Effects of Late-Season Water Lease on Forage Crops

Final Report for OW13-144

Project Type: Professional + Producer
Funds awarded in 2013: $24,950.00
Projected End Date: 12/31/2016
Region: Western
State: Montana
Principal Investigator:
Jodi Pauley
Montana State University
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Project Information

Abstract:

The Dry Cottonwood Creek Ranch and MSU Extension investigated the effects of split-season (late summer) water leases on hay crops in the Deer Lodge valley of western Montana. The specific purpose was to analyze the agronomic and economic benefits and impacts of a split-season water lease on forage crops over several years under different ranch conditions and different soil conditions. Alfalfa appears to withstand drought conditions better than anticipated, with yield losses ranging from 0 to 0.8 tons per acre for second cutting. During years 1 and 2 of the study, split season leasing had little impact on the alfalfa health in the fields studied. There was an increase in cheatgrass on year 3 and 4 in some of the fields as well as pests such as ground squirrels and pocket gophers. One of the biggest areas that helped improve the application of irrigation water was monitoring soil moisture in helping to optimize irrigation application which in turn helped to increase production and reduce costs. The economic impacts of split-season leasing varied with an average electrical savings of $50 per acre and a yield loss equivalent to $75 per acre on average. In summary split-season leasing can be a beneficial tool for decreasing inputs (labor and pumping costs) while diversifying income from entities willing to pay for leased water.

Introduction

The project was initiated in 2013 and extended through 2016 with the purpose of quantifying how forgoing irrigation water during the months of July and August affects the health and yields of forage crops, particularly alfalfa over the span of 1-4 years. A tool known as split-season leasing, which compensates ranchers/farmers for forgoing mid-summer (July-early September) water use was utilized during the course of this study across 3 different ranches as a tool to better quantify the agricultural impacts to crop plant health, soil moisture and crop yields. Increases in weeds, changes in plant communities over time and the presence of pests were also measured to assess the impacts of split-season leasing. This tool also allowed participating ranches to evaluate whether or not it might be economically beneficial in the future. An evaluation of the economics related to power savings and replacement costs of lost hay yields was performed to better assess the financial impacts of participating in a split-season lease arrangement. Given that split-season lease prices paid (which are variable) exceeded replacement costs in all situations, it appears that this can be a useful tool in certain situations for decreasing energy and labor costs associated with second crop hay production and conserving water.

Project Objectives:

1) Demonstrate split-season water leasing on 2 ranches in the Deer Lodge valley with 3 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.

Cooperators

Click linked name(s) to expand
  • Ted Beck
  • Wayne and Kathy Hadley
  • Evan Johnston
  • Hans Lampert
  • Maggie Schmidt

Research

Materials and methods:

A. Soil Moisture: 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 ft. of CAT3 telephone wire, wire nut connectors, and 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. One of the probes was moved from Dry Cottonwood Ranch in 2015 to the 2 Bar Ranch because of ground squirrel issues in that we could not keep them from chewing the wires of the soil probes. 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 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 the spring of 2014 and has been utilized since for processing the soil moisture data. In 2015 and 2016 we also added some more fields at the Lampert Ranch that had similar age stands of alfalfa and the producer was interested in the economic benefits of split season irrigation. Every year DCCR monitored the soil moisture levels and kept track of that data for use in this project. The NRCS Irrigation Water Management program was also utilized on DCCR for tracking soil moisture, irrigation inputs, precipitation and evaportranspiration.

B. Hay Yield and Clipping Methods: Hay yields were obtained from the weighing of bales harvested on each field and dividing the total weight by the number of acres harvested to arrive at a tonnage per acre on each field. Some fields that were not harvested due to insufficient growth received an producer provided estimated yield. MSU Powell County Extension also took measurements before each hay cutting using a 21 x 21 inch square and a gram scale was used to weigh the samples. Irrigated fields were paired with non-irrigated fields to monitor the weighted differences. Extension also did soil sampling and hay testing at DCCR.

C. Economics: The methods for quantifying the financial impacts of split season leasing were performed through comparisons of power records and calculations of replacement costs for diminishments in yields. To determine the power savings, usage in KWH was compared for the months of July and August during years in which the participants engaged in a split-season lease and those in which they did not. Differences in electrical usage were multiplied by current market rates and divided by the number of acres participating in split-season leasing to determine the cost savings per acre. The replacement cost of diminished yields was determined by utilizing the yield change information from second cutting and multiplying that by local market rate for alfalfa hay in that particular year.

