Americas and Oceania Group - International Plant Nutrition Institute

Elevated CO 2 , therefore, can be expected to lead to higher overall N 2 O emission by 27% and 75% under low
N and high N inputs, respectively.
Results of the present research suggest that under future elevated CO 2 atmospheres there will be an increase
in crop demand for N. To meet this demand requires higher fertilizer N application rates and the greater use of
legume intercropping using locally appropriate agricultural management practices. Increases in the terrestrial
C sink may be less than expected as CO 2 -induced increase in greenhouse gas emissions will be significant as
atmospheric CO 2 rises. ANZ-04
Climate Change Will Affect Grain Quality and Micronutrient Content
Project Leader: Nimesha Fernado, The University of Melbourne Agriculture and Food Systems, Horsham, Victoria.
E-mail: n.fernando@pgrad.unimelb.edu.au
Project Cooperators: Nimesha Fernando, Saman Seneweera, Joe Panozzo, Michael Tausz, and Glenn Fitzgerald
The impact of elevated [CO 2 ] at two different sowing times over 2 years on wheat (cv. Yitpi) grain physical,
chemical, rheological quality traits under Free Air CO 2 Enrichment (FACE) was investigated. Most of the
grain physical qualities improved under elevated [CO 2 ], but protein concentration was reduced by 12%.
Similarly, most of the grain macro- and micronutrient concentrations were reduced at elevated [CO 2 ], while
total mineral uptakes of N, P, K, Ca, Mg, S, Zn, and Fe were increased. The concentration of grain phytate
was reduced at elevated [CO 2 ], but grain fructan concentration was unchanged. The rheological characteristics
of the flour were changed at elevated [CO 2 ]. The magnitudes of reduction in grain physical, chemical, and
rheological quality parameters were greatest at elevated [CO 2 ] in 2009-TOS 2 , which experienced heat stress.
These data suggest that most of the beneficial effects of elevated [CO 2 ] on grain physical quality are
counteracted by its negative impact on grain chemical and rheological quality traits suggesting a negative
impact on human health and economy of wheat product-based industries. However, net effect of unchanged
fructans and decreasing phytate concentrations should be improved bioavailability of Fe and Zn, which could
help to partially offset the negative effects of elevated [CO 2 ]. Increased nutrient uptake suggests that nutrient
management strategies are needed to develop sustainable food production under future climate.
This research was undertaken by Nimesha Fernando, PhD student with The University of Melbourne and
has been accepted for publication in the journal Food Chemistry. ANZ-05
Effect of Rate and Timing of Potassium on Three Crops
Project Leader: Ross Brennan, Western Australian Department of Agriculture and Food, Albany, Western Australia.
E-mail: ross.brennan@agric.wa.gov.au.
In a glasshouse experiment, wheat, lupin, and canola were grown on a yellow sandy earth from a field site
where the K had never been applied. The Colwell soil extractable K was 26 mg/kg, a soil test level expected
to be deficient for the growth and yields of these three crops. Several levels of K, as sulphate of potash, were
applied to give a range of K additions from deficient to an adequate supply of K for dry weight of shoots and
grain. Fertilizer K was applied at 4 growth stages from 2 to 3 leaves to booting in cereal or bud formation in
canola and lupin.
The late application was ineffective to correct severe K deficiency in wheat. To achieve about half the
maximum shoot weight at time 3, about 4.5 times more K needed to be applied. Similarly for grain yield (g/
pot), to achieve 2 g/pot about 5 times more K needed to be applied. The maximum grain yield was halved by
delaying the correction of K deficiency. For lupins, late application was also ineffective to correct severe K
deficiency but the effects were not as drastic as for wheat. For grain yield (g/pot), to achieve 2.5 g/pot about
7 times for time 3 and 15 times for time 4 more K needed to be applied. The maximum grain yield was 75%
of maximum by delaying the correction of K deficiency to application time 4. Likewise for canola, the late
application turned out to be ineffective to correct severe K deficiency. However, the effects were similar to
wheat but less drastic than for lupin. To achieve 1.0 g/pot, about 7 times more K was required at time 3 and
15 times for time 4 more K needed to be applied.
The maximum grain yield was about halved by delaying the correction of K deficiency to application time
4. Many of the lower K application rates produced no grain. So, in terms of K responsiveness, for K applied
at 2-3 leaf stage, reducing rates from 100 kg K/ha to 50 kg K/ha gave greater (about 20%) yield loss in wheat
and canola than in lupin (5% yield loss). ANZ-07
IPNI Interpretive Summaries 57