Modeling maize growth and nitrogen dynamics using CERES-Maize (DSSAT) under diverse nitrogen management options in a conservation agriculture-based maize-wheat system.

Agricultural field experiments are costly and time-consuming, and often struggling to capture spatial and temporal variability. Mechanistic crop growth models offer a solution to understand intricate crop-soil-weather system, aiding farm-level management decisions throughout the growing season. The objective of this study was to calibrate and the Crop Environment Resource Synthesis CERES-Maize (DSSAT v 4.8) model to simulate crop growth, yield, and nitrogen dynamics in a long-term conservation agriculture (CA) based maize system. The model was also used to investigate the relationship between, temperature, nitrate and ammoniacal concentration in soil, and nitrogen uptake by the crop. Additionally, the study explored the impact of contrasting tillage practices and fertilizer nitrogen management options on maize yields. Using field data from 2019 and 2020, the DSSAT-CERES-Maize model was calibrated for plant growth stages, leaf area index-LAI, biomass, and yield. Data from 2021 were used to evaluate the model's performance. The treatments consisted of four nitrogen management options, viz., N0 (without nitrogen), N150 (150 kg N/ha through urea), GS (Green seeker-based urea application) and USG (urea super granules @150kg N/ha) in two contrasting tillage systems, i.e., CA-based zero tillage-ZT and conventional tillage-CT. The model accurately simulated maize cultivar's anthesis and physiological maturity, with observed value falling within 5% of the model's predictions range. LAI predictions by the model aligned well with measured values (RMSE 0.57 and nRMSE 10.33%), with a 14.6% prediction error at 60 days. The simulated grain yields generally matched with measured values (with prediction error ranging from 0 to 3%), except for plots without nitrogen application, where the model overestimated yields by 9-16%. The study also demonstrated the model's ability to accurately capture soil nitrate-N levels (RMSE 12.63 kg/ha and nRMSE 12.84%). The study concludes that the DSSAT-CERES-Maize model accurately assessed the impacts of tillage and nitrogen management practices on maize crop's growth, yield, and soil nitrogen dynamics. By providing reliable simulations during the growing season, this modelling approach can facilitate better planning and more efficient resource management. Future research should focus on expanding the model's capabilities and improving its predictions further.

Critical evaluation of functional aspects of evaporation barriers through environmental and economics lens for evaporation suppression - A review on milestones from improved technologies.

Climate change models predict an increase in rainfall variability, leading to floods and drought events, hence intensifying the need for reservoirs. However, up to 50% of reservoirs' capacity is lost by evaporation, affecting their function of ensuring water availability and stability. Over decades biological, chemical and physical barriers "covers" were developed for inhibiting evaporation. Such barrier's efficiency and applicability are still a matter of discussion, given their economic efficiency, environmental consequences, and operational difficulties are accounted for. In this review, we discussed the efficiency, applicability, and environmental suitability of these covers. Compared to the physical covers, the chemical and biological solutions tend to be less efficient. However, the use of physical covers is multidisciplinary, involving climate, material, and hydrological sciences, and are more efficient. Among the physical covers, the use of suspended covers and free-floating elements decreases evaporation to the tune of 85 and 80.0%, respectively. However, the economic efficiency of free-floating elements remains an open question since all studies overlooked their water footprint (water used in the manufacturing process of these covers), which was found to be very high. The use of these covers decreases heat storage, gas exchange rate, and light availability that could adversely influence dissolved oxygen, water quality, aquatic organisms, and the water ecosystem's function. These ecological consequences have not yet been investigated. The exception is the suspended covers, which have had determinate effects on dissolved oxygen and algae growth. Due to light weight, floating elements' operation is unstable and vulnerable to move due to wind effects. Therefore, such covers must be engineered to increase their stability. Free-floating elements could provide a visible and scalable solution to evaporation suppression when considering their economic visibility, environmental effects, and stability against wind and wave effects under the field conditions. However, these covers can be viable only when water availability is the limiting factor in crop production. We found that studies at reservoir scale are highly limited, therefore, investigations at reservoirs' scale emphasizing ecological aspects, cover stability and cost efficiency, are urgently needed.