Studies with 33 soils selected to obtain a wide range in properties showed that the surface area values obtained by an ethylene glycol monoethyl ether (EGME) procedure that omitted the customary pretreatments to remove organic matter and saturate the soil sample with Ca2+ were similar to, and very highly significantly correlated with, the values obtained when these time‐consuming pretreatments were included. The surface area values obtained by the simplified EGME procedure were very highly significantly correlated with the clay contents and cation‐exchange capacities of the soils studied.

No abstract

The Conservation Reserve Program (CRP) is a U.S. federal land conservation program that incentivizes grassland reestablishment on marginal lands. Although this program has many environmental benefits, two critical questions remain: does reestablishing grasslands via CRP also result in soil health recovery, and what parts of restored fields (i.e., topographic positions) recover the fastest? We hypothesized that soil health will recover over time after converting cropland to CRP grassland and that recovery will be greatest at higher topographic positions. To test this, we sampled 241 midwestern U.S. soils along a grassland chronosequence (0-40 yr, including native grasslands) and at four topographic positions (i.e., a chronotoposequence). Soils were measured for bulk density, maximum water holding capacity (MWHC), soil organic C (SOC), extractable inorganic N, potentially mineralizable C (PMC), and N. Native grasslands had superior soil health compared with cropland and most CRP soils, and even 40 yr since grassland reestablishment was not adequate for full soil health recovery. Topographic position strongly influenced soil health indicators and often masked any CRP effect, especially with MWHC and SOC. However, PMC (a measure of active C) responded most rapidly to CRP and consistently across the landscape and was 26-34% greater 19-40 yr after grassland reestablishment. Reestablishing grasslands through CRP can improve soil health, although topographic position regulates the recovery, with greatest improvements at shoulder slope positions. Patience is needed to observe changes in soil health, even in response to a drastic management change like conversion of cropland to CRP grassland.

The destruction of the South Vietnamese rice (Oryza sativa L) crop using an arsenic-based herbicide known as Agent Blue during the American Vietnam War (1965-1972) was not a secret; however, it received little media attention in the United States. Republic of Vietnam and United States (U.S.) militaries began destroying food crops (rice) in November of 1962 primarily via aerial applications in the Mekong Delta and Central Highlands of South Vietnam. Spraying of Agent Blue on 100,000 ha of mangrove forests and about 300,000 ha of rice paddies just before rice harvest time resulted in the destruction of the standing crop and rendered the land contaminated with arsenic (As). Six Rainbow herbicides, commonly called Agent Orange, Agent Green, Agent Pink, Agent Purple, Agent White, and Agent Blue, were sprayed on wetlands, rice paddies, forests, mangroves, bamboo and military base perimeter fences to defoliate jungle vegetation, reveal guerilla hiding places and destroy the food supply of enemy troops. South Vietnamese farmers, U.S. and Republic of Vietnam military personnel, and communist insurgents were exposed to these herbicides with immediate and longer term impacts on personal health, civilian household food security and population-wide famine. Agent Blue (cacodylic acid, C 2 H 2 AsO 2 ,) was the most effective of all the Rainbow herbicides in killing rice and grasses. Manufacturing of cacodylic acid began in the late 1950s in the U.S. at the Ansul Company chemical plant in Marinette, Wisconsin and Menominee, Michigan. During the Vietnam War, ocean going ships were loaded with 208-liter Agent Blue barrels and shipped via the St. Lawrence Seaway to the coast of South Vietnam. Arsenic (As) is a naturally occurring element that is found throughout SE Asia deltas including the Mekong Delta. Today arsenic contaminated rice and groundwater are grow

Crambe seed (Crambe abyssinica) is an excellent, recently established source of high-erucic acid oil. Erucic acid has a number of important and potential applications. To develop this potential, a rapid bench-scale method was desired whereby purified erucic acid in up to several 100-g quantities could be produced from crambe seed. Using the method developed, oil was expressed from dried, intact seed; clarified, degummed, and bleached; and saponified and acidified to obtain the free fatty acids. Analysis by inductively coupled plasma of the free fatty acids showed negligible levels of phosphorus and most minerals. Erucic acid was twice crystallized from 95% ethanol at −14°C, resulting in a purity of 87.1%. This process yielded 365 g erucic acid crystals per kg bleached oil. Nuclear magnetic resonance analysis showed that the prepared erucic acid had an excellent pattern of correlation with a commercial standard. The time needed to convert 1 kg of crambe seed to erucic acid is about 48 h. Crystal filtration and drying stages under the current process conditions require 30% of the overall time. The method is suitable for producing adequate quantities of erucic acid for use in studies of its bench-scale conversion. There is obviously, still, a fruitful field of work to be explored in the formalization of refining procedures for crambe oil. It seems that crambe is destined to continue expansion into the higherucic acid oil markets.Paper no. J9058 in JAOCS 76, 801-809 (July 1999).