Fertilizer micro-dosing increases crop yield in the Sahelian low-input cropping system: A success with a shadow
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Date
2016
Journal Title
Journal ISSN
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Publisher
Taylor & Francis
Abstract
Over the years, a scarcity of information on nutrient gains or losses has led to overemphasis being placed
on crop yields and economic income as the direct benefits from fertilizer micro-dosing technology. There
is increasing concern about the sustainability of this technology in smallholder Sahelian cropping
systems. This study was designed in the 2013 and 2014 cropping seasons to establish nutrient balances
under fertilizer micro-dosing technology and their implications on soil nutrient stocks. Two fertilizer
micro-dosing treatments [2 g hill−1 of diammonium phosphate (DAP) and 6 g hill−1 of compound fertilizer
Nitrogen-Phosphorus-Potassium (NPK) (15-15-15)] and three rates of manure (100 g hill−1
, 200 g hill−1 and
300 g hill−1
) and the relevant control treatments were arranged in a factorial experiment organized in a
randomized complete block design with three replications. On average, millet (Pennisetum glaucum (L.)
R.Br.) grain yield increased by 39 and 72% for the plots that received the fertilizer micro-dosing of 6 g NPK
hill−1 and 2 g DAP hill−1
, respectively, in comparison with the unfertilized control plots. The average
partial nutrients balances for the two cropping seasons were −37 kg N ha−1
yr−1
, −1 kg P ha−1
yr−1 and
−34 kg K ha−1
yr−1 in plots that received the application of 2 g DAP hill−1
, and −31 kg N ha−1
yr−1
, −1 kg P
ha−1
yr−1 and −27 kg K ha−1
yr−1 for 6 g NPK hill−1
. The transfer of straw yields accounted for 66% N, 55% P
and 89% K for removal. The average full nutrient balances for the two cropping seasons in fertilizer
micro dosing treatments were −47.8 kg N ha−1 yr−1
, −6.8 kg P ha−1 yr−1 and −21.3 kg K ha−1 yr−1 which represent
7.8, 24.1 and 9.4% of N, P and K stocks, respectively. The nutrient stock to balance ratio (NSB) for N
decreased from 13 to 11 and from 15 to 12 for the plots that received the application of 2 g DAP hill−1 and
6 g NPK hill−1
, respectively. The average NSB for P did not exceed 5 for the same plots. It was concluded
that fertilizer micro-dosing increases the risk of soil nutrient depletion in the Sahelian low-input cropping
system. These results have important implications for developing an agro-ecological approach to
addressing sustainable food production in the Sahelian smallholder cropping system.
Description
This article is published by Taylor & Francis and is also available at http://dx.doi.org/10.1080/00380768.2016.1194169
Keywords
Citation
SOIL SCIENCE AND PLANT NUTRITION, 2016 VOL. 62, NO. 3, 277–288