Agriculture Reference
In-Depth Information
Table 10.5. Comparison of SALUS simulations to field measurements for cropping
systems with either inorganic nitrogen (N) or manure additions.
Variable
Inorganic N (140 kg ha
−1
)
Manure (18 ton ha
−1
)
Biomass (kg ha
−1
)
Measured
a
20,893
21,015
Simulated
a
21,450
21,932
(RMSE
b
)
450
645
Cumulative Nitrate Leaching
c
(kg NO
3
-N ha
−1
)
Measured
279
367
Simulated
273
362
RMSE
b
15.7
14.3
Cumulative Drainage
c
(mm)
Measured
1904
1857
Simulated
1901
1862
RMSE
b
24.4
54.5
a
Corn dry biomass harvested for silage (1997).
b
RMSE = Root Mean Square Error.
c
Nitrate leaching and drainage were measured and modeled over a 6-year (1994-1999) corn-alfalfa rotation at the
W.K. Kellogg Biological Station south of the KBS LTER Main Cropping System Experiment (selected data from
Basso and Ritchie 2005).
A major concern among producers is the possibility of yield reductions associ-
ated with permanent no-till management compared to conventional tillage (Grandy
et al. 2006). Residue cover on the soil surface reflects solar radiation and acts as
an insulator, slowing warming of the soils in the spring. This effect is more notice-
able in temperate climates with wet and cool springs because high soil water con-
tent maintained by residue cover is combined with low incoming energy (Allmaras
et al. 1977). Reicosky et al. (1977) reported that on poorly drained soils, corn yields
were decreased because poorly drained soils are usually colder in the growing sea-
son due to higher water content. When vegetative corn development is delayed by
lower soil temperature because of residue cover, yield can be lost due to a short-
ened growth period. However, residue cover can improve soil water availability
by increasing infiltration, protecting the soil surface from erosion, and reducing
evaporative losses. Thus, residue cover can improve yields in lower rainfall years
and in drier locations (Basso et al. 2006, Bertocco et al. 2008).
SALUS was recently used to simulate soil carbon changes in different land use
management practices, including tillage, at the KBS LTER (Senthilkumar et al.
2009; Paul et al. 2015, Chapter 5 in this volume). The simulations of soil C changes
obtained using SALUS were consistent with measurements in the Conventional and
No-till systems of the KBS Main Cropping System Experiment (Fig. 10.2). The
model also simulated the observed large loss of soil C in fertilized, conventionally
tilled plots in an adjacent experiment.
