Accurate determination of plant water status is mandatory to optimize irrigation scheduling and thus maximize yield. Infrared thermography (IRT) can be used as a proxy for detecting stomatal closure as a measure of plant water stress. In this study, an open-source software (Thermal Image Processor (TIPCIP)) that includes image processing techniques such as thermal-visible image segmentation and morphological operations was developed to estimate the crop water stress index (CWSI) in potato crops. Results were compared to the CWSI derived from thermocouples where a high correlation was found ( $r_{Pearson}$ = 0.84). To evaluate the effectiveness of the software, two experiments were implemented. TIPCIP-based canopy temperature was used to estimate CWSI throughout the growing season, in a humid environment. Two treatments with different irrigation timings were established based on CWSI thresholds: 0.4 (T2) and 0.7 (T3), and compared against a control (T1, irrigated when soil moisture achieved 70% of field capacity). As a result, T2 showed no significant reduction in fresh tuber yield (34.5 ± 3.72 and 44.3 ± 2.66 t ha ${}^{-1}$ ), allowing a total water saving of 341.6 ± 63.65 and 515.7 ± 37.73 m ${}^3$ ha ${}^{-1}$ in the first and second experiment, respectively. The findings have encouraged the initiation of experiments to automate the use of the CWSI for precision irrigation using either UAVs in large settings or by adapting TIPCIP to process data from smartphone-based IRT sensors for applications in smallholder settings.

Sweetpotato is a crucial crop to guarantee food security in sub‐Saharan Africa, and drought events are considered one of the most critical factors affecting sweetpotato productivity in this region. In this study, airborne imagery based on reflectance (NDVI, CI_red‐edge) and canopy temperature minus air temperature (dT) indices was used to characterize sweetpotato genotypes under drought treatments in Mozambique. Two field experiments established in rainy/hot (Trial A) and dry/cool (Trial B) seasons were assessed. In Trial A, 24 genotypes were subjected to early‐ (ESD), mid‐ (MSD) and late‐season (LSD) drought stress treatments and compared against a control. In Trial B, 120 genotypes were subjected to LSD only. The percentage of reduction in vine weight (PR_VW) under drought was related primarily to temporal variation of NDVI and CI, regardless of drought treatment and seasons. dT in relation to control (dT_Amp) was associated with PR_VW in ESD‐Trial A and LSD‐Trial B, whereas under LSD‐Trial A, dT_Amp was related to total fresh storage root weight (TRW). During the rainy/hot season, higher TRW reduction was promoted under ESD; however, under LSD, it was possible to identify productive genotypes able to withstand drought stress, highlighting their relevance for drought‐tolerance selection purposes.

Canopy temperature (CT) as a surrogate of stomatal conductance has been highlighted as an essential physiological indicator for optimizing irrigation timing in potatoes. However, assessing how this trait could help improve yield prediction will help develop future decision support tools. In this study, the incorporation of CT minus air temperature (dT) in a simple ecophysiological model was analyzed in three trials between 2017 and 2018, testing three water treatments under drip (DI) and furrow (FI) irrigations. Water treatments consisted of control (irrigated until field capacity) and two-timing irrigation based on physiological thresholds (CT and stomatal conductance). Two model perspectives were implemented based on soil water balance (P1) and using dT as the penalizing factor (P2), affecting the biomass dynamics and radiation use efficiency parameters. One of the trials was used for model calibration and the other two for validation. Statistical indicators of the model performance determined a better yield prediction at harvest for P2, especially under maximum stress conditions. The P1 and P2 perspectives showed their highest coefficient of determination (R${}^2$) and lowest root-mean-squared error (RMSE) under DI and FI, respectively. In the future, the incorporation of CT combining low-cost infrared devices/sensors with spatial crop models, satellite image information, and telemetry technologies, an adequate decision support system could be implemented for water requirement determination and yield prediction in potatoes.

