Pepaya sangat potensial dibudidayakan di lahan rawa pasang surut, tetapi ketersediaan hara dalam tanahnya tergolong rendah. Nitrogen dan kalium merupakan hara yang relatif banyak dibutuhkan pepaya, sehingga budidaya pepaya di lahan rawa pasang surut perlu penambahan hara tersebut melalui pemupukan. Penelitian dilakukan di lahan rawa pasang surut eks proyek lahan gambut (PLG) sejuta hektar di Kecamatan Mantangai, Kabupaten Kapuas, Provinsi Kalimantan Tengah dari bulan Juni 2007 sampai April 2008. Tujuan penelitian ialah untuk mengetahui pengaruh pemberian hara N dan K terhadap pertumbuhan dan produksi pepaya. Benih pepaya yang digunakan ialah varietas Merah Delima. Penelitian disusun dengan rancangan acak kelompok  faktorial dengan tiga ulangan. Faktor I ialah takaran pupuk nitrogen yaitu 0, 125, 250, 375 g/tanaman dan faktor II ialah takaran pupuk kalium (K20) yaitu 0, 150, 300, 450 g/tanaman. Tiap unit perlakuan terdiri atas 10 tanaman. Parameter yang diamati meliputi sifat kimia tanah, pertumbuhan vegetatif, dan produksi tanaman. Hasil penelitian menunjukan bahwa  ketersediaan N, P, dan Fe di lokasi penelitian tergolong sangat tinggi, K rendah, sedangkan Ca dan Mg sangat rendah. Pemupukan N hingga taraf 375 g/tanaman tidak berpengaruh nyata terhadap peningkatan pertumbuhan vegetatif tanaman pepaya. Namun pada fase produktif (10 bulan setelah tanam), panjang buah secara nyata meningkat dengan pemberian N 250 g/tanaman. Pemberian K2O pada taraf 300g/tanaman secara nyata meningkatkan pertumbuhan vegetatif dan produksi tanaman (jumlah, bobot, panjang, dan PTT), sedangkan pemberian K2O yang melebihi 300 g/tanaman mengakibatkan penurunan pertumbuhan, produksi, dan kualitas buah. Hasil penelitian ini dapat digunakan sebagai landasan penelitian dan penyusunan rekomendasi pemupukan pepaya di lahan rawa pasang surut. <br /><br /><br /><br />Papaya has opportunity to be cultivated in tidal swamp land but the availability of its nutrient in the soil is low.  Nitrogen and potassium are the major nutrients needed by papaya, so that the nutrient should be added through fertilization. The research was conducted in tidal swamp land in Mantangai, Kapuas, Central Kalimantan Province, from June 2007 to April 2008. The objective of this research was to investigate the effect of nutrient N and K on growth and production of papaya in tidal swamp land. Merah Delima variety was used as a seed in this research. The factorial experiment was arranged in a randomized block design with three replications.The first factor was dosage of nitrogen of 0, 125, 250, and 375 g/plant and the second factor was amount of potassium (K2O) from 0, 150, 300, and 450 g/plant. Each unit of treatment consisted of 10 plants. The parameters observed include the chemical properties of soil, vegetative growth, and crop production. The results showed that the availability of  N, P, and Fe at the research location was classified as very high, whereas K was low, Ca and Mg were very low. Nitrogen fertilization up to level 375 g/plant did not significantly increase the vegetative growth of papaya plants because of its high availability of the nutrition on the soil. However, in the productive phase (10 months after planting), fruit length was significantly increased with application of N in dose 250 g/plant. Application of K2O fertilizer on 300/plant increased significantly vegetative growth and yield (number of fruit, fruit weight, fruit length, and TSS), whereas application of more than 300 g/plant decreased their growth, yield, and fruit quality. The results can be used as the basis to arrange and formulate fertilizer recommendation on papaya  which is mainly grown on tidal swamp land.<br /><br />