Tropic soil properties and productivity of shallot lembah palu variety A R Thaha *1) B E Somba1) D Sartika1) St Sukmawati2)
1 Lecturer of Agrotecnology of Faculty Agriculture, Tadulako University, In Palu.
2 Laboratory staf of Agrotecnology of Faculty Agriculture, Tadulako University, In Palu.
Abstract
This study aims to obtain a comprehensive description of soil properties in the development area of shallot lembah palu variety as a basis for soil management to increase the productivity which is still relatively low (average 4 ton ha-1). The first phase of the research was conducted using the survey method in the main development areas, including Tondo village (Watutela hamlet), Guntarano 1 and Guntarano 2 villages, Taipa village, Tanamodindi village, Paboya village and Kawatuna village. Soil sampling on a relatively flat topography with a depth of 20 cm was carried out systematically with a grid system. Each location consisted of 6 composite soil samples. Thus, there were 7 composite soil samples for laboratory analysis. Data on soil and crop management by farmers were collected using a questionnaire. The second phase of the research aimed to engineer low levels of soil organic matter and potassium through field experiments, using a 2-factor factorial experiment. The first factor is the dose of chicken manure 10 tons ha-1 (O1) and 15 tons ha-1 (O2) while the second factor is 48 kg S ha-1 (H1), 72 kg S ha-1 (H2), 100 kg KCl ha-1 (H3), and 200 kg KCl ha-1 (H4). The results showed that soil texture was dominated by sand and dust fractions at all locations ranging from 64-89%, soil clay content ranged from 11-36%. Soil C-organic content was very low to low (0.67-1.79%), soil N-total was very low to low (0.04-0.16%), soil pH was slightly acidic to slightly alkaline (6.3-7.9), available P2O5 levels (Bray 1/Olsen) varied from very low to moderate (2.7-15.3 ppm) except Tanamodindi (77.0 ppm). Available K2O levels (Morgan) were generally low ranging from (4.29-10.12 cmol (+) kg-1) except Tanamodindi and Poboya which were high. Soil CEC was generally low (10.70-16.08 cmol (+) kg-1) except Tondo and Poboya villages, while soil base saturation was low (25.13-45.68%). The results of the field experiment showed that the simple effect between organic fertilizers and inorganic fertilizers was the same (interaction had no significant effect). The application of organic materials equivalent to 15 tons ha-1 produced fresh tuber weight of 10.94 tons ha-1 (O2), significantly higher than the application of 10 tons ha-1 which produced fresh tuber weight of 9.67 tons ha-1 (O1). The use of KCl fertilizer at a dose of 200 kg ha-1 produced fresh tuber weight of 12.35 tons ha-1 (H4), significantly higher than 100 kg KCl ha-1 (H3), 72 kg S ha-1 (H2) and 48 kg KCl ha-1 (H1).
