|Author:||Bhattarai, S. P. ; Huber, S. ; Midmore, D. J.|
|Book Group Author:||NA|
Inadequate oxygen concentration in the root zone is a constraint to plant performance particularly in heavy, compacted and/or saline soils. Subsurface drip irrigation (SDI) offers a means of increasing oxygen to plant roots in such soils, provided irrigation water can be hyper-aerated or oxygenated. Hydrogen peroxide (HP) at the rate of 5 litre/ha at the end of each irrigation cycle was injected through SDI tape to a field-grown marrow (Cucurbita pepo cv. Blackjack) crop on a saturated heavy clay soil in Queensland, Australia in 2000. Fruit yield, number and shoot weight increased by 25, 29 and 24%, respectively, due to HP treatment compared to the control. Two pot experiments with vegetable soyabean (Glycine max cv. C784-1-2-1) and cotton (Gossypium hirsutum cv. Sicot 289i Inguard) compared the effectiveness of HP and air injection using a Mazzei air injector (a venturi), throughout the irrigation cycle in raising crop yield in a heavy clay soil kept at saturation or just under field capacity. Fresh pod yield of soyabean increased by 82-96% in aeration treatments compared with the control. The yield increase was associated with more pods per plant and greater mean pod weight. Significantly higher aboveground biomass and light interception were evident with aeration, irrespective of soil water treatment. Similarly, cotton lint yield increased by 14-28% in aeration treatments compared with the control. The higher lint yield was associated with more squares and bolls per plant which accompanied greater aboveground biomass and an increase in root mass, root length and soil respiration. Air injection and HP effected greater water use, but also brought about an enhancement of water use efficiency for pod and lint yield, and increased leaf photosynthetic rate in both species but had no effect on transpiration rate and stomatal conductance per unit leaf area. Aeration-induced enhanced root function was arguably responsible for greater fruit set and yield in all three crops, while in vegetable soyabean greater canopy cover, radiation interception and total vegetative biomass were responsible for additional yield benefit. Increased aeration of the root zone in heavy clay soils employing either air injection or HP proved beneficial to SDI irrigated crops, irrespective of the soil water conditions, and can add value to grower investments in SDI.
|Pages:||285 - 298|
|Journal:||Annals of Applied Biology|
aeration, biomass production, canopy, clay soils, cotton,crop yield, fruit set, growth, hydrogen peroxide, interception, marrows,photosynthesis, plant water relations, respiration, roots, saline soils,soyabeans, subsurface irrigation, water use efficiency, Australia,Queensland, Cucurbita, Cucurbita pepo, Glycine (Fabaceae), Glycine max,Gossypium, Gossypium hirsutum, Cucurbitaceae, Violales, dicotyledons,angiosperms, Spermatophyta, plants, eukaryotes, Cucurbita,Papilionoideae, Fabaceae, Fabales, Glycine (Fabaceae), Malvaceae,Malvales, Gossypium, Australasia, Oceania, Developed Countries,Commonwealth of Nations, OECD Countries, Australia, carbon assimilation,carbon dioxide fixation, courgettes, crown cover, leaf canopy, soybeans,zucchini, Field Crops (FF005) (New March 2000), Plant Water Relations(FF062), Plant Production (FF100), Soil Water Management (Irrigation andDrainage) (JJ800) (Revised June 2002) [formerly Soil Water Management]