The effect of NPK–Zeolite fertilizer on the growth of kopyor coconut and nutrient availability in ultisols of TasikmalayaSuwardi, Aurellia Havifah Suryadi, Octaviana Randrikasari, Sri Malahayati Yusuf, Darmawan and Putri OktarianiBIO Web Conf., 234 (2026) 01020DOI: https://doi.org/10.1051/bioconf/202623401020