ORCID Profile
0000-0002-5691-4915
Current Organisation
Lincoln University
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Publisher: Brill | Wageningen Academic
Date: 2005
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CP08415
Abstract: A generic framework was developed and validated for predicting the water extraction and water stress responses of perennial lucerne (Medicago sativa) to improve existing crop models. Perennial forages have roots established throughout a soil profile so require a different approach to quantify water extraction patterns than annual crops. Two years of experimental data from two fields in New Zealand, each containing dryland and irrigated lucerne crops, were analysed to develop the theory of the water extraction framework. This showed that the temporal pattern of water extraction was consistent and each year commenced in the shallowest layer and progressed downward. Water extraction from each soil layer was quantified as the minimum of soil water supply and crop demand for that layer. For each soil layer, water demand was represented by transpiration demand (the product of potential evapotranspiration and crop cover) minus the sum of water extraction in overlying layers. This approach gave accurate descriptions of water extraction patterns over a range of rainfall and irrigation situations. Water supply from each soil layer (l) was quantified as the product of plant-available water and an extraction rate constant (kll). The kll of lucerne could not be calculated using the traditional curve-fitting procedure so kll was calculated by integrating the water extraction framework described above with a soil water balance and fitting kll to minimise residuals for water extraction predictions in each soil layer. This gave kll values that decreased from 0.035/day in the 0–0.2 m layer of soil to 0.01/day in the deepest layer measured (1.8–2.3 m). The water extraction framework was validated against another 3 years of dryland and irrigated lucerne data and gave accurate predictions of water extraction patterns throughout the soil profile. Water stress was quantified from actual transpiration relative to transpiration demand (T/TD). The most sensitive variable was leaf area expansion, which decreased from an optimum at T/TD = 1 to zero at T/TD = 0.2, followed by radiation-use efficiency, which decreased from an optimum at T/TD = 1 to zero at a T/TD of zero. The framework for quantifying water extraction and the techniques determined for identifying appropriate parameters to measure and characterise the framework are expected to be generally applicable to perennial forages in a wide range of environments.
Publisher: Elsevier BV
Date: 05-2007
Publisher: Springer Science and Business Media LLC
Date: 07-06-2017
DOI: 10.1007/S00572-017-0782-Z
Abstract: Fine root endophytes (FRE) are arbuscule-forming fungi presently considered as a single species-Glomus tenue in the Glomeromycota (Glomeromycotina)-but probably belong within the Mucoromycotina. Thus, FRE are the only known arbuscule-forming fungi not within the arbuscular mycorrhizal fungi (AMF Glomeromycotina) as currently understood. Phylogenetic differences between FRE and AMF could reflect ecological differences. To synthesize current ecological knowledge, we reviewed the literature on FRE and identified 108 papers that noted the presence of FRE and, in some, the colonization levels for FRE or AMF (or both). We categorized these records by geographic region, host-plant family and environment (agriculture, moderate-natural, low-temperature, high-altitude and other) and determined their influence on the percentage of root length colonized by FRE in a meta-analysis. We found that FRE are globally distributed, with many observations from Poaceae, perhaps due to grasses being widely distributed. In agricultural environments, colonization by FRE often equalled or exceeded that of AMF, particularly in Australasia. In moderate-natural and high-altitude environments, average colonization by FRE (~10%) was lower than that of AMF (~35%), whereas in low-temperature environments, colonization was similar (~20%). Several studies suggested that FRE can enhance host-plant phosphorus uptake and growth, and may be more resilient than AMF to environmental stress in some host plants. Further research is required on the functioning of FRE in relation to the environment, host plant and co-occurring AMF and, in particular, to examine whether FRE are important for plant growth in stressful environments. Targeted molecular primers are urgently needed for further research on FRE.
