Estimating soil water loss from cropped land is vital for sustainable management of water resources in semi-arid and hot regions. Soil evaporation (Es) is an important process in these regions but hard to quantify. The study aimed at quantifying Es in maize field under three treatments using microlysimeters (MLs). It also aims to identify sources of challenges in the method. The treatments were; flat cultivation with mulching (FCM), without mulches (FC) and double digging (DD, manual tillage practice), were replicated trice. In each plot, two micro-lysimeters were installed, one containing soil samples to measure soil evaporation and an empty one to measure throughfall (Ʈr) under the maize canopy. The 24-hr soil samples weight change and throughfall records were used to estimate soil evaporation for each plot. The estimated mean daily soil evaporation was 3.4 mm/day in FC, 2.1 mm/day in FCM and 3.0 mm/day for DD. There was a challenge in the method during the rainfall period which lead to both negative and high Es values during rainfall period. Less throughfall from empty MLs than in soil containing MLs caused the negative Es and the opposite was true for higher Es during rainy period. We urge the method to be improved by measuring throughfall simultaneously with soil weight changes immediately after rainfall events and minimize random errors by using many MLs. To have more results on reducing water losses while increasing available water for crop growth in this water scarce environment, we suggest FCM to be combined with DD treatment.

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 < 0.05) during the Vuli 2018 season. The estimated ET was highest in FC plots, medium in DD, and FCM recorded the lowest ET value. The significant difference in ET was between FCM and other treatments. Relative to a control treatment (farmers' 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