Excessive nitrogen fertilization is a limitation to herbage yield and nitrogen use efficiency of dairy pastures in South Africa
Date
2022-04-06
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
The response of crop yields to fertilizers is a long-standing topic of agricultural production.
Currently, in dairy-pasture systems, nitrogen (N) fertilizer is used as a management tool that is said
to be directly proportional to pasture yield. We evaluated a large dataset consisting of data from
153 fields over five years to examine the effects of N fertilization on pasture yield and nitrogen use
efficiency in the Eastern Cape province of South Africa. Fertilizer application rates were grouped into
three treatments viz., <200, 200–350, and >350 kg N ha−1
, and herbage yield response over the years
was analyzed with mixed models. There were no differences found between treatments for total
annual herbage yield over the years. High N fertilizer rates did not translate to a higher herbage yield
of pastures. The N rate had a weak but significant negative correlation with the total annual yield and
only accounted for 6% of the yield variation. The N use efficiency of pastures improved with reduced
N application rates. Pasture yield varies through different seasons. Spring and summer account
for the highest yield, coinciding with warm and moist conditions favorable for N mineralization in
the soil. Farmers need to consider the time of the year and plan their monthly or seasonal fertilizer
application accordingly to account for peak N mineralization rates.
Description
CITATION: Phohlo, M. P., Swanepoel, P. A. & Hinck, S. 2022. Excessive nitrogen fertilization is a limitation to herbage yield and nitrogen use efficiency of dairy pastures in South Africa. Sustainability, 14(7), 4322, doi:10.3390/su14074322.
The original publication is available at https://www.mdpi.com
Publication of this article was funded by the Stellenbosch University Open Access Fund
The original publication is available at https://www.mdpi.com
Publication of this article was funded by the Stellenbosch University Open Access Fund
Keywords
Nitrogen fertilization, Pasture yield optimization, Nitrogen use efficiency, Dairy farming -- South Africa
Citation
Phohlo, M. P., Swanepoel, P. A. & Hinck, S. 2022. Excessive nitrogen fertilization is a limitation to herbage yield and nitrogen use efficiency of dairy pastures in South Africa. Sustainability, 14(7), 4322, doi:10.3390/su14074322.