KESESUAIAN LAHAN UNTUK KOMODITAS UNGGULAN PERTANIAN DI KABUPATEN LABUHANBATU UTARA

<p class="A04-abstrak2">As an expansion area, North Labuhanbatu District has a purpose to improve the social welfare. Meanwhile one of the significant sector in the community is agriculture. Agriculture provides the highest income for the society and has a potency to further develop and establish the area. However, the development should relevant with environment characteristic essentially. Based on preliminary survey, there are 5 agricultural commodities growing in this area namely palm oil, rubber, rice field, cocoa, and coconut which spread over the 8 sub-districts. The increasing of population triggers land use changes particularly in agriculture. Therefore analysis of land suitability for agriculture is fundamental hence policy direction can be applied in each sub-district based on agriculture commodities which suitable with their characteristic accordingly. The evaluation of land suitability is conducted by comparing the physical characteristics with the existing of land suitability criteria which prossessed by ArcGIS software. Land suitability in North Labuhanbatu is identified with 4 clases: S1 (very suitable), S2 (moderately suitable), S3 (marginally suitable), and N (not suitable). Furthermore, there are 4 limiting factors in this study: water availability, root media, nutrient retention, and erosion hazards. The result shows that rubber, rice field, and coconut have very suitable (S1) land to be planted.Therefore the recomendation is to develop agroforestry landscape practices for sustainable livelihoods in Labura District.</p>

EVALUASI KESESUAIAN LAHAN UNTUK TANAMAN KACANG TANAH DI SUB DAS PANASEN KABUPATEN MINAHASA

Peanut is a plant that has an important role in land and has a high selling value. Therefore it is necessary to take appropriate steps to develop peanut cultivation in the Panasen Sub-watershed by knowing the level of land suitability. The problems faced by the community are 1) lack of interest in the community to plant peanuts, 2) land-use change from agricultural land to lodging land 3) land evaluation has never been carried out for peanut plants in the area. The study used a land unit approach supported by soil analysis, plant growth requirements, and matching. The results showed that the research area was classified as suitable for peanut plants with a suitability class S2 (quite suitable) with a total of 4 land units, namely S2rfns (945.41 ha), S2sn (1675.15 ha), S2srn (938.05 ha), S2sn (13.45 ha) and class suitability of S3 (according to marginal) with 2 land units, namely S3s (12.95 ha), S3s (15.67 ha). The limiting factors for suitability class S2 are root media (r), nutrient retention (f), nutrient availability (n) and terrain (s). The limiting factor for suitability class S3 is the field (s). The limiting factor for N1 land suitability is nutrient availability (n), root media (r) and terrain (s). The limiting factors for conformity class N2 are the field (s) and the rooting medium (r).

Efficacy of a Phosphate-Charged Soil Material in Supplying Phosphate for Plant Growth in Soilless Root Media

A soil material high in crystalline Fe hydrous oxides and noncrystalline Al hydrous oxides collected from the Bw horizon of a Hemcross soil containing allophane from the state of Oregon was charged with phosphate-P at rates of 0, 2.2, and 6.5 mg·g−1, added to a soilless root medium at 5% and 10% by volume, and evaluated for its potential to supply phosphate at a low, stable concentration during 14 weeks of tomato (Solanum esculentumL.) seedling growth. Incorporation of the soil material improved pH stability, whether it was charged with phosphate or not. Bulk solution phosphate-P concentrations in the range of 0.13 to 0.34 mg·dm−3were associated with P deficiency. The only treatment that sustained an adequate bulk solution concentration of phosphate-P above 0.34 mg·dm−3for the 14 weeks of testing contained 10% soil material charged with 6.5 mg·g−1P, but initial dissolved P concentrations were too high (>5 mg·g−1phosphate-P) from the standpoint of phosphate leaching. The treatment amended with 10% soil material charged with 2.2 mg·g−1P maintained phosphate-P within an acceptable range of 0.4 to 2.3 mg·dm−3for 48 d in a medium receiving no postplant phosphate fertilization.