PERAN PUPUK HAYATI UNTUK PENINGKATKAN HASIL CAISIM, RESIDU KETERSEDIAAN N DAN P SERTA SERAPANNYA PADA TANAMAN | ROLE OF BIOFERTILIZER TO INCREASE CAYSIM YIELD, N AND P RESIDUES AND THEIR PLANT UPTAKE

English. Consortium biofertilizer containing Nitrogen (N) Fixing Bacteria and Phosphate (P) Solubilizing Bacteria may substitute inorganic fertilizer in vegetable production. A greenhouse experiment was conducted to evaluate the effect of some combinations and doses of consortium biofertilizer and NPK compound fertilizer on available N and P in the soil, fresh weight of caysim (Brassica chinensis L. var. parachinensis.), and their uptake by caisim shoots after grown in low fertility soil. The experimental design was a randomized block design consisting of seven combinations and doses of consortium biofertilizer and compound fertilizer; and three control treatments. All treatments were repeated three times. The results showed that the combination of the which combination treatment of inorganic fertilizer and biofertilizer had a significant effect on the fresh weight of caysim shoots, available P and N and P uptake after harvesting compared to the biofertilizer treatment alone or without fertilization. Several treatments of combined doses of biofertilizers and NPK compound fertilizer produced the same yield as NPK compound fertilizer alone. The application of 300 kg/ha of compound fertilizer combined with 3,75 L/ha of biofertilizer enabled to increase the yield up to 16% compared to NPK fertilizer alone. This experiment explained that inoculation of biofertilizers can reduce the dose of NPK fertilizer to maintain yield, available P residue in soil and P uptake

Indonesian. Inokulasi pupuk hayati konsorsium yang mengandung mikroba pemfiksasi nitrogen (N) dan pelarut fosfat (P) adalah cara untuk menggantikan sebagian pupuk anorganik dalam produksi sayuran di tanah kurang subur. Percobaan rumah kaca telah dilakukan untuk mengevaluasi pengaruh konsorsium pupuk hayati dan beberapa dosis pupuk anorganik majemuk NPK terhadap hasil caisim (Brassica chinensis L. var. parachinensis.) di tanah kurang subur; serta kadar N dan P tersedia tanah serta serapannya di tajuk caisim setelah panen. Rancangan percobaan adalah Rancangan Acak Kelompok yang terdiri atas tujuh kombinasi dosis pupuk majemuk dan pupuk hayati konsorsium; serta tiga perlakuan kontrol. Seluruh perlakuan diulang tiga kali. Hasil percobaan menunjukkan bahwa kombinasi kedua jenis pupuk berpengaruh nyata terhadap bobot segar pucuk caisim, dan P tersedia tanah setelah panen serta serapan N dan P dibandingkan dengan perlakuan pupuk hayati saja atau tanpa permupukan. Beberapa perlakuan kombinasi dosis pupuk NPK dan pupuk hayati menghasilkan hasil caisim yang sama dengan perlakuan pupuk NPK saja. Pemberian 300 kg/ha pupuk majemuk disertai 3,75 L/ha pupuk hayati berpotensi meningkatkan hasil sampai 16% dibandingkan dengan pupuk NPK saja. Hasil percobaan ini menjelaskan bahwa inokulasi pupuk hayati dapat menurunkan dosis pupuk NPK untuk mempertahankan hasil, serapan P serta residu P tersedia di tanah.