Permanent pastures produce far below their potential, as they are usually managed in the northcentral and northeastern United States. Dairy farmers in these regions generally feed their cattle year-round from stored forage and purchased concentrates, and use permanent pastures as mere holding or exercise areas, grazing them continuously. This practice involves high operating costs that, combined with lower milk prices, have resulted in greatly reduced profit margins. Farming practices that return more net income are needed. The Voisin system of rotational grazing management, which applies intensive management to forage crops on pastureland, is widely used on dairy and sheep farms in New Zealand. Farmers using the Voisin system there have low operating costs and obtain high yields of excellent quality forage over long grazing periods; increased net income results Between 1 May and 1 October 1984, 497 forage samples were taken and analyzed from permanent pastures grazed according to the Voisin management system on six Vermont dairy farms. This was done to provide farmers with current estimates of forage feeding value so that they could balance their cows' rations accordingly throughout the season, and determine if they could improve the profitability of their farms by using Voisin grazing management. Average grazingseason analyses (dry weight) were: 22.5% dry matter, 22.4% crude protein, 20.8% available protein, 28.4% acid detergent fiber, 1.18% calcium, .48% phosphorus, 1.60% potassium, .22% magnesium, and 1.58 Mcal/kg net energy lactation. Average dry forage yield was 8.9 metric tons/ha. Dry matter intake was adequate for milk production up to 36 kg/cow/day. Forage protein and energy contents were sufficient for at least 25 and 18 kg milk/day, respectively. On three farms where economic factors were calculated, net profits per cow averaged $67 more during the 5-month period from using Voisin grazing management, compared to continuous grazing of the same pastureland in the year before Voisin management was used. This profit resulted mainly from feed savings and a more favorable milk:concentrate ratio of 4.1:1 obtained with Voisin management, compared to 2.7:1 with continuous grazing and more feeding of stored or machine-harvested forage. Voisin-managed pastures can produce high yields of excellent-quality forage that can be incorporated into dairy feeding programs, thereby reducing feed costs and increasing profitability of the farming operations.

Thirteen cropping systems were analyzed with respect to profitability and risk for east-central Nebraska. The systems were developed from 1) a four-year rotation containing a small grain, 2) two row crop rotations, 3) three continuous cropped alternatives, and 4) combinations of continuous cropped alternatives. Three systems were developed from the four-year rotation including two alternative treatments of inorganic chemicals as well as an organic alternative. Eight years of experimental yields, historical prices, and estimated costs were combined to estimate net returns for each of the thirteen systems. Risk was analyzed as net return variability using statistical characteristics of the net return series. The stability component of rotation risk was separated from the diversification component. We found rotations to have higher average net returns than continuously cropped systems. Different chemical treatments (including organic) had little impact on profitability. Rotations had lower return variability than most continuous crops. The organic treatment did not decrease variability of returns compared to other chemical systems.

Multiple cropping systems are prevalent in many parts of the world, and alternating strips of corn and soybeans or dry beans have been used by farmers in the temperate region. Strip cropping has the potential to reduce erosion on hilly lands, to allow a crop rotation in the field if strips are changed from one season to the next, and to increase total system yields. Results from several experiments in Eastern and Midwest U.S. show considerable variation in production among years and locations. Corn grown in narrow strips has yielded from 10 to 40 percent over sole cropping, while soybeans or dry beans in narrow strips suffer yield reductions of 10 to 30 percent due to light, water and nutrient competition. There has been no definitive research to quantify the relative importance of these factors in the competitive interface between corn and legume rows. With wider strips there is less increase in corn yields and less reduction in legume yields compared to sole cropping. Changes in component crop yields also depend on rainfall, and may be influenced by the variety of each component crop and by the width of strips. Rarely does total yield in a strip crop system fall below the average monoculture performance. In years of adequate rainfall, production of strip crops may outyield sole crops by 10 to 20 percent. Potential production of strip cropping systems is reviewed, and projected soil conservation is estimated using the Universal Soil Loss Equation.

