Effect of Acacia mangium Based Agroforestry Systems on Soil Physical and Chemical Properties

Abstract

In an agroforestry system, woody perennial is deliberately combined with agricultural crops and/or animals in same land management unit, either in some form of spatial arrangement or temporal sequence. There are both ecological as well as economical interactions between the different components of agroforestry. An experiment was carried out to evaluate the effect of different agroforestry systems on soil physico-chemical properties. The present investigation was carried out at Central Research Station of Odisha University of Agriculture and Technology, Bhubaneswar, India. Soil chemical properties such as base saturation, cation exchange capacity (CEC), electrical conductivity (EC), pH, available nitrogen, phosphorus, potassium and organic carbon as affected by different Acacia mangium based agroforestry system. Mechanical analysis of the soil was done to find out the percentage of sand, silt and clay separately by means of bouyoucus hydrometer method to determine the texture of soil. The soil parameters we measured by using standard method. Data obtained from various observations were subjected to statistical analysis by adopting appropriate method of Analysis of Variance (ANOVA). The significance of the treatment effect was judged with the help of ‘F’ test (Variance ratio). The results revealed that different agroforestry system showed the positive impact on soil physico-chemical properties in comparison to the initial stage of the trial. Bulk density is found to decrease more in Acacia mangium with hybrid napier and with guinea grass systems (1.58 - 1.51 g/cm3) compared to less decrease in Acacia mangium with pineapple and with Aloe vera systems, the highest increase in porosity is found with Acacia mangiumin combination with mango ginger and hybrid napier (35-38%). The base saturation showed a decreasing trend over the years, except in Acacia mangium with kalmegh system (43 %)., CEC is reported to increase in Acacia mangium with pineapple system (4.3 meq kg-1) and decrease in Acacia mangium with guinea grass system (4.1 meq kg-1). EC is also found to increase in Acacia mangium with mango ginger system (0.37 dS m-1) followed by Acacia mangium with pine apple and kalmegh systems (0.25 dS m-1). The highest change in soil acidity is observed in Acacia mangium with thin napier (pH 4.90 - 6.08) followed by Acacia mangium with pineapple system (pH 4.90 - 5.93). The OC, N and P content in soil was found to increase in all the systems and the highest OC (6.19 g kg-1), N (260.31 kg ha-1) was observed in Acacia mangium with kalmegh system. The highest available phosphorus was observed in Acacia mangium with pineaple system (82.90 kg ha-1) followed by Acacia mangium with kalmegh system (76.15 kg ha-1). Acacia mangiumin combination with pine apple and mango ginger though observed increased potassium availability of 238.20 kg ha-1 and 194.67 kg ha-1 respectively; it was decreased maximum in the sole Acacia mangium system (121.28 kg ha-1) and other systems. Among all combinations, Acacia mangium with kalmegh, pineapple, mango ginger, and hybrid napier were particularly effective in improving specific soil parameters. Thus, agroforestry systems, especially those combining Acacia mangium with appropriate intercrops, are beneficial for enhancing soil health.