Evaluating New Windbreaks and Cover Crops for Tropical Fruit Crops

Evaluating New Windbreaks and Cover Crops for Tropical Fruit Crops

Summary

Due to deer damage on panax windbreaks and also problems accessing perennial peanut cultivars from USDA-Plant Materials Center on Molokai, the project is at least a year behind. A redirection of the grant has been proposed.

• Banana&perennialpeanut – having the banana and perennial peanut at the right age is vital for a good assessment of this cover crop.
• Banana Weeds – Weeds are a major problem in Dwarf Brazilian banana production, especially in a sustainable wide-spaced system utilized here. There are annual control costs both for herbicides and tillage over the life of the production system which can exceed 25 years.
• Home Garden at Harvest – Due to deer problems, a fencing system is being tested. This plastic 6 1/2 feet Tenax Cintoflex D fence was successful in protecting crops from this market garden. Crops included asparagus, red bulb onion, irish potato, Chinese taro, grape tomato, soybean (edamame), sweet corn, and others.
• Hgardenearly – The combination of sorghum-sudan hybrid grass as an infield windbreak and tall fences for deer control are vital to the success of farming in Hoolehua today.
• Ironwood – rubbing damage from deer horns are a major problem for woody crops such as fruit trees and windbreaks such as Ironwood Casuarina equisetifolia.
• Panax – Panax planted by cuttings 2 feet apart, and utilizing sorghum-sudan hybrid grass for wind control. This was before the deer found this. A total of 1500 feet of panax windbreaks were destroyed by deer.
• Ppha2089 – One of the Rhizoma peanut accessions, Arachis glabrata HA 2089 was growing very well and appear to be the most adapted under limited irrigation.
• Ppha2089closeup – Close-up of HA 2089. Perennial Peanut is being tested as a weed suppressant, nitrogen sources, and an erosion control measure in a banana plantation system.
• Panax Rubbings – Deer damage crops, including windbreaks in many ways, including eating, biting and pulling out plants, stomping, and rubbing by horns leading to the death of plants.
• Newbananas1 – a ½ acre banana field, planted in two increments, last year and the year before were too old to be utilized for the trial because the plants were too large once we received the perennial peanut accessions.

Objectives/Performance Targets

1) Evaluate different cultivars of panax, an upright growing tropical shrub native to Polynesia, as an alternative to Tall Erythrina Erythrina spp. This was our main windbreak that was wiped out by an invasive gall wasp. The need for infield and perimeter windbreak alternatives for the arid tropics cannot be overstated.

2) Evaluate Rhizoma Perennial Peanut Arachis glabrata as a cover crop in a sustainable banana planting system. A wide plant-spacing was employed as a long-term sustainable system with less plant competition for nutrients, water and light. Most of the banana production is Hawaii does not use cover crops and is high input and very intensive, with plant spacings of 12 feet by 12 feet. There are a very few cover crops that can be utilized in fruit crop systems for arid tropical conditions due to high temperatures, low rainfall, pest challenges and also root-borne diseases such as root-knot nematodes.

3) Share results of this work with the community. Through a field day and creation of workbooks, information can be disseminated throughout the farming community.

These are the deliverables and educational products agreed upon in the grant:

Educational Products

1) We will develop a report on the steps of setting up a banana production system utilizing windbreaks and cover crops. It will include data collected such as growth rates of the different panax, establishment times for the different cultivars, pest and disease problems, etc. This report will allow a farmer to follow the steps and set up this system. Annual reports will also be incorporated in this report.

2) We will develop a Power Point presentation on the steps in setting up a project and data of results. A visual presentation of field day and a work book will also be developed.

3) Planting material will be shared at the field day and will also be made available to USDA-PMC on an ongoing basis.

Outreach Plan

1) Field Day – to allow the community to view the trial. We will present all data and distribute a report of results, including background, materials and methods and results. We will provide refreshments and also distribute planting material to interested individuals. We will also write a newspaper article for the local newspaper on the field day with pictures.

2) Workshop – We will conduct a workshop with a Power Point presentation of our results and will also distribute results of the trial. We will provide refreshments.

3) Conference – We will present a Powerpoint on our results and will also distribute results of our trials. We will need to be invited to such conferences.

Accomplishments/Milestones

Due to the setbacks addressed below, all that we have is the perennial peanut growing in one of the banana fields. We expect to fill in the blanks and continue maintaining it until we can have a field day to show the results. Panax windbreaks will need to be reestablished in a fenced field. All the Outreach tasks will need to implemented.

Problems/Issues/Challenges

Windbreak Evaluation

About 1,500 feet of Panax windbreak was planted in the summer of 2010, using 12-16” cuttings planted two feet apart. Cuttings were planted in plastic mulch with T-tape drip irrigation line. Preplant dolomite and 10-30-10 was incorporated prior to laying mulch. A sorghum-sudan hybrid grass windbreak was planted adjacent to the panax row to protect it from wind damage. The majority of Panax planted was common Panax, Polyscias guilfoylei, but we also included eight other cultivars, collected mostly on Oahu. Due to extensive deer damage that has not subsided to date, most of the Panax was lost except for the common Panax that we have been able to salvage. A few surviving plants were removed and planted near our home and will produce sufficient cuttings to plant about 400 feet of row. Over 1,500 feet of Panax were damaged by eating, pulling cuttings out and debarking by horns, chewing and stomping on drip irrigation. To date, Panax has not been replanted due to high deer populations. However, based on our advice and also of others, the USDA Plant Materials Center has planted large quantities of panax for release to farmers as a windbreak alternative to tall Erythrina.

