Yield mapping at different scales to improve fertilizer decision making in the Australian sugar industry

Potential yield is one of the criteria used as an input to nitrogen (N) fertilizer management decisions when using SIX EASY STEPS (6ES), the fertilizer recommendation tool used in the Australian sugar industry. Most commonly, 6ES is implemented using a district yield potential (DYP). In this study, we use analysis of sugar mill and yield monitor data from the Herbert River cane growing district to demonstrate that yield is markedly spatially variable, with this variability following the same patterns from year to year. There would therefore be value in a more location specific consideration of potential yield and application of 6ES. Similar analyses could be readily conducted in other sugar producing regions with potentially important implications for fertilizer use efficiency and the minimization of nutrient accessions to the Great Barrier Reef.

Plant Remains from the Washington Square Mound site (41NA49), Nacogdoches, Texas

Botanical remains were identified from 27 lots from the Washington Square Mound site (41NA49). The primary occupation at the site is Middle Caddo period in age. The first pooled set of calibrated radiocarbon dates from the site fell into the period A.D. 1268-1302, while a recent set of five calibrated dates from samples of plant remains discussed in this article range from A.D. 1279 + 17; (2) A.D. 1358 + 57; and three dates on charred corn from Features 36, 81, and 86 range from as early as A.D. 1394 to as late as A.D. 1437. These dates as a group fall in the Middle Caddo period; there is limited evidence at the site for other, smaller occupations, including Late Caddo and Late Woodland/Early Caddo. At least three mounds were visible in the nineteenth century. Much of the site was never plowed, a situation that has resulted in intact shallow deposits and unusually large pottery sherds, although a high school has been built over parts of the non-mound site area. Labels of botanical lots that included excavation dates indicate a range from 1979 to 1983, associating the botanical remains with Stephen F. Austin State University Field School excavations that took place during this time. At least nine features are represented in the botanical lots. Four are described as charcoal-filled pits, one as a pit, and one as a post mold. Feature 36 was a corn cob concentration . Botanical lots for Features 62, 81, and 199 are also present. The Washington Square Mound site is situated in the city of Nacogdoches, Texas, on an interfluve between Banita Creek and La Nana Creek, which drain into La Nana Bayou and the Angelina River. The area lies squarely in the Pineywoods ecological zone, the westernmost extension of the great Southeastern Evergreen Forest that reaches across the southeastern United States to the Atlantic coast (Braun 2001:281). The dominant vegetation type in an upland area such as Washington Square during presettlement times would have been a shortleaf pine community, where shortleaf pines (Pinus echinata) share dominance with dry-site oaks such as southern red oak (Quercus falcata), post oak (Q. stellata), and blackjack oak (Q. marilandica), hickories (Carya spp.), and elms (Ulmus spp.) Springs and marshy areas nearby would have offered aquatic and wetland plants such as river cane (Arundinaria gigantea). A spring-fed pond is reported to have existed north of the site, and a marshy area to the southwest. Pollen studies indicate that use of the modern and recent vegetation is appropriate for understanding the plants and attendant animal resources available to occupants of the sites during prehistoric times. Some fluctuations in rainfall and temperature have taken place, however. In addition, more frequent fires would have made the understory in the uplands less prominent than today. Early explorers in East Texas and other parts of the Eastern Woodlands noted the open, park-like nature of many woodlands.