Shrub Restoration Planting Report - Buenos Aires National Wildlife Refuge

Oct. 29, 2020

Two hundred plants were installed along Cumero wash in unit 2 of the BAR project on Tuesday October 13, 2020.  Five species were planted and are listed as follows; Netleaf hackberry (Celtis retuculata), Honeysuckle (Anisacanthus thurberi), Whiteball acacia (Acacia angustissima), Whitethorn acacia, (Acacia constructa) and Lotebush (Ziziphus Obstifolia).  On planting day, each of the holes was pre watered before the plant was placed in the hole.   Once the plant was placed in the ground the soil was back filled and each plant was then watered in.  All of the plants had a tree protector placed around them.  Plants are arranged in plots of three or triads to then be irrigated using a tank and pump system.  The average water delivery for irrigation was approximately 200 gallons per visit. We estimate that three gallons were given to each plot of three plants.

On Wednesday October 14, 2020 an irrigation system was installed on site at unit 2 to deliver water to all the plants.  The main irrigation line consists of five hundred feet of three-quarter hose.  The main hose has 100 drip lines with one emitter which delivers water to groupings of three plants. This is called an irrigation circuit.   The plants were irrigated using this system on October 14 and 15th.  No water was given to the plants for the next two days on October 16 and 17th. On Sunday the 18th watering was resumed until Thursday October 22nd. On that day two watering cycles were given to the plants.  No water was applied to plants from Friday October 23rd through Sunday October 25th. On Monday October 26th daily watering was given and will continue through Thursday the 29th.  Water can be withdrawn to every other day, pending on soil moisture content. Problems were encountered with our irrigation system. One problem was found along the drip lines where they were broken off from the main line or chewed through.  Trying to make sure that equal water distribution is given to all three plants was also noted. Different emitter types are also being considered to maximize water delivery to the plants. 

Weather conditions on site were mainly consistent since the start of the plantings. The average high and low temperatures were nearly the same since October 13th, planting day. The one exception was Monday October 26th and daytime temperature stayed in upper 50’s and some rain occurred on and around near unit 2.   Nighttime temperatures on October 26th and 27th dipped below freezing. This did result in some frost damage on site mainly with the hackberry.

Soil moisture in Unit 2 seemed to vary slightly with the soil type. Three main soil types occur in unit 2.  Roughly 18 inches of each soil type retained moisture even after not being watered for a day or more.  There might be an issue where only part of the soil is maintaining moisture due to where the water is coming out from the emitter.

Plants started to show stress after 2 days.  This was most noticeable with Honeysuckle and Hackberry.   On October 15th, 9 hackberry and 17 honeysuckle were showing signs of stress or transplant shock. One-week later October 22nd the amount of stressed hackberry went up to 27 and honeysuckle went up to 23. The Whiteball acacia are doing well but some of them are disappearing all together.                     

The Whitethorn acacia has three very stressed plants and overall, the Lotebush is doing well and doesn’t not looked fatigued.   On October 26, 8 plants presumed to be dead were removed from unit 2. These consisted of 3 Whitehorn acacia, 2 Honeysuckle and 3 Hackberry.  This leaves the total number of plants not fatigued being 134 as of 10/26/20. 

Recommendations for future plantings are based on the experiences gained in unit 2. The following are listed. Prior to planting, attention to detail in watering needs is essential. Plants should all be watered in the pots before being removed.  Once the plants are in the ground the initial watering needs to be very deep. It is possible that two water tanks will be needed for planting day.  Planting days if possible, should occur on the first day of the employees work week. This will allow the plants to be watered in for an entire week after being transplanted.  This will ensure the highest survival rate.  The planting guidelines for the plots of three need to be streamlined for accuracy. The soil levels and plant depths need to be consistent for best possible results. This is true for both irrigation efficiency and plant survival.  The use of a soil moisture sensor would be advantageous for monitoring the plots.