Effects of Late-Season Water Lease on Forage Crops

Effects of Late-Season Water Lease on Forage Crops

Summary

The Dry Cottonwood Creek Ranch and MSU Extension are investigating the effects of split-season water leases on hay crops in the Deer Lodge valley of western Montana. The specific purpose is to analyze the agronomic and economic benefits and impacts of a split-season water lease on forage crops over several years under ranch conditions.

The project was initiated in May 2013. Two AM400 soil moisture monitoring recorders from MK Hansen Co. in Wenatchee, Washington were ordered and put in place. Each monitor was connected to four probes (block type), 500 feet of CAT3 telephone wire, and wire nut connectors. Two special tools for stripping the small wire and connecting it to the monitor were purchased. The probes were installed on June 25/26, 2013 on two ranches, Dry Cottonwood Creek Ranch (DCCR) and Lampert Ranch, all in alfalfa fields. The paired fields in each ranch were planted with the same variety in the same year.  Soil moisture was measured at “deep” and “shallow” levels; one probe being at 30″ deep and and one probe at a 12″ depth, packed in with moist soil and water. Probe wires were trenched into place. Software for these probes was obtained in spring 2014.

Lampert Ranch

Soil probes logged data at two locations in Varney Sandy Clay Loam, one irrigated and one non-irrigated (late season).  Each location contained two probes, which were buried at depths of one and three feet. The Lampert Ranch soil data demonstrates lower soil tension (wetter) in the irrigated field. For both fields, the deep probe was highly saturated with water throughout the irrigation season, which suggests an abnormally high groundwater table. The soil moisture tension for the shallow probes was also higher (drier) than anticipated. 

Irrigation use stopped on 58 acres July 8 through September 25 of 2013 and 2014. No change in water application occurred before July 8 or after September 25. 

Dry Cottonwood Ranch (DCCR)

The original probes from the East field had to be removed due to Columbian Ground Squirrel activity and the severing of wires to the probes. These probes were put in the DCCR North field. Soil probes logged data at two locations, one irrigated and one non-irrigated (late season). Each location contained two probes, which were buried at depths of one and three feet. The range in soil moisture tension was not as large as the Lampert Ranch between the shallow and deep probes. In addition, the irrigated shallow probe maintained high soil moisture as a result of irrigation. 

The data from the two deep probes is a little puzzling. The deep irrigated probe appears to have the highest soil tension (lowest moisture), which is opposite the situation with the Lampert soils.  The non-irrigated deep probe however has a low soil tension (wet).  The reason for this difference could be the proximity to Dry Cottonwood Creek.  The non-irrigated deep probe is much closer to Dry Cottonwood Creek and the deeper soils along this creek may maintain a lower soil tension as opposed to the irrigated deep probe, which was located further from the Dry Cottonwood Creek floodplain. 

Irrigation use ceased on June 4 in the acres monitored for this study. Irrigation was much more limited on these acres than in past years due to the retirement of an existing flood ditch source and limited supplies from Dry Cottonwood Creek. In addition, there was a major blowout on the on-farm flood ditch, which limited irrigation use until necessary repairs were made. As a result, the flood acres in this study received very little irrigation for first cutting and no irrigation from July 1-October 1. There was significant moisture in August, which did provide some much needed water for the alfalfa later in the year.

In addition to the soil moisture probes, additional soil moisture tests were taken in order to determine the percent moisture. This information helped inform irrigation application, which was closely tracked through flow meter. Rain and evapotranspiration data was also gathered in order to maintain a tracking spreadsheet of soil moisture in the fields through the irrigation season using the NRCS Checkbook approach. 

Jodi Pauley, MSU Powell County Extension Agent, did clippings on the fields both in 2013 and in 2014. Measurements of the samples were taken using a 21” x 21” square, a gram scale was used to weigh samples. Three samples were taken in all fields except for the wheel line field at Lampert Ranch as acreage is small and two samples were taken.

DCCR fields were flood irrigated in 2013 with a four-year old stand of alfalfa and some grass is starting to encroach the field. One hundred feet transects were also run to evaluate weeds; there were no weeds to speak of. In 2014 the DCCR put in a pivot irrigation system and did see an increase in weeds in the non-irrigated areas (knapweed, leafy spurge, and russian thistle). There was also disturbance of soil to put in the pivots, etc. that saw increased weediness but mostly annual weeds, and it is a short term problem in the irrigated areas.

On the Lampert ranch there was no noticeable increas in pests. Dry Cottonwood Ranch did see an increase in the Columbia Ground Squirrel, as a result from switching from flood irrigation to pivot.