Research results and discussion:

A. Soil Moisture Results: 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) in 2013 and 2014. 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, although demonstrated a similar trend of declining soil moisture after irrigation was shut off in early July. In addition, the irrigated shallow probe maintained high soil moisture as a result of irrigation.

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. Dry Cottonwood planted a cover crop in this field in 2015 and 2016 with the intent of improving the nitrogen and phosphorus levels.

Soil moisture measurements were conducted using the feel and appearance method and recorded using the NRCS checkbook approach, which compares soil moisture to irrigation application, evapotranspiration and precipitation. Due to poor water availability and little precipitation, soil moisture in the corners of the fields was low and subsequently production was quite low (not even cut, less than .5 tons per acre). Weeds issues were present in these non-irrigated corners. Dry Cottonwood Ranch did see an increase in the Columbia Ground Squirrel, as a result from switching from flood irrigation to pivot.

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 from 2013-2016 demonstrated lower soil tension (wetter) in the irrigated field during the month of August. 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 8th through September 25th of 2013 and 2014, 6.6 acres in 2015 and 37.4 acres in 2016. No change in water application occurred before July 8th or after September 25th.

On the Lampert ranch there was no noticeable increase in pests, although there was an increase in non-desirable grass species in some of the upper alfalfa fields participating in the split-season lease.

2 Bar Ranch- The 2 Bar Ranch was included in 2015 due to the irrigated crop types (alfalfa) and to provide diversity in both soil type and age of the alfalfa stand. The alfalfa stand was replanted relatively recently (4 years) and the partially irrigated ground was located on Carten Wetsand complex soils, while the fully irrigated comparison was located on Gregson loam soils. The two soil moisture probes were redeployed in the area irrigated after July 1 and the area that was not irrigated following first cutting on July 1.

The non-irrigated alfalfa was visibly drier, although there was no noticeable increase in weeds or impact to plant health. It is also quite possible due to the soil type and vicinity to the Racetrack Creek water source that the alfalfa benefits from a high water table and adjacent irrigation. Carten Wetsand complex soils are described as being often sub-irrigated and have poor drainage properties. The soil moisture probe data also indicates that despite a lack of irrigation beginning July 1, soil moisture did not depart from the irrigated field until late July, indicating that the roots continued to have sufficient soil moisture for nearly 4 weeks following 1st cutting.

B. Hay Yield and Clipping Results: Dry Cottonwood Ranch- 2013 Clipping data from the West field of DCCR for first crop had a total of 2550 grams between the 3 plots for an average of 850 grams. The East field of DCCR had a total of 2265 grams between the 3 plots with an average of 755 grams. A second clipping was not done on the DCCR as there was a miscommunication and 2nd cutting had already been taken off the field. Crop yields for second cutting non-irrigated alfalfa on Dry Cottonwood were approximately .25 tons per acres (producer estimate). These non-irrigated areas were not cut due to the stunted growth and excessive steminess and were instead left standing for fall cattle grazing.

2014: The West field of DCCR had a total of 2810 grams between the 3 plots for an average of 937 grams for first cutting. The East field of DCCR had a total of 2750 grams between the 3 plots with an average of 917 grams. This was an increase over 2014 partly due to more even water application by the new pivots. No clippings were conducted for second cutting since bale weights were measured and there were no acres participating in a split-season arrangement during 2014 (aside from some non-irrigated corners). 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.

2015: DCCR became increasing harder to monitor because of change in irrigation from flood to pivot and they are not turning any water off and some of the corners receive no irrigation at all. A comparison in the south field was performed (which had been done before). With the dry corner that is under flood and had not received any water this season at 460 grams and then the field under pivot was at 880 grams. This originally was the West field in other data that has been taken in the past. The dry corner in the North field was a very old stand of alfalfa grass and had 780 grams and no clippings were taken under the pivot as it was under a cover crop.

First cutting yields were down to 1.7 tons/acre and second cutting was 1.0 tons/acre for a total of 2.7 tons per acre. 2015 yields were lower due to drought conditions, aging alfafa and mechanical issues with the pivots. 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.

2016: Clippings were not taken the DCCR ranch this year due to change in irrigation and plowing of some of the field and putting in cover crops. We did do hay sampling though for DCCR.

