Effects of P,K, and liming on soil pH,Al, Mn,K, and forage barley dry matter yield and quality for a newly-cleared Cryorthod

Forage barley dry matter yield and quality, as well as soil pH, Al, and Mn were monitored in response to P, K, and lime application on a newly cleared Typic Cryorthod (Orthid Podzol). The overall yearly yield level was affected by precipitation. Without liming soil acidification occurred after three years of production. The liming rate of 2.2 Mg.ha⁻¹ was found optimal for maintaining initial pH levels (5.66) and increasing forage barley yields. It was also found optimum for K and P utilization for these first years of production. Soil pH dropped an average of 0.33 units over the three years on unlimed P plots and 0.46 units over 4 years on K plots. Phosphorus and K fertilization increased N utilization and resulted in decreased soil acidification. Phosphorus availability was greater in the first year of cropping than in subsequent years, this was likely due to the effects of higher available moisture, liming release of native P, and effects of initial fertilization. There was a 148% increase in total dry matter yield and an 85% increase in protein yield of forage barley with P application. Liming increased total forage barley yields an average of 69% and total protein yields 48%. Reduced barley yields in unlimed plots were due to low soil pH. After two years of cultivation, unlimed plots contained exchangeable Al and soluble Mn levels reported toxic for other soils. The higher liming rates of 4.4 and 6.6 Mg.ha⁻¹ reduced soluble Mn to near critically low levels. soil Al and Mn were highly correlated to pH. Soil exchangeable Al, Mn, and soluble Mn along with tissue Al were inversely correlated to percentage yield. The average yield respone to three levels of applied K, increased from zero initially to 67% by the fourth year. Total dry-matter production increased 32% and total protein yield increased an average of 32% and total protein yield increased an average of 15% with K fertilization over four years. About 60% of the yield response occurred between the 0 and 22kg K.ha⁻¹ rates. Initial soil exchangeable K levels were not maintained even at the highest 66kg K.ha⁻¹ treatment. Soil exchangeable Al and soluble Mn were elevated with dropping pH. Soil K reserves and resupply of exchangeable K in these soils over the long term will be an important factor in crop production.     

Alfalfa,Medicago sativa L., in highly weathered,acid soils

Summary The effect of lime and P application on yield (top and root weigh), nodulation, intervally collected acetylene reduction (N₂-fixation), and N and Al uptake of young alfalfa (46 days growth) were investigated in greenhouse pots containing acid Bladen or Bradson topsoils. The effect on seed germination and seedling persistence under these greenhouse conditions was also recorded.Alfalfa yield and acetylene reduction increased with lime and P additions in both soils, but, predominately, with P. There was no advantage of increasing these two parameters with liming past pH 6.0 provided P was adequate. Positive relationships (R²) existed between yield and acetylene reduction, and with both factors and root weight, nodule weight, and N uptake. Increased uptake of Al by alfalfa seedlings depressed yield, but data indicate P may block Al uptake at high soil pH. There were no treatment effects on seed germination, but P application increased plant persistence in the Bladen soil.     

Vesicular-arbuscular mycorrhizal effectiveness in an acid soil amended with fresh organic matter

A greenhouse investigation was undertaken to determine the influence of fresh organic matter on the formation and functioning of vesicular-arbuscular mycorrhizal symbiosis in Leucaena leucocephala grown in an acid aluminum-rich ultisol. In soil not amended with fresh organic matter or lime, plants failed to grow. Mycorrhizal infection level, mycorrhizal effectiveness measured in terms of pinnule P content of L. leucocephala leaves and dry matter yield of the legume increased with increase in fresh organic matter. Although VAM colonization level and dry matter yield of L. leucocephala were significantly higher if the test soil was limed (7.2 cmole OH^–) than if amended with fresh organic matter, the latter was as effective as lime in off-setting the detrimental effect of aluminum on mycorrhizal effectiveness. The lower mycorrhizal colonization level and the lower dry matter yield noted in the soil treated with fresh organic matter appears to be related to the inadequacy of Ca in the soil amended with fresh organic matter. These observations are supported by the low calcium status of soil and plant tissues in the absence of lime. It is concluded that while fresh organic matter, in appropriate amounts, could protect sensitive plants and VAM symbiosis against Al toxicity in acid soils, maximum mycorrhizal inoculation effects are not likely to be attained unless the soils are also amended with Ca.Contribution from Hawaii Institute of Tropical Agriculture and Human Resources Journal Series No 3740.     

