Estimation of critical period for weed control in soybean on agro-forestry system with kayu putih

Abstract

Background and Objective: The critical period for weed control is the period in the crop growth cycle in which weeds must be controlled to prevent yield losses. This study aimed to determine the critical period for weed control (CPWC) in soybean on the agro-forestry system with kayu putih. Materials and Methods: The experiment was conducted in Menggoran Forest Resort, Playen Forest Section, Gunung Kidul Regency, Special Region of Yogyakarta from February, 28-May, 9, 2015. The experiment was arranged in randomized complete block design (RCBD) with single factor of treatment with three blocks as replications. The treatments were weedy periods 0, 14, 28, 42 and 56 days after planting (dap) and weed-free periods 0, 14, 28, 42 and 56 dap. Statistical analysis was done by using one-way analysis of variance (ANOVA), structural equation modeling (SEM), Gompertz and logistic equations. Results: The soybean yield decreased significantly when the weedy period was done after 14 dap upto 42 dap. The soybean yield was influenced by the dry weight of annual weeds (DRAW), heterogeneity of weed (HET), soil moisture (SM), phosphorus (P) and potassium (K) concentration in the tissue. Conclusion: The CPWC in soybean for acceptable yield loss (AYL) of 5, 10, 15 and 20% began 16, 21, 24 and 27days after emergence (DAE) and ended 61, 55, 53 and 49 DAE. This study provides weed management control information on soybean in the agro-forestry system with kayu putih on Lithic Haplusterts soil type with ustic soil moisture regime.