First cutting yields improved to 2.8 tons per acre for first cutting and 2.2 tons per acre for second cutting under the West Alfalfa pivot for a total yield of 5 tons per acre. Total yields across the three pivots were down overall due to cover crops being in place in 2 of the 3 pivots. One corner in the South field was flood irrigated for first cutting and produced 1.4 tons per acre. For second cutting, 1.06 tons per acre were harvested on the South field and the yield loss of the non-irrigated corner was approximately 0.81 tons per acre.

Yields were also lower in the irrigated fields due to cover crops, aging alfalfa stands and low soil moisture at times. With so many factors at play with DCCR in 2015 and 2016, it is difficult to draw many conclusions regarding the impacts of split-season water leasing. Cover crops such as the one planted at DCCR in 2015 and 2016 did require less irrigation application overall and may not have required late season water. For ranches looking to improve soil health, decreasing or stopping irrigation of cover crops in late July or early August could be an option for those also looking to conserve irrigation water.

Lampert Ranch- 2013 Lampert Ranch fields are alfalfa grass stands that are 4 years old. Wheel line field had a total of 2145 grams between 2 plots with an average of 1072.5 grams. Pivot Field of Lampert Ranch had a total of 2795 grams between 3 plots with an average of 932 grams.

On August 26th a second clipping was taken on the Lampert Ranch, the wheel line field had a total of 990 grams from 2 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 1090 grams from 2 plots with an average of 545 grams.

The yield change of .5 tons per acre for the Lampert Ranch was consistent with prior low precipitation years for this aging alfalfa stand on well drained, sandy soils. No yield change was observed on certain lower elevation acres that benefitted from an especially high groundwater table. The biggest take-away on the Lampert Ranch was the location of certain alfalfa fields and the age of the stands. Those fields located closer to the river which benefit from a higher water table were impacted much less than those fields located closer to upland grass communities.

2014 Lampert Ranch fields are alfalfa grass stands that are 5 years old, starting to see an encroachment of quackgrass, Kentucky bluegrass and dandelions especially under the pivot.

Wheel line field had a total of 1725 between 2 plots with an average of 862.5 grams. Pivot Field of Lampert Ranch had a total of 2200 grams between 3 plots with an average of 733 grams. This is down overall from 2014 mostly attributed to grass encroachment and a cool spring.

On August 20th a second clipping was taken on the Lampert Ranch, the wheel line field had a total of 2115 grams from 2 plots with an average of 1057 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 2430 grams from 3 plots with an average of 810 grams. The yield change between the irrigated and non-irrigated fields for second crop was approximately .5 ton per acre.

2015 Only one set of clipping data was taken this year on August 18, 2015. Lampert Ranch fields are alfalfa grass stands that are 6 years old and another field the west field that as added with a stand that is at least 10 plus years old. Fields are getting more grass encroachment and dandelions. Wheel line field that had water turned off on July 8 had 970 grams total with an average of 485 grams per plot. The stand under the pivot had a total of 1275 grams with an average of 637.5 grams. Overall production is down due to Kentucky bluegrass and dandelion encroachment and aging of alfalfa plants with less production.

We put in another field at the Lamperts for the study which is the East field below the house. Irrigation ceased on half of the field on July 8 as well. Non-irrigated portion averaged 685 grams and irrigated portion had 805 grams of forage. The yield change between the irrigated and non-irrigated fields for second crop was approximately .5 ton per acre.

2016 Lampert Ranch fields are alfalfa grass stands that are 6 years old and older, the 5 acre wheel line field is about 30% alfalfa and 70 percent grass. We also included a 9 acre wheel line field that is about 60 percent grass and 40 percent alfalfa. All fields had water turned off the beginning of July. It was a dry summer and most of grass was droughted out when fields were clipped on August 27th. The field that is paired with the pivot also is seeing a lot more cheatgrass encroachment under the wheel line where water has been turned off and some pocket gopher invasion as well. Under the pivot with traditional irrigation on July 5th there was an average of 797.5 grams per plot, compared to the wheel line that had 690 grams per plot. On August 27th a second clipping was taken and the pivot had 750 grams per plot and the wheel line was at 435 grams per plot.

The 5 acre field averaged 426 grams per plot on July 5th and 257.5 grams per plot on August 27th. We added the 9 acre field as it is irrigated very similar and has an older stand of alfalfa that is comparable to the other fields at had 575 grams per plot on July 5th and 327.5 grams on August 27th. This field also has a lot of pocket gopher activity. The yield change between the irrigated and non-irrigated fields for second crop was approximately .5 ton per acre.

