Levels Of Lime Research Articles

Productivity, profitability and nutrient uptake of maize (Zea mays) as influenced by management practices in North-East India

A field experiment was conducted during the 2 winter (rabi) seasons of 201011 and 201112 at Jharnapani, Medziphema, Nagaland, to evaluate the best management practices, i.e. mulching, liming and farmyard manures for maximizing the productivity, profitability, nutrient uptake and quality of winter maize (Zea mays L.). The experi- ment was laid out in a split-split plot design, having 24 treatment combinations of mulching and lime along with farmyard manures and replicated thrice. Application of straw mulches significantly increased all the growth and yield attributes, grain yield, protein content and nutrient uptake by maize. Among the levels of lime, higher grain yield (3.91 t/ha) and stover yield (4.24 t/ha) were noted with application of lime @ 0.6 t/ha. Similarly, significantly higher grain (3.79 t/ha) and stover yields (4.17 t/ha), nutrient uptake, protein yield of maize were recorded with ap- plication of farmyard manures @ 12 t/ha. Application of straw mulch along with 0.6 t/ha lime and FYM @ 12 t/ha recorded markedly higher total rainfall and effective rainfall use efficiency. Hence, straw mulching with 0.6 t/ha fur- rows lime and 12 t FYM/ha should be adopted to obtain the maximum grain yield, net profit and nutrient uptake by winter maize.

Componentes morfológicos e produção de matéria seca de milho em função da aplicação de calcário e zinco<A NAME="top"></A>

O milho é uma das plantas que mais responde positivamente à aplicação de zinco no solo, com ganhos na produção de matéria seca e grãos. Entretanto, a disponibilidade e a absorção do elemento pelas plantas são influenciadas negativamente pela elevação do pH, da V% e do teor de P nos solos. Para estudar o efeito da calagem e do zinco aplicado na adubação, e o seus efeitos residuais sobre a produção de matéria seca e o desenvolvimento das plantas de milho, foram realizados três cultivos subsequentes, em condição de casa de vegetação, utilizando-se vasos que receberam 20 kg de um Latossolo Vermelho distrófico. O delineamento experimental foi inteiramente casualizado em esquema fatorial 3x3, com três saturações por bases (15, 50 e 70%) e três teores de zinco no solo (0,70, 5 e 10 mg dm-3), com quatro repetições. Em cada cultivo deixaram-se duas plantas de milho (híbrido tríplo XL 370) por vaso até os 57 dias após a emergência, momento em que foi realizada a colheita para a determinação da produção de matéria seca. A análise de desenvolvimento da planta foi realizada a cada sete dias, avaliando-se: altura média, número de folhas e comprimento médio de entrenós/planta, num total de oito coletas. A aplicação de zinco não alterou as variáveis morfológicas da planta de milho. A calagem incrementou a altura das plantas. O aumento da dose de calcário resultou em maior produção de matéria seca e teores de Ca e Mg nas folhas e colmos de milho. A aplicação de zinco incrementou os teores do elemento na matéria seca. Houve efeito residual da calagem e da adubação com zinco na produção de matéria seca em três cultivos de milho.

IMPROVING NUTRIENT USE EFFICIENCY OF ANNUAL CROPS IN BRAZILIAN ACID SOILS FOR SUSTAINABLE CROP PRODUCTION

In tropical acid soils, acidity is an important constraint for availability and uptake of nutrients by annual crops, and this leads to lower crop yields. Factors that contribute to low nutrient uptake efficiencies in these soils are low natural levels of most essential plant nutrients and unfavorable soil and plant environments. High P fixation capacity, Al, Mn and H toxicity, low activities of bene-ficial microorganisms, soil compaction, infestation of weeds, diseases and insects, drought and intensive monoculture are some of the major factors that contribute to the unfavorable soil and plant environments. Improving nutrient use efficiency in these soils demand adoption of special management practices. These practices include timely application of adequate levels of lime, gypsum and fertilizers to meet crop demand, use of proper crop rotation, improvement of organic matter content, control of soil erosion and use of acid tolerant crop species and cultivars within species.

