Sugar cane straw left in the field during harvest: decomposition dynamics and composition changes

Soil Research ◽  
2017 ◽  
Vol 55 (8) ◽  
pp. 758 ◽  
Author(s):  
José G. de A. Sousa ◽  
Maurício R. Cherubin ◽  
Carlos E. P. Cerri ◽  
Carlos C. Cerri ◽  
Brigitte J. Feigl

The understanding of sugar cane straw decomposition dynamics is essential for defining a sustainable rate of straw removal for bioenergy production without jeopardising soil functioning and other ecosystem services. Thus, we conducted a field study in south-east Brazil over 360 days to evaluate sugar cane straw decomposition and changes in its composition as affected by increasing initial straw amounts and management practices. The sugar cane straw amounts tested were: (1) 3.5 Mg ha–1 (i.e. 75% removal); (2) 7.0 Mg ha–1 (i.e. 50% removal); (3) 14.0 Mg ha–1 (i.e. no removal); and (4) 21.0 Mg ha–1 (i.e. no removal plus 50% of the extra straw left on the field). In addition, two management practices were studied for the reference straw amount (14 Mg ha–1), namely straw incorporation into the soil and irrigation with vinasse. The findings showed that dry mass (DM) loss increased logarithmically as a function of the initial amount left on the soil surface. An exponential curve efficiently described straw DM and C losses, in which more readily decomposable compounds are preferably consumed, leaving compounds that are more recalcitrant in the late stages of decomposition. After 1 year of decomposition, net straw C and N losses reached approximately 70% and 23% respectively for the highest initial straw amounts. Straw incorporation in the soil significantly accelerated the decomposition process (i.e. 86% DM loss after 1 year) compared with maintenance of straw on the soil surface (65% DM loss after 1 year), whereas irrigation with vinasse had little effect on decomposition (60% DM loss after 1 year). We conclude that straw decomposition data are an essential starting point for a better understanding of the environmental effects caused by straw removal and other management practices in sugar cane fields. This information can be used in models and integrated assessments towards a more sustainable sugar cane straw management for bioenergy production.

Soil Research ◽  
2019 ◽  
Vol 57 (1) ◽  
pp. 41 ◽  
Author(s):  
Letícia L. Varanda ◽  
Maurício R. Cherubin ◽  
Carlos E. P. Cerri

Brazilian bioenergy production based on sugarcane is globally known as a sustainable energy matrix. In order to supply the growing demand for biofuels, the sugarcane area expanded by 46% in the last decade in Brazil. In addition, the industry’s interest in using sugarcane straw as raw material for bioenergy production has recently increased. Thus, understanding the straw decomposition dynamics in these new frontiers is imperative to support decision-making that will define a sustainable straw removal rate. A field experiment was conducted in three sites under a climate and soil gradient (from central to south) within the sugarcane-expansion region (i.e. Goiás, Mato Grosso do Sul and Paraná states) to evaluate the straw decomposition. The amounts of 3, 6 and 12 Mg ha–1 of straw (dry mass, DM) were left on the soil surface after harvesting, representing the straw removal rates of about 75, 50 and 0% respectively. We quantified DM loss, carbon (C) and nitrogen (N) contents and biochemical composition of the straw throughout a crop cycle (300 days). In addition, visual changes in the decomposing straw were evaluated through scanning electron microscopy. An exponential model was efficiently fitted to data of DM loss, describing the pattern of straw decomposition over time. The DM, C losses and cellulose and hemicellulose contents of straw changed over time among sites, reflecting the local edaphoclimatic conditions favourable for decomposition. The C:N ratio decreased from 106:1 to 65:1 for the lowest straw amount and 41:1 for the highest straw amount, and were correlated with the lowest (65%) and highest (76%) DM loss respectively. After the crop cycle, sugarcane straw changed visually, possible due to loss of biochemical compounds. In conclusion, lower straw removal induced an increase in the straw decomposition rate (higher DM loss over time), which could boost positive agronomic impacts such as increased C stock and improved soil quality.


1989 ◽  
Vol 40 (2) ◽  
pp. 241 ◽  
Author(s):  
MM Roper ◽  
GW Marschke ◽  
NA Smith

The effects of stubble management practices on straw decomposition (C02 production) and nitrogenase activity C2H2 reduction) were examined in situ on a black earth (pH 7.4, clay content 51%)) near Gunnedah in the wheat-belt of New South Walcs. Straw treatments were: (1) mulching (bladeploughed) or surface cultivation (scarification), (2) burning and cultivation, (3) no-tillage, and (4) incorporation (disc-ploughed). In 1979, the straw was mulched on the surface in treatment 1. When moisture was applied, preliminary measurements (1 980) showed that nitrogenase activity was highest in the incorporated treatment with less in the surface mulched and no-tillage treatments respectively. There was only a small amount of activity in the burnt treatment due to some straw remaining. In a longer-term study in 1985 and 1986 straw in treatment 1 was lightly mixed near the soil surface by scarification. Following moisture application, nitrogenase activity was significantly higher in the scarified treatment than in the incorporated treatment, indicating that depth of mixing of straw with soil was important. Nitrogenase activity in the no-tillage treatment was similar to that in the incorporated treatment, and there was substantially less activity in the burnt treatment. Production of CO2 was similar in the straw-retained treatments, but significantly lower in the burnt treatment. In a series of short-term assays throughout 1985, microbial activity from January to May 1985 decreased with falling soil temperature. With the increase in temperature from July to November 1985, there was no corresponding increase in activity. Despite changes in microbial activity throughout the year, there was little change in the numbers of N2-fixing bacteria in the 14-month period from February 1985 to March 1986, indicating stability in the potential for N2 fixation. Although surface-cultivation (scarification) of straw is apparently the most favourable for free-living N2 fixation, other factors such as erosion and disease control need to be considered in deciding which straw management practice is to be adopted.


