WHITE CLOVER-GRASS PASTURE YIELD AND ITS QUALITY VARIATION DURING THE FIRST FOUR USING YEARS - Z. Kadziuliene

Lithuanian Institute of Agriculture, Akademija, Kedainiai, LT-5051, Lithuania

SUMMARY

White clover, grass swards established on a soddy gleyic loam soil can persist for a long time and can contain as much as 20-25 percent of white clover, 50-60 percent of gasses, 15-25 percent of forbs, 10 years after establishment. The greatest changes occur in the sward composition during first four years of use. The dry matter (DM) yield of late sward (Trifolium repens L., Phleum pratense L., Agrostis stolonifera L.) in the first year was 8.70-9.07 t ha^-1, that of medium early sward (Trifolium repens L., Festuca pratensis Huds., Poa pratensis L..) 9.24-10.25 t ha^-1. White clover accounted for 30-47 percent of the yield. The yield regularly decreased every year, in the fourth year it was 33-40 percent lower, the content of white clover was by one fifth or by a half lower.

White clover had a positive effect on the yield distribution during whole grazing season. The yield curve of white clover was the highest in the second-fourth grazings. While the yield of grasses and forbs regularly decreased from the first to the fifth grazing. The protein content in white clover-brass pasture is high and increases from the first-second to the fifth grazing.

Keywords: white clover, grasses, pasture, sward, grazing, yield distribution, nitrogen, protein

INTRODUCTION

In the conditions of the ecological and economic problems interaction legume - grass swards are becoming more and more important on the pasture farms due to their high nutritive value and the ability to fix air nitrogen (Frankow-Lindberg, Frame, 1996). Swards containing 20-40 percent of white clover produce a high DM yield on various soils of Lithuania (Gutauskas, Bilevicius, 1989; Daugeliene, 1995). The sward of the white clover cv. Atoliai and grasses secured a high and stable DM yield, 6.41-6.76 t ha -1 over 10 years (Gutauskas, 1996). It is important not only to produce a high annual yield but also to have well-regrowing, high-yielding and nutritions swards during the whole grazing season. In our trials variation of the yield and its composition depended little on the amount of white clover seed in the mixture, if clover was sown at a rate of 2-4 kg ha-1, 20-40 percent of the total grass seed mixture (Kisonaite, Kadziulis, 1996). A more even distribution of the yield over the grazing season can be achieved by applying nitrogen after each grazing (Vasiliauskiene et al., 1989), by proper sward utilization frequency (Gutauskas, Bilevicius, 1989) and its proper soil moisture control (Tonkunas, Kadziulis, 1977; Frame, 1992). White clover can grow well in midsummer and the pasture yield distribution is more even if proper companion grasses have been selected and a good and stable balance between grasses and white clover in swards has been achieved (Frame, 1992; Gooding et al., 1996).

MATERIALS AND METHODS

Four field experiments for four pasture using years were carried out on a soddy gley loan; Soil (pH 6.9) during 1987-1993. The seed mixture of late sward consisted of Trifolium repens L. cv. Atoliai, Phleum pratense L.cv. Velenis and Agrostis stolonifera L. cv. Gouda and in medium early sward, Poa pratensis L. cv. Dotnuva I and Trifolium repens L. cv. Atoliai (all varieties from Lithuania). There were factorial trials. Treatments of A factor: white clover seed rate and ratio with grasses (Data published: Kisonaite, Kadziulis, 1996). Treatments of B factor: P₆₀K₆₀N₀ and P₆₀K₆₀N_60-90. Pasture swards were grazed by cows five times during the season.

