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dc.contributor.authorTully, Katherine L.  Concept link
dc.contributor.authorWood, Stephen A.  Concept link
dc.contributor.authorAlmaraz, Maya  Concept link
dc.contributor.authorNeill, Christopher  Concept link
dc.contributor.authorPalm, Cheryl A.  Concept link
dc.date.accessioned2015-11-06T20:17:21Z
dc.date.available2015-11-06T20:17:21Z
dc.date.issued2015-07
dc.identifier.urihttps://hdl.handle.net/1912/7609
dc.descriptionAuthor Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Agriculture, Ecosystems & Environment 214 (2015): 10-20, doi:10.1016/j.agee.2015.08.006.en_US
dc.description.abstractSoil fertility declines constrain crop productivity on smallholder farms in sub-Saharan Africa. Government and non-government organizations promote the use of mineral fertilizer and improved seed varieties to redress nutrient depletion and increase crop yields. Similarly, rotational cropping with nitrogen (N)-fixing legume cover crops or trees is promoted to improve soil fertility and crop yields. We examined maize grain yields and partial N balances on 24 smallholder maize farms in western Kenya, where interventions have increased access to agricultural inputs and rotational legume technologies. On these farms, mineral fertilizer inputs ranged from 0 to 161 kg N ha-1 (mean = 48 kg N ha-1), and maize grain yields ranged from 1-7 tons ha-1 (mean = 3.4 t ha-1). Partial N balances ranged from large losses (-112 kg N ha-1) to large gains (93 kg N ha-1)with a mean of -3 kg N ha-1. Maize grain yields increased significantly with N inputs (from fertilizer and legumes) in 2012 but not in 2013 when rainfall was lower. Nitrogen inputs of 40 kg N ha-1 were required to produce 3 tons of maize ha-1. N balances varied both among farms and between years, highlighting the importance of tracking inputs and outputs on multiple farms over multiple years before drawing conclusions about nutrient management, soil fertility outcomes and food security. The addition of N from legume rotations was a strong predictor of grain yields and positive N balances in lower-yielding farms in both years. This suggested that legume rotations may be particularly important for buffering yields from climate variability and maintaining N balances in low rainfall years.en_US
dc.description.sponsorshipThis research was funded by an Earth Institute at Columbia University Cross-Cutting Initiative Grant, a National Science Foundation PIRE grant (IIA-0968211), and by the Bill and Melinda Gates Foundation (Gates Special Initiative Grant).en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.relation.urihttps://doi.org/10.1016/j.agee.2015.08.006
dc.subjectNitrogen balanceen_US
dc.subjectSub-Saharan Africaen_US
dc.subjectMaize yieldsen_US
dc.subjectSmallholder agricultureen_US
dc.subjectLegume rotationsen_US
dc.subjectImproved fallowen_US
dc.titleThe effect of mineral and organic nutrient input on yields and nitrogen balances in western Kenyaen_US
dc.typePreprinten_US


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