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51.
Tomas Persson Axel Garcia y Garcia Joel O. Paz Brenda V. Ortiz Gerrit Hoogenboom 《European Journal of Agronomy》2010,32(4):272-279
The interest in producing ethanol from maize has increased during recent years. However, the potential for maize-ethanol production is restricted to the extent of the feedstock production and the feedstock collection radius around an ethanol processing plant. The harvested acreage of maize in Alabama, Florida and Georgia has varied from 115,000 ha to 1.4 million ha during the last 50 years. One basic criterion for a sustainable production of renewable bio-ethanol is a positive net energy yield (NEY), i.e. more energy must be produced than the non-renewable energy that is used in the energy production chain, including the feedstock production and transportation and the biofuel processing. The goal of this study was to evaluate the potential to produce renewable energy the form of maize-ethanol in a region with typical southeastern USA maize cropping conditions. Two maize production acreages, which represent current and historical large acreages, and two feedstock collection radii of 100 and 200 km around an ethanol plant in southwest Georgia were evaluated. Maize growth and yield were simulated with the Cropping System Model (CSM)-CERES-Maize model to account for climate and soil variability. The simulations included weather data for 68 years. The potential ethanol production and NEY were calculated based on the simulated yields and energy requirements for the production. The ethanol production potential was 30–40 times greater for the large production acreage than for the small acreage. The average NEY across all simulated years was positive for all evaluated production acreages and collection radii. However, it was negative for the large production acreage under certain weather conditions. This study showed the potential to provide for an increase in renewable ethanol production from maize in the southeastern USA to meet the demand of the ethanol processing infrastructure. 相似文献
52.
BACKGROUND: The demethylation inhibitor (DMI) fungicide myclobutanil can be an effective component of spray programmes designed to control the highly destructive plant pathogen Phakopsora pachyrhizi Syd. & P. Syd., causal agent of Asian soybean rust. Myclobutanil is known from previous studies in grapevines to be xylem mobile. This study investigates the mobility profile of myclobutanil in soybean as an important component of its effective field performance. RESULTS: Over a 12 day period under greenhouse conditions, a constant uptake of myclobutanil from leaflet surfaces into the leaflet tissue was observed. Once in the leaflet, myclobutanil was seen to redistribute throughout the tissue, although no movement out of leaflets occurred owing to a lack of phloem mobility. The ability of myclobutanil to redistribute over distance within the soybean plant was revealed when visualizing movement of the compound to foliage above the point of application on the plant stem. An efficacy bioassay demonstrated that the systemic properties of myclobutanil allow control of disease at a point remote from the initial site of compound application. CONCLUSION: It is suggested that the high degree of xylem systemicity displayed by myclobutanil in soybean foliage is a contributory factor towards its commercial effectiveness for control of Asian soybean rust. Copyright © 2008 Society of Chemical Industry 相似文献
53.
Shakeel Ahmad Ashfaq Ahmad Cecilia Manuela Tojo Soler Hakoomat Ali Muhammad Zia-Ul-Haq Jakarat Anothai Abid Hussain Gerrit Hoogenboom Mirza Hasanuzzaman 《Precision Agriculture》2012,13(2):200-218
The objectives of this study were to evaluate the performance of the cropping system model (CSM)-CERES-Rice to simulate growth
and development of an aromatic rice variety under irrigated conditions in a semiarid environment of Pakistan and to determine
the impact of various plant densities and nitrogen (N) application rates on grain yield and economic return. The crop simulation
model was evaluated with experimental data collected in experiments that were conducted in 2000 and 2001 in Faisalabad, Punjab,
Pakistan. The experimental design was a randomized complete block design with three replications and included three plant
densities (one seedling hill−1, PD1; two seedlings hill−1, PD2; and three seedlings hill−1, PD3) and five N fertilizer regimes (control, N0; 50 kg ha−1, N50; 100 kg ha−1, N100; 150 kg ha−1, N150; and 200 kg ha−1, N200). To determine the most appropriate combination of plant density and N levels, four plant densities from one seedling hill−1 to four seedlings hill−1 and 13 N levels ranging from 0 to 300 kg N ha−1 (52 scenarios) were simulated for 35 years of historical daily weather data under irrigated conditions. The evaluation of
CSM-CERES-Rice showed that the model was able to simulate growth and yield of irrigated rice in the semiarid conditions, with
an average error of 11% between simulated and observed grain yield. The results of the stimulation analysis result showed
that two seedlings hill−1 along with 200 kg N ha−1 (PD2N200) produced the highest yield as compared to all other scenarios. Furthermore, the economic analysis through the mean gini
dominance also showed the dominance of this treatment (PD2N200) compared to the other treatment combinations. Thus, the management scenario that consisted of two seedlings hill−1 and 200 kg N ha−1 was the best for high yield and monitory return of irrigated rice in the semiarid environment. The mean monetary returns
ranged from 291 US $ ha−1 to 1 460 US $ ha−1 to 1 460 US ha−1 among the 52 production options that were simulated. This approaching was demonstrated as effective way to optimize the density
and N management for high yield and monetary return. It will help the rice production. 相似文献
54.