The effects of lime-pelleting and lime-superphosphate fertilizer on the growth of three annual legumes in an acid sandy soil

Summary Three pioneer pasture legume species,Trifolium subterraneum, Trifolium glomeratum andOrnithopus compressus, were grown in a sandy soil of pH 5.0. The growth and nodulation of each species was examined in the presence and absence of lime pelleting and with superphosphate and lime-superphosphate fertilizer. In each species tested, plant yield, nodule number and nitrogen recovery as maximal where lime pelleting and lime-super were applied together. Plant calcium indicated that the response to lime was due to changes in soil pH rather than to a calcium response. T. glomeratum was the species most responsive to lime application but its growth was at best only half that ofT. subterraneum andO. compressus, which produced equally under both favourable (pH 5.9) and unfavourable (pH 4.4) conditions created by fertilizer applications.     

根瘤菌对土壤铜、锌和镉形态分配的影响

以湖南郴州红壤和河北巩义褐土为供试土壤。制备Cu、Zn、Cd污染土壤。接种大豆根瘤菌(Rhi-zobium fredii)HN01,用连续提取法浸提土壤中不同形态的重金属．结果表明。褐土接种根瘤菌后固相结合态Zn总量降低10％。专性吸附态、氧化锰结合态和有机结合态Zn减少达9％～26％．红壤中结合态Zn的总量变化不显著,但专性吸附态和氧化锰结合态Zn含量显著减少。交换态Zn含量显著增加．褐土中接种根瘤菌抑制了Cu向土壤溶液的释放,固相结合态Cu总量增加18％,可交换态、专性吸附态、氧化锰结合态和有机结合态的Cu增加20％～54％．接种根瘤菌对土壤中Cd的溶解没有明显的抑制或促进作用,但改变了红壤中各形态Cd的含量高低顺序．Cd污染红壤中可交换态和有机结合态Cd含量分别增加22％和11％,专性吸附态和氧化锰结合态Cd分别减少14％和29％．根瘤菌对不同类型重金属及不同土壤中重金属形态影响的差异主要与土壤pH降低有关．     

A field comparison of lime requirement indices for maize

Due, in part, to the relative paucity of published comparisons based on field generated data, there is still poor agreement regarding the relative merits of lime requirement indices based on exchangeable Al and those based on pH. The objective of this study was to compare such indices using results obtained from long-term field experiments. Data were obtained over 22 site-years from lime trials conducted on clay (Typic Haplorthox) and sandy loam (Plinthic Paleudult) soils differing widely in organic carbon content. Relative maize (Zea mays L.) yields were used to compare the prognostic value of soil pH with indices obtained using exchangeable Al and exchangeable acidity (Al+H). Both within and across soils, pH proved to be markedly inferior to Al based indices. Exchangeable acid saturation of the effective cation exchange capacity, a readily obtained and popular index of lime requirement in some countries, proved as effective as less easily acquired indices based on exchangeable Al per se. The findings reported are consistent with those of many glasshouse studies and support the viewpoint that indices based on Al or acid saturation should replace pH as a measure of lime requirement.     

Enhancement of nitrogen fixation in lentil,faba bean,and soybean by dual inoculation with Rhizobia and mycorrhizae

The combined effect of Vesicular Arbuscular Mycorrhizae (VAM) and Rhizobium on the cold season legumes, lentil and faba bean, as well as on summer legume, soybean, were studied in soils with low indeginous VA mycorrhizal spores. Inoculation of the plant with VA mycorrhizal fungi increased the level of mycorrhizal root infection of lentil, faba bean and soybean. The inoculation with Rhizobium had no significant effect on VA mycorrhizal infection percent, but VA mycorrhizal inoculation increased nodulation of the three legumes. The inoculation with Rhizobium alone significantly increased plant dry weight and N content of lentil and faba bean as well as seed yield of soybean. VA mycorrhizal inoculation also significantly increased plant dry weight and phosphorus content of the plants as did fertilization with superphosphate. Rock phosphate fertilization, however, had no significant effect on plant growth or phosphorus uptake. The addition of rock phosphate in combination with VA mycorrhizal inoculation significantly increased plant dry weight and P uptake of the plants. The dual inoculation with both rhizobia and mycorrhizae induced more significant increases in plant dry weight, N and P content of lentil and faba bean as well as seed yield of soybean than inoculation with either VA mycorrhizae or Rhizobium alone.     