2 Bar Ranch- 2015 The Two Bar Ranch did not receive any clipping data since the harvested acres were weighed using the bale weight technique.

First cutting yields were 3.5 tons per acre and second cutting yields were 1.8 tons per acre for a total of 5.3 tons per acre in 2015. The 2 Bar Ranch exhibited much higher yields that other participants, which may have also resulted in a slightly higher loss per ton (.8 tons per acre) on the non-irrigated field (for second crop). The main lesson learned so far from the 2 Bar Ranch is that even on highly productive soils, the impacts of split season leasing on yield are not as significant as expected (.8 tons per acre less than irrigated 2nd crop).

The difference of .8 tons per acre in 2nd cutting yield may have also been greater if the age of the alfalfa stand in the irrigated area was replanted at the same time. The full season irrigated area alfalfa, which we used for comparison was predominately planted around 8 years ago. Overall, the non-irrigated area from July 1 onward was visibly drier at the time of cutting, despite producing only a .8 ton per acre difference (2.6 ton per acre irrigated, 1.8 ton per acre non-irrigated).

2016 DCCR Hay Production Workbook 2013-16 alfalfa clipping data DCCR Johnston Soil Data Lampert entire soil study

 

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

Please refer to the attached brochure, which summarizes the findings from this study and will be made available for interested landowners and also pictures taken during 2016 clippings.

SARE Brochure-FINAL RD 

Project Outcomes

Project outcomes:

The overall reaction from the Ranches participating was generally positive. The primary benefits included 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 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. In addition, fields that benefit from sub-irrigation or high groundwater tables are also well suited because the relative yield impact of reducing irrigation applications can be relatively minor for second cutting. Aging alfalfa stands and fields needing cover crops are also well suited for this type of split-season lease arrangement. The vastly different soil moisture result from the three ranches indicates that soil moisture depends a great deal on the soil type and topography.

The Lampert and Dry Cottonwood ranches within this study were located just 3 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).

The 2 Bar Ranch exhibited similar results to the Dry Cottonwood Ranch, where soil moisture was retained in the non-irrigated areas for 2-3 weeks before we saw a departure from the irrigated areas. Yields were slightly higher on the 2 Bar Ranch likely due to a younger alfalfa crop, potential access to an elevated groundwater table and a soil type that was more advantageous to retaining moisture.

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 four 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 and 2 Bar Ranch noticed no change in either pests or weeds. Certain acres on the Lampert Ranch that received no late season water did see an increased presence of cheat grass by years 3 and 4 of the study, suggesting that some of the grass communities can change over time. 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. One economic consideration that might help to reduce any actual or perceived impacts from weeds or changes in grass composition would be to budget for weed control and reseeding of drought tolerant grasses during a multi-year split-season lease.

The economic impact of split-season leasing is primarily driven by the cost of the lost production (replacement value) from second cutting. Lost production from second cutting varied by ranch and field location from 0 tons per acre to .8 tons per acre. The cost of replacing this lost production can be calculated by multiplying the rate of replacement hay ($120-150/ton in Western MT) to determine potential lost revenue or feed replacement cost during a split-season lease arrangement. As mentioned above, additional costs such as reseeding or weed control may need to be taken into consideration when calculating the agricultural cost of a longer term split-season lease. In some cases where power or labor costs are significant for producing hay, there may some additional financial benefits to the producer for participating in such an arrangement. In the case of the Lampert Ranch, up to $3,411 in electrical costs alone was saved through irrigating a slightly smaller irrigated area during July/August and utilizing a 25HP pump for the majority of the irrigation year versus a 75HP pump. In addition, some acres that benefit from high water tables where alfalfa roots are able to access that supply may see little to no economic impact from a split-season leasing arrangement, while still demonstrating a water and power savings.

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 2015 and 2016, the Dry Cottonwood Ranch also experimented with a cover crop to improve soil health and less irrigation water was required in this north field than typically required as well. In summary, split-season leasing on certain acres appears to be a generally positive and economically beneficial arrangement for the participating ranches. Further research might 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.

Economic Analysis

 

Dry Cottonwood Ranch– The Dry Cottonwood Ranch received partial grant funding towards the installation of a more efficient irrigation system. This system has allowed 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 were 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.

Due to variable irrigation water supplies to the corner of the fields, a split season lease arrangement with Dry Cottonwood Ranch only occurred in 2014 and 2016. In addition, the acres under the newly installed pivots were undergoing a cover crop experiment to improve soil health and a split season lease arrangement was not possible. No funding was requested or disbursed, although soil moisture was tracked in the irrigated fields using the NRCS checkbook approach and plant health was observed in the non-irrigated corners.