The overpopulation of Axis deer is the result of an ongoing drought and also the closure of a 55,000-acre ranch adjacent to the farm production area. As a result, there was a mass exodus of deer from the west and south side of the island looking for water and food, and they have converged on the farm area in the central plains. Last summer alone, deer were estimated to have caused almost $1 million in damage to row crops in Hoolehua alone, especially papaya and sweet potato.

The deer do not appear to be affecting our two main crops, banana and taro, to any large extent. However, they have started to eat newly planted taro plants because they are in proximity of young grass and broadleaf weeds, which they prefer. Their walking activities are also damaging the plastic mulch. Deer ate a 300 foot row of irish potatoes to the ground in the last month, something they did not do last summer.

Fencing for Deer Control

We needed to do something to protect our new crops, and one of the strategies to prevent deer damage has been to fence individual fields. This has been costly but essential to harvesting a crop. Taro and banana were not included in these enclosures. Two 30 feet by 170 feet fields were fenced with a 6.5 foot plastic fence called Cintoflex D manufactured by Tenax Corporation. Recycled 4 x 6 telephone support posts were positioned 60 feet apart, with smaller 3” diameter posts planted in between at 20 feet apart. Fence corners were fortified by nailing 1 x 3 laths over the fence into the posts, while the fence was attached to the smaller posts with a staple gun.
One field was utilized as a market garden with over 18 crops. The second field was planted with seven select avocado cultivars and will also be planted with a row of ti leaf and a row of indeterminate grape tomatoes on a plastic trellis in the next month. Two 175 foot rows of spring vegetables will also be planted in March to utilize the empty space between rows until avocado matures.

A 13,000 square foot fenced field will be constructed in late March, and it will include two rows of panax for the windbreak demonstration planted in plastic mulch. This field will also be planted in breadfruit, figs, processing guava, a bulb onion trial and an edamame trial. Cooperators include Glenn Marshburn of Champion Seed (onion), Mary Jo Wannamaker of Wannamaker Seeds (onion and edamame) and Ken Love of Hawaii Tropical Fruit Growers (figs).

Cover Crops – Rhizoma Perennial Peanut

In a wider system of planting employed for this project, weeds become a larger problem as compared to a closer planting. Farmers in Hawaii are forced to plant banana intensively at 12 feet by 12 feet spacing due to the high cost of land and the need to make adequate returns. Dwarf Apple or Dwarf Brazilian, our main variety, has its challenges since it yields half as much as Williams Banana, but they do not demand twice the price. We have tested a spacing 15 X 15 feet and were able to harvest for 25 years. In a closer planting, we would have to abandon the field before it reaches 20 years.

No farmers will utilize a 20 X 20 foot or 20 x 15 foot planting system, but with our long land tenure (100 years @ $1 per year), it makes sense to create a more sustainable system of farming. For one, plants do not require as much fertilizer since they do not compete with each other as much. This is a less stressful system to grow bananas. A major benefit is the larger bunches and larger individual bananas which give us market priority, and they will buy our bananas before the competition. The other benefit is we should be able to harvest these fields for over 30 years. The perennial peanut will provide nitrogen after it matures and stabilizes, but it may require increased phosphorus to the system. The keys to this system are less herbicides, a symbiosis, maintained soil moisture, and minimal soil loss through wind and water erosion.

To prepare for the planting of Rhizoma perennial peanut in banana, a ¾ acre plot of banana was planted; a ½ acre plot was planted over a year ago and a ¼ acre plot this past summer. The planting of these fields were required for the project but not part of the funding. The ½ acre banana field appears to be too mature to fairly evaluate the interaction between the cover crop and the banana due to its large canopies shading the perennial peanut. On the other hand, the ¼ banana plot is ideal and at the right maturity to fairly evaluate the perennial peanut in the banana system we have established.

We have focused on Rhizoma peanut Arachis glabrata, but we have also included one A. villosa and two A. pintoi cultivars for comparison. Although more difficult to establish due to lack of seed and runners and that it can only by propagated by rhizomes, Arachis glabrata was targeted due to its drought tolerance and ‘wild characteristics’ that would help them survive the hot and dry summer conditions as compared to A. pintoi. Also, little is known about their growth in Hawaii since they are more difficult to propagate, and few farms utilize them. A pintoi is more commonly used in higher rainfall areas of the state, such as Hamakua Coast on the Big Island. However, it will not survive under arid, high temperature conditions without constant irrigation.

