Pengaruh Pemupukan Nitrogen Terhadap Fisiologi Dan Karakter Laju Pengisian Biji Beberapa Varietas Kedelai

Abstract

Soybean is one of the main agricultural commodities in Indonesia. It seen from the high national demand. High demand is not accompanied by high national production, as a consequence the volume of imports is still high to meet national requirment. The large number of imports must be responded with various efforts to increase the productivity of soybean plants, one of them is by optimizing fertilization technology through studying the important role of essential nutrients in order to get optimal crop production. Nitrogen is needed by plants in large quantities. N affects the rate of single leaf photosynthetic capacity associated with size of leaf area. The rate of photosynthesis increases the production of dry matter plants, dry matter plants will be a source for seed development. Productivity is the yield of seeds per unit area of land. Seed weight is affected by the rate of seed filling per unit time during the seed filling period. This study aims to see how the characteristics of seed filling rate of varieties that have different seed sizes and the effect of N in the rate of seed fillings of plants. The study was conducted from July to November 2019 in the Cikabayan experimental station, Bogor. The experimental design used was a randomized complete group design (RCBD) with a dose factor of urea (0 and 50 kg ha-1) and soybean varieties with different seed sizes (Tanggamus, Anjasmoro, Grobogan, Biosoy 1) with two replications. The laboratories used were the Postharvest Laboratory of the Department of AGH IPB and PAU FATETA LAB IPB. The seed filling rate for each variety has a pattern that is increased towards the end of the filling phase except for Biosoy 1. Increased seed filling rate is followed by remobilization of assimilate (dry matter) and N from the canopy to the seeds. Dry matter remobilization has a positive correlation with N which is remobiliated from the canopy. Seed size does not have a correlation to the rate of seed filling, although at the beginning of filling each seed has a significantly different rate. N dose given to plants does not significantly influence the rate of seed filling. N dose influences the amount of N to be mobilized but does not affect the dry matter that could mobilized.