Department of Agricultural Sciences

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The Department of Agricultural Sciences consists of animal science, plant science and farm management and agribusiness staff members.

The range of research conducted is quite extensive including: conversion of forests into pasture, alternative dryland pasture species, grain legume agronomy, sustainability in farming systems, nitrogen fixation and nitrogen cycling, shelter on dairy farms, economic viability of NZ farming systems, animal nutrition, immunology etc.

Recent Submissions

Now showing 1 - 5 of 1872
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    In sacco digestion kinetics of plantain and ryegrass-white clover harvested in the morning and afternoon
    (New Zealand Society of Animal Production (Inc), 2018-07) Box, L; Edwards, GR; Bryant, Racheal
    The objective of this experiment was to compare rumen degradation characteristics of ryegrass (Lolium perenne), white clover (Trifolium repens) or plantain (Plantago lanceolata) harvested either in the morning (0700) or afternoon (1600). Fresh herbage material from each treatment was weighed into duplicate nylon bags and incubated in four lactating Jersey × Friesian dairy cows with rumen fistula. Differences in nutritive value between forage types was greater than effect of harvest time as was the effect on rumen degradation characteristics. Plantain had faster (P<0.001) DM disappearance rates than perennial ryegrass-white clover (12.2 vs 8.80 %/hr). The soluble fraction was greater (P=0.001) for forages harvested in the afternoon (25.2% of DM) than those in the morning (15.4% of DM) regardless of forage type. Nitrogen degradation was almost complete (>95% of N) and similar for all treatments (P>0.05). An interaction for effective degradability revealed there was no effect of harvest time on DM and OM for plantain. However, perennial ryegrass-white clover harvested in the afternoon has a greater effective degradability of DM and OM than that harvested in the morning. This suggested there is a larger influence of harvest time on some degradation characteristics of perennial ryegrass-white clover compared with plantain.
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    Understanding the growth and development of maize (Zea mays L.) : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
    (Lincoln University, 2024) Mwayawa, Annette
    A main constraint to maize production in New Zealand is yield variability due to the low rainfall supply and also the erratic distribution of rain in the summer which consequently affects crop N uptake and utilization. The aim of this study was to understand the influence of N and water on canopy development, crop growth, phenological development and yield formation. Crops with different yield potentials were created using different levels of N and water availability. Two experiments were carried out, marking the growing season, Experiment 1 in 2015/16 and Experiment 2 in 2016/17. The two experiments were carried out at two different locations at Lincoln University, Canterbury, New Zealand. Experiment 1 was arranged in a split-plot design with four nitrogen (N) levels under different water regimes. The N levels were N1- nil, N2 -75 kg N/ha, N3 – 150 kg N/ha and N4 – 300 kg N/ha, and water levels at Irr1- Irr4 as defined by the accumulated potential soil moisture deficit as 443 (rainfed), 367, 301 and 226 mm, respectively. These created grain yields that were not different in all the treatments which averaged 12.4 t/ha and only varied in total dry matter (DM) accumulated. To create more distinct differences in grain yield, this experiment was repeated at another location with a higher dose of N. Experiment 2 used two levels of water and N in a randomised block design. The treatments were for N1 –nil N and N2 - 500 kg N/ha, rainfed and irrigation (accumulated potential soil moisture deficit at 536 and 296 mm respectively). In Experiment 1, grain yield was not different across the crops and average 12.4 t/ha. The total DM was 19.1 t/ha for the rainfed crop (Irr1) and averaged 22.4 t/ha for the irrigated crops. Grain yield and total DM as explained by intercepted photosynthetic radiation (iPAR) accumulated to 570 MJ/m2 for Irr1 and was higher at 1082 MJ/m2 for Irr2. All crops GAI reached a maximum at 3.7 m2/m2 at a rate of 0.01 m2/m2/°Cd in the duration of 677 °Cd which justified the similarities in grain yield. After the linear phase, the intercepted light in Irr1 immediately reached an asymptote as the leaves withered quickly due to water stress. The radiation use efficiency (RUE) was 2.21 g/MJ for N1 and 2.49 g/MJ for N4 and mainly because of the specific leaf N (SLN). The SLN was highest at 2.1 g N/m2 for the irrigated crop with N and lower at 1.66 g N/m2 without N. The contribution of SLN to yield was reflected in total DM. In Experiment 2, grain yield increased progressively from 0.98 t/ha under rainfed to 9.0 t/ha when irrigated and further to 16.3 t/ha with N. Total DM followed a similar response with rainfed accumulating only 4.10 t/ha and 14.3 t/ha under