TITLE:
Effect of NaCl-Induced Salinity and Human Urine Fertilization on Substrate Chemical Properties
AUTHORS:
Michael Yongha Boh, Joachim Sauerborn
KEYWORDS:
Soil Sodicity; Electrical Conductivity; Urine Nitrogen; Nutrient Recycling
JOURNAL NAME:
Open Journal of Soil Science,
Vol.4 No.1,
January
22,
2014
ABSTRACT: We evaluated the effect of NaCl-induced salinity
and successive urine fertilization on changes in cultivation substrate chemical
properties in a greenhouse study. The substrate was composed of an equal volume
ratio mixture of bio-waste compost, quartz sand and silty loam soil. Salinity
was imitated by adding NaCl solutions to a known substrate weight achieving
three target salinity treatments of ECe 1.3 (S0—no
NaCl), 4.6 (S1) and 7.6 (S2) dS·m-1. Cultivation
substrate had been cropped with two cycles of maize (Zea mays L.) (crop cycles I and II) and fertilized with human urine
at N amounts of 0 (U0—no urine), 180 (U1) and 360 (U2) mg·kg-1 substrate in
the first cycle and half of the urine-N dosages in cycle II. Substrate samples
collected at the end of each cycle were analyzed for pHKCl, ECe,
exchangeable and water extractable cations (Na+, K+, Ca2+,
Mg2+), cation exchange capacity, water extractable anions (Cl-, , , ) and
exchangeable sodium percentage (ESP). Exchangeable
Na+, K+ and Ca2+ were significantly (p e significantly increased by 7.3, 5.3 and 7.6
dS·m-1 in the S0, S1 and S2 treatments following an
increase in urine from U0 to U2. In the S0 treatment, ESP increased in the
order U0 and Cl- were significantly affected by crop cycle, salinity and urine interactions (p and depended on crop cycle alone. There was a
tendency towards increasing soil sodicity with mounting urine fertilization.
The level of NaCl salinity and the amount of urine applied are important
determinants of substrate chemical properties. Adoption of appropriate
management techniques to avoid salinity/sodicity build up should be included in
urine fertilization planning.