<![CDATA[Diagnosis dan karakterisasi suatu lahan merupakan satu tahapan penting untuk mengenali kendalapeningkatan hasil, bentuk pengelolaan yang diperlukan, dan gambaran potensi hasilnya. Penelitian dilakukan diwilayah Kecamatan Ngadirojo, Kabupaten Wonogiri, Jawa Tengah. Metode penelitian adalah sigi (survey) denganmengambil contoh tanah lapisan atas (top soil) pada kedalaman 0-20 cm. Contoh tanah diambil dari 11 desa dan setiapdesa diambil dua titik pengambilan secara acak. Analisis kimiawi lengkap dikerjakan di laboratorium Balitkabi, yangmeliputi pH tanah, kadar hara N, P, K, S, Ca, Mg, Cu, Mn, Fe, Zn, KTK, dan kadar C-organik. Disampingpengambilan contoh tanah, dilakukan pula sigi hasil (yield cut survey) untuk tanaman kacang tanah yang diusahakanoleh petani menurut teknologi petani setempat. Data agronomi terhadap sigi hasil kacang tanah terdiri atas hasil ubinandan komponen hasil. Hasil diagnosis status hara tanah di wilayah Kecamatan Ngadirojo menunjukkan bahwa (1)semua desa memiliki status N rendah; (2) status P beragam: enam lokasi (27%) rendah, 11 lokasi (50%) sedang, dan 5lokasi (23 %) tinggi; (3) status K menunjukkan 45% lokasi berstatus rendah dan sisanya berstatus tinggi; (4) status Srendah hingga tinggi; (5) status Ca, Mg, dan hara mikro tergolong tinggi; (6) terdapat peluang yang cukup besaruntuk memperkecil senjang hasil kacang tanah di tingkat petani di wilayah Kecamatan Ngadirojo, Wonogiri; dan (7)hasil kacang tanah pada sistem tanam koak (2,20 t polong kering/ha) lebih tinggi dibandingkan sistem tugal (1,95 t/ha).Kata kunci: diagnosisi hara, kacang tanah, produksi, alfisol ABSTRACTDiagnosis and characterization of land is one of important step to distinguish: a constraint of increasingyield, type of management is being required, and yield potential figure. The research was done and concentrated inNgadirojo subdistrict, Wonogiri, Central Java province. The method of survey was soil sampling and taking soilsample from top soil in 0-20 cm depth. Soil samples were taken up from 11 villages, each villages was takenrandomly at two sites. Analysis of soil sample consisted of status P, K, Ca, Mg, S, pH, C-organic and micronutrients Fe and Zn. A part from soil sampling, it was done yield cut survey for groundnut at the farmer's field.The agronomic data of yield cut survey consisted of yield and component of yield.The result of diagnosisindicated that (1) all the villages area of Ngadirojo sub district have low nitrogen fertility; (2) The phosphorusfertility in Ngadirojo is vary, there are six location (27 %) having low P fertility status, eleven location (50 %)having medium P fertility status, and five location (23 %) having high P fertility status; (3) Potassium fertilitystatus in Ngadirojo indicated that 45 % area have low K fertility and high status for the rest; (4) the sulfurfertility is vary from low to high; (5). The Ca, Mg, and micronutrients are high at all location of Ngadirojo subdistrist; (6). There is a big challenge to minimize yield gap of groundnut Ngadirojo sub district; and (7) At farmerslevel, the hole planting technique by hue ("sistem koak") produced groundnut yield higher than "tugal technique"(2.20 t dry pod versus 1.95 Aa).Key words: diagnosis of nutrient, groundnut, yield, alfisol]]>