irrigation and doubling with N, creating total DM of 28.9 t/ha. The difference in total DM was explained by the differences in the total amount of iPAR. Under rainfed the total iPAR was 448 MJ/m2 and increased to 551 MJ/m2 with N, and when irrigated was 816 MJ/m2 and further increased to 1005 MJ/m2 with N. The rate and duration changed, indicating the capacity of the crop to capture light depended on the changes in pigment protein complexes, directly linked to development of the GAI as a process of leaf development and expansion. The maximum GAI was affected by the main effects of water and N where GAI increased from 2.14 to 3.49 m2/m2 with water and from 2.48 to 3.14 m2/m2 with N application. In the contribution of RUE to grain yield, SLN was a key factor connecting leaf N concentration to DM production. The SLN was 1.23 g N/m2 at 905 °Cd in all the crops, however, dissecting the canopy into cohorts, SLN varied. The main section of the canopy that supplied assimilates directly to ear development was the mid-cohort. This cohort was affected by both water and N, increasing SLN from 1.43 to 2.39 g N/m2 with water and from 1.46 to 2.37 g N/m2 with N. The changes at cohort levels were explained by GAI as parameter relating to canopy development and the allocation of N within the leaf, and light penetration through the hierarchical canopy arrangement. The amount of water used to produce the given yield in Experiment 2 depended on crop water use which was converted to WUE. Only the crop under irrigation and N was efficiently converting water to DM at 47 kg DM/mm of water. The WUE for the rainfed crops was 17.9 kg DM/mm and did not differ from the irrigated crop without N which had a WUE of 25.7 kg DM/ha/mm. Leaf and canopy photosynthesis has led to improvements in crop DM and yield through enhanced DM partitioning. In depth understanding into elements of SLN is essential for estimation of the SLN throughout the cropping season. The future of crop improvement strategies is dependent on maximising the leaf and canopy photosynthesis and converting DM accumulation into yield benefits.
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    The formulation of pasture seed mixture from a diverse pool of six forage species : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
    (Lincoln University, 2024) Shampasivam, Arulmageswaran
    Optimising pasture yield and quality is needed to meet the global food demand. Pasture sward ecosystems that create beneficial diversity and productivity effects will contribute to this. This research used a multi-species pasture mixture experiment to identify optimal seed mixture species combinations under irrigated conditions. This reseach underpins the machanism of linking species mixed pasture properties to the beneficial diversity attributed to community responses. A large-scale diversity experiment used 69 mixtures from six pasture species to investigate the impact of different functional gropus. A simple mixture of combinations of 2 to 3 species from a grass and legume functional group were the key components. On average, mixture communities produced 16% higher biomass yield and contained 64% lower weed biomass than the average performance of the monoculture swards evaluated from 2018 to 2021. Pasture sward responses differed depending on the associated component species, and over time. The model identified several binary and ternary mixture combinations for improved biomass production, weed suppression, and maximising quality; crude protein (CP) and metablizable energy (ME). The highest contributions for herbage biomass were from binary and tertiary mixes of perennial ryegrass (PR), cocksfoot (C), white clover (WC) and red clover (RC), and plantain namely; PR*WC, PR*RC, C*RC, P*WC*RC, PR*WC*RC, PR*C*P and PR*RC*SC. Among those mixture communities, PR*WC and PR*RC maintained the greatest productivity over three years, giving an annual average herbage biomass yield of 13.6 and 15.2 t/ha, when no nitrogen fertilizer was applied. The mixture components in the ternary mixture (PR*WC*RC) produced an annual biomass yield of 15 t/ha. The mixture effect on weed suppression was strong and existed in several mixture communities even though increasing species richness continuously reduced unsown species biomass. Diversity contribution to the nutritional composition of herbage material was not beneficial, but the species' relative abundance in the mixture improved the herbage quality. The optimal mixture combination was PR*RC at the ratio of 50:50 sown seeds equivalent to 12.6 : 13.4 kg/ha (26 kg/ha) viable seed rate. This gave a mean herbage biomass yield per regrowth cycle of 1.98 t/ha (16 t/ha/yr), with a mean weed biomass of 0.13 t/ha/yr, 10.8 MJ ME/kg DM and 20.7% protein content. Further, the ternary mixture PR*WC*RC at the proportion of 45:11:44 equivalent of 11.3 : 0.8 : 11.8 kg/ha (24 kg/ha) had a mean yield per regrowth cycle of 1.97 t/ha (16 t/ha) DM, 0.8 t/ha weed yield, 10.8 MJ ME/kg DM and 20.8% protein. This ternary mixture combination at the ratio of 50:15:35 was equivalent to 12.6 : 1 : 9.4 kg/ha (23 kg/ha) and produced a mean