TITLE:
Estimating Evapotranspiration of Maize under Different Management Practices in a Semiarid Tropical Area Using the Soil Water Balance Method
AUTHORS:
Kobusinge Aloys Nyabwisho, Fredrick Cassian Kahimba
KEYWORDS:
Evapotranspiration, Deep Percolation, Soil Hydraulic Properties, Makanya Catchment, Semi-Arid
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.10 No.8,
August
30,
2022
ABSTRACT: Smallholder farmers in semiarid areas face low and
erratic rainfall and need field management practices that conserve water in the
root zone. This work evaluated the effect of mulching and DD (deep tillage)
practices as a way to conserve soil moisture and thus improve water
availability and maize crop yield in this water-scarce environment. The field
experiment was carried out in which the soil moisture content (SMC) was
monitored and the other water balance components were measured to quantify the
crop ET with the soil water balance (SWB) method. The components of the SWB
(rainfall, supplemental irrigation, runoff, deep percolation and change of soil
moisture content) were measured for three consecutive seasons of 2018-2019, i.e. two long rain seasons (Masika 2018 and
2019) and one short-rains season (Vuli 2018). The estimation of the deep
percolation (DP) involved calculating water fluxes from hydraulic properties
measured in the laboratory and from hydraulic gradients measured with tensiometers in
the field plots. Treatments significantly affected ET (p ’ cultivation, FC), mulching (FCM) reduced evapotranspiration by 14% and
18% during more water-stressed seasons of Vuli 2018 and Masika 2019. The ET
reduction among the treatments was in line with the reduction in soil
evaporation, as reflected in the results (of the other article of the same
work). The crop transpiration was observed higher, which was consistent with
the higher canopy cover observations for the two treatments relative to the FC
treatment. Also, while the mulch practice did not affect ET during the first
and less water-stressed season of Masika 2018, DD reduced it by 9% and showed
no effect during other seasons.