405grows up gradually and as high as 6000 kg ha−^1 at the end of 6 years’ experiments
(Fig. 6 ). With the plantation of alfalfa and sweet clover as an artificial vegetation
restoration measure, the biomass was significantly higher than the natural recovered
abandoned land. In the perspective of ecological benefits from carbon sequestration,
solid soil, reduce soil erosion the alfalfa clearly has more advantages (Fig. 6 ).
Alfalfa as the preferred species for vegetation recovery, cutting once a year in sum-
mer also helps to maintain vegetation vigor (Guo et al. 2010 ; Yuan et al. 2015a, c).
There is a concern that alfalfa could exhaust deep soil water. Our research indi-
cated that for a cropland plowed after 9-year-old alfalfa pasture, planting annual
crops (millet grass) first year and then with different crop rotations for four years,
0–5 m soil moisture can restore up to about 90 % of soil moisture in normal annual
crop farmland (Wang et al. 2008 ). Several researchers have obtained similar results
indicating that the deeper soil drier problems led by alfalfa planting can be allevi-
ated (Wang et al. 2009 ). Alfalfa pasture is as a production system in all the researches.
And, if we use alfalfa pasture as a re-vegetation for ecological protection purpose,
and alfalfa and other species biomass are not harvested, alfalfa vegetation will lead
to weak soil water utilization, which soil moisture should not be lower than the
production system.
From the analysis above, the alfalfa pasture productivity remained lower than the
main crops (for example corn, potatoes, sometime in wheat), and it is difficult to be
the region’s major source of forage for large-scale animal husbandry development.
Natural vegetation, which was restored from abandoned land, have very low pro-
ductivity, which also cannot support large-scale grassland animal husbandry. The
local farmer’s adoption of barn feeding sheep also clearly illustrates the alfalfa pas-
ture has disadvantages in forage yield compare to rapidly expanded maize planting.
The annual crops, with maize as the representative, are becoming the major forage
source of livestock feeding. Meanwhile, the alfalfa can only be used as auxiliary
forage jointly support the development of animal husbandry mixed with the grain
and grassland production. On the other hand, due to higher productivity and vegeta-
10
a b
Aboveground biomass (t ha-1)
864202040200320052007200920112013 2011 2012 20136080100120Cover (%)Fig. 6 Perennial legume species alfalfa (Medicago sativa Linn. •) revegetation has higher aboveg-
round biomass and coverage than biennial legume species sweetclover (Melilotus officianalis
Linn. ▲) revegetation and natural restoration vegetation (■) after cropland abandonment. (From
Yuan et al. 2015b)
Integrated Dryland Agriculture Sustainable Management in Northwest China