yield of 1.95 t/ha (16 t DM/ha), 0.48 t DM/ha weed biomass, 10.1 MJ ME/ha and CP 20.2%. These higher productive mixtures were from legume and non-legume functional groups, which improved the pasture herbage biomass yield and quality compared with their monocultures. The sown species proportion of swards differed over time based on the functional species composition of the mixtures. Among the monoculture swards, grasses maintained a higher sown species proportion than legumes or plantain. On average, mixture communities suppressed the weeds, and the suppressive effect was increased with the increasing number of species in the mixture. PR*RC binary mixture maintained a higher sown botanical composition proportion over the 3 years than PR*WC. Modelled Relative Growth Rate Differences (RGRD), with the sown proportion, revealed that the equal proportion of the component species in the identified ternary mixture (PR:WC:RC) balanced the competitive growth and maintained the sown proportion until the 3rd year after establishment. This deviated from the optimal seed proportion that maximised the sward yield responses. Further, this experiment identified that the reason the sward yields differed was investigated in the third year and showed this was due to the quantity of fraction canopy light interception. Overall, species mixed pasture swards intercepted a higher fraction of canopy light (PAR). Average pre-grazing fraction light interception value of swards (2020/21) across the monocultures and two species mixture commmunities was modelled to the initial sown species component proportion. This quantified the diversity contribution of addtitonal fraction of canopy light interception. This was higher for PR*WC (0.47) than for PR*RC (0.10). The higher fraction of light interception contributed to the diversity attributed to the higher herbage biomass in PR*RC than PR*WC. The highest pre-grazing fraction of light interception and intercepted PAR energy was in summer/spring when temperature and available light levels were highest. However, the positive contribution from RC over WC appeared in autumn when the fraction of light interception from white clover may have been compromised by its shallower roots. In the third year, radiation use efficiency (RUE) of swards differed based on the functional species in the mixture community. Grasses had a lower RUE than clovers. There was a positive relationship between RUE and temperature for monocultures and binary mixtures, especially PR*WC and PR*RC. This research suggests farmers in irrigated conditions should sow a mixed pasture of 2-3 species that comprise a grass and a clover. The PR:RC mixture (50:50 = 12.6 : 13.4 Kg/ha) and PR*WC*RC in both proportion settings (45:11:44 or 50:15:35 = 11.3 : 0.8 : 11.8 kg/ha or 12.6 : 1.0 : 9.4 kg/ha) improved the pasture herbage biomass yield and quality over time compared with their monocultures. These mixtures provided diversity response that persisted and optimised biomass yield with minimal weed content and maintained the botanical composition which inturn optimised herbage quality.
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    Trial work and demonstration plots in the horticultural research area, Lincoln College
    (Lincoln College. Department of Horticulture, Landscape and Parks., 1986)
    This booklet aims to acquaint staff, visitors, and students with the experiments currently underway and the demonstration plots being used at the Horticultural Research Area, Lincoln College.
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    Potential for horticulture on the West Coast of South Island New Zealand
    (Lincoln College, Canterbury, New Zealand, 1978) Crowder, R. A.; Stevens, R. B.; Farr, D. J.
    The frame of reference for this study lies within the term potential. We have left out any reference to the term industry because this implies knowledge of economic and social aspects of an area whereas our expertise lies mainly within the agronomic aspects. 1.1. Definition of Horticulture Our interpretation of this project is to answer the question - Does the West Coast have the ability to produce horticultural crops within the framework of existing physical and climatic parameters? Horticulture is defined as the production by intensive means of fruit, vegetables, flowers and nursery stock both in the open and under protection. We have therefore two categories of production: A. Unprotected broad acre cropping, the success of which is related to the macro-environment. B. Protected often containerised production where constraints imposed by the macro-environment are minimised. Horticulture production is also very closely associated with population and it is most unusual for an area not to have some horticulture production regardless of the macroenvironment in the area. The West Coast is therefore unique in that a sizeable and isolated population is dependent almost entirely for its vegetables and fruit on "Over the Hill" supplies. The first question to answer in this report is therefore one concerning, why the West Coast does not support a local horticulture industry.