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

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 $19.04/ha ($7.71/acre) and lowest for barley-spring wheat rotation at —$23.74/ha (—$9.61/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

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

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

Zone-subsoiling relationships to bulk density and cone index on a furrow-irrigated soil

Zone subsoiling on irrigated land has been successfully used to improve potato (Solanum tuberosum L) yield and quality. Zone subsoiling under furrow irrigation may disrupt water flow and influence infiltration and soil erosion. We hypothesized that zone subsoiling, done appropriately, will maintain integrity of irrigation furrows, improve small grain and dry bean (Phaseolus vulgaris L.) growth and yield, and not adversely affect water flow, infiltration, or erosion on furrow—irrigated soils. The experiment was conducted at the USDA—ARS Northwest Irrigation and Soils Research Laboratory in Kimberly, Idaho. The soil is a Portneuf silt loam (coarse—silty, mixed, superactive, mesic Durinodic Xeric Haplocalcids). Tillage treatments were disk, disk + paratill, paratill, and no—till. There were no differences in water infiltration, runoff, or soil erosion among treatments. Bulk density differences among treatments were largest at the 0.15 to 0.20—m depth, and bulk density was about 16% to 18% greater on disk and no—till treatments than on paratill treatments. The highest frequency of low cone index (CI) values belonged to paratill treatments (65% to 80% frequency of CI values less than 2 MPa); the lowest frequency of low CI values belonged to no—till treatment (20% frequency less than 2 MPa). Cone index versus bulk density relationships depended on soil water content with a slope of 5.81 (r 2 = 0.70) in the wetter year of 1997, and 2.90 in the drier year of 1995 (r2 = 0.60). Subsoiling can be accomplished on furrow—irrigated lands with no adverse effects on runoff, infiltration, and erosion, but under our conditions did not improve crop growth and yield