Gerrit Gort Wim J. M. Koopman Alfred Stein Fred A. van Eeuwijk 《Journal of Agricultural, Biological & Environmental Statistics》2008,13(2):177-198
AFLP is a frequently used DNA fingerprinting technique that is popular in the plant sciences. A problem encountered in the
interpretation and comparison of individual plant profiles, consisting of band presence-absence patterns, is that multiple
DNA fragments of the same length can be generated that eventually show up as single bands on a gel. The phenomenon of two
or more fragments coinciding in a band within an individual profile is a type of homoplasy, that we call collision. Homoplasy
biases estimates of genetic similarity. In this study, we show how to calculate collision probabilities for bands as a function
of band length, given the fragment count, the band count, or band lengths. We also determine probabilities of higher order
collisions, and estimate the total number of collisions for a profile. Since short fragments occur more often, short bands
are more likely to contain collisions. For a typical plant genome and AFLP procedure, the collision probability for the shortest
band is 25 times larger than for the longest. In a profile with 100 bands a quarter of the bands may contain collisions, concentrated
at the shorter band lengths. All calculations require a careful estimate of the monotonically decreasing fragment length distribution.
Modifications of Dice and Jaccard coefficients are proposed. The principles are illustrated on data from a phylogenetic study
in lettuce. 相似文献
55.
van Dillen SM Hiddink GJ Koelen MA de Graaf C van Woerkum CM 《Public health nutrition》2008,11(5):478-485
OBJECTIVES: To unravel the concept of nutrition awareness, as it relates to risky personal nutrition-related behaviours, and to assess the sociodemographic and psychosocial correlates of nutrition awareness. DESIGN: Data were collected in a cross-sectional study with the aid of a face-to-face interview-assisted questionnaire that was based on the Precaution Adoption Process Model and Stages of Change Model. SETTING: Dutch consumer homes. SUBJECTS: Six hundred and three Dutch adults aged 18 to 80 years, selected from a panel. RESULTS: Our model explains nutrition awareness well (explained variance 53.7%). Psychosocial correlates were involvement with nutrition, health awareness, association with healthy food, perceived relevance of eating less fat, association with necessity, perceived relevance of vitamins, and perceived attributes of independent organisations. Sociodemographic correlates were gender and age. The relationship between nutrition awareness and nutrition-related behaviours proved to be very complicated. CONCLUSIONS: The value of our study is that it unravels the concept of nutrition awareness. Understanding the correlates of nutrition awareness can contribute to a more effective application of behavioural change models. Our results support increasing involvement with nutrition through personalising and tailoring to the motivational stage. 相似文献
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59.
GerritKarssen 《云南农业大学学报(自然科学版)》1999,14(Z1):126-126
Roo-t knot nematodes represent a relatively small but economically important group of obligate plant pathogens.They are distributed world-wide and parasitise on almost every higher plant species.More than eighty species have been described during the last fifty years. 相似文献
60.
The relative importance of the genotype × year (G × Y), genotype × location (G × L) and genotype × location × year (G × L × Y) interactions has significant implications on the testing strategy of crop breeding lines. The goal of this study was to examine the dynamic patterns of these three interactions for pod yield of peanut using a crop simulation model. Pod yields of 17 peanut lines in the early-rainy, mid-rainy and dry seasons at 112 locations covering all peanut production areas in Thailand were simulated for 30 years (1972–2002) with the Cropping System Model (CSM)-CROPGRO-Peanut. Combined analyses of variance were preformed for individual seasons and for overall seasons, with the number of year incrementally increasing from 2 to 30, and the relative contributions of the individual sources of variation were determined. This procedure was repeated four times with different starting years. The results showed that the environmental effects accounted for the major proportion of the total yield variation, followed by the genotype effects, while the genotype × environment (G × E) effects were rather small. The contributions of the individual sources changed as the number of years in the analysis changed. Increasing number of years in the analyses resulted in an increase in the magnitude of the G × Y and G × L × Y interactions, but a decline in the G × L contribution. The contributions of the G × Y and G × L interactions were greater and more fluctuated in the dry season, while those of the G × L × Y interactions were greater in the mid-rainy season. Notable increases in the G × Y interaction in the dry season were observed in certain years. The decline in the G × L interaction with increasing number of years was closely associated with the increase in the G × L × Y interaction, and both became stable when 6 or more years were included. Several cross-over in the ranks of peanut lines for mean pod yield in two contrasting years were also observed for the mid-rainy season. These results raise a question on the effectiveness of the strategy for using locations to replace years in varietal testing that is normally employed by breeders. The practical limit of multi-year evaluation of crop breeding lines could be overcome by the use of a crop simulation model. 相似文献