Experiments with Nitrogen and Magnesium Fertilizers on Coffee in Uganda

Stephens, D. F.

doi:10.1017/s0014479700022031

Cited by 4 publications

(4 citation statements)

References 5 publications

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“…The close positive association of cumulative yield with leaf N suggests N limitation of coffee yields at this site. A N limitation is consistent with responsiveness of Robusta yields to N rates encompassing and exceeding those used in our study (Byrareddy et al., 2019; Díaz et al., 2011; Marsh, 2007; Stephens, 1967), and more broadly to crop production in tropical smallholder systems (Mueller et al., 2012). The near doubling of yields under conventional (2.32 kg tree −1 ) compared to organic (1.23 kg tree −1 ) management is likely reflective of the higher total N inputs and higher N/P of inputs than in the organic NPK input treatments.…”

Section: Discussionsupporting

confidence: 87%

“…Evidence from smallholder on‐farm trials and landscape surveys indicate that soil nutrient limitation is a major productivity constraint that underpins entrenched coffee yield gaps (Bhattarai et al., 2017; Rahn et al., 2018; Wang et al., 2015). On‐farm trials have identified nitrogen (N) as a key determinant of Robusta coffee yields in smallholder settings (Stephens, 1967), though yields can be as or more strongly limited by phosphorus (P) and potassium (K) (Kiyingi & Gwali, 2012; Wairegi & Van Asten, 2012; Wang et al., 2015). In addition to shielding the coffee plant from direct sunlight, one of the potential benefits of integrating shade management into coffee agroecosystems includes direct and indirect improvement of soil nutrient availability and uptake by coffee (de Sousa et al., 2019; Pham et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

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Apparent nitrogen limitation of Robusta coffee yields in young agroforestry systems

et al. 2021

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Robusta coffee (Coffea canephora Pierre ex Froehner) is an important cash crop in the lowland tropics. Similar to Arabica (C. arabica L.), agroforestry is common in these systems, though comparatively little is known about how nutrient inputs and leguminous shade trees influence Robusta nutritional status and yield. We evaluated how shading with leguminous trees across four input systems, defined largely by quantity and form (compost vs. synthetic) of nitrogen (N), phosphorus (P), and potassium (K), influenced Robusta-based cropping systems in the Ecuadorian Amazon. Soil fertility was largely unaffected by compost and synthetic fertilizer (NPK) inputs or by shade species, and was weakly related to coffee productivity based on principal component analysis (PCA). Though litter appeared to be an agronomically appreciable source of N and P, this was only somewhat reflected in soil extractable N and P, presumably due to nutrient losses under high rainfall conditions (>3,000 mm yr −1 ). Patterns of variation suggest transfer of N and P from litter to soil to leaf. Conversely, litter K was unrelated to soil K, but soil K was closely related to leaf K. Robusta yields appeared to be largely N limited and were more influenced by input type (i.e., synthetic vs. organic nutrient sources) than by shade species or amount of N inputs in the form of compost or synthetic N, P, and K fertilizers. Additionally, yields across all treatments were significantly higher than regional averages, suggesting that slight investments in inputs can substantially increase productivity in maturing Robusta systems, irrespective of shade tree species selection. INTRODUCTIONCoffee (Coffea spp.) is a globally important cash crop produced in the tropics (Lewin et al., 2004). Worldwide, coffee production is dominated by two species, Arabica (C. arabica L.) (57%) and Robusta (C. canephora Pierre ex Froehner

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Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Apparent nitrogen limitation of Robusta coffee yields in young agroforestry systems

et al. 2021

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“…Hence, poor soil fertility is a major constraint to coffee production in the region (e.g. Stephens, 1967; Wortmann and Kaizzi, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…Esilaba et al ., 2005), fertiliser trials (e.g. Stephens, 1967) and soil nutrient balances (e.g. Wortmann and Kaizzi, 1998), and not on foliar nutrient mass fractions.…”

Section: Introductionmentioning

confidence: 99%

Norms for Multivariate Diagnosis of Nutrient Imbalance in Arabica and Robusta Coffee in the East African Highlands

Wairegi

Asten

2012

Ex. Agric.

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SUMMARYPoor soil fertility is a constraint to coffee production. Targeting fertiliser recommendations to nutrient deficiencies can contribute to improved crop response to fertiliser. This study aimed to derive and compare the Compositional Nutrient Diagnosis (CND) and Diagnosis and Recommendation Integrated System (DRIS) norms for Arabica and Robusta, and to investigate nutrient interactions using data derived from 164 plots. The high-yield sub-populations of Arabica had significantly (p < 0.01) higher P (0.23 vs. 0.14) and K (2.87 vs. 2.04), and lower N (2.96 vs. 3.61), Ca (0.99 vs. 1.50) and Mg (0.40 vs. 0.23) than those of Robusta. With respect to the CND norms, Arabica had significantly (p < 0.001) higher P and K, and lower N, Ca and Mg means of row-centered log ratios than Robusta. The relationship between the CND and DRIS indices had coefficient of determination (R2) = 0.75–0.99 for both coffee types. The relationship between nutrient imbalance indices for CND and DRIS had R2 of 0.95 (Arabica) and 0.76 (Robusta). Both coffee types had negative N–Ca, P–Mg and K–Mg interactions. Arabica had positive N–Mg and K–Ca interactions and Robusta had positive N–K, P–K and Ca–Mg interactions and negative N–P, N–Mg, P–Ca and K–Ca interactions. The study concludes, there is a need for cultivar-specific norms, but such norms developed under one set of conditions may not be applicable under different conditions. The study also concludes that both CND and DRIS can be used to determine nutrient imbalances, and fertiliser requirements could be cultivar-specific.

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Rapid Routine Soil and Plant Analysis Without Automatic Equipment

Foster¹

1971

East African Agricultural and Forestry Journal

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Experiments with Nitrogen and Magnesium Fertilizers on Coffee in Uganda

Cited by 4 publications

References 5 publications

Apparent nitrogen limitation of Robusta coffee yields in young agroforestry systems

Apparent nitrogen limitation of Robusta coffee yields in young agroforestry systems

Norms for Multivariate Diagnosis of Nutrient Imbalance in Arabica and Robusta Coffee in the East African Highlands

Rapid Routine Soil and Plant Analysis Without Automatic Equipment

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