Soil organic matter and nitrogen in varying management types of coffee-pine agroforestry systems and their effect on coffee bean yield

Abstract

Abstract. Sudharta KA, Hakim AL, Fadhilah MA, Fadzil MN, Prayogo C, Kusuma Z, Suprayogo D. 2022. Soil organic matter and nitrogen in varying management types of coffee-pine agroforestry systems and their effect on coffee bean yield. Biodiversitas 23: 5884-5891. Coffee cultivation in agroforestry systems is mostly planted without soil fertility management. While there are several management interventions to improve soil quality in agricultural practices, it is not clear whether particular treatments, such as adding organic fertilizers and nitrogen fertilizers could increase coffee production in agroforestry settings. This study aimed to analyze soil organic matter and nitrogen in varying management types and its effect on coffee bean yield in a coffee-pine agroforestry setting in East Java, Indonesia. We evaluated four types of coffee management (treatments) namely: (i) no management, (ii) pruning coffee plant branches, (iii) a combination of pruning and addition of fertilizers with a planting distance of pine trees of 3 x 2 m, and (iv) pruning under pine trees with a planting distance of 6 x 2 m. The soil organic matter, total and available soil nitrogen were measured at 0-0.2 m and 0.2-0.4 m soil depths. We measured coffee bean yield to 100 coffee plants per plot. The coffee bean yield in the no-management treatment reached 376 kg ha^-1, while the yield under the other three treatments increased up to 3.9 times compared with no-management. This increasing coffee bean yield did not correlate with soil organic matter in topsoil, with a correlation between coffee bean yield and total ant available soil nitrogen being positive and negative, respectively. We concluded that the limitation of N in the coffee-pine agroforestry system would require management intervention in the form of adding nitrogen fertilizers to increase coffee bean yield.