Soil conservation waterways – plants for stabilisation
Waterways are used to collect runoff from contour banks in cropped paddocks and to convey the runoff to a Planting waterways drainage line or creek. Plants protect the channel from Recently constructed waterways with no cover are most erosion by reducing flow velocities by providing cover vulnerable to erosion during the wettest months from and by binding the soil together. The plants also assist in December to March. Depending on seasonal conditions, filtering sediments, nutrients and pesticides out of runoff. it could take two to three years before there is sufficient This fact sheet provides guidelines on selecting and cover to provide a stable waterway that is ready to accept establishing plants for waterways in soil conservation runoff from contour banks. layouts. Such plants would also have an application for Most grass species have small seeds that may lead to use in dams by washes, gully control measures, and germination difficulties on the cracking clay soils that are corridors used for roads, railway lines, pipes and power common in many Queensland cropping lands. Moist lines. It should be read in conjunction with the fact sheets seedbed conditions, coupled with cloudy and showery listed under Further information. conditions give the best results for establishment. Planting in hot, dry conditions should be avoided. Species As the area occupied by a waterway is relatively small The plants listed in Table 1 could be considered for a the best quality seed should be used with planting rates range of stabilisation projects. They are mostly exotic two or three times the recommended rates for pastures. grasses that are commonly grown in agricultural areas. The use of a general fertiliser containing the required Local advice should be obtained to determine the most plant nutrients is recommended. Some species require suitable species or cultivar for a particular situation. planting by runners or sods. If available, irrigation will Issues to consider when selecting a species include: speed up the rate of establishment • a sod–forming grass that has runners (stolons) or A crop such as millet (summer) or oats (winter) can be rhizomes and a dense root system offers the best planted in a waterway to provide rapid erosion protection. erosion protection A waterway grass can be planted at the same time or into the crop stubble after it has been slashed. Light sowing • availability and viability of seed rates should be used for the cover crop to provide good • speed of establishment cover without providing too much competition for light, water and nutrients for the emerging waterway grasses. • plants with non–viable seed are planted vegetatively Irrigation would speed up plant establishment. • tall plants retard flows and require regular slashing Further information • climate and soil type For more information refer to the department's website • tolerance to drought, frost, salinity and shade
Table 1: Species to consider for use in soil conservation waterways and other stabilisation projects in Queensland cropping areas
Seek local advice before choosing a species (or one of its cultivars) for a specific situation.
Location
Species Comment Soils Darling Downs Western Downs South East Qld Central Hgls. North Qld Stolons/ rhizomes rhizomes Stolons/ African star grass CL Planted vegetatively. Has not survived dry conditions in the Central 3 3 3 3 3 Cynodon nlemfuensis to C Highlands. Weed potential where rainfall >850 mm. L to Also called Floren bluegrass Has no stolons but provides reasonable Angleton grass 3 3 3 3 3 2 Dicanthium aristatum C ground cover. Especially suited to heavy clays. Fine leaved, creeping grass commonly used in lawns. Browns off in Blue couch S to 3 3 3 drought but responds quickly to rainfall. OK for sandy, low fertility Digitaria didactyla L soils. Buffalo grass SL Many varieties including Sir Walter. Also called soft leaved buffalo Stenotaphrum 3 3 to 3 grass. A common lawn species. Planted vegetatively. Tolerates secundatum LC shade. L to Tolerates drought and low fertility. Hatch variety prefers clays. Bissett Creeping bluegrass 3 3 3 3 3 3 Bothriochloa insculpta C variety prefers clay loams and its runners root better than Hatch. Green couch S to 3 3 3 3 A low growing species used in lawns, salt tolerant. Cynodon dactylon C Humidicola S to Also called Koronivia grass or Tully grass. A vigorous creeping grass 3 3 Brachiaria humidicola C for high rainfall. Tolerant of waterlogging, salinity and very acid soils. The main recommendation for soil conservation waterways in Indian bluegrass SL 3 3 3 cracking clay soils in the Central Highlands. Can be slow to Bothriochloa pertusa to C establish. Planted by runners or seed. Dense creeping grass in high fertility Kikuyu L to 3 3 3 3 soils in subtropical areas or tablelands Prefers annual rainfall Pennisetum clandestinum C >750 mm. Makarikari grass Also called Bambatsi panic grass. . Deep fibrous root system, best 3 3 3 3 C 2 Panicum coloratum suited to heavy clays. Drought resistant. Requires regular slashing. Narrow leaved carpet Previously known as Axonopus affinis. Also referred to as mat grass. S to 3 3 3 grass LC Planted vegetatively. Common in low fertility, run-down dairy Axonopus fissifolius pastures in South Queensland. Pangola grass SL, Planted vegetatively, suitable for light textured soils. May need 3 3 3 Digitaria decumbens irrigation to get established. Paspalum S to Lacks stolons and requires regular slashing. Suitable for wetter 3 3 2 Paspalum dilatatum C conditions but has some drought tolerance. Prefers high fertility. Pinto peanut S to Used as a ground cover in frost free areas but would have suitability 3 3 3 Arachis pintoi L for waterways in higher rainfall areas. Requires an innoculant. Premier Digit Grass S to A tufted species, suitable for poorer, light textured soil types, cold 3 3 3 3 2 Digitaria eriantha CL tolerant, slow establishment, very persistent. C to A native species. Has no runners but provides good cover. Often Queensland Blue Grass 3 3 3 3 3 2 Dicanthium sericium HC colonises a waterway after other species no longer persist. L to Has a number of cultivars. Often used in waterways on brigalow soils Rhodes grass 3 3 3 3 3 3 Chloris gayana C on the Western Downs. Does well on sodic soils in the south east. Provides a dense cover. Grows in a wide range of soils in higher Signal grass S to 3 3 rainfall areas but is susceptible to waterlogging. Responds to good Brachiara decumbens C fertility. Strickland grass S to Also called Tall Finger grass or Jarra digit grass. Suitable for poorer, 3 3 3 3 Digitaria milanjiana CL light textured soil types. May require irrigation in North Qld. Sweet smother grass S to Also called Durban grass. Planted vegetatively. Suitable for shady 3 3 3 Dactyloctenium australe L conditions. Used as a ground cover in orchards and in lawns. Water couch L to 3 3 3 High salt tolerance, suitable for poorly drained waterways. Paspalum distichum C Zoysias L to Used in lawns. Slow to establish (the variety Empire is the fastest) 3 3 Zoysia japonica C but provides good cover, shade tolerant Soil abbreviations: S=sand; L=loam; SL=sandy loam, CL=clay loam, C=clay: HC=heavy clay
2