Amir Sadeghpour

Assessing Tillage Systems for Reducing Ammonia Volatilization from Spring-Applied Slurry Manure

The effect of tillage management on NH3-N volatilization and its influence on succeeding corn (Zea mays L.) silage production were studied at the University of Massachusetts Agricultural Experiment Station (South Deerfield, MA) during 2010–2012 growing seasons. Tillage treatments consisted of disking before and after manure application, solid-tine aeration before and after manure application, and no-till management. The greatest NH3-N loss (61 percent) occurred within the first 8 h after slurry manure application regardless of tillage management. The greatest NH3-N emission occurred with surface application (no-till), which ranged between 5.2 and 10.3 kg NH3-N ha−1 (9–20 percent of NH3-N applied) over the 3 years of the study. Immediate incorporation of manure into soil through disking reduced NH3-N loss by 66 to 75 percent. Ammonia loss abatement with aeration before or after manure application ranged from 13 to 41 percent compared with surface manure application. Tillage management did not influence corn silage yield or quality.

Biochar Application and Drought Stress Effects on Physiological Characteristics of Silybum marianum

ABSTRACT Soil amending with biochar has been viewed as a sustainable way to improve soil moisture holding capacity. The potential of biochar application to improve water status of crops under drought stress has not been extensively evaluated. In this study, we evaluated the impact of biochar application (0%, 1%, and 2% w/w soil) on some important physiological traits of milk thistle (Silybum marianum L. Gaertn) under moderate and severe drought stress conditions in a controlled environment. Although, the application of biochar at the higher rate slightly improved soil moisture holding capacity, the magnitude of its effect was not sufficient to influence plant performance under drought stress. To get the positive effects of biochar application on milk thistle performance under drought stress, application with higher rates is probably necessary.

RESPONSE OF ALFALFA SEED YIELD AND YIELD COMPONENTS TO PHOSPHORUS FERTILIZING SYSTEMS AND SEEDING RATE AT SEMI-SALINE SOIL CONDITIONS

To study the effects of phosphorus (P) fertilizer (cow manure, phosphorus solublizing bacteria) and sowing density on seed production of alfalfa, an experiment was laid out in a three-replicated split-split plot design with four phosphorus fertilizer rates (0, 30, 60 and 90 kg ha−1) in main plots, three phosphorus-solublizing bacteria (9, 41strains, and no bacteria) in sub-plots and three sowing densities (2, 6 and 10 kg ha−1) in sub-sub plots. The highest seed yield resulted from 60 and 90 kg P ha−1. Application of bacteria strain 41 was more efficient than bacteria strain 9 in seed yield and 1000-seed weight. Seed yield at 6 seed kg ha−1 treatment was higher than 10 kg ha−1, although there was no significant difference between them. Based on the results of this experiment the triple application of P60, B41 and SD6 could be recommended as the best treatment for seed production of alfalfa (Cultivar ‘Nikshahri’) under the semi-saline condition.