Silvicultural, hydro-orological and economic aspects of a combination of vegetative (Falcataria moluccana-Vigna cylindrica) and terrace systems in soils of different slopes

Abstract

Abstract. Karyati, Sarminah S, Karmini, Rujehan, Lestari VFE, Panorama WS. 2019. Silvicultural, hydro-orological and economic aspects of a combination of vegetative (Falcataria moluccana-Vigna cylindrica) and terrace systems in soils of different slopes. Biodiversitas 20: xxxx. Soil and water conservation techniques involving a combination of vegetative and mechanical systems will increase the benefits from both conservation aspect as well as economic aspect. This study was aimed at analyzing the silvicultural, hydro-orological and economic aspects of a combination of vegetative (Falcataria moluccana-Vigna cylindrica) and terrace system in soils of different slopes (a steep and a very steep slope gradient). The silvicultural parameters examined in this study were the ground coverage of V. cylindrica growth and survival rate, stem diameter and height of F. moluccana trees. The hydro-orological parameters included erosion rate, erosion hazard index, erosion hazard class, and erosion hazard level. The economic parameters included total cost, total revenue, and profit. The result showed that the survival rate, diameter increment and height increment of F. moluccana, and ground coverage of V. cylindrica in the land with the steep slope (>25-45%) was 90%, 2.02 cm year-1, 1.54 m year-1, and 80-90%, respectively. The erosion rate, erosion hazard index, erosion hazard class, and erosion hazard level in this steep slope was 0.38 ton ha year-1, 0.03 (low), I (very low), and very low, respectively. In the steeper ground (>45%), the survival rate of F. moluccana reached 90%, the V. cylindrica coverage was 70-79% and the diameter and height increment of F. moluccana was 1.63 cm year-1 and 1.19 m year-1, respectively. The erosion rate was 1.81 ton ha-1 year-1, erosion hazard index of 0.13 (low), erosion hazard class was I (very low), and erosion hazard level was low in the very steep slope land. The profit from V. cylindrica was Rp 3,865,000.00 ha-1 cropping season-1 and Rp 665,000.00 ha-1 cropping season-1 in steep slope and very steep slope, respectively. The application of the proposed combination of vegetative and terrace system could reduce surface runoff and erosion rate in the long term, in addition to providing short term economic benefits.

Conservation and economic aspects of a combination of forestry-agricultural crops (Neolamarckia cadamba-Phaseolus vulgaris) and terrace systems in different slope classes

“…Soil erosion on land with application of agroforestry and terraces on sloping land is smaller than on the land with a combination of soil-water conservation techniques and agroforestry (Sumarno et al, 2011) and agroforestry (N. cadamba -Glycine max and F. moluccana -Arachis hypogaea) in slightly steep and steep slopes Sarminah et al, 2018). However, our results showed that combination of planting N. cadamba -P. vulgaris and terraces on land with steep and very-steep slopes resulted in greater soil erosion than the combined planting of F. moluccana -V. cylindrica and terraces on two classes of the same slope (Karyati et al, 2019). Moreover, forest canopy and crop cover play a role in restraining the rate of rainwater and reducing surface runoff and eroded soil mass.…”

“…The profit of P. vulgaris cultivation in implementing agroforestry (N. cadamba and P. vulgaris) and terrace on sloping lands (Table 5) was higher than Arachis hypogaea, Glycine max, Vigna cylindrica, and Sorghum bicolor yields as intercropping in an agroforestry system (Karmini et al, 2017;Karyati et al, 2020;Karyati et al, 2019). The total costs, total revenue, and profit of application of A. hypogaea as an intercropping in the agroforestry of F. moluccana and A. hypogaea were IDR 10,985,000.00 ha -1 cropping season -1 , IDR 14.000.000,00 ha -1 cropping season -1 , and IDR 3,015,000.00 ha -1 cropping season -1 (Table 5).…”

“…The total costs, total revenue, and profit of implementation of this combination on the steeper ground were IDR 9,181,128.47 ha -1 cropping season -1 , IDR 650,000.00 ha -1 cropping season -1 , and (-)IDR 8,531,128.47 ha -1 cropping season -1 , respectively (Karyati et al, 2020). Karyati et al (2019) reported that the implementation vegetatives (F. molucccana -V. cylindrica) and terrace on steep slope gradient gave total costs of 16,135,000.00 IDR ha -1 cropping season -1 , total revenue of IDR 20,000,000.00 ha -1 cropping season -1 , and profit of 3,865,000.00 ha -1 cropping season -1 . Meanwhile, the economic analysis of this implementation on very slope gradient showed total costs, total revenue, and profit were IDR 16,135,000.00 ha -1 cropping season -1 ; IDR 16,800,000.00 ha -1 cropping season -1 ; and IDR 665,000.00 ha -1 cropping season -1 , respectively.…”

“…Planting Glycine max as an intercropping in agroforestry of Anthocephalus cadamba -G. max in the first year of first planting season needs IDR 11,019,000.00 ha 1 per cropping season, and results in a total income of IDR 3,500,000.00 ha 1 per cropping season and a profit of IDR 7,519,000.00 ha 1 per cropping season (Karmini et al, 2017). Several studies on the silvicultural and economic aspects of applying different combinations of two plants or agroforestry and soil slopes have been reported (Karmini et al, 2017;Karyati et al, 2020;Karyati et al, 2019;Sarminah et al, 2018). The growth parameters, such as diameter and height increments of forestry crops and crop production were reported to be higher on less steep land compared to the steeper land, while erosion rate, erosion hazard index, erosion hazard class, and erosion hazard level were found higher on soils with steep slopes than with less steep slopes (Karyati et al, 2020;Karyati et al, 2019;.…”

“…Several studies on the silvicultural and economic aspects of applying different combinations of two plants or agroforestry and soil slopes have been reported (Karmini et al, 2017;Karyati et al, 2020;Karyati et al, 2019;Sarminah et al, 2018). The growth parameters, such as diameter and height increments of forestry crops and crop production were reported to be higher on less steep land compared to the steeper land, while erosion rate, erosion hazard index, erosion hazard class, and erosion hazard level were found higher on soils with steep slopes than with less steep slopes (Karyati et al, 2020;Karyati et al, 2019;. The economic benefit of agroforestry system was obtained from crop yields in the short term while the forestry plants are expected to conserve the soil and water in the long term (Karmini et al, 2017).…”