Soil testing occurred in each of the irrigated fields at DCCR and analyzed for organic matter, phosphorus, potassium, magnesium, calcium, soil PH, and nitrates. Overall, soil nutrients were within normal ranges of healthy, although some inputs of additional nitrogen and phosphorus are needed in the north field. Instead of using chemical fertilizers, Dry Cottonwood is planning to plant a cover crop in this field in 2015 with the intent of improving the nitrogen and phosphorus levels. 

A nutrient analysis was completed using bale core samples from three different fields for a combination of first and second cutting. Samples were collected by Jodi Pauley of MSU Extension and the lab analysis was completed by Midwest Laboratories, Inc.  The lab analysis included moisture, dry matter, protein, fiber, total digestible nutrients, net energy, and relative feed value. For first cutting, most fields produced relatively high feed values, although a couple of the fields were a little low in total digestible nutrients. One of the factors that may have decreased the total digestible nutrients was the late timing of first cutting (second and third week of July). For second cutting, total digestible nutrients were much higher and relative feed values all exceeded 100%. By mixing and matching bales from first and second cutting and grass to alfalfa, an improved balance of feed values can be achieved.

Economics

Lampert Ranch

The compensation for the split water lease in 2013 and 2014 was through the Columbia Basin Water Transactions Program (CBWTP) and a lease price was determined based on the replacement cost for the second cutting of $150 per ton for alfalfa and $125 per ton for grass hay, minus the electrical input and harvesting costs.  he agreed upon lease price for these 41 acres of alfalfa and 17 acres of grass hay was $76 per acre or approximately $4,400 in lost production.     

Dry Cottonwood Ranch

The Dry Cottonwood Ranch received $146,894 in 2014 towards the installation of a more efficient irrigation system from NRCS and the CBWTP.  An additional $80,000 in grant funds is still pending from the State of Montana Natural Resource Damage Program. This system will allow the ranch to conserve water on the previously flood irrigated acres and perform a permanent split season lease on 6.52 acres in the corners of the fields. These corners will continue to be flood irrigated up until July 1 of each year from Dry Cottonwood Creek. The payments received in 2014 went directly into the pivot purchase costs necessary to justify this long term project. In prior years, where payments were received for lost production under typical flood irrigation practices, there was a benefit according to the ranch manager at DCCR of reducing labor costs, equipment use, and having capital to purchase hay as needed. During milder winters, in which the ranch incurred lower feeding requirements the costs of purchasing hay were lower and it was possible to incur surplus revenue from the water lease payments.  

• 30 inch hole for soil moisture block
• DCCR interns putting in soil moisture blocks with PVC pipe
• 2014 Soil Moisture profiles
• Soil moisture block

Objectives/Performance Targets

1)  Demonstrate split-season water leasing on two ranches in the Deer Lodge valley with three other cooperating producers for further study and develop outreach programs that promote this tool and bring together agricultural producers to evaluate the agronomic and economic viability of split-season water leasing. 

2) Evaluate the agronomic effect, over time, of withholding irrigation water from hay crops (alfalfa and grass hay) for two months at the end of irrigation season (late July to early September).

3)  Evaluate the economic effects of split-season leasing on hay production and production costs under various scenarios, considering lease prices as a variable. 

Accomplishments/Milestones

General reactions from Split-Season Leasing

So far the overall reaction from the ranches participating has been generally positive. The primary benefits include diversified income, labor savings, reduced equipment, and power costs (in sprinkler irrigation situations). It also appears that split-season leases are better suited for certain acres. We have found that those acres producing low yields (possibly as a result of poor soils) and acres served by costly and inefficient irrigation systems are some of the best suited.   

Lessons learned (so far)

The vastly different soil moisture result from the two ranches also indicates that soil moisture depends a great deal on the soil type and topography. The two ranches within this study were located just three miles apart and were irrigated with similar regularity; however, the ability of the soil to retain moisture during a split-season lease depended on the soil type profile. As expected, soil moisture decreased without the presence of irrigation and crop yields also decreased, although some yields were still obtained due to carryover moisture and precipitation (.25-.5 ton/acre).  

Further research is needed to better understand how different crop types respond to the absence of late-season irrigation. Alfalfa appears to withstand drought conditions without any noticeable die off or patchiness, although only two years of split-season lease have been observed so far. Some die off has occurred on the Dry Cottonwood Ranch, although this appears to be primarily a result of the age of the alfalfa stand.    

