Can application of organic matter, cover crops and tree planting improve infiltration rate of soil covered by pyroclastic materials?

Abstract

Pyroclastic materials from volcanic eruption is easily compacted and may develop surface crust, which potentially decreases water infiltration. We conducted research in Ngantang, regularly affected by Mt. Kelud eruption, as an attempt to improve water infiltration using organic matter and cover crop. The organic matter (20 Mg.ha-1) used was sweet potato leaves (Bsp) and Tithonia diversifolia leaves (Btd). Cover crops (Arachis pintoi (Tap) and Tithonia diversifolia (Ttd)) and tree (Paraserianthes falcataria (P1)) were planted. Ring infiltrometer was used to measure infiltration rate on initial soil, on soils covered by pyroclastics after 3 months organic matter and cover crops application, and after one year tree planting. The result showed that infiltration rate of initial soil was significantly decreased with time, when covered by eruption materials. After 3 months application of organic matter and cover crops, infiltration rate was significantly higher than untreated soil covered by volcanic materials. Planting tree increased infiltration rate with the highest infiltration rate occurred in combination with organic matter Tithonia diversifolia leaves and Tithonia diversifolia cover crops. Infiltration rate increased with increasing total pores, but decreased with increasing of meso-pores, especially 12 months after application organic matter, together with planting cover crops and tree.