Isotope Tracer Technique·Ecology and Environment·Physiology
XIE Weiqing, GUO Huachun, FANG Yanjie, XU Yinping, SHE Yongxin, LYU Tai, LI Fangdi, WANG Peng
To determine influence of nitrogen, phosphorus and potassium fertilizers and fertilization indexes in the main potato producing areas under dry weather, 3-year fertilizer experiment was conducted to clarify soil basic nutrient status, correction coefficient, nutrient utilization rate and other parameters, and to explore the abundance and deficiency indexes of soil nitrogen (N), phosphorus (P) and potassium (K) nutrients, relative yield and recommended fertilizer application amount. The correction coefficient of soil alkali-hydrolyzed nitrogen, available phosphorus, available potassium and soil available nutrient, the function equation of recommended fertilizer amount and the effect model of N, P and K fertilizer were established to study the effect of fertilizer combined application on potato yield. Results showed that the soil nutrients were low nitrogen, medium phosphorus, high potassium, low organic matter and slightly alkaline. There was a significant power exponential negative correlation between the correction coefficient of soil available nutrient and the contents of alkali-hydrolyzed nitrogen, available phosphorus and available potassium. The average contribution rate of soil fertility in the experimental area was 54.39%; the relative yields by N, P and K were 77.64%, 87.57% and 84.22%, and the yield increased by N, P and K were 30.74%, 16.68% and 23.08%, respectively. The nutrient absorption and utilization rates of nitrogen, phosphorus and potassium were 32.58%, 16.32% and 45.40%, respectively. The correction coefficients of available nutrients in soil were nitrogen 0.56, phosphorus 0.48 and potassium 0.35. The amount of nutrients absorbed by100 kg tuber was N 0.4 kg, P2O 0.15 kg and K2O 0.9 kg, respectively. Under the experimental conditions, the single factor and interaction effect of increased application of N, P and K on potato yield were firstly increased and then decreased. The highest yield combination of combined application of N, P and K was N2P2K2。The maximum yield was 24 860.32 kg·hm-2, the fertilizer amount N∶P2O5∶K2O=1∶0.97∶0.92 (N: 165 kg·hm-2), and fertilization profit of 34 472 yuan·hm-2; The optimal economic yield was 24 774 kg·hm-2, the fertilizer amount N∶P2O5∶K2O=1∶1.04∶0.79 (N: 154 kg·hm-2), and the fertilizer profit was 34 603 yuan·hm-2. The findings provided scientific basis and technical reference for balanced fertilization in potato production in the dry area.