Irrigation Management Strategies for Fodder Beet (\u3ci\u3eBeta vulgaris\u3c/i\u3e L.) Crops

The production of fodder beet (Beta vulgaris L.) in New Zealand is concentrated in the South Island, and often requires irrigation to achieve high yields. Development of efficient irrigation management strategies requires information on the effect of timing and rate of irrigation on crop growth. A field study was conducted on a moderately deep soil at Chertsey, Canterbury, New Zealand, to evaluate crop growth responses to five irrigation managements: Rain-fed (control), weekly replacement of full evapotranspiration (FullET-weekly), and 50% of evapotranspiration replaced weekly (HalfET-weekly), fortnightly (HalfET-2weekly) or 3-weekly (HalfET-3weekly). Irrigation to replace ET was adjusted to account for rainfall received between irrigation events. The crop was sown on 11 October 2015. Dry matter (DM) and green leaf area index (LAI) were quantified at 4-weekly intervals from 21 December 2015 until 16 May 2016. Water use efficiency (WUE) was calculated from weekly time domain reflectometry and neutron probe measurements of volumetric soil water content (to 0.8 m depth) and crop biomass. Final yield was lowest for Rain-fed (17.1 t DM/ha) and highest for FullET-weekly (28.9 t DM/ha) treatments. The remaining treatments did not differ in yield, producing 22.4±1.6 t DM/ha, but differed significantly from the Rain-fed and FullET-weekly treatments. Yield differences were associated with the rate of leaf area expansion and duration of critical LAI values (≥ 3.0 m2/m2), which were greater for FullET-weekly than for other treatments. Rain-fed and FullET-weekly treatments resulted in the highest and lowest WUE (81 versus 47 kg DM/ha/mm). The remaining treatments did not differ in WUE, averaging 67±3.6 kg DM/ha/mm. Our results show yield benefits from irrigation, with the best outcome from FullET-weekly given the soil type and weather conditions. However, under water restriction conditions, the HalfET-3weekly management is recommended over more frequent partial ET replacements because it would reduce irrigation costs without penalising yield

Evaluation of profitability and future potential for low emission productive uses of land that is currently used for livestock: SLMACC Project 405422

Agriculture accounts for 48% of New Zealand’s gross greenhouse gas (GHG) emissions with nearly 75% of the emissions coming from methane (CH₄) production from ruminant animals (enteric-CH₄) (Ministry for the Environment 2020). Changes to alternative low biogenic greenhouse gas emission (BGE) land uses is an option for reducing national GHG and meeting national reduction targets for overall GHG and CH₄. However, large land use change will have implications for New Zealand’s economy. To address this, replacing profitable livestock with alternative profitable land uses would potentially overcome this concern. This report describes work conducted in the Ministry for Primary Industries (MPI) Sustainable Land Management and Climate Change (SLMACC) Project 405422 - Evaluation of profitability and future potential for low emission productive uses of land that is currently used for livestock. The aim of the project was to evaluate potential agricultural land uses (including crop and forest options) that could provide an alternative to livestock production based on market growth opportunities, GHG footprints and suitability for current climate and soil conditions. Our approach was to produce a framework whereby we could consider the trade-offs between BGE and profitability. Firstly, we identified potential high value crops that could increase their production areas based on an assessment of market opportunities. Secondly, we assessed their growing requirements and identified where they might grow throughout New Zealand. Then, for each crop we estimated potential BGE and ranges in profitability; we also considered the role of forestry in emission reductions and as a profitable land use. Finally, we considered CH₄ emissions reduction scenarios where these alternative land uses might replace livestock. Through the various stages of the work we ground-truthed our findings with stakeholders and industry experts