these acid soils from tropical and subtropical regions and thus improved soil fertility.

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Changes in Soil Chemical Properties Under Different Land-Use Systems and Soil Depth Layers: A Case Study from the Central Highlands of Ethiopia

10.21203/rs.3.rs-74895/v1 ◽

2020 ◽

Author(s):

Yadesa Bato ◽

Tamrat Bekele ◽

Sebsebe Demissew

Keyword(s):

Land Use ◽

Soil Ph ◽

Eucalyptus Globulus ◽

Soil Depth ◽

Chemical Properties ◽

Natural Forest ◽

Soil Chemical Properties ◽

Plantation Forest ◽

Mean Values ◽

Land Use Systems

Abstract Background: Soil chemical properties have changed under different land-use systems and soil depth layers either by increasing or decreasing. Hence, scientifically information on the soil chemical properties dynamics under different land-use systems and soil depths are crucial for best land management practices, and to avoiding ecological negative impacts of it for sustainable development. The study aimed to evaluate the soil chemical properties dynamics under different land-use systems and soil depths in the central highlands of Ethiopia. The land-use systems included natural forest, four exotic tree plantation species (Eucalyptus globules, Cupressus lusitanica, Grevillea robusta, and Pinus patula), grassland, grazing land, and cropland. Results: The analysis of variance (ANOVA) for the majority of soil chemical properties of OC, TN, Avial. P, soil pH, EC, CEC, and exchangeable bases (Ca, Mg, K, Na) were showed that significant variations among land-use systems (P<0.0001). The highest mean values of OC (3.49 % DM ), TN ( 0.31 % DM) , Avail.P (31.52 mg/kg of soil ), CEC ( 33.63 meq/100gm soil), Exch. Ca (17.13 cmol(+)/kg soil), Exch. Mg (5.37 cmol(+)/kg soil), and Exch. K ( 3.60 cmol(+)/kg soil) were observed under natural forest than others of land-use systems. The results also showed that the lowest mean values of OC (1.47 % DM), TN (0.13 %DM), soil pH (5.38), CEC (18.98 meq/100gm soil), Exch. Ca (9.93 cmol(+)/kg soil), Exch. K (1.20 cmol(+)/kg soil), and Exch. Na (0.22 cmol(+)/kg soil) were recorded under cropland than other land-use systems. The highest mean values of EC (3.47ds/m), and Exch. Na (0.60 cmol(+)/kg soil) were observed under Eucalyptus globulus plantation forest. The overall mean values of OC, TN, Avail.P, CEC, Exch. Mg, Exch. Ca, Exch. K, and Exch. Na accumulation at the topsoil layer was higher than that of the subsoil layer except for soil pH and EC. Conclusion: In general, the majority of soil chemical properties under cropland and Eucalyptus globulus plantation forest were poorer than the soils subjected to other land-use systems which indicated that changes in land use systems were significantly affected soil chemical properties.

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The influence of Pinus radiata, Quercus suber, and improved pasture on soil chemical properties

Soil Research ◽

10.1071/s98081 ◽

1999 ◽

Vol 37 (3) ◽

pp. 509 ◽

Cited By ~ 14

Author(s):

A. D. Noble ◽

I. P. Little ◽

P. J. Randall

Keyword(s):

Soil Ph ◽

Pinus Radiata ◽

Soil Acidification ◽

Chemical Properties ◽

Radiata Pine ◽

Quercus Suber ◽

Cork Oak ◽

Water Soluble ◽

Soil Chemical Properties ◽

Permanent Pasture

Soil acidification and related land degradation issues are assuming increasing importance in Australia and challenging the concept of sustainability of current land management systems. In this study, the impacts of tree plantations of 2 species and permanent pasture on soil chemical properties are compared. Soil samples were collected from the top 50 cm (0–5, 5–10, 10–15, 15–20, 20–30, and 30–50 cm depths) from 3 adjacent sites carrying pasture and monocultures of Pinus radiata (radiata pine) and Quercus suber (cork oak) on a deep-surfaced yellow podzolic soil, and differences in soil pH and other soil chemical properties were examined. In the surface 0–5 cm, pH was similar at all 3 sites. Below that depth, soil pH was significantly lower and exchangeable Al greater under the cork oak stand than at the other 2 sites. Consistent with a decrease in soil pH there was significantly less exchangeable Ca under cork oak. Also, less clay was observed under the cork oak stand and this is taken as evidence of the degradational impact of soil acidification. An estimate of Ca in the top 50 cm of the soil implies considerable loss of Ca under oak, probably by leaching and loss of litter down the slope. Evidence is presented to show that there has been more Fe and Al movement under oak than under pasture and pine, this being ascribed in part to the greater Al and Fe mobilising capacity of the water-soluble component extracted from freshly fallen leaf litter of oak. The Fe and Al composition of the oxalate extract from concretionary material at 10–30 cm under oak is consistent with a process similar to podzolisation. Pseudogleying of Fe and Al may have accompanied the leaching of bases from the system and a reduction of pH.

