Among several candidate perennial taxa, Miscanthus  giganteus has been evaluated and promoted as a promising bioenergy crop. Owing to several limitations, however, of the sterile hybrid, both at the taxon and agronomic production levels, other options need to be explored to not only improve M.  giganteus, which was originally collected in Japan, but to also consider the development of other members of its genus, including Miscanthus sinensis, as bioenergy crops. Indeed, there is likely much to be learned and applied to Miscanthus as a bioenergy crop from the long history of intensive interaction between humans and M. sinensis in Japan, which in some regions of the country spans several thousand years. Combined with its high amount of genetic variation, stress tolerance, biotic interactions with fauna, and function as a keystone species in diverse grasslands and other ecosystems within its native range, the unique and extensive management of M. sinensis in Japan as a forage grass and building material provides agronomists, agroecologists, and plant breeders with the capability of better understanding this species in terms of potential contribution to bioenergy crop development. Moreover, the studies described in this review may serve as a platform for future research of Miscanthus as a bioenergy crop in other parts of the world.

Core Ideas The geographic scope, scale, and unique collaborative arrangement warrant documenting details of this work. The purpose of this article is to describe how the research was undertaken, reasons for the research methods, and the project's potential value. The project generated a valuable dataset across a wide array of weather and soils that allows evaluation of N decision tools. Due to economic and environmental consequences of N lost from fertilizer applications in corn (Zea mays L.), considerable public and industry attention has been devoted to the development of N decision tools. Needed are research and databases and associated metadata, at numerous locations and years to represent a wide geographic range of soil and weather scenarios, for evaluating tool performance. The goals of this research were to conduct standardized corn N rate response field studies to evaluate the performance of multiple public‐domain N decision tools across diverse soils and environmental conditions, develop and publish new agronomic science for improved crop N management, and train new scientists. The geographic scope, scale, and unique collaborative arrangement warrant documenting details of this research. The objectives of this paper are to describe how the research was undertaken, reasons for the methods, and the project's anticipated value. The project was initiated in a partnership between eight U.S. Midwest land‐grant universities, USDA‐ARS, and DuPont Pioneer. Research using a standardized protocol was conducted over the 2014 through 2016 growing seasons, yielding a total of 49 sites. Preliminary observations of soil and crop variables measured from each site revealed a magnitude of differences in soil properties (e.g., texture and organic matter) as well as differences in agronomic and economic responses to applied N. The project has generated a valuable dataset across a wide array of weather and soils that allows investigators to perform robust evaluation of N use in corn and N decision tools.

This ethnoarchaeological study at the Q'eqchi' Maya village of Las Pozas, Guatemala, aimed to refine the understanding of the relationship between soil chemical signatures and human activities for archaeological applications. The research involved phosphorus, exchangeable ion (calcium, potassium, magnesium, sodium), and trace element analysis of soils and earth floors extracted by Mehlich II, ammonium acetate, and DTPA chelate solutions, respectively. The results showed high levels of phosphorus, potassium, magnesium, and pH in food preparation areas, as well as high phosphorus concentrations and low pH in food consumption areas. The traffic areas exhibited low phosphorus and trace element contents, whereas refuse disposal areas were enriched. These results provide important information for the understanding of space use in ancient settlements. ᭧

Compared with traditional cropping systems, integrated crop-livestock systems have shown greater effi ciency in improving soil quality and crop yield. Th e objective of this study was to determine how an integrated crop-livestock system aff ected soil properties and corn (Zea mays L.) yield when compared with continuous corn (CC). Th e study was conducted from 2004-2008 on a large-scale research farm located near Pana, IL, USA. We evaluated the following soil and crop variables: soil organic matter (SOM) fractions, total nitrogen (TN) and total organic carbon (TC), soil microbial biomass carbon (SMBC), water aggregate stability, soil penetration resistance (PR), and corn yield. Th ree treatments were used in this study: winter cover crops (WCCs) and cool-season pastures (CSP), considered integrated system treatments and a nonintegrated CC monoculture. In the integrated system, CSP and WCC treatments combined, had signifi cantly higher TN (P = 0.0926) than CC. Water aggregate stability was also higher in the integrated system (P = 0.0039). Greater percentages of TC and TN were represented by particulate organic matter (POM) POM-N and POM-C in the WCC treatment, followed by CSP, and CC. Th e PR for CSP (928 kPa) was not signifi cantly diff erent than WCC (921 kPa). However, both were signifi cantly diff erent than CC (655 kPa). Averaged across years, corn grain yield for WCC (11.5 Mg ha −1 ) was signifi cantly higher than CC (10.8 Mg ha −1 ) (P = 0.0780). Th ese results confi rm that WCC and CSP used within integrated crop-livestock systems should improve soil quality, SOM dynamics, and crop yield despite moderate soil compaction caused from cattle presence.

