JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING, cilt.152, sa.1, ss.1-11, 2025 (SCI-Expanded, Scopus)
Rainwater harvesting (RWH) systems, particularly plastic-covered ridges and furrow RWH techniques, have gained significant
importance in recent years due to the need to address frequent drought events, mitigate the effects of climate change, and ensure food security
for the growing global population. This study aimed to determine the yield and growth response of dry beans, which are essential for human
nutrition and food security, to RWH. Additionally, four approaches Eqs. (1)–(5) from the literature, along with a new method, were compared
for crop evapotranspiration (ET) under RWH in rain-fed farming areas in Türkiye. All ET equations are derived from the soil moisture budget
method (SMBM). Eq. (1) represents the conventional SMBM, Eq. (2) the SMBM for the furrow area, Eq. (3) the SMBM for RWH, Eq. (4) the
SMBM for RWH with a runoff estimator, and Eq. (5) the SMBM for the simplified RWH approach. RWH treatments consisted of three-row
distances (50, 75, and 120 cm), compared to conventional rain-fed farming (CRF) practices. All plant growth and yield parameters were
significantly enhanced under RWH. The overall seed yield for CRF was 103 and 348 kg=ha in 2020 and 2021, while for RWH, it was 484 and
1,594 kg=ha, respectively. Compared to CRF, RWH increased seed yield by 370% and 377%, respectively, while water use efficiency improved
by 392% and 395%, respectively. Significant differences in ET results were found for the five approaches. For Eq1, Eq2, Eq3, Eq4, and
Eq5, the overall ET values were 134.8, 251.9, 139.0, 124.5, and 131.0 mm, respectively. Except for Eq2, all methods can be used for RWH,
but the Eq. (5) allows for a simple estimate. The RWH method, with 45-cm-covered ridges and 30-cm furrows, is recommended for dry beans
in the semiarid regions of Türkiye.