Anderson Rotter Meda

Alleviating soil acidity through plant organic compounds

A laboratory experiment was conducted to evaluate the effects of water soluble plant extracts on soil acidity. The plant materials were: black oat, oil seed radish, white and blue lupin, gray and dwarf mucuna, Crotalaria spectabilis and C. breviflora, millet, pigeon pea, star grass, mato grosso grass, coffee leaves, sugar cane leaves, rice straw, and wheat straw. Plant extracts were added on soil surface in a PVC soil column at a rate of 1.0 ml min-1. Both soil and drainage water were analyzed for pH, Ca, Al, and K. Plant extracts applied on the soil surface increased soil pH, exchangeable Caex and Kex and decreased Alex. Oil seed radish, black oat, and blue lupin were the best and millet the worst materials to alleviate soil acidity. Oil seed radish markedly increased Al in the drainage water. Chemical changes were associated with the concentrations of basic cations in the plant extract: the higher the concentration the greater the effects in alleviating soil acidity.

Potencial de extratos de resíduos vegetais na mobilização do calcário no solo por método biológico

Soil surface applied lime shows low efficiency in alleviating subsoil acidity. Lime efficiency is increased through water-soluble organic compounds released from plant residues. A biological test was evaluated to verify the capacity of plant extracts on lime mobility in the soil. The test presents the following steps: plant material preparation; extraction of water soluble organic compounds; soil column preparation; soil surface lime addition; plant extract addition; irrigation with distillated water; biological test with an indicator plant (wheat, cultivar Anahuac); and root growth evaluation. Surface applied lime without plant residue increased pH and Ca, and decreased Al in the top 5 cm of soil. Lime with black oats and oil seed radish extracts increased pH and Ca and decreased Al up to the 20 cm soil depth. Wheat residue had no effect on lime mobility. Indicator root growth followed the effect of treatments on soil chemical composition: lime without plant residue enhanced root growth in the top 10 cm depth and lime with black oats and oil seed radish enhanced root growth up to the 20 cm depth. The biological test was efficient to evaluate the ability of plant residues in relation to lime mobility in the soil.

Evaluation of oat extracts on the efficiency of lime in soil

A baixa mobilidade dos componentes soluveis do calcario aplicado na superficie do solo limita a sua eficiencia na reducao da acidez das camadas subsuperficiais de solos com cargas variaveis. Foram conduzidos experimentos de laboratorio com latossolo acido para avaliar a eficiencia de extratos de aveia na mobilidade do calcario aplicado na superficie do solo. Foram avaliadas as seguintes cultivares de aveia: Argentina 5VL3, UPF 90H400-2, IAPAR 61, IA96101-b, SI 83400, EMBRAPA 29, LD 9102, FAPA 1, ER 93247, ER 90148, ER 89144, ER 93152, Alpha 94124, Alpha 94206 and Preta comum. O calcario e a aveia foram aplicados em doses equivalentes a 5 e 10 Mg ha-1, respectivamente. O efeito da calagem sem residuos vegetais limitou-se nos 10 cm superficiais do solo. A calagem na presenca de extratos de aveia aumentou o pH e Ca-trocavel e diminuiu Al-trocavel ate 25 cm de profundidade. As cultivares SI 83400 e UPF 90H400-2 foram as melhores transportadoras de Ca no perfil do solo. Os resultados sugerem que compostos soluveis contidos nos extratos de aveia, melhoram a eficiencia do calcario aplicado na superficie dos solos.

Efficiency of maize cultivars for zinc uptake and use

Zinc deficiency usually occurs in maize grown in Brazilian acidic soils. The aim of this study was to evaluate commercial maize cultivars for their Zn uptake and utilization efficiency. A greenhouse experiment using nutrient solution with young plants was carried out at Campinas, State of Sao Paulo, Brazil, in 2002. Treatments consisted of: 0.0; 0.1; 0.2; 0.4 and 0.8 mg L-1 Zn in the main plots and 24 commercial maize cultivars in the subplots, in a randomized complete block design. Zn concentration in shoot dry matter (SDM) ranged from 28.4 to 41.6 mg kg-1 among cultivars, clearly indicating a dilution effect, since a negative relation between SDM and plant height was shown. Total Zn-shoot content was a good parameter to discriminate cultivars, once correlated with plant height and SDM (r = 0.66** and r = 0.67**, respectively). Analysis of variance and polynomial regression for total Zn-shoot content was highly significant among cultivars and for the interaction cultivar vs Zn-concentration. Plants under low Zn presented up to three-fold differences among efficiency index values (E.I. = 8.59 to 26.42 mg2 DM mg-1 Zn). The results with young plants indicated six maize cultivars classified as Zn-efficient and responsive (AG 7575, Tork, AL Bandeirante, AL 34, AGN 2012, Master) and six cultivars classified as efficient non-responsive (P30F33, P30K75, P30F80, AS 1533, DOW 8420 e AL 30). Other nutrient concentrations in the SDM were within normal limits (K, P, Ca, Mg, Cu, Fe, Mn) for maize young plants.

