Landcare - Umuwa Project 3

The direct seeding projects undertaken by the Pitjantjatjara Council Land Management Unit in the fringe areas around communities and homelands have involved planting seeds of grasses, herbs, trees and shrubs. It has not been possible to plant trees and shrubs from bag stock without providing some kind of irrigation to establish them.

During the winter of 1994, another Landcare group in Central Australia in conjunction with the Conservation Commission of the Northern Territory (CCNT), conducted some trials establishing trees and shrubs around cattle watering points using a new technique for providing water to plants while they were being established. The trials were conducted through the winter months and were very successful.

The new technique involved using a compound called AQUAGEL to supply water to the plant during its establishment. Aquagel is a slow release water gel which provides a constant supply of water to the plant for about ten weeks. It is supplied in one litre cartons which are similar to milk cartons. Aquagel is a biodegradable, non-toxic food material which holds a large quantity of water which it releases slowly when placed next to the root ball of a tree or shrub.

In September 94 the Pitjantjatjara Council Land Management Unit conducted two trials using Aquagel. One trial was establishing umbrella bush (acacia ligulata) and witchetty bush (a. kempeana) at Site 1 next to Umuwa and the other was establishing old man saltbush (Atriplex nummularia) at Site 3 in the Ernabella creek floodout area.

The following pictures demonstrate the results:

Picture 1. A spiral was ploughed at site 3 and the 19 old man saltbush plants were planted six metres apart (Sept. 94).

Picture 2. The plant was placed in the hole which had been filled with ten litres of water. Dry soil was then back filled into the water around the root ball of the plant (Sept. 94).

Picture 3. About 20 cm. out from the base of the plant a hole was dug in the soft soil on an angle to the bottom of the root ball of the plant. The bottom of the one litre carton of Aquagel was removed and the gel can be seen in the photograph (Sept. 94).

Picture 4. The gel was contained in the carton with the right hand while the carton was placed in the hole, allowing the gel to make contact with the root ball (Sept. 94).

Picture 5. The hole containing the carton of gel was back filled with soil. The top of the carton was covered with 25 mm of damp soil so birds couldn't peck it open and eat the gel (Sept. 94).

Picture 6. Each plant then received a further ten litres of water and then another ten litres the next day. Tree guards were installed to protect the plants from birds and animals (Sept. 94).

Picture 7. View of old man saltbush plants ten weeks after planting (Nov. 94). At this time the plants had received no rain. The only water the plants had received in the first ten weeks of establishment was the 30 litres when they were planted and that from the Aquagel. During weeks eleven and twelve, the plants were given another 70 litres of water. The old Aquagel carton was removed and a new one buried in the same hole.

Picture 8. View of the old man saltbush plants 27 weeks after planting (March 95). The soil had consolidated which was from rainfall during the new year period. No further irrigation or Aquagel treatments were given to the plants.

Picture 9. View of old man saltbush plants sixteen months after planting (Jan. 96). Galahs and donkeys kept the plants pruned within the tree guards.

Picture 10. General view of the spiral on which 18 old man saltbush plants have survived (Jan. 96).

This trial was very encouraging especially as it was conducted through the summer months under arid conditions. The total treatment the plants received was 100 litres of water (ten buckets) and two by one litre cartons of Aquagel (effective for 20 weeks). It was not possible to record rainfall figures, however no rain was received in the first ten weeks. The condition of the plants after sixteen months suggests that the rainfall received in that period was sufficient. Similar results were obtained at Site 1 next to the Umuwa Resource Centre.