Influence of Fertilization on Growth and Lead Content of Pepper under Lead Stress

To investigate the effect of fertilization on Pb content in vegetables, pepper was planted in L₁₆4⁵ (the 5 influencing factors are fertilizers (N, P, K), organic fertilizers (sheep manure) and Pb²⁺; the 4 levels are blank, low, medium and high; a total of 16 treatments) pot orthogonal experiment. The effects of fertilizers on the growth and Pb content in various parts of pepper under Pb stress were analyzed. The results showed that: (1) The Pb content in pepper fruit ranged from 0.011 mg·kg^-1 to 0.085 mg·kg^-1, which did not exceed the limit value (0.1 mg·kg^-1) in the National Standard for Food Safety-Limit of Contaminants in Food (GB2762-2017); (2) The effect order of fertilization on pepper fruit weight was P₂O₅ > sheep manure > N > K₂O; The horizontal combination of factors that promoted the maximum fruit weight of pepper was N (0.15 g·kg^-1), P₂O₅ (0.225 g·kg^-1), K₂O (0.15 g·kg^-1) and sheep manure (9 g·kg^-1); (3) The order of fertilizer effects on Pb content in pepper fruit was Pb²⁺ > K₂O > N = sheep manure > P₂O₅; the factor level combination that resulted in the maximum Pb content in pepper fruits was N (0.15 g·kg^-1), P₂O₅ (0 g·kg^-1), K₂O (0.45 g·kg^-1), sheep manure (6 g·kg^-1) and Pb²⁺ (350 mg·kg^-1); (4) Based on the soil fertility characteristics of Urumqi, the recommended optimal fertilizer application rate was: high phosphorus fertilizer P₂O₅ (495 kg·hm^-2), low-level potassium fertilizer K₂O (330 kg·hm^-2), medium-level nitrogen fertilizer N (660 kg·hm^-2) (or low-level nitrogen fertilizer N (330 kg·hm^-2) + high-level organic manure sheep manure (19,800 kg·hm^-2), which can achieve high yield while ensuring that the Pb content in the fruits does not exceed the standard. Strengthening control of effective and reasonable fertilization methods in Urumqi agricultural land is helpful to reduce the Pb content in vegetables.