In 2016, 1.43 tons were harvested from the flood irrigated corners on Dry Cottonwood Ranch during first cutting. That corner was not irrigated past July 1, 2016 and second cutting yields were approximately 1.06 tons per acres, which demonstrates of yield loss 0.81 tons/per acre from the split season lease in 2016. Cover crops were maintained under two of the three pivots in 2016 in an attempt to improve soil health. The decision to put these irrigated fields into cover crops reduced the total harvested yield by 148 tons, costing the ranch approximately $15,000 in replacement hay.

Lampert Ranch– The compensation for the split water lease in 2013 and 2014 was through the Columbia Basin Water Transactions Program (CBWTP) and by the SARE grant in 2015 and 2016. The 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. The 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 for 2013 and 2014. In 2015, the same price of $76 per acre was utilized, however only 6.6 acres participated in a split season water lease at a cost of $501.60. In 2015, 37.4 acres participated in the split season lease at the $76 per acre rate for a total of $2,842. The reason for the reduced acreage was due to budget limitations and landowner interest.

Power usage was also analyzed on the Lampert Ranch between 2012 and 2016 (refer to table below). The total Kilowatt Hours (KWH) used per year are much lower (31,072 KWH) in years where more acres were in split-season lease (2013, 2014, 2016) and the Lampert Ranch was able to irrigate in July/August with a 25HP pump versus a 75 HP pump. According to NW Energy company’s 2017 rate for commercial customer of $0.109779/KWH, a saving of 31,072 KWH equates to $3,411 per year in cost savings when 58 acres are in split-season lease. Lampert Ranch Power Usage by Month and Year:

 

2012

2013

2014

2015

2016

June

231

7,022

10,086

13,280

1,666

July

28,150

27,179

28,491

31,710

16,266

August

21,444

9,729

13,422

20,394

18,969

September

14,452

7,051

5,582

19,832

16,591

October

12,775

3,222

764

59

2,581

Total (KWH)

77,052

54,203

58,345

85,275

56,073

Acres in Split-Season Lease

0

58.0

58.0

6.6

37.4

2 Bar Ranch– The compensation for the 2 Bar Ranch for not irrigating past July 1, 2015 was $150 for approximately 1 acre of 4 year old alfalfa irrigated via hand lines. The rate of compensation was calculated at a slightly higher level than other properties (on a per acre basis) based on a higher projected loss in yield and minimal power savings. The actual loss in yield was .8 tons per acre from second cutting. Although there is not a significant power savings by not irrigating this 1 acre of hand lines that is part of a much larger irrigation system served by a single pump, there is likely a labor savings from not having to move pipe for handlines.

Farmer Adoption

Because of this research we do have some on the ground data to prove that partial season irrigation can be a beneficial tool to decreasing labor and pumping costs while diversifying income from leased water. Developing tools and educating the rancher that by using soil moisture monitoring tools and irrigating at key times may be more crucial to the bottom line than just simply turning the pump on and never shutting it off in a season. If ranchers can see an electrical savings with very little decrease in yields then there will be adoption. By working with the Lampert Ranch in this study and by having some on the ground proof this will give other ranchers the confidence that this will work for them as well.

Recommendations:

Areas needing additional study

Three seasons of partial season irrigation may not be enough to fully understand the ramifications of how alfalfa crops will be affected long term and how it may affect the composition of this crop. For example will grass encroachment happen faster with partial season irrigation, will weed encroachment or pests move into a field more rapidly. Additional study into the types of crops that might be best suited to forgo late season (mid-July through August) irrigation and produce yields winter feeding would be beneficial. This study only focused the impacts to irrigated alfalfa crops, which proved to be a relatively drought tolerant species. It would be helpful from a water savings and economics perspective to know if there might be crop compositions that would be better suited to forgoing July/August irrigation (and reduces risk of certain grass and weed encroachment). More participating ranches under different soil types, crops and growing conditions would help to make this study more applicable to a larger geographic area than the Deer Lodge Valley. Additional economic analysis and quantification of haying inputs (labor/fuel/equipment) on a larger number of ranches might assist in identifying more precisely the conditions where forgoing late season irrigation in exchange for a payment is most economically beneficial. This application certainly will not fit every operation or will it fit every field depending on soil types, crops and growing conditions.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.