Abstract:

To explore the effects of decomposed broad bean straw as a substitute for chemical fertilizers on rice growth and nutrient absorption, and to determine the optimal use of straw resources under the “fresh broad bean + high-quality rice” rotation system, a field experiment was conducted. This study investigated the impact of different proportions of broad bean straw replacing chemical fertilizers on rice yield, nutrient absorption, and soil physical and chemical properties under equivalent nitrogen conditions. The results showed that compared with CK (no fertilizer), CF (conventional fertilization), CF50(50%base fertilizer replacement) and CF20 (20% base fertilizer replacement) significantly increased rice yield, with no significant difference in rice yield among CF20 (20% base fertilizer replacement), CF50 (50% base fertilizer replacement), and CF (conventional fertilization). The total nitrogen content in rice grains was significantly higher in CF10 (10% base fertilizer replacement), compared with CK (no fertilizer) and CF (conventional fertilization). Soil alkaline-hydrolyzable nitrogen, available phosphorus, and available potassium content in CF50 (50% base fertilizer replacement) differed significantly from CF (conventional fertilization), indicating an improvement in soil nutrient status.In summary, for the “fresh broad bean + high-quality rice” planting system in the Lishui area, controlling the proportion of decomposed broad bean straw used as a fertilizer substitute to around 20% after the broad bean season can stabilize rice yield. Controlling the substitution proportion to 20%-50% can effectively improve soil fertility.

Key words: broad bean, straw returning, nutrient substitution, fertility