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.MIMET.2022.106455
Abstract: The purpose of developing this high throughput assay was to determine whether there was evidence of pH adaptation in strains of rhizobia which nodulate subterranean clover (SC) and white clover (WC), and whether this was related to the pH of the soil of origin. pH is a first-order factor influencing the niche preferences of soil microorganisms and has been convincingly shown to be a key driver of soil bacterial communities. Naturalised strains of Rhizobium spp. that are pH-adapted may have the potential to better compete and/or persist in acidic or alkaline soils compared with introduced commercial strains. Three pilot studies were conducted to design the optimised bioassay. This bioassay tested the effect of pH-amended yeast mannitol broth (seven pH values from pH 4.5-9.0), across three time points, on the in vitro growth of 299 Rhizobium strains isolated from the nodules of SC and WC. The media pH where strains demonstrated fastest growth was related to the pH of the soil that strains were isolated from. However, the correlation between media pH and soil pH was strongly influenced by the growth of strains from alkaline soils (alkaline adaptation), especially in strains isolated from SC nodules.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR06020
Abstract: Sweet corn kernel yield responds to phosphorous (P) supply, but whether the response is mediated through a general increase in crop biomass or increased partitioning to kernels is unclear. Furthermore, changes in ear quality (ear length, diameter, and unfilled tip length) may also result from changes in crop biomass or partitioning. This research quantifies the partitioning between vegetative and reproductive (including ear quality) components for field-grown sweet corn crops, with a range of total biomass yield resulting from different rates of P fertiliser. To do this, ‘Challenger’ sweet corn was sown in 2 consecutive seasons (2001–02 and 2002–03) on a low-P site (Olsen P = 6.5 μg/g) at Lincoln, Canterbury, New Zealand. Five rates of P fertiliser were applied in each season. In 2001–02, 0, 50, 100, 150, or 200 kg P/ha was applied. These were followed by an additional 0, 0, 10, 20, and 40 kg P/ha in 2002–03. This gave a fertiliser range of 0–240 kg P/ha over 2 years. The resulting range in crop biomass (9.7–16.7 t DM/ha) was conservatively partitioned to vegetative (45%), rachis and husk leaf (32%), and kernel (23%) fractions, indicating that kernel yield responses were solely related to changes in crop biomass. The number of harvestable ears increased by 0.39 ears/m2 for every 1 t DM/ha increase in crop biomass. Similarly, ear quality was related to the kernel yield per primary ear. Specifically, the unfilled tip length decreased by 3.1 mm and in idual kernel dry mass increased by 16 mg for every 10 g increase in kernel DM per ear. These results show that P fertiliser should be applied at optimum rates (in these experiments ≥100 kg P/ha) to maximise sweet corn crop biomass, which in turn will lead to maximum kernel yield and ear quality. The conservative partitioning of crop biomass suggests that other agronomic factors that increase total biomass production are likely to have a similar effect on crop yields.
Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/AR01182
Abstract: The timing of flowering in canola (Brassica napus) is an important determinant of adaptation to its environment. Cultivars of canola varying in maturity are grown over a wide range of photoperiod and temperature conditions in Australia. A quantitative understanding of the genotypic and environmental control of time to flowering can be used to improve breeding programs and crop management strategies. Controlled environment and field studies were used to determine the responses of 21 cultivars of canola and breeding lines of Indian mustard to vernalisation, temperature, and photoperiod. The number of days to flowering in all genotypes was reduced in response to vernalisation and long days, due to a reduced duration between sowing and buds visible. The vernalisation response was saturated with c. 25 days at 3°C. Base and optimum temperatures for development were confirmed at 0 and 20°C, respectively. The photoperiod response occurred between 10.8 and 16.3 h, and plants responded to photoperiod from emergence. A simulation model incorporating these effects was developed, which predicted days to flowering with a mean deviation of c. 5 days. Later flowering genotypes had model parameters that indicated greater responses to vernalisation and photoperiod than early-flowering genotypes.
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 06-2011
Publisher: Elsevier BV
Date: 08-2008
Publisher: Elsevier BV
Date: 08-2008
Publisher: Oxford University Press (OUP)
Date: 15-03-2021
DOI: 10.1111/JAM.15050
Publisher: Elsevier BV
Date: 02-2020
No related grants have been discovered for Derrick Moot.