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1.
Alexander S. de Resende Rogério P. Xavier Octávio C. de Oliveira Segundo Urquiaga Bruno J. R. Alves Robert M. Boddey 《Plant and Soil》2006,281(1-2):339-351
Since the 1970s the area under sugarcane in Brazil has increased from 2 million to over 5 million ha (M ha), and it is expected
to pass the 7 M ha mark in 2007. More than half of the cane is harvested to produce bioethanol as a fuel for light vehicles.
The distilleries produce approximately 13 L of distillery waste (vinasse) for each litre of ethanol produced. In the 1980s
there was considerable concern over the long-term effects of the disposal of this material (containing about 1% carbon and
high in K) on cane yields if it was applied to the field. At the same time there was a growing movement to abandon the practice
of pre-harvest burning and some research was showing that some Brazilian varieties of sugar cane were able to obtain significant
contributions of N from plant-associated biological nitrogen fixation (BNF). For these reasons an experiment was installed
on a cane plantation in the state of Pernambuco, NE Brazil to investigate the long-term effects of vinasse and N fertiliser
additions and the practice of pre-harvest burning on crop and sugar yield, soil fertility parameters, N balance and soil C
stocks. The results showed that over a 16-year period, trash conservation (abandonment of burning) increased cane yields by
25% from a mean of 46 to 58 Mg ha−1. Vinasse applications (80 m3 ha−1 crop−1) increased mean cane and sugar yield by 12 to 13% and the application of 80 kg N ha−1 as urea increased cane yields by 9%, but total sugar yield by less than 6% (from 7.0 to 7.4 Mg ha−1 crop−1). The total N balance for the soil/plant system when only the surface 20 cm of the soil was considered was positive in plots
where no N fertiliser was added. However, the data indicated that during the 16 years of the study considerable quantities
of soil organic matter were accumulated below 20 cm depth such that the N balance considering the soil to 60 cm depth was
strongly positive, except where N fertiliser was added. The data indicated that there were considerable BNF inputs to the
system, which was consistent with its low response to N fertiliser and low N fertiliser-use-efficiency. There were no significant
effects of vinasse or urea addition, or trash conservation on soil C stocks, although the higher yields proportioned by trash
conservation had potentially significant benefits for increased mitigation of CO2 emissions where the main use of the cane was for bioethanol production. 相似文献
2.
Pushpa Singh Archna Suman Priyanka Tiwari Namita Arya Asha Gaur A. K. Shrivastava 《World journal of microbiology & biotechnology》2008,24(5):667-673
Pretreatment of lignocellulosic biomasses, the first step in their conversion to utilizable molecules requires very high energy
(steam and electricity), corrosion resistant high-pressure reactors and high temperatures. These severe conditions not only
add to the cost component of the entire process but also lead to the loss of sugars to the side reactions. Microbial pretreatments
have been reported to be associated with reducing the cost factors as well as the severities of the reactions. Eight bioagents,
including fungi and bacteria, were screened for their pretreatment effects on sugarcane trash. They narrowed down the C:N
ratio of trash from 108:1 to a varying range of approximately 42:1 to 60:1.The maximum drop in C:N ratio of 61% was observed
using Aspergillus terreus followed by Cellulomonas uda (52%) and Trichoderma reesei and Zymomonas mobilis (49%). The bioagents helped in degradation of sugarcane trash by production of cellulases, the maximum being produced by
A. terreus, (12 fold) followed by C. uda (10 fold), Cellulomonas cartae (9 fold) and Bacillus macerans (8 fold). The microbial pretreatment of trash rendered the easy accessibility of sugars for enzymatic hydrolysis, which can be directed
for production of alcohol. 相似文献
3.
4.
Value of cane trash in nitrogen nutrition of sugarcane 总被引:1,自引:0,他引:1
The significance of trash containing 0.3 to 0.5% N in the N nutrition of sugarcane (Saccharum hybrid sp.) was investigated in pot- and field experiments using15N-labelled trash. The data obtained from the pot study with 2 silty-clay loams (a Humic Nitosol and a Humic Acrisol) showed
that surface-applied trash (10 tonnes/ha), although ground to pass a 1-mm sieve, contributed less than 10% of N removed by
sugarcane. Uptake of trash N was most active during the initial 6 months of the experiment though at the end of the study
period of 18 months less than 15% of trash N was altogether recovered by sugarcane.
In the absence of fertilizer N in a field study on the Humic Acrisol (C/N ratio 22), unground trash (5 tonnes. ha−1) depressed soil N uptake by sugarcane by immobilizing available soil N. The field study moreover confirmed that the contribution
of trash N in the supply of N to sugarcane is negligible. The value of trash would reside in its capacity to increase over
the long term the organic matter level in the soils. 相似文献
5.
Sugarcane trash (ST) was converted to ammonium carboxylates using a novel bioprocessing strategy known as long-term air-lime pretreatment/mixed-culture fermentation. At mild conditions (50 °C, 5 weeks, 1-atm air, and excess lime loading of 0.4 g Ca(OH)2/(g dry biomass)), air-lime pretreatment of ST had moderate delignification (64.4%) with little loss in polysaccharides. Without employing detoxification, sterility, expensive nutrients, or costly enzymes, the feedstock (80% treated ST/20% chicken manure) was fermented to primarily ammonium acetate (>75%) and butyrate by a mixed culture of marine microorganisms at 55 °C. In the best four-stage countercurrent fermentation, the product yield was 0.36 g total acids/(g VS fed) and the substrate conversion was 64%. Model predictions indicate both high acid concentrations (>47.5 g/L) and high substrate conversions (>70%) are possible at industrial scale. 相似文献
6.
