NILAI KADAR AIR KAPASITAS LAPANG BERDASARKAN METODE DRAINASE BEBAS DAN PRESSURE PLATE PADA BERBAGAI JENIS TANAH BERTEKSTUR LEMPUNG BERPASIR BERTANAMAN PAKCOY (Brassica rapa L.) (Levels of Field Capacity by Free Drainage - Elvita Fitri; Sumono Sumono (Universitas Sumatera Utara, 2018)
ABSTRACT Plant’s growth is affected by field capacity that depends on texture and organic matter of the soil. The objective of this research was to study the levels of field capacity at sandy loam entisol and inceptisol with 24 and 48 hours free drainage and pressure plate (pF) methods and the response of pakcoy’s growth. Research was held on greenhouse scale using a completely non factorial randomized design. The observed parameters were organic matter, N, P, pH, porosity, evapotranspiration, wet weight and dry weight of pakcoy.The results showed that both soil had acidic with organic matter and N which were classified as very low, while P at entisol was very high and at inceptisol was very low. Porosity at entisol was low (40-50%) and at inceptisol was bad (30-40%). Evapotranspiration at entisol was higher than inceptisol. pF method at entisol and inceptisol showed higher results and significantly different than the 24 and 48 hours free drainage. Pakcoy’s wet weight was ranged from 4-17/plant and dry weight was ranged from 0.20-1.08 g/plant. Keywords : Field Capacity, Free Drainage, Pakcoy, Pressure Plate, Soil Types ABSTRAK Pertumbuhan tanaman dipengaruhi oleh kapasitas lapang yang bergantung pada tekstur dan bahan organik tanah. Tujuan penelitian ini adalah mengetahui nilai kadar air kapasitas lapang pada tanah entisol dan inceptisol bertekstur lempung berpasir menggunakan metode drainase bebas (DB) 24 jam, 48 jam, dan pressure plate (pF) dan pengaruhnya terhadap pertumbuhan tanaman pakcoy. Penelitian dalam skala rumah kaca menggunakan rancangan acak lengkap non faktorial. Parameter yang diamati meliputi bahan organik, N-total, P-tersedia, pH, porositas, evapotranspirasi, bobot basah dan bobot kering tanaman. Hasil penelitian menunjukkan bahwa kedua jenis tanah tergolong asam dengan kandungan bahan organik dan N sangat rendah, sedangkan kadar P pada entisol sangat tinggi dan pada inceptisol sangat rendah. Porositas pada entisol kurang baik (40-50%) dan pada inceptisol buruk (30-40%). Evapotranspirasi pada entisol lebih besar dari inceptisol. Penentuan kadar air kapasitas lapang dengan metode pF pada tanah entisol dan inceptisol menunjukkan hasil bobot tanaman pakcoy yang tertinggi dan berbeda nyata dibandingkan dengan metode DB 24 jam dan DB 48 jam. Bobot basah berkisar 4-17 g/tanaman dan bobot kering berkisar 0,20-1,08 g/tanaman. Kata Kunci: Drainase Bebas, Jenis TanahKapasitas Lapang, , Pakcoy, Pressure Plate