SariABSTRACTDegraded land in the Carita Research Forest, West Java is commonly found in slopes. As a result, erosion, runoff and nutrient loss often occur in this area. To address these problems, the application of soil and waterconservation techniques with a vertical mulch technique is required. The aim of the study was to determine the effect of vertical mulch treatment on the amount of runoff, erosion, nutrient loss and also its impact on thegrowth of S. johorensis, G. gnemon, and P. speciosa. The results showed that soil and water conservation techniques with vertical mulch are very effective in reducing runoff, erosion and nutrient losses (N, P, K, Ca and Mg). The vertical mulch of mixed planting pattern between S. johorensis and G. gnemon could decrease the surface run off and erosion by 61.74% and 57.14%, respectively, while the mixture of S. johorensis and P. speciosa decreased the runoff and erosion rate equal to 81.39% and 17.64%, respectively. In addition, the use of vertical mulch could also increase the growth of the tree species until the age of 3 years in the field compared to those without treatment.ABSTRAKLahan terdegradasi banyak dijumpai di Hutan Penelit ian Carita, Jawa Barat, khususnya di lahan-lahan berlereng. Akibatnya seringkali terjadi erosi, aliran permukaan dan hilangnya unsur hara. Untuk mengatasi haltersebut perlu dilakukan penerapan teknik konservasi tanah dan air dengan teknik mulsa vert ikal. Tujuan penelitian adalah mengetahui pengaruh perlakuan mulsa vert ikal terhadap besarnya aliran permukaan, erosi dan kehilangan unsur hara serta dampaknya terhadap pertumbuhan tanaman S. johorensis, G. gnemon, dan P. speciosa. Hasil penelit ian menunjukkan bahwa teknik konservasi tanah dan air dengan mulsa vertikal sangat efektif dalam mengurangi laju aliran permukaan, erosi dan kehilangan unsur hara (N, P, K, Ca dan Mg). Mulsa vertikal pada pola tanam campuran jenis S. johorensis dan G. gnemon, dapat menurunkan aliran permukaan dan erosi masing-masing 61,74% dan 57,14%; sedangkan campuran S. johorensis dan P. speciosa, menurunkan laju aliran permukaan dan erosi sebesar masing-masing 81,39% dan 17,64%. Selain itu, penggunaan mulsa vertikal juga dapat meningkatkan pertumbuhan ketiga jenis tanaman yang diusahakan sampai umur 3 tahun di lapangan dibanding tanpa penggunaan mulsa vertikal.