Survival and growth analysis of multipurpose trees, shrubs, and grasses used to rehabilitate badlands in the subhumid tropics

Abstract

Vegetation plays a vital role for sustainable rehabilitation of degraded lands such as badlands with active gully erosion. However, the establishment of plant species on badlands remains a long‐lasting challenge in most regions, including the subhumid tropics. To address this challenge, 18 multipurpose plant species (six trees, three shrubs, and nine grasses), which were preselected from the regional species pool in Southwest Ethiopia, were planted in a badland and monitored from July 2011 to June 2014. The experiment had a split‐plot design with farmyard manure (FYM) application as main plot and plant species as subplot factors repeated in three blocks. The study revealed that grasses were the most successful to survive and rehabilitate the gully within the monitoring period compared with trees and shrubs. The survival rate of the four most successful grass species, Chrysopogon zizanioides, Pennisetum macrourum, Pennisetum polystachion, and Pennisetum purpureum ranged from 61% to 90% with FYM application and from 20% to 85% without FYM, while most of the well‐known indigenous and exotic trees and shrubs failed to survive. For the grass P. purpureum, shoot height, shoot, and root biomass were enhanced by 300%, 342%, and 578%, respectively, due to FYM application, with a remarkably higher response to FYM compared with all the other studied species. The overall results demonstrate that badlands can be effectively restored by using early successional species such as locally adapted and selected grasses before the plantation of trees and shrubs.

A review of the magnitude and response times for sediment yield reductions following the rehabilitation of gullied landscapes

“…Stokes et al ., 2014). Revegetation of gullies can be difficult, and significant efforts are now being put into understanding the most effective species and strategies in some areas (Talema et al ., 2019). As such, better understanding the optimal types and locations of vegetation for gully erosion prevention remains an important research need.…”

“…Trees provide long‐term stability, and grasses have many above and below‐ground characteristics that are critical for more rapid erosion control (De Baets et al ., 2009; Vannoppen et al ., 2017). As such, a combination of grasses and trees can be expected to give the best results for preventing gully erosion and reducing their sediment yields, however, it is acknowledged that many semi‐arid areas are not suitable for tree growth due to the limited rainfall and soil moisture (Chen and Cai, 2006; Talema et al ., 2019).…”

Rehabilitation effects on gully sediment yields and vegetation in a savanna rangeland

“…Similar to runoff diversion, revegetation of hillslopes above gullies has been shown elsewhere to reduce the amount and erosive effect of runoff on gully head cut erosion and sediment yields (e.g., Chen & Cai, 2006;Talema et al, 2019). In this study, however, pasture renovation by ploughing and seeding of perennial pastures in approximately 30% of the gully catchment area was ineffective at reducing hillslope runoff, evidenced by relatively high headcut retreat rates in the post-treatment period.…”

“…However, it is less well understood whether they effectively reduce yields of fine sediment (silt and clay) affecting downstream aquatic ecosystems, and the extent to which they support gully revegetation in specific environments. Further, there are only a small number of studies on gully revegetation outcomes in response to rehabilitation measures (Heede & DeBano, 1984;Molina et al, 2009;Reubens et al, 2009;Rey & Burylo, 2014;Talema et al, 2019). While the physics of erosion and sediment transport are universal, the intersection of climate, terrain, soil and vegetation characteristics means that the performance of different rehabilitation approaches will be somewhat spatially explicit (Bartley et al, 2020).…”

Effect of forage grass (Pennisetum pedicellatum) and legume (Stylosanthes hamata) revegetation on recovery of soil fertility in a reclaimed hazardous waste dump

“…Addition of legume M. sativa also increased aboveground net primary productivity along with soil carbon (C), nitrogen (N) and phosphate (P) storage in a sandy grassland amended with sediment (Wu et al, 2019). Grass species, such as Chrysopogon zizanioides , Pennisetum macrourum ,Pennisetum polystachion, and Pennisetum purpureum were used to restore wastelands in Southwest Ethiopia (Talema et al, 2019). Under drought stress conditions, root length and root area of grasses are more than legumes at the 30-60 cm depth of soil (Wang et al, 2020).…”