Effects of Different Basal and Topdressing Ratios on Nitrogen and Phosphorus Nutrient Loss and Economic Traits of Tobacco Leaves in Lake Basin

PurposeTo reduce the nitrogen (N) and phosphorus (P) loss of tobacco farmland, protecting water quality and increasing the economic income of flue-cured tobacco in lake basin.

MethodsThree ratios of basal and topdressing fertilizer treatments such as 100∶0 treatment (BTF₁₀₀), 70∶30 treatment (BTF₇₀) and 30∶70 treatment (BTF₃₀) were designed in Erhai Lake Basin and Fuxian Lake Basin.

ResultsThere was no significant difference in terms of total runoff and infiltration among all treatments (P>0.05). The N, P loss of runoff in BTF₃₀ treatment was less than that of BTF₇₀ treatment and BTF₁₀₀ treatment, which decreased by 9.16%-66.44% for N loss and 6.16%-9.36% for P loss compared to BTF₁₀₀ treatment, and decreased by 3.90%-67.77% for N loss and 2.25%-17.45% for P loss compared to BTF₇₀ treatments. Similar results were observed in the N, P loss of infiltration, and the nutrient loss in infiltration of BTF₃₀ treatment was decreased by 0.56%-67.54% for N loss and 4.20%-33.33% for P loss compared to BTF₁₀₀ treatment, and decreased by 21.59%-26.89% for N loss and 10.08%-20.00% for P loss compared to BTF₇₀ treatment. Furthermore, the yield and economic income of BTF₃₀ treatment was higher than BTF₇₀ treatment and BTF₁₀₀ treatment, which increased by 24.08%-24.18% for yield and 8.81%-39.04% for economic income compared to BTF₁₀₀ treatment, and increased by 1.44%-2.26% for yield and 2.56%-5.55% for economic income compared to BTF₇₀ treatment.

ConclusionThe application of base-topdressing ratio of 30∶70 in the lake basin of Yunnan Plateau can reduce the risk of non-point source pollution and ensure the high-quality production of tobacco leaves in the lake basin.