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–Chapter 4 4. Land degradation assessment Why LD assessment?? •To improve understanding of causes, impacts, degree and links with climate, soil, water, land cover and socio-economic factors. •A primary goal in decision support systems for reversing degradation 4.1 Indicator of Land degradation Assessing the degradation of productive capacity of land requires assessment of indicators of land degradation. Indicators are variables which may show that land degradation has taken place The indicators used may be: The piling up of sediment against a downslope barrier may be an 'indicator' that land degradation is occurring upslope. Similarly, decline in yields of a crop may be an indicator that soil quality has changed, which in turn may indicate that soil and land degradation are also occurring. The condition of the soil is one of the best indicators of land degradation. 4.2 Methods of land degradation assessment Different methods have been developed and used to assess and monitor land degradation. Six extensively used methods for Land Degradation assessments –Expert opinion – Land users opinion –Modelling –Field observations, monitoring and measurements –Productivity change estimates –Remote sensing and GIS • The methods have been applied to different approaches which use either qualitative or quantitative measures or both. • Details are identified at the global, national, regional, local and field/farm level. 4.2 Available models for different levels/scales USLE, RSLE Reading assignment) Chapter 5 5. Rehabilitation and/or restoration of degraded Land What is the difference between Rehabilitation and Restoration? • Rehabilitation is bringing back to its productivity • Restoration is bringing back to ecological function 5. 1 Vegetation 5.1.1 Area closure and re-vegetation – Area closure suitable for degraded areas in most aggro-climatic parts of the country. – Improvement required both on the soil and the establishment of vegetative cover or natural regeneration – Area closure alone (without support measures) is a slow recovery process •Combined with different soil and moisture conservation measures (multipurpose and nitrogen fixing trees, grass and specific cash crops) •Require supplementary structural measures as per their specific requirements (trenches or eyebrow basins or Improved pits check dams and brush woods, cutoff drains and waterways or combinations of these) •Exclusion livestock or limited human interference until 80% grass cover is obtained (3-5 years) • Requirements for area closure i) Consider severely degraded area • plant cover reduced < 10% • soil depth reduced to <= 25cm • stoniness increased to 80% • gullies in advanced stage ii) Planning and implementation arrangements • people’s participation a prerequisite • agreed and phased. • discuss with the farmers before (Preparation for sharing of area closure required) • alternatives to substitute benefits lost by closing ( as access to grazing land reduced in the short term. • planning and design of core and supplementary measures • Management and utilization plan prepared and agreed. • clear undesirable species for better species growth • minimum physical conservation measure • regular supervision for desired changes • keep inventory and records on activities and development 5.1.2 Reforestation and/or afforestation • What the difference between reforestation and afforestation Reforestation is the reestablishment of forest cover either naturally by natural seeding, coppice or root suckers or artificially by direct seeding or planting. Afforestation is the establishment of forest or stand of trees in area where there was no forest. 5. 2 Soil restoration • Resorting the soil condition is possible through Improved fallow-systems Residue management Minimum soil disturbance 5.3 Wetland Restoration • Wetlands are defined as "lands that have a predominance of hydric soil; are inundated or saturated by surface water or ground water at a frequency and duration sufficient to support a prevalence of hydrophytic vegetation typically adapted for life in saturated soil conditions; and under normal circumstances do support a prevalence of hydrophytic vegetation" Restoring hydrology • Wetland hydrology restoration often involves the use of various types of structures to restore, enhance, or regulate hydrology on the restoration site. • Buffering : managing the catchment to protect the wetland • Restoring vegetation by natural and artificial means: an overview of considerations –Natural regeneration –Active re vegetation –Propagule –Seed bank