Yield,root morphology and chemical composition of two pasture legumes as affected by lime and phosphorus applications to an acid soil

Summary Effects of increasing rates of lime (0, 900, 1725, and 3000 kg Ca(OH)₂/ha producing soil pH of 4.0, 4.7, 5.1 and 5.6) and P (50, 150, 250 and 350 kg P/ha) on top and root yield, root morphology and chemical composition of lotus (Lotus pedunculatus Cav.) and white clover (Trifolium repens L.), were studied, using an acid soil in a greenhouse experiment. Increasing rates of applied lime and phosphate resulted in substantial increases in top yields of both species but concomitant increases in root yield were small. In the unlimed soil, lotus out-yielded (tops and roots) white clover at all P levels. However, in the three limed treatments, white clover clearly out-yielded lotus. Yield response curves to applied P levelled off at the two highest lime rates for lotus but not for white clover. Nodulation and N content of white clover increased significantly with increasing lime applications, but for lotus there was a significant decrease in nodulation at the highest lime rate. Increased P rates had a small stimulatory effect on nodulation in both species. Of the total root weight, the percentage contribution of the tap and primary lateral root fractions was smaller and that of the secondary plus tertiary lateral roots was greater for lotus than for white clover although root length per unit weight tended to be larger for white clover at the two highest lime rates. Furthermore, lotus possessed longer and more numerous root hairs than white clover. Lime applications significantly decreased the percentage contribution of the tap and primary lateral roots to the total root weight and increased the percentage contribution of the secondary plus tertiary lateral roots. Al and Mn contents of tops and roots of both species decreased with increasing lime rates. There was a highly significant negative correlation between relative yield and Al content of lotus and white clover tops. In comparison with the limed treatments, in the unlimed treatments a greater percentage of total P, Al, Mn and N content accumulated in the roots of both species. In addition, lotus accumulated a much greater percentage Al in its roots than white clover.     

Effects of liming on soil chemical characteristics and grass growth in laboratory and long-term field-amended soils

Summary The influence of liming on soil solution composition was compared in two laboratory amended soils and one field amended soil. In the laboratory study, soil solutions were sampled by miscible displacement at intervals of 1 and 10 weeks after liming. In addition to increases in pH and Ca, there were large reductions in the concentrations of Mg, K, Na, Si and Mn. Solution concentration of free Al decreased with liming; however, organically complexed Al increased, as did soluble organic matter. Liming also stimulated mineralization of N as indicated by increased solution NO₃ levels. The field amended soils were obtained from a long-term cutting trial investigating the effects of lime on pasture. Despite the passage of a 16-year interval since application, the effects of lime on soil solution characteristics were still clearly evident and generally consistent with those observed in the laboratory study. Estimated leaching losses of Ca from limed soil were relatively low, amounting to 12%, 27% and 44% of the 4.2, 8.4 and 12.5 t lime ha⁻¹ applied, respectively. The results suggest that, in Eastern Ireland, a lime treatment would maintain and elevated pH and would influence the avialability and mobility of plant nutrients for some decades following application.     

Response of introduced Bradyrhizobium strains infectinga promiscuous soybean cultivar

Two field experiments were established to assess the competitiveness of foreign bradyrhizobia in infecting the promiscuous soybean cultivar TGX 536-02D. Seeds were inoculated with antibiotic mutants of the bradyrhizobia strains before planting after land preparation. Soybean plants were harvested at pre-determined days after planting for estimating nodule number, nodule dry weight, nodule occupancy, shoot dry weight and seed yield. Results show that nodule number and dry weight significantly increased and showed great variability at 84 days after planting (DAP), probably due to differences in the ability of inoculant bradyrhizobia to form nodules with the soybean cultivar TGX 536-02D. Increased shoot dry weight, %N, total N and seed yield were a result of increased nodulation by the effective and competitive inoculant Bradyrhizobium strains. Strain USDA 110 occupied the highest percentage of nodule sites because it was more competitive than the other Bradyrhizobium strains. These results show that there was high potential for increasing growth and seed yield of the promiscuous soybean cultivar TGX 536-02D by inoculation with foreign Bradyrhizobium strains.     

Seed pelleting in relation to nodulation and nitrogen fixation byPhaseolus aureus L. in a saline alkali soil

Summary In pot experiments using a saline alkali soil it was shown that pelleting ofPhaseolus aureus L. seeds with lime and gypsum together withRhizobium inoculation, significantly increased growth, nodulation and nitrogen fixation.     

