Long-Term Productivity and Profitability of Conventional and Alternative Farming Systems in East-Central South Dakota: A Case Study

A small body of evidence has begun to emerge over the last 3 to 4 years on the comparative productivity and profitability of conventional farming systems and alternative systems which (1) avoid or use very small amounts of synthetic chemical fertilizers and pesticides, and (2) place greater emphasis on crop rotations, especially rotations which involve forage and green manure legumes. Most of the evidence thus far has been based on only a few years of data, however. In contrast, South Dakota State university (SDSU) has recently completed three relatively long-term studies comparing conventional and alternative systems. Two of the studies were conducted at SDSU\u27s Northeast Research station, north of Watertown, S.D. in Codington County. Conventional, reduced tillage, and alternative farming systems were compared there, over the period 1985-92 in one study and over 1985-93 in the other study. Results of those studies appear in Dobbs (1994a), Dobbs, et ale (1994), Smolik and others (1994), Smolik, et ale (1993; and forthcoming), and Smolik and Dobbs (1991)

Soybean Cyst Nematode

The soybean cyst nematode (SCN), Heterodera glycine is a serious threat to South Dakota soybean production. It was first detected in South Dakota in Union County in 1995, and in 1996 it was also found in a number of fields in Turner County. It very likely is also present in several other southeastern South Dakota counties

Economic Results of Alternative Farming Systems Trials at South Dakota State University\u27s Northeast Research Station: 1985-1988

This report contains baseline economic results for the first four years of a set of experiment station trials comparing particular low-input (alternative) farming systems with conventional and reduced tillage systems in which chemical inputs are used

Sustainable Agriculture in South Dakota

This is a report of the views and experiences of 32 South Dakotans who follow sustainable/regenerative agriculture practices on their farms. It is based on a mail survey undertaken during the summer of 1988. The research reported here complements that undertaken by South Dakota State University (SDSU) since 1984 on large experimental field plots at the University\u27s Northeast Research Station near Watertown

The Role of Nematodes in a South Dakota Grassland Ecosystem

In an attempt to elucidate the role of nematodes in a grassland ecosystem nematode taxa, number and biomass data was gathered over a three year period at the Cottonwood International Biological Program Grassland Biome site in western South Dakota. The effects of grazing intensity, sampling date and sampling depth were studied. Nematicide treatment of range grasses in field and greenhouse studies was also used to evaluate the role of nematodes. Biomass data was used to estimate the intake of plant feeding nematodes. Results obtained demonstrate that soil inhabiting nematodes constitute a significant proportion of the consumer biomass at the Cotton[1]wood site. Biomass of plant feeding forms was significantly greater in the ungrazed treatment due mainly to the high numbers of dagger nematode, Xiphinema americanum. Biomass of predacious forms was also greater in the ungrazed treatment and overall nearly equaled that of the plant feeding forms, thus indicating their potential as agents of biological control. Biomass of saprophagous forms was considerably less than that of the other trophic levels and also showed little treatment response. An inverse relationship between numbers of Tylenchorhynchus spp. and Helicotylenchus spp. was noted in the grazed treatment. Tylenchorhynchus spp. appeared nearly limited to the upper 10 cm of soil with Helicotylenchus spp. predominating with increasing depth, indicating a possible antagonistic relationship between these taxa. The diversity of taxa was found to decrease with increasing sampling depth, a response attributed to a decrease in variety of food sources. Total number of nematodes also decreased with increasing sampling depth and approximately 70% of the nematodes occurred above 20 cm. Nematicide treatment of range grasses in field and greenhouse studies significantly reduced nematode populations, increased above ground herbage weight, and further, provided a demonstration of the importance of nematodes as controllers of productivity in range. A formula was used to estimate nematode intake at the Cottonwood site and, surprisingly, plant feeding nematodes were found to consume more range grass than cattle. In addition, comparisons of nematode intake with that of several other consumer populations indicated that nematodes are major consumers at the Cottonwood site. The large biomass, high metabolic rate and indigenous nature of the nematode populations were suggested as probable reasons for the high intake. Overall, it is apparent that soil inhabiting nematodes constitute a significant pathway of energy flow in a grassland ecosystem. They also are probably responsible for a significant proportion of the belowground nutrient recycling

Tylenchorhynchus Nudus and Other Nematodes Associated with Turf in South Dakota

In 1963, it was estimated that the cost of maintaining turf grass in the Midwestern United States was 300 to 500 million dollars per year (51). With the exception of the work of Perry (34) in Wisconsin, the role of plant parasitic nematodes in relation to turf decline in the Midwestern United States has received little study. The decline of Kentucky bluegrass (Poa pratensis L.) turf in South Dakota is not uncommon during hot, dry periods of the summer months. Nematode injury in South Dakota may also affect yield in Kentucky bluegrass seed-producing areas. Nematode damage might also be assumed to increase maintenance costs of homeowner lawns and golf courses due to increased water and fertilizer applications necessary to maintain vigorous turf. A stylet nematode, Tylenchorhynchus nudus (Allen) has been frequently associated with Kentucky bluegrass turf in northeastern South Dakota, but its effects on turf have not been established. Stylet nematodes feed ectoparasitically and obvious damage to root systems is usually not evident, although plant growth may be reduced. Objectives of the present study were to determine the distribution of Tylenchorhynchus nudus in South Dakota, to investigate reproductive ability of T. nudus on certain grasses and to determine effects of T. nudus on growth of Kentucky bluegrass under greenhouse conditions. Influence of temperature on the reproduction and gross morphology of T. nudus was also studied. In addition, field experiments were conducted to determine the effect of nematicides treatments on the growth of turf grass and the ability of the nematicides to control nematodes in turf

Crop and Livestock Enterprises, Risk Evaluation, and Management Strategies on South Dakota Sustainable Farms

This report presents findings from personal interviews undertaken in January-March 1989 with 22 of the 32 sustainable/regenerative farmers in South Dakota who responded to a Summer 1988 mail survey concerning their sustainable farming practices. [For the mail survey results, see Taylor, Dobbs, and Smolik, 1989.] The major purpose of the personal interview part of the study reported herein was to gain greater insight into (1) the sustainable crop rotations and livestock enterprises on these farmers\u27 farms and (2) the judgments of these farmers about the riskiness and managerial strategies for meeting selected challenges of sustainable agriculture