67 research outputs found
Fall contour ripping increases water infiltration into frozen soil
Crop residue management to trap snow and soil management to
improve water infiltration into frozen soil might reduce spring runoff
and increase soil water storage. We hypothesized that soil macropores
created by tillage would improve water infiltration when the soil was
frozen. This hypothesis was tested by ripping a Dooley sandy loam
(fine-loamy, mixed Typic Argiboroll) in the fall of the year and then
measuring water infiltration when the soil was frozen. A single subsoiling
shank was used to rip soil to a depth of 0.3 m at 6-m contour
intervals. Ripping was compared with no ripping using a randomized
experimental design having three replications. Studies were conducted
during 4 yr near Culbertson, MT, on plots seeded annually to spring
wheat (Triticum aestivum L.). Soil water was measured with neutron
attenuation and gravimetric methods. We used a constant-head (100
mm) method to measure water infiltration into frozen soil and a
rainfall simulator for unfrozen soil. Final infiltration rate on frozen,
ripped soil averaged 16 vs. 2 mm h-1 without ripping. Final unfrozen
infiltration rate in spring was 34 mm h-1 with ripping vs. 15 mm h-1
without ripping. Average spring water content of the top 1.2 m of
soil, to a distance 1.5 m downslope from a rip, was 32 mm greater
with ripping than without ripping at comparable slope positions. There
were no wheat yield differences between treatments. Contour ripping
can decrease water runoff, and seems best suited where spring runoff
and soil erosion caused by heavy winter snows is a problem
CRP on sandy soils: Leave it in grass or break it up?
Some people are faced with the question of
whether to break up land that has been in
CRP for the past 10 years and return it to
small grain production, or leave it in grass and
harvest it for hay. A three-year study in Roosevelt
County sheds some light on the pros and cons of
either choice
Economics of tillage practices and spring wheat and barley crop sequence in the Northern Great Plains
Our objective was to analyze economics of spring wheat (Triticum aestivum L.)
and barley (Hordeum vulgare L.) cropping and tillage practices after 10 years of evaluation. We
initiated the study in 1983 on a Dooley sandy loam (fine-loamy, mixed Typic Argiboroll) 11 km
(7 mi) north of Culbertson, Montana. Annually cropped tillage treatments included sweep tillage
in fall with spring disking, sweep tillage in spring, and no-till. A conventional fallow-crop rotation
was included. Spring wheat yields ranged from 74 kg/ha (1.1 bu/acre) to 3,465 kg/ha (51.5
bu/acre). Net return was highest for no-till annually cropped wheat at 7.71/acre)
and lowest for barley-spring wheat rotation at β9.61/acre). Under conditions of
this 10-year study, in a 356 mm (14 in.) precipitation zone, we conclude that annually cropped
no-till wheat production was the most profitable cropping practice
Multiple polyacrylamide applications for controlling sprinkler irrigation runoff and erosion
Runoff under sprinkler irrigation systems causes soil erosion and reduces water infiltration uniformity.
Previous studies have shown that applying polyacrylamide (PAM) with irrigation water can reduce runoff and soil loss.
We hypothesized that applying PAM with three consecutive irrigations would more effectively control runoff and erosion
than applying the same total amount of PAM with a single irrigation. This study was conducted in the laboratory with a
Rad silt loam (coarse silty, mixed, superactive mesic Durinodic Xeric Haplocambid) at 6.5% slope. Water was applied at
80 mm h- 1 (3.2 in. h-1 ) for 10 min [13 mm (0.5 in.) application depth] for four irrigations. PAM was applied at 3 kg ha-1
(2.7 lb a-1 ) with irrigation water during the initial irrigation (single) or at 1 kg ha- 1 (0.9 lb a-1 ) during the first three
irrigations (multiple). Both multiple and single PAM treatments caused significantly less runoff than the control for all
four irrigations. However, the multiple PAM treatment reduced runoff approximately 30% more than the single
application during the last two irrigations. Applying PAM at 3 kg ha-1 (2.7 lb a-1 ) with one irrigation reduced cumulative
soil loss by 60% compared to the control. Applying PAM at the same rate in three consecutive irrigations reduced
cumulative soil loss by 80%. Both single and multiple PAM applications reduced runoff and soil loss, but multiple
applications more effectively controlled runoff longer than a single application
Infiltration and soil properties as affected by annual cropping in the northern great plains
Fallow-wheat (Triticum aestivum L.) cropping systems may be responsible
for declines in soil organic matter and degradation of soil physical
properties. A change to annual cropping may improve or at least maintain
soil properties. Tillage and crop sequence effects on soil properties
and water infiltration were tested after 9 yr of cropping on a Dooley
sandy loam (fine-loamy, mixed Typic Argiborolls) derived in glacial till.