Fator de retardamento e coeficiente de dispersão-difusão para o crômio (III) em solos muito intemperizados, influenciados pelo pH, textura e matéria orgânica

O objetivo principal deste trabalho foi analisar a variação dos fatores de retardamento (R) e dos coeficientes de dispersão-difusão (D) para o crômio (III) em dois solos muito intemperizados, considerando diferentes atributos edáficos: textura, pH e matéria orgânica. Utilizaram-se amostras dos horizontes A e B com diferença marcante no teor de matéria orgânica de dois solos coletados no estado de São Paulo: Latossolo Vermelho eutroférrico textura argilosa (LVe) e Latossolo Vermelho-Amarelo distrófico textura média (LVd). A alteração do pH das amostras do horizonte superficial foi realizada com adição de carbonato de cálcio para elevar a saturação por bases a 70%. Foram realizados experimentos de adsorção em condições estáticas e de lixiviação em colunas de solo, utilizando a teoria do deslocamento miscível. Os Rs obtidos para o LVe foram maiores em comparação aos obtidos para o LVd. O aumento do pH do solo propiciado pela adição de carbonato de cálcio resultou em aumento no R. No LVe, a presença significativa de ácidos fúlvicos na matéria orgânica propiciou um R menor no horizonte superficial em relação ao subsuperficial. Não foi evidenciada relação nítida entre D e os diferentes solos, níveis de calagem e horizontes.

Growth response of coffee tree shoots and roots to subsurface liming

In the greenhouse growth of two coffee-tree varieties, Catuai (sensitive) and Icatu (tolerant) to aluminum, was evaluated in surface-fertilized and limed soil following subsurface treatment with seven lime levels (0.0; 0.49; 1.7; 2.9; 4.1; 6.6 and 9.3 t/ha). Plants were grown for 6.5 months in soils in PVC columns, subdivided into two horizons. In the lower 12 – 34 cm depth horizon, soil Al saturation varied between 93 and 0%. For both varieties evaluated, shoot dry weight and leaf area remained unchanged following limestone application. This fact shows that surface layer correction permitted normal shoot growth. High Al saturation resulted in decrease of root dry weight percent, root length percent and root surface percent in the 12–34 cm horizon, which were compensated by higher percentages of these properties in the upper 0–12 cm horizon. The ratio between root surface – root dry matter (cm2/g) of Catuai variety was increased by limestone application to the lower soil horizons, indicating that roots turn longer and thinner, when Al soil saturation decreased. This also shows a great sensitivity to Al of the Catuai variety. In contrast, in the Icatu variety, all root characteristics remained stable at all levels of Al tested.

Kombinasi Optimal cara Olah Tanah dan Tingkat Pengapuran untuk Pola Tumpangsari Jagung di antara Karet pada Tanah Podzolik Merah Kuning

Technical modification of rubber based intercropping system are still needed due to the appearance of various problems, either bio-physical or socio-economie factors. At different areas, where labour is limited, substitution of manual tillage and manual seeding with mechanical equipment and manual weed control with chemical control has to be taken into account. Research on rubber based intercropping, combining two tillage systems. Conventional or full tillage, where soil was plowed and harrowed 2 and 2 times respectively,. and reduced tillage where soil tillage was done only one plowing and one harrowing and four liming levels atintercrop rows at 20 cm with (maize, variety of C7) was carried out in Sembawa Research Institute since 1998. The presented data were collected tillage system and liming dose was observed, however the grain yield difference was reduced up to 22%. During dry season cowpea (Vigna anguikulata), planted after maize, produced 870 kg/ha. The cost of production of cropping maize as rubber intercrop using full tillage system at optimal liming level was about Rp. 2,1 million. If the grain price is Rp. 1200/kg then the break-even point will be reached at grain yield of 1750k g/Ha. Rubber growth of IRR 39 clone, a latex and timber clone, was very good. Until 13 months stem diameter was not affected by tillage systems and levels of liming for intercrop. Key words: Intercropping, Rubber, Maize, Cowpea, Soil tillage, Liming, Ultisol

Efeito de níveis crescentes de calagem no crescimento e estado nutricional de fedegoso