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Fertility Status of Acid Soils under Different Land Use Types in Wolaita Zone, Southern Ethiopia

Applied and Environmental Soil Science ◽

10.1155/2020/3713967 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Mesfin Kassa Cholbe ◽

Fassil Kebede Yeme ◽

Wassie Haile Woldeyohannes

Keyword(s):

Land Use ◽

Soil Acidity ◽

Acid Soil ◽

Acid Soils ◽

Southern Ethiopia ◽

Land Use Type ◽

Grazing Land ◽

Exchangeable Acidity ◽

Fertility Status ◽

Land Use Types

Information on soil fertility status of acid soil of a particular area as affected by land use type is important for developing sound soil management systems for improved and sustainable agricultural productivity. The main objective of this study was to assess the fertility status and effect of land use change on soil physicochemical properties. In this study, adjacent three land use types, namely, enset-coffee, crop, and grazing land use were considered in four districts (i.e., Bolos Sore, Damot Gale, Damot Sore, and Sodo Zuria) of Wolaita Zone, southern Ethiopia. Soil samples were collected from a depth of 0–20 cm from each land use type of the respective districts for physicochemical analyses. The results showed that land use types significantly affected ( P ≤ 0.05 ) soil properties such as bulk density, available P, exchangeable potassium, exchangeable acidity, exchangeable bases (Na, K, Ca, Mg), exchangeable acidity, and CEC. Besides, soil pH, OC, and TN were influenced significantly ( P ≤ 0.05 ) both by districts and land use types. The very strongly acidic soils were found predominantly in the crop and grazing lands whereas a neutral acidity level was found in the enset-coffee land use type of four districts. In conclusion, the study proves that land use type change within the same geographic setting can affect the severity of soil acidity due to over cultivation and rapid organic matter decomposition. Finally, the study recommends an in-depth study and analysis on the root causes in aggravating soil acidity under crop and grazing land use types.

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The ameliorative effects of low-grade palygorskite on acidic soil

Soil Research ◽

10.1071/sr19178 ◽

2020 ◽

Vol 58 (4) ◽

pp. 411

Author(s):

Jin-Hua Yuan ◽

Sheng-Zhe E ◽

Zong-Xian Che

Keyword(s):

Soil Ph ◽

Cation Exchange Capacity ◽

Soil Amendment ◽

Acid Soil ◽

Chemical Properties ◽

Exchange Capacity ◽

Acidic Soil ◽

Low Grade ◽

Incubation Experiments ◽

Acid Neutralisation

Mineral composition and alkaline properties of palygorskite (Pal), and its ameliorative effects on chemical properties of acid soil were investigated. Dolomite was the main form of alkali in Pal and the acid neutralisation capacity of Pal was 215 cmol kg–1. Incubation experiments indicated that Pal incorporation increased soil pH, cation exchange capacity, base saturation and exchangeable K+, Na+, Ca2+ and Mg2+ contents, and decreased the levels of exchangeable H+, Al3+ and acidity, over a 1-year period. The ameliorative mechanisms were the dissolution of major alkaline matter in Pal (i.e. dolomite), and the exchange between released Ca2+ and Mg2+ with H+ in acidic soil. Hence, Pal can be used as a moderate acidic soil amendment.

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LONG-TERM EFFECTS OF LIME ADDITIONS ON SUGARCANE YIELD AND SOIL CHEMICAL PROPERTIES IN NORTH QUEENSLAND

Experimental Agriculture ◽

10.1017/s0014479700003112 ◽

2000 ◽

Vol 36 (3) ◽

pp. 397-413 ◽

Cited By ~ 13

Author(s):

A. D. NOBLE ◽

A. P. HURNEY

Keyword(s):

Acid Soil ◽

Ion Pairs ◽

Chemical Properties ◽

Exchange Capacity ◽

Cane Yield ◽

Long Term Effects ◽

Exchangeable Acidity ◽

Long Term Study ◽

Highly Weathered Soils

In many highly weathered soils of the humid tropics, crop exploitation of the subsoil environment is limited through acid soil infertility. Since the use of mechanical profile modification is often prohibitive, surface incorporation of soil amendments is often the only means available to rectify this problem. A field trial was established with sugarcane on a strongly Acidic Dystrophic Brown Dermosol (Oxic Humitropept) in 1978 to evaluate the effects of surface incorporated lime additions on yield and performance of sugarcane. Eighteen years after the establishment of this trial, significant responses in cane yield were still evident following a single application of 5 t lime ha−1 made in 1978, as well as repeated applications of 5 t ha−1 on three occasions over the past 18 years. Progressive reductions in exchangeable acidity were accompanied by increases in subsoil Ca2+ and Mg2+. Soil pH increased significantly to a depth of 100 cm, this being attributed to the formation of ion pairs with NO3 in the surface soil, the subsequent leaching of these complexes and the differential uptake of NO3 at depth by roots. The results from this long-term study indicate that surface incorporation of lime is an economically viable approach to the remediation of subsoil acidity on soils such as those studied, namely, those with a low inherent cation exchange capacity and anion exchange capacity.

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