According to literature, some A. glabrata cultivars are more shade tolerant than others, and hopefully this variable will manifest itself in the test planting. It was also decided that instead of utilizing pop-up sprinklers to irrigate both banana and perennial peanut, as was called for in the proposal, that drip irrigation would be used for the perennial peanut and also microsprinklers for the banana, with some coverage to the perennial peanut. The reason for the modification includes the need to conserve water, and the cost of the pop-up sprinklers plus installation, which would be more costly to establish. The second reason was that the drip irrigation allowed for better weed control of the perennial peanut, so this part of the proposal was modified. This modification will be easier to transfer to other farmers due to cost and ease of installation.

A problem we encountered was the lack of availability of perennial peanut cultivars from USDA-Plant Materials Center (PMC) due to drought. A mandatory cutback on water use was imposed every summer for several years now. As a result, the plants at the center were irrigated at a minimum just to keep them alive, which did not allow for growth or enough material to share for field evaluations. In late September 2011, planting material was made available to this project. In light of the time and resources lost on the project, and the need to meet the obligations of this project, it was decided to evaluate ten (10) cultivars instead of four (4) cultivars proposed in the grant. All except three newly planted accessions at PMC were made available.

Ten perennial peanut accessions were planted by rhizomes and runners over a one week period; 7 A. glabrata, 2 A. pintoi and 1 A. villosa. The ten (10) cultivars were planted in four 150 foot rows in an unduplicated planting. Accessions include A. villosa HA2104, A. pintoi cv. Amarillo, A. glabrata cv. Brooksville 68, A. glabrata cv. Arb peanut HA2088, A. glabrata HA2092, A. glabrata HA2089, A. glabrata HA3370, A. pintoi cv. Forrajero, A. glabrata, cv. Arblick, and A. glabrata, cv. Ecoturf. Two accessions not available because they were newly planted with insufficient material included A. glabrata accessions Florigraze and Arbrook.

The time of planting imposed on us by the availability of perennial peanut was not the best time of year for planting due to short days, cold overcast weather and rains effecting stand establishment and weed control. Sure enough, rains in November and December caused a major weed explosion. Plans had to be modified to address this problem. The original plan was to plant perennial peanut in late spring, around May when the threat of rain had passed. This would keep the weeds in check. The first step in planting would be to utilize a sterile bed technique to germinate weeds and kill them by flaming or herbicide. Instead, four (4) furrows were made in a rush, and lines were limed and planted. As a result, weeds were a major challenge.

There are no tried and tested technique to propagate A. glabrata since few farmers are growing them, so this will need to be refined. A. pintoi is more commonly used and is planted by stolons or runners, whereas A. glabrata is planted by rhizomes. The technique we decided to use in planting glabrata was to cut mats in 2-3” wide strips laid tip-to-tip in the furrow. This was a laborious chore as some accessions were easy to cut while others were more wiry or woody. Planting material was then lightly covered with dirt. Drip irrigation was laid and triggered the weeds, which were so thick that no perennial peanut could be seen except for the pintoi stolons used as planting material.

The sudden weeds forced us to think-on-our-feet and employ control strategies very quickly, so Gramaxone or Paraquot was sprayed two weeks apart and gave excellent results in killing both grasses and broadleaves with little, if any impact on the perennial peanut.

Another problem we encountered were constant high winds in the 35-50 mph range in the first two months after planting, filling the furrow with dirt. This is believed to have affected growth as planting material were now too deep. Relatively cold weather followed, which slowed establishment even further.

Then the rains came. As a result, the weeds were two feet high and the perennial peanut could not be seen. This may have been a blessing in disguise, because the deer came in and ate the tips of weeds but did not touch the perennial peanut. My guess was that Perennial Peanut was not their food of choice, but this will need to be determined. Round-up was sprayed as close to the plant rows as possible to knock back weeds without touching the Perennial Peanut. This was followed by hand-weeding next to the plants in the drip irrigation row. Plants appear to have taken root and are in good condition, but some areas are not as thick as others. Flats will be grown and made into plugs to fill in blank spots. Preliminary observations show marked differences. For example, A. glabrata HA 2089 is well established and dark green, while A. pintoi Forrajero appears to be lighter green, with young leaves appearing chlorotic.

Due to the challenges faced above, a request for modification has been proposed.

ADDENDUM
List of Arachis spp. Accessions
from USDA Plant Materials Center, Molokai, HI.
Received September 20-29, 2011

1. A. villosa, HA2104, Acc # 9079870
2. A. pintoi, Cv. Amarillo, HA4762, Acc # 90799796
3. A. glabrata, Cv. Brooksville 68, HA2090, Acc # 9079873
4. A. glabrata, Cv. Arb peanut, HA2088, Acc # 9079877
5. A. glabrata, Cv. Brooksville 67, HA2092, Acc # 9079872
6. A. glabrata, Cv. , HA2089, Acc # 9079875
7. A. glabrata, Cv. , HA3370, Acc # 9079864
8. A. pintoi, Cv. Forrajero, HA5838, Acc # 9079808
9. A. glabrata, Cv. Arblick – New Accession May 2101
10. A. glabrata, Cv. Ecoturf – New Accession May 2010

Impacts and Contributions/Outcomes

There are no impacts to date. The perennial peanut cultivars have been planted in a banana field, but deer continued to plague other aspects of this project. Because of this, we are requesting to modify the project.

Collaborators: