Corn nitrogen rate recommendation tools’ performance across eight US midwest corn belt states

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\u27s diverse growing environments, suggesting that additional tool development is needed to better represent N inputs and crop utilization at a larger regional level

Navigating the Socio-Bio-Geo-Chemisty and Engineering of Nitrogen Management in Two Illinois Tile-Drained Watersheds

Reducing nitrate loads from corn and soybean, tile-drained, agricultural production systems in the Upper Mississippi River basin is a major challenge that has not been met. We evaluated a range of possible management practices from biophysical and social science perspectives that could reduce nitrate losses from tile-drained fields in the Upper Salt Fork and Embarras River watersheds of east-central Illinois. Long-term water quality monitoring on these watersheds showed that nitrate losses averaged 30.6 and 23.0 kg nitrate N ha-1 yr-1 (Embarras and Upper Salt Fork watersheds, respectively), with maximum nitrate concentrations between 14 and 18 mg N L-1. With a series of on-farm studies, we conducted tile monitoring to evaluate several possible nitrate reduction conservation practices. Fertilizer timing and cover crops reduced nitrate losses (30% reduction in a year with large nitrate losses), whereas drainage water management on one tile system demonstrated the problems with possible retrofit designs (water flowed laterally from the drainage water management tile to the free drainage system nearby). Tile woodchip bioreactors had good nitrate removal in 2012 (80% nitrate reduction), and wetlands had previously been shown to remove nitrate (45% reductions) in the Embarras watershed. Interviews and surveys indicated strong environmental concern and stewardship ethics among landowners and farmers, but the many financial and operational constraints that they operate under limited their willingness to adopt conservation practices that targeted nitrate reduction. Under the policy and production systems currently in place, large-scale reductions in nitrate losses from watersheds such as these in east-central Illinois will be difficult

Bio-Physical and Social Barriers Restrict Water Quality Improvements in the Mississippi River Basin

The Gulf of Mexico hypoxic zone that was measured in July of 2013 was 15 120 km2, the result of riverine losses of nitrate and total P from the Mississippi River Basin (MRB). Despite twelve years of an action plan calling for reducing the zone to a five-year running average of 5000 km2 by 2015, little progress has been made (ref 1, Figure 1). To meet the hypoxic zone target, the 2007 plan called for 45% reductions in total N and total P. (2) There is no evidence that nutrient loading to the Gulf has decreased during this period. Here we discuss the biophysical and social barriers that have limited measurable progress. We suggest that the most viable approach to developing the suite of practices needed to reduce nutrient losses from agricultural fields is a partnership of researchers working closely with farmers to develop realistic practices on real-world farms (where the constraints that influence management are present), to document the effectiveness, and to communicate the environmental and socioeconomic results regionally. To widely implement the resulting nutrient reduction practices will require substantial new funding if we are to continue using our current agronomic production systems in the MRB

Tobacco mosaic virus delivery of phenanthriplatin for cancer therapy

Phenanthriplatin, cis-[Pt(NH(3))(2)Cl(phenanthridine)](NO(3)), is a cationic monofunctional DNA-binding platinum(II) anticancer drug candidate with unusual potency and cellular response profiles. Its in vivo efficacy has not yet been demonstrated, highlighting the need for a delivery system. Here we report tobacco mosaic virus (TMV) as a delivery system for phenanthriplatin. TMV forms hollow nanotubes with a polyanionic interior surface; capitalizing on this native structure, we developed a one-step phenanthriplatin loading protocol. Phenanthriplatin release from the carrier is induced in acidic environments. This delivery system, designated PhenPt-TMV, exhibits matched efficacy in a cancer cell panel compared to free phenanthriplatin. In vivo tumor delivery and efficacy were confirmed using a mouse model of triple negative breast cancer. Tumors treated with PhenPt-TMV were 4× smaller than tumors treated with free phenanthriplatin or cisplatin, owing to increased accumulation of phenanthriplatin within the tumor tissue. The biology-derived TMV delivery system may facilitate translation of phenanthriplatin into the clinic

Influência da minhoca Pontoscolex corethrurus na distribuição do acaricida dicofol em um Argissolo Effects of earthworm Pontoscolex corethrurus on distribution of acaricida dicofol in a Podzolic soil

O objetivo deste trabalho foi estudar a importância da minhoca Pontoscolex corethrurus na distribuição do pesticida dicofol em um Argissolo. Como modelo foram utilizados microcosmos contendo solo tamizado e acondicionado na densidade 1,25 g cm-3. Em microcosmos com e sem Pontoscolex corethurus, foram aplicados 14C-dicofol, e após um período de 52 dias fez-se uma simulação de chuvas torrenciais. Na camada de 0-1 cm, recuperou-se 75% da radioatividade no solo sem minhoca, e no solo com minhoca, a recuperação foi 9% inferior. Nas camadas mais profundas, os valores da radioatividade ficaram abaixo de 20%, e as diferenças entre os tratamentos não ultrapassaram 2%. Esta espécie de minhoca, muito freqüente no Brasil, mostrou não ter influência relevante na distribuição do pesticida no solo.<br>The aim of this work was to study the influence of earthworm on pesticides distribution in a Podzolic soil. The experimental model used was a microcosm filled with sieved soil to a final density of 1.25 g cm-3. In microcosms with or without Pontoscolex corethurus 14C-dicofol was applied, and after a period of 52 days strong rain simulation was performed. In the layer of 0-1 cm 75% of the radioactivity in the soil without earthworms were recovered, and in the soil with earthworms the recovery was 9% inferior. In the deepest layers the values of the radioactivity were below 20% and the differences among the treatments did not surpass 2%. This earthworm species of large occurrence in Brazil showed no important influence on the distribution of the pesticide in soil