K.D. Giannoulis

Panicum virgatum L. Could Be an Alternative Environmental Friendly Feedstock for Energy Production

The investigation of alternative energy sources environmentally friendly is necessary, due to the decrease of fossil fuel reserves, the increased world population needs and the increased CO2 emissions. During the past two decades, researchers started to investigate the case of producing energy through crop production. Switchgrass is a perennial crop of low input requirements and high biomass production, which could produce high amounts of energy per hectare equivalent to oil. A three years field experiment was conducted in case to examine the effects of four nitrogen fertilization and two irrigation levels, in two different soils, at two different growing stages (vegetative stage and seed mature) on dry biomass yield, calorific value and ash content of switchgrass Alamo variety. It was found that higher dry yield (27-30 t ha) reached on the aquic soil while on the xeric remained at lower levels (14-15 t ha). In the case of the average calorific value it was observed a slight increase (from 17 to 17.3 MJ/kg) according only to crop maturation, while in the case of the average ash content crop maturation had the opposite effect (5.4 and 4.5%). Therefore, it is really important to refer that switchgrass cultivation is able to produce 466 GJ ha and 1.2 t ha ashes which can be used for fertilization and its introduction in future land use systems for an environmentally friendly energy production should be seriously taken into consideration.

THE USE OF UREASE INHIBITOR FERTILIZERS (AGROTAIN) AND THEIR EFFECT ON CEREAL CROPS AND COTTON YIELD

Many commercial compounds exist that promise the increasing efficiency of urea fertilizers by inhibiting urease activity in soils. Such a compound gaining in commercial importance in the last decades is N-(n-butyl) thiophosphoric triamide, broadly known with its registered trade name of “Agrotain”. In this paper, the effect of nitrogen fertilizer dressings using Agrotain versus conventional (urea) fertilizers was studied under field conditions. In particular, the effect of three different nitrogen dressings using conventional N-fertilizers and Agrotain was investigated on the growth and final yield of (rainfed) durum wheat, and (irrigated) maize and cotton, grown on a fertile clay loamy soil in Velestino (Thessaly plain) area in central Greece in the year 2015. It was demonstrated that all three crops fertilized Agrotain obtained greater chlorophyll contents and reached significantly higher biomass and grain yields comparing to the crops receiving traditional nitrogen fertilization, obviously due to the more effective nitrogen release and uptake by the crops.Therefore, application of urease inhibitor fertilizers, such as Agrotain, might reduce nitrogen application dressings, reduce N-losses and nitrification, and their introduction to existing crop rotations is highly advisable.