375ability. Economically, the watershed programs are beneficial and viable with a
benefit:cost ratio of 1:2.14 and an internal rate of return of 22 % (Joshi et al. 2005 ).
4.1.2 Soil Management
Soils hold the key to productivity and resilience to climate vagaries in dryland agri-
culture in South Asia. The potential limiting factors for productivity enhancement
in these regions are the loss of fertile soil as erosion, depletion of soil organic mat-
ter, emerging secondary and micronutrient deficiencies, soil compaction, surface
crusting, and loss of soil biodiversity. Soil management systems should not only
take into account the risks inherent in the farm and field locations but also in the
choice of crops, cultivation methods and/or stocking levels. Soil health restoration
can be addressed through better management practices, which include (i) timely
tillage at suitable moisture levels to prevent bringing up clods which require more
tillage, (ii) reducing secondary tillage, no-till, or ridge–tillage systems to leave crop
residues on the soil surface, (iii) using crop rotations which include grasses and
legumes where possible, (iv) using cover crops, (v) using manure to build soil
organic matter, and (vi) if a crust has formed before the crop emerges, using a rotary
hoe to break up the crust to assist with crop emergence. The main emphasis in rain-
fed farming systems is to build soil organic matter (SOM) for soil health restoration.
Management to improve and restore soil health involves a combination of practices
that enhance the soil's biological, chemical, and physical suitability for crop produc-
tion, including erosion control, correction of nutrient deficiencies, reclamation of
problematic soils, reducing compaction by decreasing heavy equipment traffic, and
using best nutrient management practices such as integrated nutrient–water man-
agement (Fig. 3 ).
Fig. 3 Components of recommended management practices (RMPs) for soil health restoration
(Source: Srinivasarao et al. 2015a or b?)
Dryland Agriculture in South Asia: Experiences, Challenges and Opportunities