2 results for Abrahamson, Mike

  • Tussock country management: principles and practice

    Abrahamson, Mike

    Book
    Lincoln University

    This study is a distillation of farmer opinions and practices collected on visits to 91 South Island hill and high country farmers and of the research work and theory related to the management of the tussock country and values of tussocks. The study initially measured sheep and cattle stocking loads on hill and high country runs. Grazing management records were made for some of the high and hill country farms visited. However, there were difficulties in recording stock movements for some properties as the frequency of shifts and uses of each block were often not available. Only those runs where stock movements were easy to record had complete grazing records. The sample of farms with good records was thus mainly high country stations of limited subdivision, and only represented one situation. A list of the runs and some of their characteristics are shown in the appendix. The properties cannot be identified in this table because of the need for confidentiality. The study is in two main parts: the first section is concerned with tussock country management and is divided into topics that appeared to be of concern in tussock country stocked with beef cattle and sheep; the second section is on the value of tussocks in the tussock grasslands as indicated by runholders in the hill and high country and by a review of the relevant literature.

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  • Phosphorus requirements and use for pastoral agriculture in New Zealand

    Abrahamson, Mike; Darkey, C.

    Book
    Lincoln University

    Pasture phosphorus requirements to replace on farm losses through animals and soil were calculated for a range of soil sets, and summarised for major soil groups economic farm classes and provinces. Predicted responses to P fertiliser on South Island "unimproved" soils were similar for 33 major soil groups out of 401Five further groups were almost similar in response. Olsen P data collected recently were similar to an earlier set (1977-79), and corresponded to relative pasture yields of top farmers within each group of soils. There were differences between the MWD estimates of stocking rates and census data of 578,000 stock units for the South Island and 100,000 for the North Island with however more variability between provincial totals (average of 1,031,000 +- 600,000 for the North Island and 519,000 +- 400,000 for the South Island). For the South Island, if Olsen P levels were below 10.2 for low producing pastures and 11.0 for high producing pastures, more P was needed for first year maintenance than for long-term at average farmer stocking rates. At top farmer stocking rates below an Olsen P of 12.4 more P was needed in the first year than for long-term on low producing pastures, while on soils with high producing pastures only one major soil group needed more P in the first year than for long-term. At potential farmer stocking rates all major soil groups with high producing pastures needed more P in the first year than for long-term maintenance, while all soils with high producing pastures with an Olsen P < 19.5 needed more P in the first year. Less P is needed for first year maintenance than for long-term at average and top farmer stocking rates for almost all the economic farm classes of the South Island. Unimproved soils of the North Island appear to be low in Olsen P and there are only two major soil groups where less P is needed for the first year than for long-term at average and top farmer stocking rates Olsen P levels of improved soils in the North Island were not available. Olsen P levels of "unimproved" soils in the South Island were correlated with P retention levels, demonstrating an important relationship (effect) of P retention on their P status. Pasture utilisation (and relative yields) for North Island low and high producing grasslands were similar, but there were lower levels on low producing than on high producing pastures for the South Island. Although efficiency of P use (kgP/s.u.) decreases rapidly at relative yields approaching the potential farmer stocking rates, on some soils, e.g. South Island high country yellow grey earths, efficiency of P use is better than for some North Island soils at average farmer stocking rates where soil P losses are high.

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