RESULTS AND DISCUSSION

Average findings of the two experiments show that in the first year of use the DM yield of the late sward was 8.70-9.07 t ha^-1 (Table 1), it consistently decreased every year and in the fourth year amounted to 5.02-5.037 t ha^-1, i.e. declined by 40 percent. White clover yield in the first year was 4.10-4.02 t ha^-1 and in the fourth year as low as 1.20-0.88 t ha^-1. The DM yield of medium early sward in the first year was 9.24-10.25 t ha^-1 and in the fourth year 6.33-6.64 t ha^-1. The yield of this sward did not decrease so consistently, since it was lower in the third year (very dry summer) than in the fourth year and did not decline markedly as that of the late sward. Similar variations occurred in the white clover yield of the same sward. Nitrogen fertilization was not very effective, it was slightly effective in late years of the sward use.

White clover yield decreased faster from the second to the fifth year of sward. Therefore, white clover, if their content in the sward decreases annually, is not a factor stabilizing yield in the course of sward senescence. White clover plays a more important role during the growing season. During each season white clover helps to maintain a more stable yield during the period from May till August (Figure 1). The curve of white clover growing strength when grown mixed with grasses reaches its highest point during the season later than that of grasses, therefore, the distribution legume-grass sward yield over the summer is more even than that of grasses alone, especially if they receive low rates of nitrogen. The yield distribution of both swards over the season was similar, however, it was slightly better than that of medium early sward than that of late swards. The yield reduction from the second to the fifth grazing was only insignificantly affected by nitrogen fertilizer.

Figure 1. Distribution of sward dry matter over the grazing season without N (Average data of two trials, four using years, for each sward).

Table 1. DM yield of white clover and of total sward (Dotnuva, average data, 1988-1993 m).

In the yield of both swards the protein content was high. There was a smaller surplus of protein in the yield of the first grazings, this content increased during the period from June to September.

Average crude protein content in the DM yield of the 1^st, 2^nd, 3^rd, 4^th and grazings without nitrogen fertilizers was 19.3, 18.3, 20.4, 22.0 and 25.1 percent, respectively. This surplus protein can be utilized by extra feeding grazing livestock on 1ow protein forage.

CONCLUSIONS AND SUGGESTIONS

In the first four years of use of white clover grass pasture swards, 7.16-7.51 of DM was produced.

The yield of these swards decreases from the first to the fourth year and in the fourth year is on average 33-40 percent lower than in the first year. White clover has a stabilizing effect on the distribution of the whole yield during the grazing season. With a view to adjusting to the sward yield curve during the season, it is expedient to use grass surplus in the first half of the summer for preparation of winter feed, if the area of pasture is large, or to supplement livestock feeding with other green forage in the second half of summer if the pasture is hardly sufficient for the first half of the season. White clover-grass is rich in protein. Therefore, supplement feeding should be on low protein forage.

REFERENCES

Daugeliene, N.P. 1995. Selection of mixtures of grasses with white clover for variously nitrogen fertilized pastures. Zemdirbyste: LZI darbai, vol. 46: 63-68.

Frame, J. 1992. Improved grassland management. Farming Press, Ipswich, 351.

Frankow-Lindberg, B.E. & Frame, J. 1996. Developments and challenges in sustainable grassland production. Proc. of the 16th General Meeting of the European Grassland Federation, 243-246.

Gooding, R.F., Frame, J. & Thomas, C. 1996. Effects of sward type and rest periods from sheep grazing on white clover presence in perennial ryegrass/white clover association. Grass and Forage Science vol. 51:180-189.

Gutauskas, J. 1996. The influence of intensive grazing and minimal nitrogen fertilizer on long-term productivity of white clover. REU Technical Series, 42:129-131.

Kisonaite, Z. & Kadziulis, L. 1996. White, clover seed rate and ratio with grasses for pasture sward. REU Technical Series, 42:84-87.

Tonkunas, J. & Kadziulis, L. 1977. Pievos it ganyklos. Mokslas, Vilnius. 304.

Vasiliauskine, V., Dapkus, R. & Masauskiene, A. 1989. Rates of nitrogen and its distribution on late pasturable herbages on derno-gleyic loamy soils Zemdirbyste: LZI darbai, Vol. 37: 96-106.