Effect of Nutrition and Soil Function on Pathogens of Tropical Tree Crops

McMahon, Peter

doi:10.5772/32490

Cited by 22 publications

(19 citation statements)

References 88 publications

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“…In such soils, SOM plays a critical role in nutrient availability by providing exchange sites and immobilisation by microorganisms, therefore, preventing rapid leaching and improving availability of nutrients to plants by gradual release in the rhizosphere (Burger and Jackson, 2003). An active and diverse soil microbial community directly and indirectly stimulates plant growth and reduces the severity of pests and disease (McMahon, 2012). SOM includes several functional pools defined by the turnover rates of C, including leaf litter (an active, labile pool of microbial biomass, soluble carbohydrates, proteins and extra-cellular enzymes), a less active pool (slow pool) consisting of particulate organic matter and a stable pool that includes various humates and fulvates (humus) (Woomer et al, 1994).…”

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confidence: 99%

Effect of Organic and Inorganic Amendments on Productivity of Cocoa on a Marginal Soil in Sulawesi, Indonesia

Mulia

McMahon

Purwantara³

et al. 2017

Ex. Agric.

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SUMMARYReduced soil fertility and damage from pests and diseases have contributed to a decline in productivity of cocoa (Theobroma cacao L.) smallholdings in Sulawesi, Indonesia over the last decade. In a trial on a marginal, acidic soil in South Sulawesi, young PBC123 cocoa trees were supplied with compost, mineral fertiliser (NPK fertiliser and urea) or dolomite, alone and in combination. After 20 months, the trees supplied with compost were taller, flowered more profusely and had a five-fold higher dry bean yield than other treatments. Treatments had no impact on incidence of cocoa pod borer, Phytophthora pod rot and vascular streak dieback. All of the trees supplied with compost survived, while the control, mineral-fertiliser- and dolomite-treated trees had a mortality rate of 22–45% and symptoms of interveinal necrosis. Leaf concentrations of N, P and K were within the normal range in all treatments. In the control and mineral fertiliser treatments, leaf concentrations of Ca (0.28–0.30%) and Mg (0.11–0.15%) were deficient, but were higher in trees supplied with compost (0.78–1.21% and 0.26–0.29%, respectively). The Mg/K ratio in soil-exchangeable cations and leaves was increased three-fold by the combined compost/dolomite treatment. Supplying mineral fertiliser alone resulted in 3.3 cmol kg−1 exchangeable Al, compared to 2.2 cmol kg−1 in control soils. Since 10 kg tree−1 year−1 compost was supplied, a rate that is not practical on most cocoa smallholder farms, further investigation of cost-effective applications of organic matter in conjunction with appropriate formulations of inorganic fertilisers is recommended.

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Effect of Organic and Inorganic Amendments on Productivity of Cocoa on a Marginal Soil in Sulawesi, Indonesia

Mulia

McMahon

Purwantara³

et al. 2017

Ex. Agric.

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“…Souza et al (2016), testando doses de 0 a 240 kg N ha -1 , observaram resposta quadrática a infecção de grãos de milho por patógenos, com máxima redução de infecção com dose teórica de 132 kg N ha -1 . O desequilíbrio nutricional de nitrogênio torna o milho mais suscetível a doenças, seja pela falta ou excesso de nitrogênio disponível (MCMAHON, 2012). O que foi evidenciada pelo comportamento da incidência de grãos ardidos na área de monocultivo, com menor incidência quando aplicado 300 kg de N ha -1 .…”

