@article{Irwan Sukri Banuwa_Kuswanta Futas Hidayat_Iskandar Zulkarnain_Purba Sanjaya_Afandi_Ali Rahmat_2020, title={SOIL LOSS AND CASSAVA YIELD UNDER RIDGE TILLAGE IN HUMID TROPICAL CLIMATE OF SUMATERA, INDONESIA }, volume={18}, url={https://geomatejournal.com/geomate/article/view/467}, abstractNote={<p>Erosion is one of problem threatens the soil resource caused soil degradation. Applying the <br>ridges system and organic fertilizer contributes to suppressing runoff and erosion. This study aims to <br>determine the effect of applying different ridges system and the organic fertilizer on the runoff, soil erosion, <br>nutrients loss of soil, nutrient enrichment ratio, starch content, growth, and yield of cassava on 12.5% slope <br>land. The research was conducted at the field experiment, University of Lampung, under a humid tropical <br>climate. This study used a Randomized Complete Block Design, which was arranged factorially with two <br>factors, ridges system and organic fertilizer (organonitrofos) and four replications. Factor one is consists of <br>G1 (ridges in the same direction with the slope) and G2 (ridges in the opposite direction with the slope), <br>while factor two is consists of P0 (Organonitrofos 0 tons/ha) and P1 (Orgononitrofos 20 tons/ha). The results <br>showed that the application of the ridges in the opposite direction with the slope significantly reduces the <br>runoff 42.63%, soil erosion 61.68%, and suppress nutrient loss of N-total by 61.85%, P-available by 57.92%, <br>K-total by 80.41% and C-organic by 61.22%, compared to ridges in the same direction with the slope. <br>However, ridges systems do not give a significant difference to starch content, growth, and cassava yield. <br>Physical obstacles formed by ridges in the opposite direction with the slope will force water to infiltrate into <br>the soil so that the runoff rate, erosion, and nutrients loss can be reduced significantly. In reverse, the organic <br>fertilizers do not affect all variables. The ridges system and the organic fertilizer did not significantly affect <br>the starch content, growth, and yield of cassava. That caused by the application of synthetic fertilizers at the <br>same dose (standard dose for planting cassava) in each experimental unit that fertilizer already enough to <br>grow optimally.</p>}, number={67}, journal={GEOMATE Journal}, author={Irwan Sukri Banuwa and Kuswanta Futas Hidayat and Iskandar Zulkarnain and Purba Sanjaya and Afandi and Ali Rahmat}, year={2020}, month={Mar.}, pages={1–7} }