Effect of grazing management and season on nitrogen and phosphorus content of leaves and stolons of white clover in mixed swards

Abstract

To cite this article: M. J. M. Hay , P. Nes & M. R. Robertson (1985) Effect of grazing management and season on nitrogen and phosphorus content of leaves and stolons of white clover in mixed swards, New Zealand Journal of Experimental Agriculture, 13:3, 209-214, DOI: 10.1080/03015521.1985 The nitrogen (N) and phosphorus (P) contents of leaf, surface stolon, and buried stolon of white clover (Trifolium repens L.) were measured in samples taken every 2 months, from pasture under rotational grazing by cattle (RGC) and set stocking by sheep (SSS), for 3 years. The effect of the system of grazing management of sheep on Nand P content of 3 herbage classes of white clover was examined during a I-year period by analysing samples taken monthly from pastures with 3 different management backgrounds; set stocked (SS), rotationally grazed (RS) or set stocked from lambing to drafting, then rotationally grazed for the rest of the year (CS). In the 3-year study, the content of N did not differ between the RGC and SSS treatments but the mean values of 4.59% in leaf, 2.75% in surface stolon, and 2.22% in buried stolon all differed. However, P contents differed between treatments: with RGC treatment, mean P levels decreased (0.43, 0.29, and 0.23% for leaf, surface stolon, and buried stolon respectively) whereas, with SSS treatment, contents in each of the respective herbage classes were higher and differences among the herbage classes were much smaller, the only significant difference occurring with buried stolon (0.51,0.51, and 0.47% for leaf, surface stolon, and buried stolon respectively). The system of sheep grazing management affected both Nand P contents in the same manner, with contents decreasing in the order SS > CS > RS. Again, there was a marked decrease in mean N content of the herbage classes in the order leaf (4.35%), surface stolon (2.97%), and buried stolon (2.11%), whereas the mean P contents of the herbage classes differed Received 21 March 1985. revision 10 May 1985 much less, with buried stolon (0.43%) being lower than leaf and surface stolon (both 0.51%). Seasonal variation in both Nand P content of each of the herbage classes in both studies followed the same trend -higher values during the moist, cooler part of the year (May-September) and lower values during the drier, warmer period (January-March).

Accumulation and Loss of Nitrogen in White Clover (Trifolium repens L.) Plant Organs as Affected by Defoliation Regime on Two Sites in Norway

“…In early spring the proportion of stolon N had increased further owing to the decline in leaf N during the winter, but 6 weeks later the largest part of the plant N was located in leaves. These results are in agreement with studies by Hay et al (1985) who found that more than 50% of the N was located in the below cutting-height tissue at certain times of the year and with the finding of Høgh-Jensen and Schjoerring (2001) that the N content of the stubble including stolons exceeded that of the macro roots with more than 50% at final harvest in late autumn. In our investigation, defoliation decreased the total accumulation of plant N during the growing season, probably because a reduction in the photosynthetic capacity limited the N capture through fixation in defoliated plants (Gordon and Kessler, 1990;Ryle et al, 1985).…”

Temporal variations in some plant and soil P pools in two pasture soils of widely different P fertility status

“…lc), consistent with the greater sensitivity of clover to soil moisture and temperature (Hay et al, 1985). Despite soil water deficits of up to 200mm (Fig.…”

“…la), and of ryegrass and white clover from Waikanae soil (Fig. lc, d) varied seasonally, generally following the pattern (Hay et al, 1985) of higher values during the moist, cooler part of the year, and lower values during the drier, warm period. The P concentrations in the herbage from the low-fertility soil were considerably lower than those from Waikanae soil, occasionally falling below 0.2 percent, which is considered to indicate P deficiency in grass-clover pastures (Smith and Cornforth, 1982).…”

Impact of Soil Temperature and Moisture on Mehlich-3 and Morgan Soil Test Phosphorus

“…Tate et al (1991) observed a pattern of higher values during the moist cooler part of the year and lower values during the drier warm period in two pasture soils. The same pattern was observed by Hay et al (1985). Contradictory to these findings, Van der Paauw (1962) observed increased soluble P levels during dry periods (years) and decreased levels in wet periods, possibly resulting from reduced crop uptake in dry years, whereas Saleque et al (1996) reported that available P in an incubation study was higher at 30-C than at 20-C, and that the difference was greater in a continuous waterlogged treatment than in an alternate wetting and drying regime.…”

“…A number of studies contribute seasonality of STP values to moisture and temperature variability over the growing season (Akbari et al, 1981;Hay et al, 1985;Saleque et al, 1996;Tate et al, 1991;Van der Paauw, 1962). However, results are not necessarily consistent across studies.…”