我国23个土壤磷素淋失风险评估Ⅱ.淋失临界值与土壤理化性质和磷吸附特性的关系

从13个省（市）采取23个耕地表层土壤,通过室内模拟试验测定其磷素淋失临界值和pH、有机质、＜0.01mm、＜0.002mm、交换性钙镁、活性铁铝、磷等温吸附特性等,以建立土壤磷素淋失临界值与土壤基本理化性质和磷吸附特性之间的关系.结果表明：土壤pH＜6.0时,随土壤pH提高临界值增加,土壤pH与临界值之间呈显著的指数关系;而当土壤pH＞6.0时,随土壤pH提高临界值减小,在pH6.5左右土壤磷素淋失临界值最高.土壤磷素淋失临界值与土壤有机质、活性铁（铝）、交换性钙之间存在显著的相关,而与交换性镁、CEC、＜0.01mm、＜0.002mm、K、Qm的相关性受土壤酸碱度影响.可以通过测定土壤有机质或活性铁的含量,来计算土壤磷素淋失临界值,评价土壤磷素淋失的风险.供试的23个土壤,除了采自湖北潜江的20号水稻土存在比较大的磷素淋失风险,其余土壤发生磷素淋失的风险很小.     

The effect of cobalt on the growth of young lucerne on a siliceous sand

Summary The nodulation and growth of young lucerne plants on a moderately acid siliceous sand were greatly increased by inoculation and the application of lime. In addition cobalt treatment significantly increased the yield of nitrogen per nodulated plant and the amount of nitrogen fixed per nodulated plant but had no effect on non-nodulated plants. Cobalt significantly increased the fresh weight of nodules per plant, due to greater nodule size. Furthermore the amount of nitrogen fixed per unit fresh weight of nodular tissue was substantially increased. The effects of cobalt on symbiotic nitrogen fixation led to significant increases (29 to 77 per cent) in the dry-matter yield of lucerne tops.     

The effect of lime on phosphorus adsorption and barley growth in three acid soils

For three acid soils from Santa Catarina, Brazil, lime application and time of incubation with lime had little effect on the adsorption of added phosphorus. In two soils with high contents of exchangeable aluminium, solution P and isotopically exchangeable P were decreased by incubating with lime for 1 month: phosphorus was probably adsorbing on freshly precipitated aluminium hydrous oxides. In one soil with less exchangeable aluminium, P in solution was increased by liming. After 23 months lime increased solution and exchangeable P possibly due to crystallization of aluminium hydrous oxides reducing the number of sites for P adsorption. All these changes were however small. In a pot experiment, lime and phosphorus markedly increased barley shoot and root dry matter and P uptake. Although liming reduced P availability measured by solution P, isotopically exchangeable P and resin extractable P, it increased phosphorus uptake by reducing aluminium toxicity and promoting better root growth. The soil aluminium saturation was reduced by liming, but the concentration of aluminium in roots changed only slightly. The roots accumulated aluminium without apparently being damaged.     

Dry matter yield,root traits,and nodule occupancy of lucerne and Caucasian clover when grown in acidic soil with high aluminium concentrations

Aims and methods

Lucerne and Caucasian clover dry matter were measured in response to recommended lime and capital P inputs for six years in an acidic soil in the New Zealand high country. The initial three years of the field experiment indicated successful establishment and persistence of both legumes. Lucerne dry matter (DM) yield was up to 4 t/ha/yr in this period and higher than Caucasian clover yields. However, a lack of persistence of lucerne was apparent from this point forward compared with Caucasian clover which produced 7.7 t DM/ha in Year 6. An experiment using tubes of soil was used to investigate whether differences in root traits, nodulation and nodule occupancy were responsible for the differences observed in field persistence over time.

Results

These showed that when rhizobia inoculant was added, the fine root length of Caucasian clover was unaffected (R² = 0.14) by aluminium (Al) content of the soil. In contrast, fine root growth of lucerne was suppressed (R² = 0.79) by the soil Al content. Nodulation of Caucasian clover was unaffected by soil pH or Al when the rhizobia inoculant was provided which suggests the viability of the commercial genotype ICC148 in this soil with a pH of 5.5 and Al ca. 7 mg/kg soil. For lucerne, the maximum nodulation score of 7.3 occurred with 2 t/ha of lime added (soil pH ca.6, Al ca. 0.3 mg/kg) plus inoculant.

