10.5061/DRYAD.5QR62
Tully, Katherine L.
University of Maryland, College Park
Columbia University
Hickman, Jonathan
Columbia University
McKenna, Madeline
Columbia University
Neill, Christopher
Brown University
Palm, Cheryl A.
Columbia University
Data from: Effects of fertilizer on inorganic soil N in East Africa maize
systems: vertical distributions and temporal dynamics
Dryad
dataset
2016
2016-03-01T16:01:43Z
2016-03-01T16:01:43Z
en
https://doi.org/10.1890/15-1518.1
87017 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Fertilizer applications are poised to increase across sub-Saharan Africa
(SSA), but the fate of added nitrogen (N) is largely unknown. We measured
vertical distributions and temporal variations of soil inorganic N
following fertilizer application in two maize (Zea mays L.)-growing
regions of contrasting soil type. Fertilizer trials were established on a
clayey soil in Yala, Kenya, and on a sandy soil in Tumbi, Tanzania, with
application rates of 0–200 kg N/ha/yr. Soil profiles were collected (0–400
cm) annually (for three years in Yala and two years in Tumbi) to examine
changes in inorganic N pools. Topsoils (0–15 cm) were collected every 3–6
weeks to determine how precipitation and fertilizer management influenced
plant-available soil N. Fertilizer management altered soil inorganic N,
and there were large differences between sites that were consistent with
differences in soil texture. Initial soil N pools were larger in Yala than
Tumbi (240 vs. 79 kg/ha). Inorganic N pools did not change in Yala (277
kg/ha), but increased fourfold after cultivation and fertilization in
Tumbi (371 kg/ha). Intra-annual variability in NO−3-N concentrations (3–33
μg/g) in Tumbi topsoils strongly suggested that the sandier soils were
prone to high leaching losses. Information on soil inorganic N pools and
movement through soil profiles can h vulnerability of SSA croplands to N
losses and determine best fertilizer management practices as N application
rates increase. A better understanding of the vertical and temporal
patterns of soil N pools improves our ability to predict the potential
environmental effects of a dramatic increase in fertilizer application
rates that will accompany the intensification of African croplands.
Bi-Weekly soil N in KenyaBi-weekly potassium chloride-extractable N in
soils collected 0-15cm in field sites in Yala, Kenya. Data span
26-Apr-2012 to 4-Dec-2013.WeeklyKCl_KE.csvBi-Weekly soil N in
TanzaniaBi-weekly potassium chloride-extractable N in soils (0-15cm) in
Tanzania plots. Collection dates span 9-Nov-2012 to
2-Apr-2014.WeeklyKCl_TZ.csvInitial soil data from depth profiles in Kenya
and TanzaniaInitial soil NO3-N, NH4-N and pH from 0-400 cm depth
profiles.Initial_DP_KETZ_zeroN.csvSoil depth profile data from Kenya and
Tanzania after 2 years of cultivationSoil NO3-N, NH4-N, pH from maize
trials in Kenya and Tanzania collected after 2 years of cultivation in
unfertilized (0N) and fertilized (200 N) plots.Yr2_DP_KETZ_zero200.csvSoil
depth profile data from Tanzania after 2 years of cultivation (organic vs.
inorganic comparison)Soil NO3-N, NH4-N, and pH in Tanzania plots receiving
either 75 kg of N as inorganic fertilizer or 75 kg N as organic fertilizer
from Gliricidia sepium leaves. Depth profiles collected after 2 years of
maize cultivation.Yr2_DP_TZ_Glir75.csvDepth profile data from Kenya after
3 years of maize cultivationSoil data from depth profiles collected in
Kenya plots after 3 years of cultivation. Note that there are fewer depth
categories. Also, plots were bulked by fertilizer treatment, so there is
no replication in this data set. These data were used for qualitative
comparison to the other profiles, but not in statistical
analyses.2014_CIAT_DP.csv