Maize nitrogen uptake and productivity under reduced and conventional tillage

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ORIGINAL ARTICLE

Maize nitrogen uptake and productivity under reduced and conventional tillage Jephita Gotosa . Jefline Kodzwa . Willis Gwenzi . Justice Nyamangara

Received: 26 August 2019 / Accepted: 4 November 2020 Ó Springer Nature B.V. 2020

Abstract Reduced tillage (RT) systems have been promoted for crop production intensification in low potential areas through enhancement of fertiliser response of degraded soils and drought mitigation. A 3 year study was conducted from 2015/2016 to 2017/2018 growing seasons in sub-humid (650–1000 mm rainfall year-1) Zimbabwe to determine nitrogen (N) uptake and maize yield response to nitrogen fertilisation rate (0, 30, 60, 90 120 150, 180 k gha-1) under RT and conventional tillage (CT). The

J. Gotosa Department of Natural Resources, Bindura University of Science Education, P. Bag 1020, Bindura, Zimbabwe

experimental design was a split plot, with the two tillage systems as main plot and seven N rates as the sub-plot treatments. Four sites were established in smallholder farmer fields with clayey soils (160–400 g clay kg-1; Chromic Luvisols and Rhodic Ferralsols) and sandy soils (40–100 g clay kg-1; Eutric Regosols). Results show that the study sites had rainfall deficits of 4–47% in the first and third growing seasons. Nitrogen uptake rates of 8–60 kg ha-1 resulted in fertiliser N recovery efficiencies of 5–40% which were two fold higher under RT than under CT system. Maize grain yields (0.3–11 t ha-1) were 33% higher under RT than CT and increased 1.88–2.72 fold under N fertilisation compared to the control. The mismatch between top dressed N and peak crop demand require precision fertilisation in the dry seasons. Agroecology based quadratic modelling revealed that maximum maize yields of 2–13 t ha-1 were obtainable at optimum N fertilisation rates that were lower under RT than CT. The study provided a robust starting point in the improvement of nitrogen fertiliser management for maize under reduced tillage and climate variability.

W. Gwenzi Department of Soil Science and Agricultural Engineering, University of Zimbabwe, P.O. Box MP167, Mount Pleasant, Harare, Zimbabwe

Keywords Agroecology  Apparent fertiliser nitrogen recovery efficiency  Nitrogen footprint  Nitrogen uptake  Optimum yield  Quadratic model

Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10705-020-10104-7) contains supplementary material, which is available to authorized users. J. Gotosa (&)  J. Kodzwa Department of Environmental Science and Technology, Chinhoyi University of Technology, P.O. Box 7724, Chinhoyi, Zimbabwe e-mail: [email protected]

J. Nyamangara Department of Environmental Science and Technology, Marondera University of Agricultural Sciences and Technology, P.O. Box 35, Marondera, Zimbabwe

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Nutr Cycl Agroecosyst

Introduction The sub-Saharan Africa (SSA) region has the highest food insecurity in the world whilst the current cereal consumption that accounts for 50% of all caloric in