The implementation of low external input sustainable agriculture system to increase productivity of potato (Solanum tuberosum L.)

The implementation of Low External Input Sustainable Agriculture (LEISA) system can be one of possible answers to national and international issues such as (1) resilience for food and nutrition security, (2) sustainable agriculture, and (3) environmentally friendly agriculture. The use of cow and chicken manure compost can support the effectiveness of LEISA system on potato cultivation. This study was aimed to assess changes in soil, particularly in its physical and chemical properties and evaluate the productivity and quality of potatoes produced. This study used a factorial design employing fertilizer dose and fertilizer type as the factors. A fertilizer dose of 10-25 ton ha-1 of compost coupled with a fertilizer dose of 250 kg ha-1 of NPK fertilizer was applied to potato plants. The potato planting was done from 2011 to 2015 by five farmers who had been selected out of 30 potato farmers. The parameters measured were the physical properties of soil, soil fertility, the productivity and quality of potato tubers produced. The compost from chicken manure used in fertilization with a dose of 20 ton ha-1 could improve soil organic matter content from 4.49% to 6.2%, increase the cation exchange capacity (CEC) from 21.91 to 29.00 me/100 g, alter soil pH from an average 6.71 to 6.84. In addition, LEISA system could improve soil porosity from 35% to more than 50% or in an ideal condition of potato cultivation. As a result, the water content in the soil especially at the root zone was available for the potatoes to grow for 13-17 days. The application of LEISA system also increased the potato production from 17 ton ha-1 to 31.33 ton ha-1. The increased production of potatoes was followed by improved quality of potato tubers, potato super class from 6.08±5.1% to 15.90±4.1%. Key words: LEISA system, physical and chemical properties, fertilization, composting, potato.