Fahmuddin Agus, Diah Setyorini, Wiwik Hartatik, Sang-Min Lee,Jwa-Kyung Sung, and Jae-Hoon Shin
Understanding the net nutrient balance in a farming system is crucial in assessing the system sustainability. We quantified N, P and K balances under vegetable organic farming in a Eutric Hapludand in West Java, Indonesia in five planting seasons from 2005 to 2007. The ten treatments and three replications, arranged in a completely randomized block design, included single or combined sources of organic fertilizers: barnyard manure, composts or green manures. The organic matter rates were adjusted every planting season depending on the previous crop responses. The results showed that the application of 20 t ha-1 barnyard manure per crop resulted in positive balances of N, P, and K, except in the second crops of 2006 where potassium balance were -25 to -11 kg ha-1 under the treatments involving cattle barnyard manure, because of low K content of these treatments and high K uptake by Chinese cabbage. Application of 20 to 25 t ha-1 of plant residue or 5 t ha-1 of Tithonia compost also resulted in a negative K balance. Soil available P increased significantly under 25 t ha-1 barnyard manure and that under chicken manure had the highest available P. Accordingly, chicken barnyard manure gave the highest crop yield because of relatively higher N, P and K contents. Plant residues gave the lowest yield due to the lowest nutrient content among all sources. Reducing the use of barnyard manure to 12.5 t ha-1 and substituting it with Tithonia compost, Tithonia green manure or vegetable plant residue compost gave insignificantly different yield compared to the application of 25 t ha-1 barnyard manure singly. In the long run, application of 25 t ha-1 cattle, goat, and horse manure or about 20 t ha-1 chicken manure is recommendable for sustaining the fertility of this Andisol for vegetable production.
Key words: Nutrient balance, vegetable crops, barnyard manure, organic farming, Andisol
Makalah diterbitkan pada Korean Journal of Soil Science Fertilizer. 42(1). 1-13 (2009)