A distribuição e desenvolvimento de plantas, a exemplo daquelas que infestam as áreas agrícolas, é influenciada por diversos fatores, a como aqueles ligados às caraterísticas do solo, naturais ou impostas pelo homem. Assim, o presente trabalho de pesquisa foi desenvolvido em condições de casa-de-vegetação com o objetivo de estudar o efeito de níveis crescentes de calagem no crescimento e estado nutricional de Senna obtusifolia, planta daninha comum em ecossistemas agrícolas. O delineamento experimental adotado foi o inteiramente casualizado, com seis tratamentos e quatro repetições. Os tratamentos constituíram-se em quantidades de calcário dolomítico calcinado com 38% de CaO e 20% de MgO, com um poder de neutralização total (PRNT) de 104%: 0, 2, 4, 6, 8 e 10 t/ha. As parcelas experimentais constituíram-se de recipientes de plástico com capacidade de 5 litros, preenchidos com terra coletada na camada arável de um latossolo vermelho escuro distrófico, "A" moderado, textura média. Após um período de crescimento de 56 dias as plantas foram coletadas e separadas em seus componentes vegetativos, sendo colocados a secar em estufa de circulação forçada de ar (70ºC por 72 horas) para determinação do peso seco. O material foi pesado e moído e analisado a nível de composição de nutrientes. Os resultados mostraram efeitos negativos dos níveis crescentes de calcário, sobre o crescimento das plantas de S. obtusifolia, evidenciando-se decréscimos nos valores da matéria seca acumulada a partir da dose de 4 t/ha de calcário (pH 5,8), com efeitos mais marcantes nas raízes. A aplicação de doses crescentes de calcário promoveu um aumento progressivo nos teores de Ca e Mg no solo, o que talvez possa ter estimulado a competição entre cátions, reduzindo a absorção do K. Os elementos N e P foram os mais absorvidos pela planta.

Shelterwood harvesting in root-disease infected stands — post-harvest soil disturbance and compaction

Soil disturbance and compaction are described for an integrated project, testing the use of shelterwood harvesting and root removal treatments. Sites were winter harvested and assessed the following summer using criteria from the Forest Practices Code (FPC) of British Columbia. At two installations, pushover harvesting caused a significantly greater level of counted soil disturbance and forest floor displacement than hand felling combined with ground skidding. Disturbance levels increased with basal area removal on pushover harvested treatment units. The highest disturbance was on the clearcut–pushover treatment at the Golden site, where levels averaged 36% for both variables. Soil disturbance on the Nakusp site was lower for a number of reasons. Pushover harvesting at the Golden site also resulted in over 25% of the sample points becoming calcareous at the surface, due to exposure and deposit of calcareous subsoil; as opposed to less than 5% on the hand felled treatment units. Pushover harvesting at Golden, compared to the Nakusp site, also yielded a greater proportion of the treatment units occupied by stump holes, because of larger tree size and finer soil textures. Soil compaction significantly increased total bulk density at Golden and decreased total porosity and two measures of aeration porosity at both sites. Machine disturbance not meeting the disturbance survey criteria of the FPC occupied up to 16% of treatment units at the Golden site. This uncounted disturbance was not significantly different from countable compaction for five physical properties. Compaction impacts were usually significant, irrespective of the harvesting method or basal area retention on a treatment unit. Aeration porosities for some compacted samples were at or below ‘critical’ values of 15% on both sites. Tree growth at Golden is expected to be reduced because compaction has reduced aeration porosity and push felling exposed greater levels of free lime. Site sensitivity guidelines for pushover harvesting are exceeded for the soil conditions at Golden. More recent harvesting on other sites has resulted in less disturbance than reported here. It appears that countable soil disturbance can be limited to 15% for pushover harvesting under operational conditions.

