Effects Of Different Management Practices Research Articles

Calcareous fens in south Sweden. Previous use, effects of management and management recommendations

A report written in the Swedish language has been abridged and rewritten for foreign readers. Each calcareous fen site is a unique feature though it is possible to generalise such fens into five types according to soil type and most frequent plant communities. Previously most fen sites were used for hay and/or grazing, which gradually decreased from the middle of the 19th century and, since the 1950s has become very unusual. The effects of different management practices are still insufficiently known, observations on species are often contradictory and hence experimental studies are needed. The future management should be adjusted to the sensitivity of each site, the fen type, the main plant communities and the purposes of the preservation.

EFFECTS OF COLD, ACUTE STARVATION AND PREGNANCY ON SOME INDICES OF ENERGY METABOLISM IN LINCOLN AND SOUTHDOWN SHEEP

Blood samples were drawn at weekly intervals from 24 pregnant and 16 nonpregnant Lincoln and Southdown ewes kept over winter in a sheltered, unheated yard. Samples were analyzed for plasma glucose, free fatty acid (FFA) and ketone concentrations. Records were kept of mean daily air temperature and individual food intake.Air temperature (7-day mean) ranged from −3 to −32 C. Air temperature had no effect on food intake, FFA or ketone concentrations. However, glucose concentrations did rise with increasing cold stress. Acute starvation induced large increases in plasma FFA and ketone concentrations and a fall in plasma glucose. The increases were most marked in the pregnant animals, ketones rising, on average, from 2.5 to 31 mg/100 ml. Food intake and plasma glucose concentrations in late pregnancy fell below values recorded in nonpregnant sheep. Ketones and FFAs were slightly higher. Differences were small compared with those observed after fasting.The results are discussed in relation to the effects of different management practices on the pathogenesis of pregnancy toxemia in sheep.

Factors Involved in Seed Production of Red Clover Clones and Their Polycross Progenies at Two Diverse Locations1

To assess the role of differential seed‐producing capacity as a factor in genetic shifts during seed multiplication, we examined seed production of red clover (Trifolium pratense L.) clones and their progenies at Lexington, Ky., and at Prosser, Wash.Number of heads was the primary factor in governing seed yields per clonal plant. Number of seeds per head and seed weight were of less importance within each of the locations.Clonal and progeny seed yields within and between locations were not correlated. Significant correlations indicated that, at Prosser, early clones produced the most heads and the highest seed yields. Progenies of these clones also produced the highest seed yields. Some evidence suggested that the high yielding progenies were also earlier than average to flower. Although this earliest to flower‐high seed yield relationship was not significant at Lexington, we inferred that it might have been present if seed had been harvested throughout the season rather than from only the regrowth following the harvest of the first crop as hay.This work suggests that the higher seed production by early clones could account for some of the shifts found when red clover seed is multiplied. This indicated the need for further investigation of this possible relationship and the effect of different management practices on natural selection for undesirable forage characteristics.

Stated monthly meeting, October 18, 1939

Soil surface characteristics affect soil–water interactions and are in turn influenced by a variety of soil properties. Likewise, the state and temporal change of soil surface roughness are major drivers for the interaction between soil and water.The use of different tillage tools such as plough or chisel directly affects soil roughness parameters. Moreover, soil roughness and soil consolidation after management may also be affected indirectly through the effect of different management practices on soil properties.This study examines the effects of two different long-term soil management experiments on soil roughness and the process of soil consolidation. At site Fuchsenbigl (FB), conventional tillage has been compared to reduced tillage since 1988. At site Ritzlhof (RH), three different methods of fertilization (green waste, mineral fertiliser, no fertiliser application) have been tested since 1991. We assumed that the different management practices had influenced soil properties – most likely organic carbon content – affecting soil roughness and soil consolidation.The photogrammetric method was applied to test these assumptions, and various soil surface roughness indices (random roughness, orientated roughness, limiting slope, limiting distance, tortuosity) successfully identified different initial roughness values.The limiting elevation difference index (Linden and van Doren, 1986) revealed significant differences between the sites FB 2012 (17 mm) and RH 2012 (28 mm) and between different years RH 2013 (22 mm) after chiselling. We attributed the site distinction to the different soil textures and the temporal differences to the different water contents at time of management.The decay of roughness for all sites and treatments (n = 276) parameterized by the RR Index followed the equation RR = 94.6 e−0.001.We were also able to distinguish significant consolidation effects of different long-term treatments with respect to tillage intensity at site FB. The maximum consolidation for reduced tillage was 13.8 mm compared to 16.8 mm for conventional treatment. In contrast, no effects of different fertiliser application at site RH were observed. For all sites and treatments (n = 35), soil consolidation (C in mm) due to precipitation (P in mm) followed the equation C = 4.23 × ln(1 + P) with an r2 of 0.71.