Conclusions

This suggests an Al toxic threshold of <1.0 mg Al/kg soil for effective lucerne nodulation. From the lucerne nodules, eight naturalized strains of Ensifer meliloti were identified. In contrast, only one R. leguminosarum strain was detected in the Caucasian clover nodules. The competition between those rhizobia genotypes may negatively affect the efficiency of biological nitrogen fixation in lucerne. Therefore, the lack of genetic diversity of R. leguminosarum bv. trifolii in New Zealand soils might be an advantage especially if the commercial strain is acid soil tolerant.

     

Influence of pH,exchangeable aluminium and 0.02M CaCl2-extractable aluminium on the growth and nitrogen-fixing activity of white clover (Trifolium repens) in some New Zealand soils

The effects of soil acidity on the growth and N₂-fixing activity of white clover in seven acid topsoils and subsoils of New Zealand were investigated using a glasshouse experiment.The application of phosphate (Ca(H₂PO₄)₂) to the soils resulted in very large increases in white clover growth on all soils. The application of phosphate, as well as increasing P supply, also decreased 0.02M CaCl₂-extractable Al levels, but had little effect on exchangeable Al levels.Where adequate phosphate was applied, increasing rates of lime (CaCO₃) resulted in increased plant growth on most soils. N₂[C₂H₂]-fixing activity was increased by the first level of lime for one soil, but generally remained approximately constant or declined slightly at higher rates of lime. Up to the point of maximum yield, white clover top weight was more highly correlated with 0.02M CaCl₂-extractable soil Al than with exchangeable Al or pH. At pH values greater than 5.5, plant yield declined on some soils, apparently because of Zn deficiency. The data suggest that white clover is unlikely to be affected by Al toxicity at 0.02M CaCl₂-extractable Al levels of less than about 3.3 g g^–1. However, there were differences between soils in apparent plant tolerance to 0.02M CaCl₂-extractable Al, which appeared to be caused by differing C levels in the 0.02M CaCl₂ extracts.     

Bacterial growth rate and growth pouch nodulation profile differences as possible ways of Bradyrhizobium japonicum strain screening for low P soils

This work studied the effects of P fertilization on nodulation of field-grown soybean by two Bradyrhizobium strains (SMGS₁ and THA₇), and checked if differences between strains were consistent with bacterial growth and growth pouch nodulation ability in response to P availability. In the field, nodule dry weight and nitrogen fixation activity of inoculated soybean were studied on typical acid soils of Thaïland at the flowering (R₁) stage and at the end of grain filling. Grain yield, growth and phosphorus content were recorded. The bradyrhizobial strains were cultivated in culture medium, and growth parameters recorded. Nodulation patterns were observed during growth pouch experiments: infective root cells were inoculated with strains cultivated at two P concentrations in their culture media, namely 1 M and 1 mM. Ten days after inoculation, the position of each nodule was measured relative to the root tip (RT) mark, expressed relative to the smallest emerging root hairs-RT distance in the nodulation frequency profile, and the consistency of responses was tested. In the field, on P deficient soils, dry weight of nodules was higher with Bradyrhizobium japonicum strain SMGS₁ than with strain THA₇. P supply increased the number and dry weight of nodules for both strains, with a higher dry weight response for THA₇ than for SMGS₁. It also had a positive effect on tissue phosphorus status and grain yield at R₈ stage. In growth media, significant differences were recorded between strains under P-limiting conditions: The growth rate was higher for strain SMGS₁, as well as the maximal number of bacterial cells supported. With growth pouch, inoculating plants with bacteria grown in P-deficient medium resulted in a less intense nodulation of roots by THA₇, and with nodules appearing earlier on roots than in the case of SMGS₁. At 1 mM P, there was no significant difference between strains. Thus, strain THA₇ is more affected by P deficiency than strain SMGS₁. Although P was not supplied in the same way in the soil and in the growth pouch experiments, this consistency of behaviour between work scales indicates that phosphorus availability is a key component for a successful inoculation. Furthermore, the study of bacterial growth rates and nodulation profile represents an interesting step for bacterial screening for low P soils. [-11pt]     

Effect of phosphate rock,coal combustion by-product,lime, and cellulose on ryegrass in an acidic soil

