Nutrient Management Strategies for Sloping Lands in Guizhou

This project will quantitatively evaluate the effectiveness of alley cropping on reduction of soil and potassium (K) loss and develop a balanced fertilizer program specifically for regions with erosive soils and landscapes in Guizhou as well as southwest China. Daylily plus chinese prickly ash (D+C) and Polygonum cymosum trev. plus plum (P+P) were selected as two patterns of hedgerow crops. An engineered terrace (ET) was used as a comparison treatment. Balanced nitrogen (N), phosphorus (P), and potassium (K), and zinc (Zn) fertilization was compared with common farmer practice.

After three years of comparing common farmer practice (FP) of applying 270-105 kg N-P₂O₅/ha to balanced fertilization (BF) with 270-105-105 kg N-P₂O₅-K₂O/ha plus 6 kg ZnSO₄/ha alone or in combination with (D+C) alley cropping significantly increased corn yield by 668 to 1,140 kg/ha (21 to 35%). Compared to FP, soil erosion for BF, BF plus (D+C), and BF plus (P+P) was dramatically reduced from 7,340 kg/ha to 5,920, 3,380, and 3,500 kg/ha (19, 54, and 52%), respectively. Unfortunately, as plum trees grew (P+P), the resulting increase in shade and nutrient competition led to reduced corn yield. Engineered terraces reduced soil loss by 1,945 kg/ha (33%) compared to BF; however, crop yield was also reduced by 378 kg/ha (16%) due to a loss in cropping area after terrace construction.

This technology can be applied to 9,030 hectares (ha) of sloping lands in Guizhou Province. Its effect on P and K consumption will be significant. Guizh-NMS 03