Tolerance to aluminum toxicity by tropical leguminous plants used as cover crops

Leguminosas herbaceas sao plantas de cobertura utilizadas como adubo verde que tambem atuam na recuperacao de solos agricolas. Devido aos beneficios economicos e ambientais da adubacao verde, tem aumentado consideravelmente a adocao desta tecnica no Brasil. Entretanto, nao ha informacoes sobre estas especies quanto a toxicidade de aluminio (Al). O presente estudo teve como objetivo avaliar 17 especies de leguminosas quanto a tolerância ao aluminio. Tambem foram incluidas nos testes, tres cultivares de soja e duas de milho. Houve uma grande diferenca entre as especies testadas, possibilitando de acordo com a metodologia empregada, a seguinte classificacao: muito tolerantes (Mucuna nivea, M. deeringiana, M. aterrima Vigna unguiculata cv. BR 17 e Lablab purpureus cv. Rongai); tolerante (Cajanus cajan cv. IAPAR 43, Canavalia brasiliensis, Calopogonium mucunoides, Cajanus cajan cv. Fava larga, e Crotalaria paulina); moderadamente tolerante (Crotalaria ochroleuca, Canavalia ensiformis, Crotalaria spectabilis, e C. mucronata); sensivel (Neonotonia wightii, Crotalaria breviflora e C. juncea cv.IAC-KR1). As tres cultivares de soja foram classificadas em moderadamente tolerante (Biloxi) e tolerantes (IAC 13 e IAC 9).

A laboratory method to estimate the efficiency of plant extract to neutralize soil acidity

Water-soluble plant organic compounds have been proposed to be efficient in alleviating soil acidity. Laboratory methods were evaluated to estimate the efficiency of plant extracts to neutralize soil acidity. Plant samples were dried at 65oC for 48 h and ground to pass 1 mm sieve. Plant extraction procedure was: transfer 3.0 g of plant sample to a becker, add 150 ml of deionized water, shake for 8 h at 175 rpm and filter. Three laboratory methods were evaluated: S (Ca+Mg+K) of the plant extracts; electrical conductivity of the plant extracts and titration of plant extracts with NaOH solution between pH 3 to 7. These methods were compared with the effect of the plant extracts on acid soil chemistry. All laboratory methods were related with soil reaction. Increasing S (Ca+Mg+K), electrical conductivity and the volume of NaOH solution spent to neutralize H+ ion of the plant extracts were correlated with the effect of plant extract on increasing soil pH and exchangeable Ca and decreasing exchangeable Al. It is proposed the electrical conductivity method for estimating the efficiency of plant extract to neutralize soil acidity because it is easily adapted for routine analysis and uses simple instrumentations and materials.

Dolomite Lime's Reaction Applied on the Surface of a Sandy Soil of the Northwest Paraná, Brazil

Low Ca and Mg are serious limitations to crop production in sandy soils of the northwest Parana, Brazil. Thus soil samples of an Oxisol collected in this region were packed into 30cm long columns. Dolomite lime (2.0, 0.84, 0.30, and < 0.30 mm screen) was added on soil surface, then leached with deionized water. Thereafter, the columns were dismantled and the soil cut into 5cm segments for chemical analysis. Dolomite lime increased pHCaCl2,, KCl-exchangeable Ca and Mg and residual CO3 mostly in the top surface layers. Surface dolomite lime had no effect on pH, Ca, Mg, and CO3 in the leachate, independent on the lime particle size. These results indicated that surface dolomite lime application had no effect on subsoil composition and mostly of the calcium and magnesium carbonates are still unreacted on the soil surface.

An integrated analysis of mRNA and sRNA transcriptional profiles in Coffea arabica L. roots: insights on nitrogen starvation responses

Coffea arabica L. is an important agricultural commodity, accounting for 60% of traded coffee worldwide. Nitrogen (N) is a macronutrient that is usually limiting to plant yield; however, molecular mechanisms of plant acclimation to N limitation remain largely unknown in tropical woody crops. In this study, we investigated the transcriptome of coffee roots under N starvation, analyzing poly-A+ libraries and small RNAs. We also evaluated the concentration of selected amino acids and N-source preferences in roots. Ammonium was preferentially taken up over nitrate, and asparagine and glutamate were the most abundant amino acids observed in coffee roots. We obtained 34,654 assembled contigs by mRNA sequencing, and validated the transcriptional profile of 12 genes by RT-qPCR. Illumina small RNA sequencing yielded 8,524,332 non-redundant reads, resulting in the identification of 86 microRNA families targeting 253 genes. The transcriptional pattern of eight miRNA families was also validated. To our knowledge, this is the first catalog of differentially regulated amino acids, N sources, mRNAs, and sRNAs in Arabica coffee roots.