Remediation of soil acidity is crucial for increasing crop production and improving environmental quality of acid infertile soils. Soil incubation and greenhouse pot experiments were carried out to examine the interactions between phosphate rock (PR), coal combustion by-product (BP), dolomitic lime (L), and cellulose (C) in an acidic soil and their effects on ryegrass (Lolium perenne L. cv Linn) growth. BP and PR application increased plant P content and dry matter yield (DMY) of shoots and roots by improving soil Ca availability and reducing Al toxicity. Application of BP at low rates (5 to 10 g BP kg^-1) with PR appeared to decrease both plant P content and DMY compared to PR application alone. The reduced DMY is due to an increased Al concentration in soil solution as a result of displacement of sorbed Al by Ca of BP. Increases in DMY were obtained by addition of lime along with PR and BP at low rates or by increasing BP application rates above 15 g kg^-1. This improved plant response was likely related to alleviation of Al toxicity by CaCO₃ contained in the BP. In addition to raising the pH to an acceptable level for plant growth, the dolomitic lime supplied needed Mg for plants, thereby maintaining a good balance between available Ca and Mg for plants in the BP- and PR-amended soils. The addition of cellulose to the BP- and PR-amended soils reduced water-soluble Al and increased DMY. Plant growth increased PR dissolution by 2.4 to 243% in a soil with low available P. Use of BP at moderate rates with PR and dolomitic lime appears to be the best combination in increasing crop yields on infertile acidic soils.     

模拟酸雨对主要酸性土壤中铝的溶出及形态的影响

本文研究了模拟酸雨对主要酸性土壤中铝的溶出及形态变化的影响。结果表明,模拟酸雨对土壤酸化的影响较小,但对土壤铝的溶出却影响明显,尤其在pH<4.0时;模拟酸雨对不同类型土壤的影响是不同的,其中以高度风化的酸性土壤较为敏感。模拟酸雨对土壤游离铝形态的影响是重要的,酸处理后,交换性铝略有增加,无定形活性铝增加较多,而有机络合态铝有减少的趋势。这表明在酸雨的长期作用下,铝终将转化为交换性铝和水溶性铝而进入环境并危害生态系统。     

Responses of maize grain yield to changes in acid soil characteristics after soil amendments

An experiment was conducted from 1997 to 2000 on an acid soil in Cameroon to assess the effectiveness of cultivating acid tolerant maize (Zea mays L.) cultivar and the use of organic and inorganic fertilizers as options for the management of soil acidity. The factors investigated were: phosphorus (0 and 60 kg ha^?1), dolomitic lime (0 and 2 t ha^?1), organic manure (no manure, 4 t ha^?1 poultry manure, and 4 t ha^?1 of leaves of Senna spectabilis), and maize cultivars (ATP-SR-Y – an acid soil-tolerant, and Tuxpeño sequia – an acid susceptible). On acid soil, maize grain yield of ATP-SR-Y was 61% higher than the grain yield of Tuxpeño sequia. Continuous maize cultivation on acid soil further increased soil acidity, which was manifested by a decrease in pH (0.23 unit), exchangeable Ca (31%) and Mg (36%) and by an increase in exchangeable Al (20%). Yearly application of 60 kg ha^?1 of P for 3 years increased soil acidity through increases in exchangeable Al (8%) and H (16%) and a decrease in exchangeable Ca (30%), Mg (11%) and pH (0.07 unit). Lime application increased grain yield of the tolerant (82%) and susceptible (208%) cultivars. The grain yield increases were associated with a mean decrease of 43% in exchangeable Al, and 51% in H, a mean increase of 0.27 unit in pH, 5% in CEC, 154% in exchangeable Ca, and 481% in Mg contents of the soil. Poultry manure was more efficient than leaves of Senna producing 38% higher grain yield. This yield was associated with increases in pH, Ca, Mg and P, and a decrease in Al. The highest mean grain yields were obtained with lime added to poultry manure (4.70 t ha^?1) or leaves of Senna (4.72 t ha^?1). Grain yield increase was more related to the decrease in exchangeable Al (r = ?0.86 to ?0.95, P<0.01) and increase in Ca (r = 0.78–0.94, P<0.01), than to pH (r = ?0.57 (non-significant) to ?0.58 (P<0.05)). Exchangeable Al was the main factor determining pH (r = ?0.88 to ?0.92, P<0.01). The yield advantage of the acid tolerant cultivar was evident even after correcting for soil acidity. Acid soil-tolerant cultivars are capable of bringing unproductive acid soils into cultivation on the short run. The integration of soil amendments together with acid soil-tolerant cultivar offers a sustainable and comprehensive strategy for the management of acid soils in the tropics.