Effects of Irrigation Regimes on Crop Growth and Yield of Chile Peppers Under Sprinkler Irrigation in the Semiarid Climate

Irrigation management is essential for successfully cultivating Chile peppers (Capsicum spp.), as it influences plant yield, fruit quality, and susceptibility to soil-borne diseases. This study investigates the effects of various sprinkler irrigation regimes on different Chile pepper varieties to optimize water use efficiency and enhance overall production. The varieties included in the study are ‘TAM Mild Jalapeno’, ‘Anaheim’, ‘Sandia’, ‘NM#6’, ‘California Wonder’, and ‘Red Knight’. Field experiments were conducted at the Agricultural Science Center in Farmington during the 2024 and 2025 growing seasons. A split-plot design with three replicates was employed to assess the effects of varying irrigation levels (100%, 80%, and 60% ET), which corresponded to 0%, 20%, and 40% water savings, respectively. Each plot comprised three rows of 10 plants, with 0.762 m between rows and 0.305 m between plants. In both 2024 and 2025, the amounts of applied irrigation and total water supplied varied across the irrigation treatments, with greater depths under the 100% ET regime and progressively lower amounts at 80% ET and 60% ET. Irrigation Water Use Efficiency (IWUE) values varied from 4.06 kg m−3 in ‘NM#6’ to 9.57 kg m−3 in ‘TAM Mild Jalapeno’ in 2024. In 2025, IWUE values ranged from 4.62 kg m−3 in ‘California Wonder’ to 8.76 kg m−3 in ‘TAM Mild Jalapeno’. On average, ‘TAM Mild Jalapeno’ consistently had the highest IWUE across both years, while ‘NM#6’ had the lowest. Evapotranspiration Water Use Efficiency (ETWUE) values ranged from 5.41 kg m−3 in ‘NM#6’ to 12.13 kg m−3 in ‘TAM Mild Jalapeno’ in 2024. In 2025, ETWUE values ranged from 6.99 kg m−3 in ‘California Wonder’ to 12.82 kg m−3 in ‘TAM Mild Jalapeno’. On average, ‘TAM Mild Jalapeno’ consistently had the highest ETWUE across both years, while ‘NM#6’ had the lowest. Results indicated that both ‘TAM Mild Jalapeno’ and ‘California Wonder’ achieved the highest marketable yields in 2024, while ‘TAM Mild Jalapeno’ and ‘Red Knight’ had the greatest marketable yields in 2025. Moderate deficit irrigation (20% water savings) maintained or improved marketable yield and water use efficiency. In contrast, a 40% water savings strategy led to significant reductions in both yield and plant growth. ‘TAM Mild Jalapeno’ exhibited the greatest adaptability to water-limited conditions, consistently achieving the highest irrigation and evapotranspiration water use efficiency. Conversely, ‘California Wonder’ was more sensitive to severe water deficits.