Crop Fertilization on Texas High Plains Soils.

4 p

NITROGEN CARRY-OVER IMPACTS IN IRRIGATED COTTON PRODUCTION, SOUTHERN HIGH PLAINS OF TEXAS

A dynamic optimization model which introduces an intertemporal nitrate-nitrogen residual function is used to derive and evaluate nitrogen fertilizer optimal decision rules for irrigated cotton production in the Southern High Plains of Texas. Results indicate that optimal nitrogen applications critically depend on initial nitrate-nitrogen levels and nitrogen-to-cotton price ratios. Also, the results indicate that single-year optimization leads to suboptimal nitrogen applications, which helps explain long-term cotton yield declines in the Southern High Plains of Texas; but single-year optimization does not significantly impact the net present value of returns of irrigated cotton operations.Crop Production/Industries,

Phosphate Fertilizer Reactions under Various Soil Conditions

Agronomy (Soils

Crop Fertilization on Texas High Plains Soils.

4 p

Opportunities and Alternatives of Modern Radiation Oncology and Surgery for the Management of Resectable Brain Metastases.

Postsurgical radiotherapy (RT) has been early proven to prevent local tumor recurrence, initially performed with whole brain RT (WBRT). Subsequent to disadvantageous cognitive sequalae for the patient and the broad distribution of modern linear accelerators, focal irradiation of the tumor has omitted WBRT in most cases. In many studies, the effectiveness of local RT of the resection cavity, either as single-fraction stereotactic radiosurgery (SRS) or hypo-fractionated stereotactic RT (hFSRT), has been demonstrated to be effective and safe. However, whereas prospective high-level incidence is still lacking on which dose and fractionation scheme is the best choice for the patient, further ablative techniques have come into play. Neoadjuvant SRS (N-SRS) prior to resection combines straightforward target delineation with an accelerated post-surgical phase, allowing an earlier start of systemic treatment or rehabilitation as indicated. In addition, low-energy intraoperative RT (IORT) on the surgical bed has been introduced as another alternative to external beam RT, offering sterilization of the cavity surface with steep dose gradients towards the healthy brain. This consensus paper summarizes current local treatment strategies for resectable brain metastases regarding available data and patient-centered decision-making

INCORPORATION OF SOIL TEST RESULTS IN THE DEVELOPMENT OF OPTIMAL LONG-TERM FERTILIZER POLICIES FOR FARMERS

The economics of using soil test results for making fertilizer recommendations in the presence of nutrient carry-over are discussed. A model for maximizing long run returns with nutrient carry-over is presented. Dynamic programming is used to determine fertilizer applications for grain sorghum given an initial soil test value