Pengaruh Kombinasi Pupuk Organik dan Anorganik terhadap Sifat Kimia Tanah, dan Hasil Tanaman Jagung di Lahan Kering Masam

Effect of Organic and Inorganic Fertilizers Combination on Soil Productivity and Crop Yield of Maize Farming in Acid Upland Soil. Continous use of inorganic fertilizers on maize farming in acid upland soil causes negative impacts on soil productivity and environment. The research aimed was to study the effect of manure and sludge combined with inorganic fertilizers to the changes in soil chemical properties, growth, production and profit of maize farming in acid upland soil. The research was conducted at Tamanbogo Experimental Farm, East Lampung from March to July 2013 using a randomized block design with four replications. The treatment consisted of 5 t/ha of cattle manure, 5 t/ha of dried sludge (by product of biogas production) and its combination with 50% and 75% of recommended rates of inorganic fertilizers (RRIF). The results showed that application of manure or sludge in combination with 50% RRIF gave the best growth and yield of maize. The plant height was between 177.85-195.75 cm, the dry grain yield was between 4.01-4.45 t/ha and the harvest residues was between 4.62-4.58 t/ha. Most of maize biomass were accumulated at the grain (46.20%) and the rest was almost evenly distributed on the roots, stems, leaves, cob and husk. The biggest ratio of dry grain to the harvest residues was 89.52%, it was achieved by the treatment of sludge with 50% RRIF. Keywords: organic fertilizers, inorganic fertilizers, maize growth and yield ABSTRAK Penggunaan pupuk anorganik secara terus menerus pada usahatani jagung di lahan kering masam menimbulkan dampak negatif terhadap produktivitas tanah dan lingkungan. Penelitian bertujuan untuk mempelajari pengaruh penggunaan pupuk kandang dan sludge yang dikombinasikan dengan pupuk buatan/anorganik terhadap perubahan sifat kimia tanah, pertumbuhan, produksi dan keuntungan pada usahatani jagung di lahan kering masam. Penelitian dilakukan di KP Tamanbogo, Lampung Timur pada bulan Maret sampai Juli 2013 menggunakan  Rancangan Acak Kelompok dengan 4 ulangan. Perlakuan terdiri dari 5 t/ha pupuk kandang, 5 t/ha sludge (hasil samping pembuatan biogas) dan kombinasinya dengan 50% dan 75 % dosis pupuk anorganik rekomendasi (DPAR). Hasil penelitian menunjukkan bahwa kombinasi antara pupuk kandang atau sludge dengan 50% DPAR memberikan pertumbuhan dan hasil jagung terbaik. Tinggi tanaman mencapai 177,85-195,75 cm, hasil biji pipilan kering antara 4,01-4,45 t/ha dan brangkasan sisa  panen antara 4,62-4,58 t/ha. Sebagian besar biomassa jagung terakumulasi pada bagian biji (46,20%) dan sisanya tersebar hampir merata pada bagian akar, batang, daun, janggel, dan kelobot. Rasio pipilan kering jagung terhadap brangkasan sisa panen terbesar adalah 89,52% yang dicapai oleh perlakuan sludge disertai pupuk anorganik pada 50% DPAR. Kata kunci: pupuk organik, pupuk anorganik, pertumbuhan dan hasil jagung