Integrasi Budidaya Kedelai pada Perkebunan Kelapa Sawit Menghasilkan dengan Rekayasa Jarak Tanam Ditinjau dari Aspek Produksi dan Ekonomi serta Lingkungan

Abstract

The use of intercropped land in immature oil palm plantations has been widely studied and has even been widely applied. Meanwhile, land use between mature oil palm plantations with spacing engineering has never been studied or applied. Therefore, research has been carried out with the aim of evaluating the productivity of soybean cultivated in intercrops of mature oil palm (4 years old) with spacing engineering, evaluating the productivity of oil palm with spacing engineering integrated with soybeans, evaluating environmental characteristics due to spacing engineering. integrated oil palm and soybeans, evaluating the economic value of the oil palm and soybean integration system with plant spacing engineering. The study was designed using a split split plot design with oil palm spacing engineering as the main plot, soybean spacing as subplots and varieties as subplots. The main plot consisted of a standard oil palm spacing of 9 m x 9 m (J1) and an engineered oil palm spacing of 9 m x 15.6 m (J2). Subplots are soybean planting distances consisting of T1 = 30 cm x 20 cm; T2 = 35cm x 25cm; T3 = 40 cm x 15 cm; and T4 = 40 cm x 20 cm. The plots were soybean varieties consisting of V1 = Dena 1 and V2 = Grobogan. The study with a soybean plot area of 2 m x 3 meters was repeated 3 times to obtain 48 experimental plots. The research was conducted in two growing seasons, namely the first season in April – July 2022 and the second growing season in August – November 2022. Data analysis was carried out on data on soybean growth, soybean production, oil palm production, soybean planting anatomy, soybean plant physiology, characteristics soil chemistry and nutrients, and economic analysis. The results showed that the engineering spacing of oil palm had a very significant effect on the growth and production of soybeans, but the engineering spacing of soybeans did not have a significant effect on the growth and production of soybeans both in the first and second growing seasons. In terms of the anatomy and physiology of soybean plants consisting of leaf stomata, leaf thickness, root anatomy, and the amount of chlorophyll showed better characters in the integration of spacing engineering than standard oil palm spacing and relatively the same compared to soybean monoculture plants. In terms of the Land Equivalent Ratio (LER) aspect, a value of > 1 (1.06) was obtained in the integration of the Dena1 soybean variety with oil palm spacing engineering in the first growing season. Meanwhile, in the second planting season, the LER was only 0.56, meaning that the integrated productivity of soybean plants was lower than monoculture productivity due to extreme weather factors, especially rainfall in October and November 2022. Viewed from the aspect of the advantages of the soybean integration system in oil palm, it gives an R/C value of 1.79, which means it provides greater benefits compared to soybean and oil palm monocultures in the first growing season. While in the second growing season the R/C value of soybean and oil palm integration was smaller than the oil palm monoculture but greater than the soybean monoculture. The soybean integration systems in oil palm plantations provide improvements to the environment, especially marked by increased nitrogen levels and soil organic C levels.