Influence Of Amendments Research Articles

Gypsum amendment influences performance and mineral absorption in wheat cultivars grown in normal and saline‐sodic soils

AbstractIn arid and semi‐arid regions, soil salinity and sodicity are the most common constraints to agriculture production, in particular in North Africa. The effect of gypsum application has been widely studied in saline‐sodic soils. However, the gypsum amendment's influence on the performance, productivity and mineral absorption of salt‐sensitive and tolerant wheat cultivars in both saline‐sodic and normal soils under field conditions has not yet been investigated. A two‐season (2016–17 and 2017–18) field experiment was undertaken to investigate the impact of gypsum on wheat growth, yield and minerals uptake for salt‐tolerant and sensitive cultivars grown in normal (EC = 1.3 dS m−1, pH = 8.4 and ESP = 7.1–8.0%) and saline‐sodic soils (EC = 5.8–6.2 dS m−1, pH = 8.8 and ESP = 19.3–22.4%) in the western Nile delta, Egypt. The gypsum requirement was applied to decrease the initial ESP from 19.3–22.4 to 10.0% was calculated for 0.3 m soil depth. Gypsum application (6.0 and 4.7 ton ha1, for the first and second season, respectively) reduced soil pH, EC and ESP of saline‐sodic soil by 31.6, 7.3 and 39.0%, respectively (two‐season mean). Furthermore, gypsum application increased Ca2+, Mg2+ and K+ in the flag leaf by 54.7, 24.5 and 45.7%, respectively (2‐season mean) under saline‐sodic soil. While, in the normal soil, gypsum application increased Ca2+, Mg2+ and K+ by 67.3, 32.7 and 78.7%, respectively. In contrast, gypsum applications decreased Na+ and Cl− content by 17.2 and 15.0% and by 40.0 and 35.5%, respectively, in the saline‐sodic and normal soil, respectively. Under saline‐sodic and normal soils, gypsum application significantly increased the K/Na ratio by 90.0 and 175.2%, respectively (2‐season mean). Interestingly, across cultivars, gypsum amendment increased grain yield by 20.7% (6.9 to 8.3 t ha−1) for normal soil and by 8.0% (5.8 to 6.3 t ha−1) for saline‐sodic soil. The positive impact of gypsum was more pronounced under the normal soil and for the salt‐sensitive cultivars than in saline‐sodic soil and for salt‐tolerant cultivars. Growers can cultivate salt‐tolerant cultivars and use gypsum as a precaution to reduce saline‐sodicity build‐up and to increase nutrient absorption.

Physician Personal Services Contract Enforceability: The Influence of the Thirteenth Amendment.

We explore the influence of the Thirteenth Amendment to the US Constitution on the enforceability of personal services contracts for physicians. This influence extends from the ambiguous definition to the legal interpretation of personal services contracts. The courts have struggled with determining contracts to be a personal service and whether to grant injunctions for continued performance. The award or denial of damages due to a breach of contract is vested in these enforceability complications. Because of the Thirteenth Amendment's influence, courts and contracting parties will continue to struggle with physician personal services contract enforceability; although other points of view may exist. Possible solutions are offered for health care contract managers dealing with challenges attributable to physician personal services contracts.