Annual cropping tillage of fall sweep and spring disk (AWFST), and
no tillage (AWNT) were compared with conventional tillage in wheat-fallow
(FWCT) as the control. Statistical design was a randomized complete
block with four replications. Soil samples were taken at 0.03-m
increments to a depth of 0.3 m and were used to measure organic carbon
(OC), pH, bulk density (BD), and particle size. Point resistance was
measured in 0.02-m increments. Water infiltration into dry and wet soil
was measured using a rainfall simulator. Maximum soil BD was 1.61
Mg m-3 on FWCT and 1.56 Mg m-3 on AWNT. Soil BD was not
changed by one winter of freezing and thawing. Maximum point resistance
was 2.2 MPa on FWCT and 1.7 MPa on AWNT. Cumulative 3-h
infiltration into dry soil was 52 mm for FWCT and 69 mm for AWNT.
Final infiltration rate into wet soil was 5 mm h-1 for FWCT and 6 mm
h-1 for AWNT. There was a significant difference in the depth distribution
of OC between annual crop and FWCT treatments. Mass of OC
in the top 0.09 m of soil was 1.65 kg m-2 on annual crop treatments
and 1.45 kg m-2 on FWCT. Greater amounts of OC on the annual crop
treatments compared with the FWCT attest to the beneficial aspect of
annual cropping in maintaining a level of soil quality that is greater
than FWCT. From a soil conservation perspective, no-tillage has an additional
advantage because surface cover is maintained throughout the
year, thereby reducing the potential for soil erosion
Terrace formation in cropping strips protected by tall wheatgrass barriers
Tall wheatgrass barriers have been successfully tested in the northern Great Plains
for wind erosion control and plant protection. Our objective was to document the passive formation
of hillside terraces occasioned by grass barriers on a variable 2 to 4% west to east slope.
Eleven double-row tall wheatgrass [Elytrigia elongata (Host) Nevski) barriers with 10 15-m-wide
cropping intervals 530 m long were established in 1967 on a Williams loam (fine-loamy
mixed, Typic Argiboroll) 11 km north of Culbertson, Montana. The barriers were oriented north
and south in traditional field orientation. In 1991 we established four transects 15 m apart
across the barrier system and designated five sampling points along the transects in each cropping
interval for a total of 200 sampling points. To avoid confounding by slopes parallel to the barriers,
we selected a segment of the barrier system on a near 0% north to south slope for the measurements.
Elevation was determined at each point, and soil cores were taken to a depth of about 90
cm to determine depth to CaCO3 layer, and to determine total and organic carbon by 5 cm increments.
A stair-step pattern, with a maximum drop of 30 cm from one grass barrier to an adjacent
cropping interval, was documented. Depth to CaCO3 and organic carbon concentration increased
downslope between barriers, showing soil movement. Grass barriers may serve as a
substitute for mechanically built terraces
Wheat response and residual soil properties following subsoiling of a sandy loam in eastern Montana
Shallow tillage pans resulting from the use of the same tillage tools may lead to wheat (Triticum aestivum L.) yield reductions.
We hypothesized that occasional deep tillage to fracture shallow tillage pans would improve water utilization and result in
increased wheat yield. Our hypothesis was tested by comparing paired crop and soil responses on plots that were subsoiled
using a paratill (PT) or not subsoiled (NOPT). Soil was a Dooley sandy loam (US soil taxonomy: fine-loamy, mixed Typic
Argiboroll; FAO taxonomy: Kastanozem) derived in glacial till near Culbertson, Montana, USA. Effects of PT or NOPT were
compared in a long-term cropping study that included annual wheat using no tillage (NT), annual wheat using fall and spring
tillage (FST) and wheat rotated with fallow (FWCT). Plots that were subsoiled (PT) were paratilled once in autumn 1992 to
about 0.3 m deep. Cone index of the top 0.3 m of soil 2.5 years after subsoiling was lower on PT (891 kPa) compared with
NOPT (981 kPa). Soil bulk density was 1.34 Mg M -3 on PT and 1.36 Mg m-3 on NOPT plots. Final water infiltration rate
averaged 15 mm h - on PT and 6 mm h - I on NOPT plots for nine months after subsoiling. Average water content of the top
1.2 m of soil in the spring of the year was 21 mm greater on PT than on NOPT plots. There were no differences due to
treatments in wheat yield; average grain yield was 1820 kg ha 1 on annual wheat plots and 2380 kg ha-1 on wheat/fallow
plots. Residual effects of subsoiling on soil properties were detected for 2.5 years after subsoiling, but soil changes attributed
to subsoiling had no effect on wheat yield
Water infiltration into a glacial till soil following subsoiling and secondary tillage
Water limits crop production in the semiarid northern Great Plains of the United States.