Section: Resultsunclassified

Sanidade de híbridos de milho em função da época de semeadura, doses de Nem áreas com e sem rotação de culturas

et al. 2019

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ResumoO sistema de rotação de culturas, a época de semeadura e a disponibilidade de nitrogênio afetam a intensidade de doenças na cultura do milho. Este trabalho foi conduzido com o objetivo de avaliar o efeito da época de semeadura e de doses de nitrogênio em cobertura sobre a incidência de podridão de colmo, grãos ardidos e a sustentação do colmo de híbridos de milho com ciclos contrastantes, em ambientes manejados com e sem rotação de culturas. Foram implantados dois experimentos a campo em Santa Catarina, Brasil: o primeiro em monocultivo, em Lages; e o segundo em rotação de culturas, em Atalanta. Foram testados dois híbridos: AG9025 PRO3 (ciclo super-precoce) e P30F53 VHY (ciclo precoce); duas épocas de semeadura: preferencial (início da primavera) e tardia (final da primavera); e quatro doses de nitrogênio em cobertura: 0, 150, 300 e 450 kg de N ha -1 . O híbrido AG9025 PRO3 apresentou maior incidência de podridões de colmo e grãos ardidos do que o P30F53 VYH na semeadura tardia, principalmente na área em monocultivo. O efeito do N sobre estas variáveis dependeu do híbrido, época de semeadura e local, evidenciando que tanto o excesso quanto a falta de N podem favorecer a incidência de doenças no milho. O incremento na dose de N aumentou o diâmetro do colmo e a altura de inserção de espigas, o que incrementou a percentagem de colmos acamados do híbrido P30F53 VYH na semeadura tardia em Atalanta. Palavras-chave: doenças de colmo; podridão de espiga; grãos avariados; acamamento; plantio direto; zea mays.

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“…This partly due to less competition occurs among coffee trees planted with shade trees in farms. Nutrient stress predisposes coffee to disease infection especially during heavy bearing stages of growth (Agrios, 2005;McMahon, 2012). The low CLR incidence and severity in very low shade level of coffee farms can be attributed to less competition for resources such as soil nutrients, moisture and light which occurs among coffee inter-planted with shade trees.…”

Section: 68mentioning

confidence: 99%

Current status on coffee leaf rust (hemileia vastatrix) in sidama and gedeo zone, southern Ethiopia

et al. 2021

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Coffee is the most important and second traded commodity next to oil in the world. In Ethiopia, coffee leaf rust caused by Hemileia vastatrix is one of the third most economically important diseases of Coffee Arabica. The current status of coffee leaf rust was intensively assessed and examined in 189 sample coffee farms from six districts across major coffee growing areas of the Southern Ethiopia. At each farm, ten randomly selected trees on a diagonal transect across the farm were assessed for disease incidence and severity. The survey data showed that coffee leaf rust was present in all assessed district varying in magnitude and extent of damage. The highest overall mean of rust incidence (38.6%) and severity (13.80%) was recorded at Dilla zuria while the lowest incidence (10.52%) and severity (1.38%) was at Yergachaffee district. The highest altitude range was obtained at Yergachaffee (1838-2056) while the lowest was at Dilla zuria (1434-1825) district. Overall mean severity and incidence result indicate that, there was statistical (p = 0.058 for severity, p = 0.044 for incidence) and negative correlation between intensity and altitude (severity, r= -0.80 and incidence, r= -0.82). The linear regression equation of severity and incidence obtained from the data was Y= -0.036X+73.16 and Y = -0.074X +158.9 (where Y= percentage CLR severity and incidence, respectively and X= altitude). This regression equation implies that, in higher elevation areas the rust intensity was low as compare to the lower elevation. Finally, the disease was remarkably increasing from time to time in all assessed coffee farms. Therefore, appropriate measurement like farmers’ awareness creation and training on how to control disease as well as appropriate agronomic managements has to be seriously undertaken. In addition, development of coffee leaf rust resistant varieties to southern Ethiopia through resistant breeding has to be set high priority.

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Effect of Nutrition and Soil Function on Pathogens of Tropical Tree Crops

Cited by 22 publications

References 88 publications

Effect of Organic and Inorganic Amendments on Productivity of Cocoa on a Marginal Soil in Sulawesi, Indonesia

Effect of Organic and Inorganic Amendments on Productivity of Cocoa on a Marginal Soil in Sulawesi, Indonesia

Sanidade de híbridos de milho em função da época de semeadura, doses de Nem áreas com e sem rotação de culturas

Current status on coffee leaf rust (hemileia vastatrix) in sidama and gedeo zone, southern Ethiopia

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