Exploring the optimization of water and fertilizer management practices for potato production in the sandy loam soils of Northwest China based on PCA

Abstract Reasonable water and fertilizer management technology can improve water use efficiency (WUE), fertilizer use efficiency, potato (Solanum tuberosum L.) tuber yield and quality, but there is little research on water and fertilizer management techniques with these parameters simultaneously reaching a relatively better level. We used principal component analysis (PCA) to evaluate and optimize the water and fertilizer management technology with high potato tuber yield, quality, WUE and water and fertilizer use efficiency in Northwest China. To investigate the effects of irrigation amount, dripper discharge rate, and fertilizer application rate on potato tuber yield and quality, irrigation water use efficiency (IWUE), and partial factor productivity (PFP), an orthogonal experiment with three factors and three levels [irrigation amounts: I1, 100 %ETC (ETC is the crop evapotranspiration), I2, 80 % ETC and I3, 60 % ETC; dripper discharge: D1, 1 L h−1, D2, 2 L h−1 and D3, 3 L h−1; fertilizer (N–P2O5–K2O) rates: N240, 240–120–300 kg ha−1, N180, 180–90–225 kg ha−1 and N120, 120–60–150 kg ha−1] was conducted on potatoes in a sandy loam soil in 2017 and 2018. The potato tuber yield, largest tuber weight, commodity tuber weight, dry matter accumulation, and vitamin C content increased with the increase in the fertilizer application rate and the dripper discharge rate. The content of reducing sugar and PFP decreased with increasing fertilizer rate. On average, across all treatments, the potato tuber yield of N240 was 6.7 % and 23.9 % higher than that of N180 and N120, respectively. On average, across all treatments, the starch content of N240 was 23.8 % and 28.9 % higher than that of N180 and N120, respectively. On average, across all treatments, the vitamin C content of N240 was 39.8 % and 60 % higher than that of N180 and N120, respectively; the vitamin C content at 3 L h–1 was 6.2 % and 7.8 % higher than that at 2 L h–1 and 1 L h–1, respectively. On average, across all treatments, the reducing sugar content of N120 was 13.2 % and 29.9 % higher than that of N180 and N240, respectively. On average, across all treatments, the PFP at 80 % ETC was 19.8 % and 20.3 % higher than that of 60 %ETC and 100 %ETC, respectively; the PFP for 2 L h–1 was 11.3 % and 12.3 % higher than that for 1 L h–1 and 3 L h–1, respectively. Interestingly, the T4 treatment (irrigation amount of 80 %ETC, dripper discharge of 3 L h–1, and fertilizer rate of N180) was twice ranked first after combinational evaluations. In conclusion, the proper application of the T4 (I2D3N180) treatment may be a good compromise for growing potatoes in sandy soil with regard to tuber yield and quality, IWUE, and PFP. The present study sheds light on the contributions of these practices, clarifies their impacts, and provides a basis for evaluating and selecting better management practices for growing potatoes.