Crescimento e produção de alcalóides totais de quebra-pedra em função da calagem e da adubação nitrogenada

Foram cultivadas, em casa-de-vegetação, cinco plantas de Phyllanthus niruri L em vasos com volume de 3,4 dm³, tendo como substrato um Cambissolo Álico, com textura média, coletado no município de Nazareno - MG. As sementes de quebra-pedra foram oriundas de Belém - PA. Os tratamentos consistiram de cinco doses de N (0, 30, 60, 100 e 150 mg/dm³) e o uso ou não de calcário, sendo que nos tratamentos com calcário visava-se a elevação do pH para 6,0. O delineamento experimental foi inteiramente casualisado com seis repetições. As plantas foram colhidas aos oitenta dias de ciclo, quando foi avaliado o peso da matéria seca da parte aérea e da raiz e efetuadas as análises químicas e fitoquímicas da parte aérea das plantas. O quebra-pedra é uma espécie responsiva à calagem e à adubação nitrogenada, apresentando na dose de nitrogênio de 77,81 mg/dm³ de solo o equivalente a 90% da produção máxima média (12,25 g/vaso) de matéria seca total, quando na presença de calagem. Na ausência de calagem a produção de matéria seca total decresce linearmente (de 3,9 g/vaso a 2,0 g/vaso) com o aumento das doses de N. O teor de P, S, Ca e Mg nas plantas foi maior nos tratamentos com calagem, independente das doses de N. Na ausência de calagem, o conteúdo dos macronutrientes na matéria seca total foi menor em conseqüência da menor produção de matéria seca total. na presença de calagem. Na presença de calagem, observou-se aumento na matéria seca da parte aérea e na concentração de alcalóides à medida que se aumentaram as doses de nitrogênio aplicadas. A máxima produção de alcalóides totais foi de 0,676 mg/g de matéria seca total da parte aérea, que corresponde à dose de N equivalente a 90% para máxima produção de matéria seca da parte aérea.

Evaluation of nutrient status and grain yield of two corn cultivars under different soil aluminum levels after liming

This study was conducted to evaluate the effects of decreasing levels of Al saturation through the addition of lime under field conditions in the nutritional status and grain yield of two corn (Zea mays L.) cultivars: one tolerant and one non-tolerant to Al. The experiment was conducted on Red Yellow Latosol (Oxisol) at the Paraná, Brazil. Control plots received no lime (T0), the treatment T3 received lime to achieve 0% Al saturation and treatments T1 and T2 recieved 33.3% and 66.6%, respectively, of the lime applied to treatment T3. At full bloom stage, representative leaves ("nutritional leaves") were analysed for macro, micronutrients and Al contents, and in treatments T0 and T3 were also analyzed for Al distribution in shoot plants parts (stem, node, internode and leaves). Liming increased concentrations of N, P and Mg and decreased concentrations of Mn and Al in the "nutritional leaves"of both cultivars. The Al distribution in the shoot plant parts showed that its concentration was higher in the leaves than in any other plant part, independent of liming level. Grain yield of the tolerant cultivar was higher, although for both cultivars increase in yield was correlated with decrease in Al saturation.

Rationale on composition of slags in oxygen steelmaking processes

A study of plant analytical data on slags for the BOS and OBM processes revealed consistent interrelations between the concentrations of FeO, CaO, and SiO2 in the slag at the end of the oxygen blow. Over a wide composition range, the amounts of CaO and SiO2 decrease with increasing FeO, slag basicity increases with increasing FeO, and the amount of MgO decreases with increasing slag basicity. At all levels of lime and silica contents, the amount of FeO in the slag varies by 5–6% between the low and high contents. Consequently, the slag/ metal distribution ratios (%P)/[%P] and (%S)/[%S] as functions of basic and/or acidic oxide contents are within a composition range bordered by the equilibrium curves for the low and high FeO contents.

