QUANTIFICATION OF TOTAL NITROGEN CHANGE IN SOIL AND BLACK SOYBEAN (GLYCINE SOJA L.) DETAM-1 PLANT TISSUE DURING FIELD CULTIVATION DINDA RARASWATI | 11416034 AGRICULTURAL ENGINEERING STUDY PROGRAM, SCHOOL OF LIFE SCIENCE AND TECHLONOLOGY, BANDUNG INSTITUTE OF TECHNOLOGY

• Main Author: Raraswati, Dinda
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/50035
• Institution: Institut Teknologi Bandung

Soybean is one of main Indonesian crops after paddy and maize. It is favored by Indonesian people due to high nutriotional content and low price. It has high protein content (about 34% dry matter). Soybean used in this research was black soybean variety Detam 1. Seed yield of black soybean Detam 1 is the highest compared to other blak soybean varieties (such as Detam 2, Detam 4 Prida, Cikuray, and Malikka). Seed yield of Detam 1 is about 2.51 ton/ha, while seed yield of other varieties is in the range of 1.7 -2.5 ton/ha. Soybean is commonly cultivated in mixed cropping system with other plants because it can fix nitrogen from air so that enhances the soil fertility. This research aims to quantify total nitrogen, in soil and plant tissue of Detam-1 soybean throughout cultivation period. The cultivation was conducted in the field in Tangjungsari, Sumedang, West Java. Soybeans are planted in 3 × 2 meters land with 32 holes. Cultivation was conducted according to standard operational procedure made by Balitkabi. Optimal condition for soybean growth is air temperature at 22 – 27° C; soil pH at 6.0 – 6.5; air humidity at 60 – 90%; and soil humidity at 75 – 85% of field capacity. Parameters observed in this research including microclimate, soil condition, plant dry matter, number of pods, number of seeds, and total nitrogen in soil and plant tissue. Observation and nitogen analysis were done in Biomass Engineering Laboratory, Downstream Process Laboratory, Microbiology Laboratory, and Instructional Laboratory at ITB Jatinangor. Total nitrogen was determined using Kjeldahl analysis method. Microclimate and edaphic condition in the field observed were air temperature at 21.94 – 26.26° C; soil pH at 5.42 – 6.66 ; soil humidity at 80%; and air humidity at 62.45 – 81.77%. Environmental conditions of the research field is suitable for soybean growth, except for soil pH. Based on these environmental conditions, this research showed that nitrogen content in soybean tissue increased starting from the vegetative stage (from 0% to 3.92% dry matter) until flowering and pod formation stage (from 3.92% to 8.68% dry matter), but decreased to 3.08% dry matter during seed formation. While the nitrogen content in soybean tissue was fluctuated, nitrogen content in soil was stable at 0.28 – 1.68% dry matter during soybean growth. It can be concluded that nitrogen content in soybean tissue fluctuated due to the growth stage of soybean. Rate of nitrogen content change in soybean tissue was at 0.65% N/week (vegetative stage), 0.95% N/week (flowering and pod formation stage), and -1.86% N/week (seed formation and harvest).