CHANGES IN HYDROLOGICAL RESPONSE OF FOREST CONVERSION TO AGROFORESTRY AND RAINFED AGRICULTURE IN RENGGUNG WATERSHED, LOMBOK, EASTERN INDONESIA
ABSTRACT: Forest is an ideal
ecosystem for a hydrological cycle, however converting forests to agroforestry
or rainfed agriculture is inevitable.
This study elaborates a hydrological response of infiltration, runoff,
and soil moisture in three land uses at Renggung watershed. Field measurements were conducted in
2014−2015 in those system with soil types of entisols at upstream, inceptisols
at the middle, and vertisols at downstream.
Results showed that constant infiltration rate at upstream in forest was
55.6 cm hr-1, in 15−30 years agroforestry was 32.4 cm hr-1 on average and in
rainfed was 26.4 cm hr-1. Infiltration
in agroforestry at the middle and downstream was 16.8 cm hr-1 and 11.2 cm hr-1,
respectively, while in rainfed was 2.4 cm hr-1 and 4.8 cm hr-1. Runoff at upstream with 29.3 mm hr-1 rainfall
in forest was zero, in agroforestry was 0.026 mm hr-1 and in rainfed was 0.071
mm hr-1. Runoff in agroforestry at the
middle and downstream with 37.1 mm hr-1 and 23.8 mm hr-1 rainfall were 0.045 mm
hr-1, and 0.026 mm hr-1. There was a
half and one third of that in rainfed.
Soil water content in successive order from high to low was in forest,
agroforestry, and rainfed. So, capacity
of agroforestry in sustaining the hydrology cycle was in between forests and
rainfed agriculture.
KEYWORDS: land use;
deforestation; infiltration; runoff; soil water
Author: Muhamad Husni Idris,
Mahrup
Journal Code: jpkehutanangg170011