More test cases are needed before any definitive conclusions can be made regarding the increase in pests or weeds. Dry Cottonwood Ranch observed an increase in both, while the Lampert Ranch noticed no change in either pests or weeds. Other factors such as increased vehicles presence, earth moving activities, and the installation of center pivots may have contributed to increasing gopher and weed numbers on Dry Cottonwood Ranch.  These factors may need to be weighted in the economics of split-season leasing if they in fact do increase. 

Closely monitoring soil moisture did help improve the application of irrigation water for optimal crop growth on Dry Cottonwood Ranch. By tracking available soil moisture through precipitation, irrigation amounts, and evapotranspiration using the NRCS Checkbook approach, the Dry Cottonwood Ranch was able to optimize irrigation application. Only the necessary irrigation water was applied in order to reduce power costs and optimize plant growth. By being closely involved in the tracking of soil moisture, Dry Cottonwood Ranch gained a much better understanding of how to conserve irrigation water, improve yields, and save money.  In addition, the labor saved was utilized in other much needed areas of the ranching operation. In summary, split-season leasing on certain acres appears to be a generally positive and economically beneficial arrangement for the participating ranches. Further research will assist in better defining the types of ranches that benefit the most as well as specific crop types that may be best suited for temporary split-season leases. 

Impacts and Contributions/Outcomes

Dry Cottonwood Ranch

Crop yields for second cutting non-irrigated alfalfa on Dry Cottonwood were approximately .25 tons per acres. These non-irrigated areas were not cut due to the stunted growth and excessive steminess and were instead left standing for fall cattle grazing. Irrigated alfalfa for first cutting weighed in at 2.24 tons/acres and second cutting weighed in at 1.61 tons/acre for a total of 3.85 tons/acre.  In addition to the lack of water on the non-irrigated acres, the alfalfa was also reaching the end of its productive life, which may have also contributed towards a lower yield. 

Lampert Ranch

The yield for the Lampert Ranch was up on tons/acre for the non-irrigated second cutting and was greater than the prior year due to well-timed rains during August in 2014, which contributed to additional crop growth. 

2013 Clipping Data

The West field of DCCR had a total of 2,550 grams between the three plots for an average of 850 grams. The East field of DCCR had a total of 2,265 grams between the three plots with an average of 755 grams.

Lampert Ranch fields are alfalfa grass stands that are four-years old. Wheel line field had a total of 2,145 grams between two plots with an average of 1,072.5 grams. Pivot Field of Lampert Ranch had a total of 2,795 grams between three plots with an average of 932 grams.

A second clipping was not done on the DCCR as there was a miscommunication and second cutting had already been taken off the field.

On August 26 a second clipping was taken on the Lampert Ranch. The wheel line field had a total of 990 grams from two plots with an average of 495 grams. Irrigation had ceased on this field on July 5. The field had a very healthy stand with an average temperature of 81 degrees Fahrenheit and rainfall for July was 1.42 inches and August was 1.46 inches of rainfall. The pivot field had a total of 1,090 grams from two plots with an average of 545 grams.

2014 Clipping Data

The West field of DCCR had a total of 2,810 grams between the three plots for an average of 937 grams. The East field of DCCR had a total of 2,750 grams between the three plots with an average of 917 grams. This is an increase over last year partly due to more even water application by the new pivots.

On September 3, 2014 a second clipping was taken on the DCCR. The west field had at total of 1,725 grams with an average of 575 grams. The East field had a total of 1,710 grams with an average of 570 grams.

Lampert Ranch fields are alfalfa grass stands that are five-years old, starting to see an encroachment of quackgrass, Kentucky bluegrass, and dandelions, especially under the pivot.

Wheel line field had a total of 1,725 between two plots with an average of 862.5 grams. Pivot Field of Lampert Ranch had a total of 2,200 grams between three plots with an average of 733 grams. This is down overall from last year, mostly attributed to grass encroachment and a cool spring.  

On August 20 a second clipping was taken on the Lampert Ranch. The wheel line field had a total of 2,115 grams from two plots with an average of 1,057 grams. Irrigation had ceased on this field on July 8. The field had a very healthy stand with an average temperature of 80 degrees Fahrenheit and rainfall for July was 1.67 inches and August was 1.29 inches of rainfall. The pivot field had a total of 2,430 grams from three plots with an average of 810 grams.

• Lampert 2014 Wheeline 1st cutting
• Lampert 2014 2nd cutting
• DCCR 2014 2nd cutting
• DCCR 2014 West Field 1st cutting
• 2013-14 Clipping data

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