ABSTRACT The existence of soybean varieties and soil type interaction causes differences in productivity of soybean varieties in agroforestry systems with kayu putih. Soil quality parameters (physical, chemical and biological characteristics) will affect the productivity of soybean varieties. The objective of this study was to reveal the relationship between soil quality parameters with soybean varieties suitability in agroforestry system with kayu putih over three locations in which their soil type were different, i.e. Lithic Haplusterts, Ustic Epiaquerts and Vertic Haplustalfs. The study was conducted from May to August, 2018 in Menggoran Forest Resort, Playen District, Gunungkidul Regency, Special Province of Yogyakarta, Indonesia. The highest yield of soybean per hectare on Dering I grown in Lithic Haplusterts and Ustic Epiaquerts was 1.38 and 1.27 tons.ha-1, respectively, while Grobogan in Ustic Epiaquerts 1.24 tons.ha-1. Dering I showed the mean of the highest yield and most suitable in all soil types, while Gema showed the mean of the lowest yield and not suitable in all soil types. Soil quality parameters that had a significant influenced on the production of soybean varieties in agroforestry systems with kayu putih were chemical characteristic consisting of availability of P, Mg, NH4 +, Mn and Ca.

ABSTRACT Waste resulted from the distillation of kayu putih leaves is a problem in almost all kayu putih refineries throughout Indonesia due to its enormous availability and un-utilization. It has potential to be used as an organic fertilizer source due to its nutrient content (macro and micro) which is higher than organic fertilizer from animals. The use of kayu putih waste is useful to complement and increase the efficiency of nitrogen fertilizer in soybean intercropping with kayu putih . This study aimed to determine the optimum values of kayu putih waste and nitrogen fertilizer based on three scenarios: economic, environmental, and eco-environmental. A two-year experiment (2018-2019) was carried out in a central composite design (CCD) with two replications as the response surface methodology (RSM) at the Menggoran Forest Resort, Playen District, Yogyakarta Forest Management, Indonesia. The treatments consist of biochar and compost levels made from kayu putih waste (0, 2.5, and 5.0 t ha-1) and nitrogen fertilizer levels supplied by ammonium sulfate (0, 50, and 100 kg ha-1) as independent variables. The observations conducted on nitrate reductase activity (NRA), total chlorophyll (TC), leaf photosynthesis rate (LPR), nitrogen loss (NL), nitrogen use efficiency (NUE), and seed yield (SY). The response variables were fitted in a full quadratic polynomial model. The results showed that the resource-based on the eco-environmental scenarios was the most favorable cropping strategy for the soybean production intercropping with kayu putih with the optimum value of 2.890 t ha-1 of biochar, 2.27 t ha-1 of compost, and 67.85 kg ha-1 of ammonium sulfate. This recommendation can reduce the use of ammonium sulfate by 32.15 % and increase of NRA, TC, LPR, NL, NUE, and SY by 12.96, 2.80, 17.18, 21.66, 7.23, and 17.29 %, respectively, compared to the single application of ammonium sulfate fertilizer.