Rice-based systems have recently been recognized as the most critical plant source of C emissions worldwide. Globally, rice production is highest in Asia. Actions to introduce sustainable intensification practices into existing rice lands or diversifying with lower C-emitting crops such as potatoes will be crucial to mitigate climate change. The objective of this study is to analyze the effect of potato cultivation under zero/minimum-tillage and/or organic mulching (with emphasis on rice-straw) (PZTM) on key performance indicators that are crucial to achieving agronomic gains in Asia. Forty-nine studies were selected and systematically reviewed to address the study objective. Studies reveal a consensus of increase in yield, profitability, nutrient-use efficiency, and water productivity, promoted by the significant soil moisture conservation in PZTM. There is inconsistent evidence that zero-tillage benefits weed control, but its effectiveness is enhanced by mulching. Even if soil organic matter is increased (+13–33%) and zero-tillage is the main factor driving the reduction in C footprint, no values of kg CO₂ eqha⁻¹ have been reported in PZTM to date. Only a small fraction (∼2%) of the rice-cultivated areas (RCA) is intensified with potato cultivation. That way, scaling-up PZTM among rice farmers has large potential (∼24% RCA) to increase the sustainable intensification of rice-based systems in Asia.

Low radiation is one of the most important factors which limits potential yield in potato. Under humid conditions, the dominance of diffuse radiation not only imposes challenges for radiation use efficiency in crops but also limits the water status surveillance through non-invasive methods like infrared radiometry. This study was carried out in the humid desert of the Peruvian central coast with the aim to relate maximum stomatal conductance (g_{s_max}, an important water status indicator) with leaf and air temperature (dT) and crop water stress index (CWSI). In a potted trial, g_{s_max} vs. dT were compared along the day in well-irrigated (field capacity) and water restricted (half field capacity) plants. In an additional field experiment, CWSI was validated by testing two irrigation timing treatments with pre-established g_{s_max} threshold (0.15 [T1] and 0.50 [T2] mol H₂O m⁻² s⁻¹) against a control (frequently irrigated). An acute stomatal closure sensitivity was detected which drove a g_{s_max} fall (g_s↓) near the solar noon. The intense stomatal closure caused a dT rise which showed positive higher values (> 2 °C) after g_s↓. The significant yield reduction of T1 in relation to the control (− 38.2 ± 10.7%) highlighted that g_{s_max} values > 0.15 must be used to warrant a high potato yield. These findings support the use of CWSI values ≤ 0.3–0.4 as thresholds for an appropriate irrigation in potatoes with assessments taken at around 15:00 hours, time in which plants have accumulated enough radiation allowing an appropriate detection of thermal emission under humid conditions.

Crop efficiencies associated with intercepted radiation, conversion into biomass and allocation to edible organs are essential for yield improvement strategies that would enhance genetic properties to maximize carbon gain without increasing crop inputs. The production of 20 potato landraces—never studied before—was analyzed for radiation interception ( ${\epsilon }_i$ ), conversion ( ${\epsilon }_c$ ) and partitioning ( ${\epsilon }_p$ ) efficiencies. Additionally, other physiological traits related to senescence delay (normalized difference vegetation index (NDVI) ${}_{slp}$ ), tuberization precocity ( $tu$ ), photosynthetic performance and dry tuber yield per plant (TY) were also assessed. Vegetation reflectance was remotely acquired and the efficiencies estimated through a process-based model parameterized by a time-series of airborne imageries. The combination of ${\epsilon }_i$ and ${\epsilon }_c$ , closely associated with an early tuber maturity and a NDVI ${}_{slp}$ explained 39% of the variability grouping the most productive genotypes. TY was closely correlated to senescence delay (r ${}_{Pearson}$ = 0.74), indicating the usefulness of remote sensing methods for potato yield diversity characterization. About 89% of TY was explained by the first three principal components, associated mainly to $tu$ , ${\epsilon }_c$ and ${\epsilon }_i$ , respectively. When comparing potato with other major crops, its ${\epsilon }_p$ is very close to the theoretical maximum. These findings suggest that there is room for improving ${\epsilon }_i$ and ${\epsilon }_c$ to enhance potato production.