Foliar application of nitrogen and methanol on soybean

Soybean productivity in Indonesia is still low (1.2 ton/ha) compared with other's centre of soybean production (USA, Barzil and China) which can achieve 2.0 ton/ha. Leaf absorption and low rate photosynthesis as C3 crop is one of constraint to increasing soybean yield. Green house and field experiment was conducted to evaluate the effects of nitrogen and methanol during dry season 1995. Randomized block design was used with four replications. Two cultivars Wilis and Kerinci, and one cultivar Wilis were used in green house and field trials, respectively. Ten combination treatments of N and methanol were evaluated in greenhouse and eighteen combination treatments of N and methanol were evaluated in the field. The results showed that combination of 50 kg urea/ha and 25 percent methanol affected plant height, number of branches, and number of fertile node/plant in green house. In the field, there is an interaction effect between nitrogen and methanol on plant height, seed weight/plant, seed yield; figures of combination of 50 kg urea/ha + 50 percent methanol were 12-18 percent heigher than with single application of 50 kg urea/ha. Application of nitrogen and methanol needs to be evaluated in more depth, especially on mechanisme of nutrient in the plant./Produktivitas kedelai di Indonesia masih relatif rendah (1,2 t/ha) dibanding negara penghasil kedelai lain (USA, Brazil, China) yang telah mencapai rata-rata 2,0 t/ha. Keluruhan daun yang lebih awal dan rendahnya efisiensi fotosintensis sebagai tanaman C3 merupakan salah satu faktor yang membatasi peningkatan produktivitas kedelai. Percobaan rumah kaca dan lapang telah dilaksanakan selama musim kemarau 1995 menggunakan rancangan acak kelompok dengan empat ulangan. Dua varietas yaitu Wilis dan Kerinci serta satu varietas Wilis dievaluasi responnya terhadap kombinasi perlakuan pupuk N dan takaran metanol serta saat penyemprotan metanol, masing-masing sebanyak 10 kombinasi perlakuan di rumah kaca dan 18 kombinasi perlakuan di lapang. Hasil penelitian menunjukkan bahwa di rumah kaca, kombinasi pemberian pupuk N dan metanol berpengaruh terhadap tinggi tanaman, jumlah cabang dan jumlah buku subur/tanaman. Penyemprotan pupuk urea 50 kg/ha secara terpisah atau kombinasi dengan 25 persen metanol lebih tinggi dibanding kontrol. Sedangkan di lapang perlakuan kombinasi pemberian pupuk 50 kg urea/ha dan 50 persen metanol 12-18 persen lebih tinggi daripada apabila hanya disemprot dengan pupuk N pada parameter tinggi tanaman, berat biji/tanaman dan berat biji(t/ha).