Management techniques to maximise legume production in dryland farming

Abstract

A study was undertaken to evaluate the legume content in dryland pastures. Most dryland farmers continue to sow ryegrass/white clover pasture mixtures, but white clover fails to persist in drought conditions, leading to poor quality pastures. The objective of the study was to find out how much lucerne and subterranean clover are currently being utilised, to see which clovers are sown and the to assess the persistence of clovers, based on farmers' visual assessments of their pastures. A postal questionnaire was sent to 360 light land farmers in Canterbury and North Otago. The questionnaire focussed on pasture types, sowing rates, the use of greenfeeds, pasture management and animal carrying capacities on each property.

A total of 82 questionnaire responses were received (26%), 7 were discounted due to the small size of the properties, leaving 75 for the analysis. For the analysis of the results the respondents were stratified into those growing lucerne (n=50) and those growing pastures only (n=25). From the questionnaire respondents ten were selected for in-depth interviews, five that grew larger areas of lucerne and five that had predominately subterranean clover based pastures. The interviews and pasture assessments were conducted in October and November 2000.

The results showed that for the farms growing lucerne (66.7%) the average area is only 17% of the total farm area. The lambing percentage (survival to tailing) was 132% on lucerne farms and 117% on farms with 'no lucerne', but for the interviewed farmers growing lucerne the lambing percentage was 147%, with 124% for the no lucerne farms. The improved lambing percentage may be attributed to better ewe nutrition resulting in heavier liveweight ewes and the ability to flush ewes over mating. The predominant ewe breed was Border Corriedale (45% of the farms surveyed), Corriedale (24%) followed by Coop worth and Border Romney. The preferred sire was Polled Dorset (24%), Border Corriedales (22%) then Dorset Downs and Texels.

The white clover cover as a percentage of total pasture cover was estimated by farmers as being 21 % in young pastures, but they estimated that this declined to 13% in older pastures. Ninety seven percent of the surveyed farmers sowed white clover in their pasture mixes at an average sowing rate of 2.35kg/ha. Farmers believed that white clover persisted in their pastures for 6.2 years on average, yet they only renewed their grass/clover pastures every 9.9 years for the lucerne farmers and 12.2 years for pasture only farmers. This implies that pastures are without white clover for between one third to one half of the lifetime of the pasture. Red clover is sown by 38% of the farmers at an average of 2.35 kg/ha, but has little contribution to pastures at less than 1 % of pasture cover on average. Only 32% of farmers sowed subterranean (sub) clover in their pasture mixes despite the fact they believed it persists for 15.4 years on average (beyond their current pasture renewal date). The farm owners visually estimated the sub clover botanical cover to constitute 11 % in young and 6% in older pastures on the surveyed farms. On the interview farms, sub clover made up 41 % of the pasture cover in young and 35% in old pastures. Meanwhile on the farms with no lucerne, sub clover was estimated to comprise 22% in young and 21 % in the older pastures of the lucerne farms, when the farms were visited in mid/late spring.

The average area of winter greenfeed sown was 15 hectares (8% of farm area) for the sheep and beef farmers who did not winter graze additional stock, but 18 hectares (10%) for the sheep and beef farmers who wintered dairy cows or deer. The latter group represented 18% of all the farmers surveyed. Annual grass was the most commonly sown greenfeed type (25%), followed by turnips (18%) and then turnips and grass (14%). There was little difference in the area of greenfeed sown between lucerne and pasture only farms.