Data and R code for: Soil lambda-cyhalothrin residues, arthropod abundance and diversity across potato growth stages on smallholder farms in Kenya

Data and R code for: Soil lambda-cyhalothrin residues, arthropod abundance and diversity across potato growth stages on smallholder farms in Kenya. Authors: Benson K. Langat (ORCID 0009-0006-5730-8999), Ann G. Ngari and Flora N. Namu, Karatina University, Karatina, Kenya. Contact: Benson K. Langat, [e-mail]. Study: One unsprayed control farm (Keringet) and three farms sprayed with lambda-cyhalothrin by their owners (Farm 1 Chebara, Farm 2 Milimet and Farm 3 Tembwo) in Kuresoi South, Nakuru County, Kenya. Arthropods were sampled with white, blue and yellow pan traps and sweep nets in three 10 m × 10 m plots per farm, and composite topsoil samples (0–15 cm) were analysed for lambda-cyhalothrin by gas chromatography–mass spectrometry at four potato growth stages: pre-planting (15–16 March 2026), sprouting (28 April 2026), tuber bulking (28 May 2026) and maturation (27–28 June 2026). Contents: four R scripts (detection limits, residues, arthropod abundance and arthropod diversity) and the CSV files they use, including the GC-MS calibration standards, every soil sample with its qualifier-ion results and detection status, residues per farm and stage (main analysis with values below the limit of detection of 4.85 µg/kg set to zero, and values as reported by the laboratory), arthropod abundance per farm and stage, and all specimen records identified to family. The README file gives the run order and explains every column.