Effect of liming and cadmium application in an acid soil on cadmium availability to sudangrass

A greenhouse pot experiment was conducted, using an acid sandy loam Dystric Cambisol derived from schist, in order to evaluate the effect of liming and cadmium (Cd) application on Cd availability to sudangrass (Sorghum sudanense cv.Tama). The soil was incubated with four levels of lime and three levels of Cd. After soil incubation, sudangrass was then sown. During the experiment the pots were maintained at 70% of field moisture capacity. After harvest, the air‐dried soil samples were analyzed for extractable Cd using 0.01 mol L‐1 CaCl2, 0.43 mol L‐1 HNO3, and 1 mol L1 AcNH, pH 7 reagents. Although liming increased soil pH from 4.3 to 6.6, the effect of liming on soil pH was dependent on Cd level (p=0.05). Soil exchangeable calcium (Ca) increased due, not only to CaCO3 addition, but also to the exchange sites created by Al3+ desorption. However, a significant decrease of exchangeable Ca with added Cd was observed mainly for the first CaCO3 level. Liming significantly lowered exchangeable magnesium (Mg) and potassium (K), the latest being dependent on Cd application level. Cadmium sorption increased with the rate of Ca. Therefore, sorption was directly related to the pH and soil mineralogy. Liming induced significantly higher values of DM yield, although depending on Cd application level. The plant Cd concentration decreased significantly (p=0.05) with the application of 4.5 g kg‐1 of CaCO3 at 1.0 mg kg‐1 of Cd, reaching values of plant Cd within the range of critical concentrations. The decreasing of Cd uptake was only observed with rates of CaCO3 higher than 1.5 g kg‐1. Soil pH of 5.1 is probably the critical value on Cd uptake.

Ectomycorrhizal community structure in a limed spruce forest

The aim of this study was to compare the ectomycorrhizal community structure in spruce stands treated with different levels of dolomite lime. ITS-typing of randomly sampled mycorrhizas, without prior morphotyping, was used. Sixteen different ITS-RFLP patterns were found. By comparison with the available reference material, nine of these could be identified at least to genus level. Variation within treatments was large and statistically there were no significant differences between treatments with respect to specific taxa. A similarity assessment did, however, show less similarity between control and high dolomite (HD) than between low dolomite (LD) and either control or HD, suggesting a shift in the community structure as a result of the treatment. The fruitbody production at Hasslov had been recorded in a different study during 1985–92 and 28 ectomycorrhizal species had been found in the treatments examined in the present study. Except for three species, all were present in the reference material used for identification of the ITS-types. Only three species, Russula ochroleuca, Lactarius necator and Boletus chrysenteron were found as both mycorrhizas and fruitbodies. There were five taxa which occurred on over 5% of the screened roots. These were Thelephora terrestris , 21.5%; Tylopilus felleus , 13%; Tylospora fibrillosa , 13%; and two unidentified taxa, 10% and 6%. Together these five taxa colonized over 60% of the mycorrhizal roots investigated, yet none of them was found among the fruitbodies recorded in the above-ground study. Despite the differences in taxa found below and above ground, similarity tests between treatments using the fruitbody data also revealed a shift in community structure.

Nutrition of container‐grown freesias

As limited information is available on the nutrition of freesias an experiment was carried out to examine the influence of nutrients on foliage and corm growth, and flowering of container‐grown plants. The experiment ran for 10 months using seedlings grown in a peat:sand (3:1,v:v) medium with combinations of varying levels of nitrogen (N), phosphorus (P), potassium (K), and lime. Nitrogen fertilization had a significant effect on many aspects of flowering and growth while the response to P was similar except for a lack of influence on spike production. Fertilization of 600–800 g N m‐3 and at least 200 g P m‐3 are recommended for strong leaf and corm growth with good flowering. There were few significant responses to added K, except in early foliage growth, while liming increased foliage development. High flowering, leaf, and corm growth should be achieved with a media pH of 5.9 and foliar nutrients of 2.2–2.3% N, 0.25–0.30% P, 4.0–4.5% K, 0.65–0.80% calcium (Ca) and 0.20–0.25% magnesium (Mg).