A few farmers in the Midwest produce corn (Zea mays L.) commercially by using organic methods, i.e., use no synthetic fertilizers or pesticides. Studies have been conducted previously on organic vs. conventional fields to compare yield, soil properties, stalk lodging and rot, and crude protein. However, pith cell death in stalk internodes, an important trait related to stalk lodging and stalk rot, has not been studied previously under organic and conventional management systems. Fertility differences exist between organically-managed and conventionally-managed fields which can influence pith cell death and related traits. This study was conducted to compare pith cell death in corn stalks on matched pairs of organic and conventional fields (2 in Illinois, 2 in Iowa, and 1 in Minnesota). For the four lowermost consecutive internodes above the brace roots examined in this study, there was no consistent pattern for pith cell death differences among pairs. In three of five pairs, the second internode pith cell death was higher on organic fields than on conventional fields. The same pattern was observed for the third stalk internode. Numbers of European corn borer (Ostrinia nubilalis Hübner) were less in the stalks on organic plots, a plausible cause for greater stalk lodging and rot resistance on organically-managed fields. Further study of pith cell death and stalk rot relationship under organic and conventional managements is needed to elucidate fertility relations and other unique factors at work on organic and conventional fields. It appears that while there are some factors that affect pith cell death, stalk rot, and stalk lodging similarly, there may be other factors that affect these three traits differentially.

“Sustainable agriculture” means many things to different people in agriculture. At least three different definitions of sustainability are available: sustainability as food sufficiency; sustainability as stewardship; and sustainability as community. Since increased human populations will cause demands for food to continue to grow in the foreseeable future, agricultural sustainability needs to be assessed in ways that will incorporate competing definitions. We suggest that analyzing agriculture as a hierarchical system is the appropriate way to incorporate different concepts of sustainability. Using this concept, we propose a hierarchical definition of sustainability. Agronomic sustainability refers to the ability of a tract of land to maintain productivity over a long period of time. Microeconomic sustainability is dependent on the ability of the farm, as the basic economic unit, to stay in business. Ecological sustainability depends on the maintenance of life-support systems provided by non-agricultural and non-industrial segments of a region. Macroeconomic sustainability is controlled by factors such as fiscal policies and interest rates which determine the viability of national agriculture systems. In our view, there are critical constraints to sustainability at different scales of the agricultural hierarchy. We propose that agronomic constraints are most important at the field scale; microeconomic constraints are dominant at the farm scale; ecological constraints override at the watershed or landscape scale; and macroeconomic constraints are foremost at the regional and national scale. In this paper, we describe the actions of these critical constraints, discuss interactions among various hierarchical levels, and propose ways that agricultural researchers and policy makers can integrate the various views of sustainability.

The process of microbial decomposition of cellulose is important in many agricultural situations. Study of the nature of the process, however, has been slowed by the inadequacy of methods of measurement. A highly sensitive alkali-swelling technique originally devised for detection and measurement of damage in raw cotton fibers in the field before harvest was later found to be useful also for basic studies of the process of cellulose decomposition by microorganisms and their cellulose enzymes. A weighed sample of cotton fiber is swollen in an 18% solution of sodium hydroxide, centrifugea free of interfibrillar solution, and then reweighed to determine the amount of alkali absorbed. The percentage weight increase is termed the fiber's “alkali-centrifuge value” or “AC value”. This test is applied before and after exposure of a test sample of fiber to growing microorganisms or to solutions of their cellulose enzymes. The cellulose enzyme complex measured in this fashion has been termed “the swelling factor” or “S factor”. Data reported here illustrate the use of the test in measuring effects on cotton fiber of microorganisms and associated S factor. The basic swelling measurement is simple to perform, involves only standard laboratory equipment, is adaptable to a wide range of fiber sample sizes, is inexpensive, and is capable of yielding highly reproducible results. The method can be easily and beneficially applied by scientists in both developed countries and in developing countries, since expensive and sophisticated laboratory equipment is not required.