Influence of Planting Date on Potato Yield in Gircha Highland, Arba Minch, Ethiopia

Potatoes are the world's fourth most important food crop, with climate, variety, seed quality, planting timing, nutrition, irrigation, pests, illnesses, and weeds all influencing its growth and productivity. Planting timing is critical for maximizing yields since it regulates temperature and light. Planting date effects on potato development and yield were investigated in an experiment at Gircha Farmland, Arba Minch, from February 8, 2020 to August 19, 2020. The impact of planting dates on potato production response was investigated using the Decision Support System for Agro-technology Transfer (DSSAT) model software application program. The experiment used Gudene cultivar potato root crops in Gircha highland plot areas, with gross plot area, rows per plot, length, and spacing. Harvest area was 2.3 m<sup>2</sup>, with two rows, and soil depth was 15 cm. No additional irrigation was supplied, and 150 kg/ha N and 80 kg/ha P fertilizer was applied. Eight planting dates—February 8, February 18, February 28, March 9, March 19, March 29, April 8, and April 18—were selected for this investigation. The relationship between observed and simulated potato yield performance, with RMSE (7.256), IOA (0.842), and R<sup>2</sup> (0.962), and validation values (19.658), IOA (0.827), and R<sup>2</sup> (0.974), indicating good agreement. The latest planting date of April 18 marked the pinnacle of potato output. Furthermore, on April 18, 2020, the planting date that was closest to March 30, 2020, the maximum tuber fresh weight of 48.73 mg/ha was recorded, while on February 8, 2020, the minimum tuber fresh weight of 16.08 mg/ha was acquired. Similar to this, the planting date of April 18<sup>th </sup>yielded the maximum potato production (9746 kg/ha), while February 8<sup>th</sup> yielded the lowest yield (3215 kg/ha). Gircha's higher rainfall, lowest solar radiation, and warmer temperatures may have contributed to the crop's increased production. Potato planting date significantly affects growth and yield, with April 18, 2020 being the best date for highest yield. Delays in planting led to increased crop growth and production, influenced by rainfall, solar radiation, and mean temperature.