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The ancient Maya thrived for centuries in the Petén rain forest of Guatemala. Their impressive architecture and the evidence of highly populated centers attest that the Maya farmers were capable of producing food surpluses. In the eighth to ninth centuries CE the Classic Maya civilization collapsed. The processes leading to its decline are still debated, but unsustainable agricultural practices and exhaustion of natural resources may have contributed. This paper reports on soil formation rates, soil taxonomy, phytolith analysis, and δ13C values of soil organic matter in a rural area near the ancient city of Piedras Negras. Our objective was to understand ancient Maya rural life by linking soil characteristics to ancient agricultural resources and anthropogenic activities. We found that these soils formed at a rate of approximately 0.09 mm yr−1 All 15 soil profiles belonged to the order Mollisols. The soils of the back‐slope locations were shallow (<25 cm) and were probably severely eroded at the time of abandonment (ninth century CE). The soils located at the valley's floor were deep, well developed, and potentially good for sustainable agriculture. Phytolith analysis indicated that in ancient times panacoid grasses were dominant in these soils and provided evidence that the forest was cleared for maize (Zea mays L.) agriculture. Stable C isotopes provided evidence that the vegetation shifted from forest (C3) to C4 vegetation during the time of Maya occupation. The toe‐slope soils were observed to be less enriched in 13C in profiles closer to Piedras Negras than in those farther away.

Fertilizer placement is oft en designed to improve nutrient availability. Our objective was to determine the eff ect of P and K rate and placement in no-till and strip-till on grain yield; water, P, and K values in the soil; and the distribution of corn (Zea mays L.) roots. A 4-yr fi eld experiment was setup near Urbana, IL, with a corn-soybean [Glycine max (L.) Merr.] rotation. Tillage/ fertilizer placement was the main plot [no-till/broadcast (NTBC), no-till/deep band (NTDB), and strip-till/deep band (STDB)]; deep band was 15-cm beneath the crop row. Phosphorus fertilizer rate (0, 12, 24, and 36 kg P ha -1 yr -1 ) was the subplot, and K-fertilizer rate (0, 42, 84, and 168 kg K ha -1 yr -1 ) was the sub-subplot. Measurements included grain yield and yield components, grain and shoot P and K concentrations, root parameters, and soil-water, P, and K values. Strip-till/deep band produced greater kernels row -1 and 9.43 Mg ha -1 yield that was 7.8% greater than NTBC and 7.9% greater than NTDB. Deep banding increased soil P and K test values beneath the crop row and lowered soil surface test values compared with broadcast applications, but had no eff ect on root distribution. Across treatments, greatest apparent P and K uptake occurred in the surface layer where most roots were present and where precipitation replenished water to a greater extent than deeper layers. Relative to NTBC, STDB had 24% greater apparent-P and 23% greater apparent-K uptake rates. Th e results indicate that improved conditions for nutrient uptake provide a competitive advantage for production with STDB relative to no-till treatments.

Determining which corn (Zea mays L.) N fertilizer rate recommendation tools best predict crop N need would be valuable for maximizing profits and minimizing environmental consequences. Simultaneous comparisons of multiple tools across various environmental conditions have been limited. The objectives of this research were to evaluate the performance of publicly‐available N fertilizer recommendation tools across diverse soil and weather conditions for: (i) prescribing N rates for planting and split‐fertilizer applications, and (ii) economic and environmental effects. Corn N‐response trials using standardized methods were conducted at 49 sites, spanning eight US Midwest states and three growing seasons. Nitrogen applications included eight rates in 45 kg N ha−1 increments all at‐planting and matching rates with 45 kg N ha−1 at‐planting plus at the V9 development stage. Tool performances were compared to the economically optimal N rate (EONR). Over this large geographic region, only 10 of 31 recommendation tools (mainly soil nitrate tests) produced N rate recommendations that weakly correlated to EONR (P ≤ .10; r2 ≤ .20). With other metrics of performance, the Maximum Return to N (MRTN) soil nitrate tests, and canopy reflectance sensing came close to matching EONR. Economically, all tools but the Maize‐N crop growth model had similar returns compared to EONR. Environmentally, yield goal based tools resulted in the highest environmental costs. Results show that no tool was universally reliable over this study's diverse growing environments, suggesting that additional tool development is needed to better represent N inputs and crop utilization at a larger regional level.