Out of 10 thermophilic fungi isolated from wheat straw, farm yard manure, and soil, only three showed highest cellobiase,
carboxymethyl cellulase, xylanase, and FPase activities. They were identified as Aspergillus nidulans (Th4), Scytalidium thermophilum (Th5), and Humicola sp. (Th10). A fungal consortium of these three fungi was used to compost a mixture (1:1) of silica rich paddy straw and lignin rich
soybean trash. The composting of paddy straw for 3 months, during summer period in North India, resulted in a product with
C:N ratio 9.5:1, available phosphorus 0.042% and fungal biomass 6.512 mg of N-acetyl glucosamine/100 mg of compost. However, a C:N ratio of 10.2:1 and highest humus content of 3.3% was achieved with
1:1 mixture of paddy straw and soybean trash. The fungal consortium was effective in converting high silica paddy straw into
nutritionally rich compost thereby leading to economical and environment friendly disposal of this crop residue. 相似文献
7.
Abstract An active component of the female sex pheromone of Chinese locust moth, Cydia Trash Meyrick, was identified as (E, E)-8, 10-dodecadienyl acetate (E8, E10–12:Ac) by GC, GC—MS analyses and microchemical reactions. The results of field trials showed that synthetic E8, E10—-12: Ac was very attractive to the male moths. 相似文献
8.
Waldo T. Boyd 《Science activities》2013,50(4):28-29
Students examine the bacterial expansion pattern and attempt to relate what they discover to expanding powers of two. They also relate what they see and discover to increasing living space requirements in a world of infinite space and finite space to discover that living space decreases as a function of one over expanding powers of two. The population doubling effect is also related to refuse generation and food supply requirements as well as human drinking requirements. During their investigations, students engage in a series of concrete activities to demonstrate the various effects of unabated population expansion. 相似文献
9.
Contribution of N from green harvest residues for sugarcane nutrition in Brazil 总被引:1,自引:0,他引:1
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Danilo A. Ferreira Henrique C. J. Franco Rafael Otto André C. Vitti Caio Fortes Carlos E. Faroni Alan L. Garside Paulo C. O. Trivelin 《Global Change Biology Bioenergy》2016,8(5):859-866
Brazil is recognized as a prominent renewable energy producer due to the production of ethanol from sugarcane. However, in order for this source of energy to be considered truly sustainable, conservation management practices, such as harvesting the cane green (without burning) and retaining the trash in the field, need to be adopted. This management practice affects mostly the nitrogen (N) cycle through the effect of trash on immobilization–mineralization of N by soil microorganisms. The aim of the experiments reported here was to evaluate N recovery from trash (trash‐N) by sugarcane during three ratoon crop seasons: 2007, 2008 and 2009. Two field experiments were carried out, one in Jaboticabal and the other in Pradopolis, in the state of Sao Paulo, Brazil. The experiments were set up in a randomized block design with four replications. Within each plot, microplots were installed where the original trash was replaced by trash labelled with 15N, and maintained up to the fourth crop cycle. Trash‐N recovery was higher in the Jaboticabal site, the most productive one, than in the Pradópolis site. The average trash‐N recovery across the two sites after three crop cycles was 7.6 kg ha?1 (or 16.2% of the initial N content in trash), with the remaining trash‐N being incorporated into soil organic matter reserves. While these results indicate that the value of trash for sugarcane nutrition is limited in the short term, maintaining trash on the field will serve as a long‐term source of N and C for the soil. 相似文献
10.
Agronomic and environmental implications of sugarcane straw removal: a major review 总被引:1,自引:0,他引:1
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João Luís Nunes Carvalho Roberta Corrêa Nogueirol Lauren Maine Santos Menandro Ricardo de Oliveira Bordonal Clovis Daniel Borges Heitor Cantarella Henrique C. Junqueira Franco 《Global Change Biology Bioenergy》2017,9(7):1181-1195
Large‐scale bioenergy demand has triggered new approaches to straw management in Brazilian sugarcane fields. With the progressive shift from a burned to a nonburned harvest system, most of the straw presently retained on the soil surface has become economically viable feedstock for bioenergy production. The trade‐offs between the need to preserve soil quality and produce more bioenergy have been the subject of intense discussion. This study presents a synthesis of available information on the magnitude of the main impacts of straw removal from sugarcane fields for bioenergy production and therefore represents an easily available resource to guide management decisions on the recommended amount of straw to be maintained on the field to take advantage of the agronomic, environmental, and industrial benefits. Crop residues remaining on sugarcane fields provide numerous ecosystem services including nutrient recycling, soil biodiversity, water storage, carbon accumulation, control of soil erosion, and weed infestation. Furthermore, several studies reported higher sugarcane production under straw retention on the field, while few suggest that straw may jeopardize biomass production in cold regions and under some specific soil conditions. Pest control is among the parameters favored by straw removal, while N2O emissions are increased only if straw is associated with the application of N fertilizer and vinasse. An appropriate recommendation, which is clearly site specific, should be based on a minimum mass of straw on the field to provide those benefits. Overall, this review indicates that most of the agronomic and environmental benefits are achieved when at least 7 Mg ha?1 of dry straw is maintained on the soil surface. However, modeling efforts are of paramount importance to assess the magnitude and rates of straw removal considering the several indicators involved in this complex equation, so that an accurate straw recovery rate could be provided to producers and industry toward greater sustainability. 相似文献