Article #1
Brummer, E. Charles, et al. "Emergence and survival of legumes seeded into pastures varying in landscape position." Crop Science 44.1 (2004): 227+. Academic OneFile. Web. 20 Nov.
2012.

Summary:

Brummer and associates acknowledged that legumes plants are known for improving the quality of the forage with increased crude protein to a pasture system. Legumes grow faster throughout the year due to their ability convert nitrogen from the atmosphere to usable nitrogen for the plant. Although legume increase the entire pasture yield, back slopes often produces more dry matter then summits proved by Harmony et al .(2001). Brummer and associates analysed establishment of legumes in pasture systems under a number of conditions. They investigated how grass height, dayly sun light, and fertilizer affected establishment of legumes. Their experiment involved creating several plots with different scenarios. They tested several legumes including red clover, alfalfa, and birdsfoot trefoil proportionally on several landscapes. To control competition they cut the grass and added fertilizer. At the growing seasons end legumes were pulled, sorted, and counted to measure the results of the experiment.
Brummer and associates results supported Harmony et al .(2001) That back slopes allowed a greater amount of legumes to emerge compared to summits when turf height was not reduced greatly or at all. When the grass did not exceed 5 cm back slope and summit compared equally or close to. In all experiments red clover emergence excelled that of birdsfoot trefoil and alfalfa. Although sward height and back slope affected the emergence of legumes it appeared the all breeds were affected equally.
Brummer and associates acknowledges that legumes compete better with grasses due to the ability to fixate their own nitrogen. Applying nitrogen had minimal effect on emergence but grasses grew more rapidly. Cutting the turf reduced the effects of the increased growth rate but, in uncut sward height nitrogen reduced all legumes survival by 68% when fertilized compared to unfertilized uncut plots. Both backslope and summit legume survival were reduced by fertilizer.
Brummer and associates concluded from their experiment that increased competition from grasses directly correlated to lower survival rate of legumes. As grass height increased, legume emergence suffered. Fertilization increased the growth rate of grass further inhibiting sunlight from reaching legume seedling. Sunlight increases ground temperature helping the germination process of a seedling. It appeared that reduced sunlight had greater effects on alfalfa and birdsfoot trefoil seedlings than red clover further proving (Tilman, 1993). When turf height was reduced to 5 cm or more sunlight penetrated to the soil and alfalfa and birdsfoot trefoil rivaled germination percentage of red clover. Brummer and associates recommend that “legumes be seeded on back slope landscape positions in pastures and that N fertilizer not be applied, and sward height be reduced before seeding.” Article #2
Block, H.C., et al. "Economic effects and energy use efficiency of incorporating alfalfa and fertilizer into grass-based pasture systems." International Journal of Biological and Life
Sciences 1.2 (2009): 74+. Academic OneFile. Web. 20 Nov. 2012.

Summary: Rising cost of feed for cattle have beef producers searching for alternatives feeds and ways improve yields of cattle feeds. A common practice for beef producers is fertilizing pastures to increase pasture yields and animals gains. Although common practices such as fertilizer and pesticides improve productivity they also increase energy inputs and may not be profitable. 80% of current energy use on farms producing grain come from fuel and inorganic fertilizer. Block, H.C. and associates compared several different pasture systems productivity and non-renewable energy. Block H.C. and associates conducted a 10 year study of several plots. They created 4 plots a grass only unfertilized pasture, grass only fertilized pasture, grass and alfalfa mix unfertilized, and grass and alfalfa mixed fertilized. Cattle rotationally grazed the plots and fertilizer applied each spring. Throughout the season samples were taken and analysed for quality and amount. Each of the beef cattle were weighed at the start of grazing season and end. Block H.C. and associates compared pasture systems net income and energy useage. As assumed incorporating alfalfa and nitrogen improved the yield of the pasture but did not directly correlate to a larger income. Grass only pasture proved to produce the least forage compared to others especially fertilized pastures which more than doubled production. Although fertilizer more than doubled forage production fertilizer has become increasingly expensive increasing input cost. Only incorporating alfalfa may not have increased the yield to the extent of fertilizer it did have substantial increases in production with out the large increase of input cost. The grass only unfertilized pasture system required the least amount of input and was closely followed by unfertilized alfalfa grass mix. Both fertilized pastures required more input cost, the alfalfa mix only required about a third of the fertilizer cost as grass only, due to the ability of legumes to create their own nitrogen. The grass only pasture took the least amount of input but produce the least output making it an inefficient choice. Adding fertilizer only compounded the inefficiency problem of the grass only pasture. Adding alfalfa improved forage quality and amount making it the overall best choice. Adding fertilizer had negligible effects on the alfalfa grass system since alfalfa only fixates nitrogen when the nitrogen in the ground ceases to suffice the needs of the plant. The overall consensus of Block H.C. and company was that incorporating alfalfa into old pasture system proved to be most profitable and required the least energy input to greatest energy output.
Comparison/Contrast:
Although Brummer and Block H.C.’s experiments resulted with different recommendation they both support each other to an extent. Both Brummer and Block H.C. investigated incorporating legumes into an existing pasture for economic and natural reasons. Brummer noted that legumes can improve soil structure through nitrogen fixation. Meanwhile Block H.C. proved that legumes can increase a soils nitrogen level by only needing to apply a third of the fertilizer when compared to the grass only pasture. Despite common practice of spring fertilizing pasture both reviewed this ideology and recommended fertilizer not be applied. Block H.C. advised not fertilizing and including alfalfa at the time of seeding or re-seeding the pasture. While Brummer proposed re-seeding with red clover,on backslope, grass height be reduced, and not apply fertilizer. Despite their alikes each made strong points against each other. Both disagree on which legumes are most economically suited for improving a pasture. Adding legumes proved the most efficient way to improve a pasture in Block’s test but he felt that alfalfa would be the best choice of legume. Brummer decided survival rate of legume seeds overwhelmed other advantages and felt red clover should be applied since it repeatedly dominated alfalfa and birdsfoot trefoil in his trials. Brummer also pointed that legumes did not prove to be nearly productive enough on summits for him to advise seeding legumes on summits. Although Block H.C. may not have investigate nearly as much into backslope and summit he still advised seeding alfalfa on the entire pasture. Brummer conducted his experiment using a mechanical machine to reduce his grass height while Block H.C. rotationally grazed the test plots.
Analysis:
Brummer and Block H.C. main goal was to improve pasture efficiency for the farmer. I feel that with rising feed and land cost the is becoming ever important on the farm. Both advised planting legumes in the pasture although each recommended different ones. I must agree with brummer that red clover would be best suited for adding to a pasture system. Although alfalfa may be the more productive legume once established it’s useless unless it is established. Red clover emerged better in all investigation including when turf height was reduced to 5 cm and 13 cm which would imitate a rotational grazing system which allows cattle to graze pasture down to about 7 cm and allowed time to regrow to about 14 cm before being nipped of again. On a dry year like this year farmers were scrounging for pasture and probably overgrazed. Overgrazing causes stress on legume plants making them weaker more susceptible going into winter. Most farmer will need to re-seed in spring due to a large winter kill on legume plants. Re-seeding pastures can be the single largest expense for a grazing system especially when farmers do not fertilize. Many farmer would be extremely interested in which legumes and what landscape will yield the greatest return for their investment. Pastures are usually situated along creeks were modern machinery can not fit. In these areas Brummer suggest that legumes will be less effective than on backslope since emergence and establishment of legume seeds are greatly inhibited by grass competition. I think the most appropriate way to improve a pasture is seed red clover on back slopes, reduce turf height by rotational grazing, and not apply fertilizer to the pasture.