Calagem para uma rotação de culturas no sistema plantio direto

Agricultores que adotaram o sistema plantio direto (SPD) pretendem não mais arar o solo para incorporar calcário com o objetivo de corrigir a acidez do solo, dai a busca de novos métodos para a correção dessa acidez. Dois experimentos foram realizados, no período 1993-1996, para avaliar a resposta de soja, trigo, milho, aveia e cevada a calcário aplicado na superfície de solos com 380 g kg-1 de argila (LEd-Passo Fundo) e com 580 g kg-1 de argila (LRd-Sarandi), manejados no sistema plantio direto. Os experimentos foram desenvolvidos no delineamento de blocos ao acaso, com três repetições. Os tratamentos foram escolhidos conforme a necessidade de calagem dos solos, determinada pelo método SMP, para pH 6,0, em amostras de solo coletadas na profundidade de 0-20 cm a saber: testemunha, calcário incorporado e cinco níveis de calcário aplicados na superfície dos solos (1, 1/2, 1/4, 1/8 e 1/16 SMP). Apenas a soja, em 1994, e a soja e cevada, em 1996, mostraram respostas à aplicação do calcário. Na dose recomendada de calcário (1 SMP), não houve diferenças significativas entre calcário incorporado e não incorporado. Considerando as relações custo/benefício, as doses que proporcionaram maior retorno financeiro foram de 1/16 SMP, para o solo LEd, e de 1/8 SMP, para o solo LRd, quando se desconsiderou a cevada. Quando esta foi incluída na análise econômica, as doses que deram maior retorno financeiro foram de 1/4 e 1/2 SMP, para os solos LEd e LRd, respectivamente. Amostras de solo coletadas aproximadamente três anos após a aplicação do calcário revelaram que a adição de calcário na superfície dos solos corrigiu a acidez e aumentou significativamente o pH somente na camada de 0-5 cm. Conclui-se que não há inconveniência no uso de calcário na superfície de solos com acidez já corrigida pelo método convencional há alguns anos e que apresentem bom nível de nutrientes.

Optimisation of treatment conditions of wheat straw with lime: Effect of concentration, moisture content and treatment time on chemical composition and in vitro digestibility

Chopped wheat straw (0.5–1.5 cm) was treated with different levels of lime (2–5% w/w), moisture (40–60%) and treatment time (1–3 weeks). Treated samples were kept in a laboratory at about 35°C in a 4×3×3 factorial arrangement, to study the effect of different factors on chemical composition and in vitro organic matter digestibity (IVOMD). Results showed that lime treatment appears to be effective in solubilising the cell wall constituents (CWC) and increasing the IVOMD significantly ( P<0.01). Neutral detergent fibre (NDF) and hemicellulose (HC) contents decreased significantly ( P<0.01) due to the lime treatment; and the respective decrease were to the extent of 5.40 and 16.00% in comparison to untreated wheat straw. Similarly, acid detergent lignin (ADL) was solubilised to the extent of 46.70% by lime treatment. IVOMD increased ( P<0.01) with increasing concentration of lime and the maximum value (59.71%) was noticed at 5% lime concentration. The other factors like moisture content, reaction time and their interactions also showed significant effect on the enhanced solubilization of CWC. Lime (5%) with 60% moisture for three weeks reaction period was an appropriate condition for the maximum response of treatment in wheat straw under laboratory conditions.

Propriedades físicas do solo sob plantio direto influenciadas por calagem, preparo inicial e tráfego

No sistema de plantio direto, a ausência de revolvimento do solo, aliada ao tráfego de máquinas, promove a compactação excessiva do solo em superfície. Com o objetivo de estudar alguns fatores que interferem na compactação do solo em plantio direto, foi realizado um experimento no município de Ponta Grossa (PR), nos anos agrícolas de 1989/1990 e 1990/1991. Comparou-se o efeito de três métodos de preparo inicial do solo - com arado de discos, aivecas e rotativo - e dois níveis de calagem sobre algumas propriedades físicas de um Latossolo Vermelho-Escuro argiloso no sistema de plantio direto com tráfego controlado. Utilizou-se a seqüência de culturas em rotação: ervilhaca, milho, aveia-preta e soja. Avaliaram-se a densidade, a porosidade do solo e o teor de água retido entre os potenciais de -0,006 e -0,5 MPa. Não houve efeito significativo da calagem sobre as propriedades físicas estudadas. Os resultados demonstraram efeitos significativos do tráfego, aumentando a densidade do solo e reduzindo a sua porosidade e o conteúdo de água retido entre aqueles potenciais. A distribuição, em profundidade, das cargas aplicadas pelo tráfego de máquinas, principalmente de colheitadeiras, foi, provavelmente, influenciada pelo volume de solo revolvido pelos diferentes sistemas de preparo inicial. Nas parcelas em que a estrutura do solo foi submetida a pressões por meio do tráfego, obteve-se redução na produtividade da soja, em comparação às áreas com ausência de tráfego, no período em que o estudo foi realizado.