Summer fallow is commonly practiced to store water in the soil for use by a later crop (Haas,
el al., 1974). However, high evaporation rates makes summer fallowing inefficient in storing
water (Tanka, 1985; Tanka and Aase, 1987). Additionally, the fallow-wheat (Triticum
aestivum L.) crop sequence has been implicated as the cause of serious declines in soil
organic carbon (Rasmussen and Parton, 1994). A recent report by Aase and Pikul (1995)
showed that annually grown spring wheat was an acceptable alternative to the traditional
fallow-wheat crop sequence in eastern Montana, USA. To successfully grow a crop every
year, however, it is essential to conserve as much precipitation as possible between harvest
and seeding.
Specialized tillage is thought to improve water infiltration and soil water storage. Pikul et al.
(1996) have shown that soil ripping on the contour may improve water infiltration into frozen
soil and possibly increase soil water storage. Objectives were to 1) determine the effect of soil
ripping on water infiltration and 2) evaluate the durability of tillage induced soil structure
following repeated wetting and drying cycles
Water use in a modified summer fallow system on semiarid northern Great Plains
Wheat (Triticum aestivum L.) is the major crop on semiarid northern Great Plains of the USA.
Attempts to introduce alternate crops have had limited success. Alternate fallow-spring wheat
rotation is the most common cultural practice. Our objective was to investigate water use and water
use efficiency and suitability of alternative crops in semiarid northern Great Plains agricultural
environment. The study was on glacial till Williams loam (fine-loamy mixed, Typic Argiboroll)
11 km north of Culbertson, MT. Plots, replicated four times in randomized blocks, were
12 m x 15 m. Rotations were: (1) fallow, sunflower (Helianthus annuus L.), barley (Hordeum
vulgare L), winter wheat; (2) fallow, safflower (Carthamus tinctorious L.), barley, winter wheat; (3)
fallow, buckwheat (Fagopyrum esculentum Moench.), annual legume/grain forage crop, spring
wheat; (4) fallow, buckwheat, annual legume/grain forage crop, winter wheat; (5) fallow, spring
wheat; (6) continuous spring wheat. Soil water to 1.8 m depth was determined near time of seeding
and of harvest by neutron attenuation. The soil reached an upper drained limit of 0.20-0.25 m 3 m-3
water in a 1.8 m profile, equating to no more than 450 m water. Safflower and sunflower used ca.
500 mm water, more water than any of the other crops used. The greatest growing season water use
efficiency was captured by the annual forage crop. Except following safflower and sunflower, soil
water every spring was near the upper drained limit. Deep rooted crops can have a place in rotations
on the semiarid northern Great Plains. But one must be prepared for variable yields and potential
reduced yields following deep rooted crops, and for an occasional crop failure. Crop and soil
management for alternative crops differ from that of small grain management, requiring some
adaptation of management practices
Controlling sprinkler irrigation runoff, erosion, and phosphorus loss with straw and polyacrylamide
Controlling runoff and soil erosion are important for maintaining soil productivity and reducing off-site
impairment due to sediment and nutrient enrichment. Previous research has shown that crop residue and polyacrylamide
(PAM) can reduce runoff and soil erosion. We compared the combined effects of surface residue and PAM on runoff soil
loss, and phosphorus loss from sprinkler irrigated soil in the laboratory. We hypothesized that surface residue would
enhance the effectiveness of sprinkler-applied PAM by allowing PAM to stabilize the soil surface with less disturbance by
water drops. Steel boxes (1.5 m long, 1.2 m wide, and 0.2 m deep) were filled with Roza loam (fine, smectitic, mesic
xerertic Haplocambids) and irrigated at 80 mm h-1 for 15 min. Wheat straw was applied for two separate tests (70% and
30% straw cover). The PAM was applied at 0, 2 or 4 kg ha-1 during the first irrigation, followed by two water-only
irrigations. Applying PAM to straw-covered soil controlled runoff, erosion, and phosphorus losses equally or better than
using either PAM or straw alone. The 70% straw cover reduced cumulative runoff for the three irrigations 75 to 80%
compared to 30 to 50% reduction with PAM alone. Polyacrylamide alone or 30% surface cover alone produced similar
results, both reducing cumulative runoff 10 to 20% compared to untreated bare soil. Since runoff, erosion and phosphorus
loss were reduced when PAM and surface residue were used individually and to a greater extent when used together,
management choices should depend on overall costs and control needed to meet water quality and production goals
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