Department of Plant Sciences

In northwest China the lack of knowledge on soil nutrient fertility and of appropriate nutrient management practices has restricted potato production. Field trials were conducted from 2002 to 2007 to determine the main limiting nutrients for potato (Solanum tuberosum L), and to evaluate the nutrient management practice (NMP) based on an Agro Services International (ASI) systematic approach. Results indicated that average potato yields in nutrient omission plots were in the order 0-N (22.2 t ha-1) ≈ 0-P (22.4 t ha-1) < 0-K (31.5 t ha-1). N deficiency is a general feature of irrigated potato in northwest region, but P and K supply are frequently additional limiting factors. The mean agronomic efficiencies (AE) of N, P and K were 34.4 kg tuber kg-1 N, 32.4 kg tuber kg-1 P2O5 and 41.3 kg tuber kg-1 K2O, respectively, and the mean partial factor productivities (PFP) of N, P and K were 220 kg tuber kg-1 N, 291 kg tuber kg-1 P2O5 and 306 kg tuber kg-1 K2O, respectively. There was a significant negative relationship between AE or PFP of N, P or K and the respective nutrient rate. The positive relationship between yield of nutrient omission plots and PFP and AE suggests nutrient use efficiency is affected by soil indigenous productivity. NMP based on an ASI systematic approach produced significant higher yields, nutrient use efficiencies and economic returns than farmer’s practice.