Nutrition of container‐grown Acalypha hispaniolae

Rooted cuttings of Acalypha hispaniolae were grown in peat/composted bark (7: 3 v/v) medium for 4 months to evaluate their response to five levels of nitrogen (N), phosphorus (P), potassium (K), and lime. There was a linear response to added N with foliar dry matter increasing over the range 0–600 g N/m3 and a leaf N content of c. 3.3% at this highest rate of N. Predicted maximum flower dry weight occurred at 400 g N/m3. P additions suppressed growth and flowering. Foliage P content needs to be held at c. 0.2%. Chlorosis of mature leaves was most severe with N deficiency but was also caused by P toxicity. Chlorosis in immature leaves was attributed to P‐induced iron deficiency and was most severe when the P: Fe ratio in the leaves was 62: 1. Liming reduced P toxicity and the lime rate for maximum growth was 6–9 kg/m3 and a pH of c. 5. K additions had little effect on growth. A foliage K content of c. 2% is recommended.

Growth response of native shrubs to acid mine spoil and to proposed soil amendments

Successful reclamation of acid mine sites may be enhanced by revegetating with species that are tolerant to acid mine spoil conditions. This study was conducted to assess the response of four native shrub species, Amelanchier alnifolia Nutt., Symphoricarpos albus (L.) Blake, Berberis repens Lindl., and Ceanothus sanguineus Pursh, to 1) pyritic acid mine spoil amended with various levels of lime and composted sewage sludge with added ammonium nitrate (CSS+N) and 2) acidified granitic spoil, with and without CSS+N. Species responded to soil acidity and nutrient supply similarly in both spoil materials. Berberis and Amelanchier exhibited acid soil tolerance, Symphoricarpos grew poorly in acidic soils but had low mortality, and Ceanothus responded to low pH with very poor growth, high mortality, or both. Amelanchier was conservative in growth and did not respond to either soil pH or nutrient supply with significant differences in biomass accumulation. Symphoricarpos varied in response to CSS+N but was most productive at neutral or higher pH. Berberis responded to nutrient availability with substantial increases in biomass production, including significant growth in strongly acidic spoil. Ceanothus responded to nutrient availability with large increases in biomass and was most productive with added CSS+N at neutral or higher pH. Nitrogen fixing nodules developed on the roots of Ceanothus plants grown in granitic spoil without CSS+N. The results indicated that these species differ significantly in acid soil tolerance and in their potential for growth, stress tolerance, and resource acquisition.

Effect of molybdenum, phosphorus, and lime application to acid soils on dry matter yield and molybdenum nutrition of lentil

Deficiency of molybdenum (Mo) in acid soils causes poor growth of pulses. An experiment was, therefore, conducted in greenhouse to study the effect of Mo, phosphorus (P), and lime application on the dry matter yield and plant Mo concentration of lentil (Lens esculenta L.) in two Mo‐deficient acid alluvial soils. The experiment was conducted using a factorial design with three levels of lime (no lime, half, and full lime requirement), three levels of P (0, 25, and 50 mg kg‐1), and two levels of Mo (0 and 1.0 mg kg‐1). Plants were grown for 60 days and at harvest their dry matter yield and Mo concentration were recorded. The three treatments significantly increased dry matter yield, Mo concentration and Mo uptake, the increase being most pronounced with Mo application followed by lime and P. Increases due to applied Mo were greater in presence than in absence of added P; while the reverse was true with the liming treatments. Liming and P application at their lower levels also interacted positively for better Mo nutrition of plants. Results thus indicated that the severity of Mo deficiency in the lentil plants may be reduced by lime and P application in Mo‐deficient acid alluvial soils.