Nitrogen, energy and land use efficiencies of miscanthus, reed canary grass and triticale as determined by the boundary line approach

Abstract

The quantities and use efficiencies of nitrogen (N) fertilizer and energy input are seen as important indicators for the environmental impact of the production of energy crops. On the other hand, the high targets set in Europe for the production of biofuels will require high energy yields and efficient use of available agricultural land. The aim of this study is to describe the N, energy and land use efficiencies in relation to the N supply, for the energy crops triticale (Triticosecale Wittmack) -harvested as whole crop -reed canary grass (Phalaris arundinacea L.) and miscanthus (Miscanthus  giganteus). Field trials in Southwest Germany (48-498N latitude) were performed to measure the biomass and bioenergy yields at different N fertilizer levels. The nitrogen use efficiency (NUE), defined as the ratio of biomass yield to N supply (sum of soil NO 3 À -N and N fertilized) and the energy use efficiency (EUE) (net energy yield/energy input), were derived from data on biomass and bioenergy yields by the boundary line approach. For all three crops, NUE and EUE decreased with increasing N fertilizer rates. NUE and EUE were at all N and energy inputs highest for miscanthus and lowest for reed canary grass. At an N supply of 100 kg ha À1 a À1 , the NUEs of miscanthus, triticale and reed canary grass were 0.35, 0.14 and 0.11 t dry biomass/kg N, respectively. At an energy input of 10 GJ ha À1, the EUEs for miscanthus, triticale and reed canary grass were 54, 26 and 13 GJ bioenergy per GJ energy input, respectively. The highest net energy yields (here used as indicator for the land use efficiency) of triticale and reed canary grass were harvested at the highest N fertilizer level of 140 kg N, with maximum values of 281 and 129 GJ ha À1 a À1, respectively. These results show that for triticale and reed canary grass, the maximization of NUE, EUE and land use efficiency are conflicting. Only for miscanthus, the N, energy and land use efficiencies were simultaneously highest at the lowest N supply level. A maximum net energy yield of 590 GJ ha À1 a À1 was harvested from miscanthus. It was concluded that the best way to maximize resource use efficiency in biomass production is to choose for the production of the perennial C4 crop miscanthus, at those locations that are suitable for miscanthus production. #

Concentration- and flux-based ozone dose–response relationships for five poplar clones grown in North China

“…It was assumed that there is no strong correlation between f VPD and f temp , even though VPD was estimated based on temperature (Pleijel et al, 2002). These mathematical functions were parameterized using a boundary line technique, which was first introduced by Webb (1972), and has been widely used in plant and soil science models (Bhat and Sujatha, 2013;Blanco-Macías et al, 2010;Lewandowski and Schmidt, 2006;Topp et al, 2013;Vizcayno-Soto and Côte, 2004). It was based on the principle that biological materials have an upper response limit to a given variable (Imhoff et al, 2010).…”

Effects of Application of Solidified Sewage Sludge on the Growth of Bioenergy Crops in Reclaimed Land

“…그러나 식량자원을 에너지자원으로 이용하게 되면서 국제 식량의 가격 폭등과 제 3세계의 식량 부족현상 등의 식량 윤리문제를 야기하게 되었다 (Koonin, 2006) (Atkinson, 2009;Chou, 2009;Greef et al, 1997;Moon et al, 2010). 억새는 질소 이용률이 높아 질소 무비재배가 가능하고 (Lewandowski & Schmidt, 2006), 병해충에 강한 내성을 가지고 있으며 (Beale & Long, 1995), 영년생 작물 이기 때문에 한번 재식한 이후 매년 경운, 파종 등의 농작 업을 생략할 수 있어 타 에너지 작물에 비해 에너지 산출/ 투입 수지가 높다 (Moon et al, 2010). 더 나아가 한발, 염 해, 저온 등의 불리한 환경에 대한 내성이 강하고 염해지 토 양조건에서 적응력이 탁월하여 간척지 등에 재배 가능한 가 장 유망한 비 식량 바이오에너지 작물이라 할 수 있다 Moon et al, 2010).…”

A survey of the combined effects of waterlogging and salinity on fruit yield in the date palm groves of the Wargla basin, Algeria

“…At the boundary limit, the independent variable is assumed to be the main factor limiting the dependent variable, while the effects of other factors are insignificant. In the situations described by the data located below the boundary line, yield is limited by one or more other factors [13,16]. One weakness of this approach is that the influence of the factors is analyzed one at a time; the method is thus only appropriate if one is interested in the effects of only one or two limiting factors [17].…”

“…The principle of the boundary line approach was described by Webb [12], and subsequently applied to describe the effect of environmental variables such as soil nutrients [13], salinity [11,14] or a combination of factors [15]. This approach assumes that the boundary line at the outer rim of the data body depicts the functional dependence between a dependent variable (e.g., crop yield) and an independent variable (e.g., soil salinity), and may be of greater interest than the line of best fit through the cloud of data [11].…”