Author(s):  
J. Hodgson

Recent assessments of the relative importance of stocking rate. stocking policy and grazing management on the output from pastoral systems are used as a starting point to argue the need for objective pasture assessments to aid control of livestock enterprises to meet production targets. Variations in stocking rates, stocking policy and other management practices all provide alternative means of control of pasture conditions which are the major determinants of pasture and animal performance. Understanding of the influence of pasture conditions on systems performance should provide a better basis for management control and for Communication between farmers, extension officers and researchers. Keywords: Stocking rate, pasture condition, pasture cover


Agriculture ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 47
Author(s):  
Kai Yang ◽  
Zejun Tang ◽  
Jianzhang Feng

Sandy soils are prone to nutrient losses, and consequently do not have as much as agricultural productivity as other soils. In this study, coal fly ash (CFA) and anionic polyacrylamide (PAM) granules were used as a sandy soil amendment. The two additives were incorporated to the sandy soil layer (depth of 0.2 m, slope gradient of 10°) at three CFA dosages and two PAM dosages. Urea was applied uniformly onto the low-nitrogen (N) soil surface prior to the simulated rainfall experiment (rainfall intensity of 1.5 mm/min). The results showed that compared with no addition of CFA and PAM, the addition of CFA and/or PAM caused some increases in the cumulative NO3−-N and NH4+-N losses with surface runoff; when the rainfall event ended, 15% CFA alone treatment and 0.01–0.02% PAM alone treatment resulted in small but significant increases in the cumulative runoff-associated NO3−-N concentration (p < 0.05), meanwhile 10% CFA + 0.01% PAM treatment and 15% CFA alone treatment resulted in nonsignificant small increases in the cumulative runoff-associated NH4+-N concentration (p > 0.05). After the rainfall event, both CFA and PAM alone treatments increased the concentrations of NO3−-N and NH4+-N retained in the sandy soil layer compared with the unamended soil. As the CFA and PAM co-application rates increased, the additive effect of CFA and PAM on improving the nutrient retention of sandy soil increased.


Author(s):  
Xue Hu ◽  
Hongyi Liu ◽  
Chengyu Xu ◽  
Xiaomin Huang ◽  
Min Jiang ◽  
...  

Few studies have focused on the combined application of digestate and straw and its feasibility in rice production. Therefore, we conducted a two-year field experiment, including six treatments: without nutrients and straw (Control), digestate (D), digestate + fertilizer (DF), digestate + straw (DS), digestate + fertilizer + straw (DFS) and conventional fertilizer + straw (CS), to clarify the responses of rice growth and paddy soil nutrients to different straw and fertilizer combinations. Our results showed that digestate and straw combined application (i.e., treatment DFS) increased rice yield by 2.71 t ha−1 compared with the Control, and digestate combined with straw addition could distribute more nitrogen (N) to rice grains. Our results also showed that the straw decomposition rate at 0 cm depth under DS was 5% to 102% higher than that under CS. Activities of catalase, urease, sucrase and phosphatase at maturity under DS were all higher than that under both Control and CS. In addition, soil organic matter (SOM) and total nitrogen (TN) under DS and DFS were 20~26% and 11~12% higher than that under B and DF respectively, suggesting straw addition could benefit paddy soil quality. Moreover, coupling straw and digestate would contribute to decrease the N content in soil surface water. Overall, our results demonstrated that digestate and straw combined application could maintain rice production and have potential positive paddy environmental effects.


Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 249
Author(s):  
Emmanuel Frossard ◽  
Frank Liebisch ◽  
Valérie Kouamé Hgaza ◽  
Delwendé Innocent Kiba ◽  
Norbert Kirchgessner ◽  
...  

New management practices must be developed to improve yam productivity. By allowing non-destructive analyses of important plant traits, image-based phenotyping techniques could help developing such practices. Our objective was to determine the potential of image-based phenotyping methods to assess traits relevant for tuber yield formation in yam grown in the glasshouse and in the field. We took plant and leaf pictures with consumer cameras. We used the numbers of image pixels to derive the shoot biomass and the total leaf surface and calculated the ‘triangular greenness index’ (TGI) which is an indicator of the leaf chlorophyll content. Under glasshouse conditions, the number of pixels obtained from nadir view (view from the top) was positively correlated to shoot biomass, and total leaf surface, while the TGI was negatively correlated to the SPAD values and nitrogen (N) content of diagnostic leaves. Pictures taken from nadir view in the field showed an increase in soil surface cover and a decrease in TGI with time. TGI was negatively correlated to SPAD values measured on diagnostic leaves but was not correlated to leaf N content. In conclusion, these phenotyping techniques deliver relevant results but need to be further developed and validated for application in yam.


Agriculture ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 83
Author(s):  
Gabriela Mühlbachová ◽  
Pavel Růžek ◽  
Helena Kusá ◽  
Radek Vavera ◽  
Martin Káš

The climate changes and increased drought frequency still more frequent in recent periods bring challenges to management with wheat straw remaining in the field after harvest and to its decomposition. The field experiment carried out in 2017–2019 in the Czech Republic aimed to evaluate winter wheat straw decomposition under different organic and mineral nitrogen fertilizing (urea, pig slurry and digestate with and without inhibitors of nitrification (IN)). Treatment Straw 1 with fertilizers was incorporated in soil each year the first day of experiment. The Straw 2 was placed on soil surface at the same day as Straw 1 and incorporated together with fertilizers after 3 weeks. The Straw 1 decomposition in N treatments varied between 25.8–40.1% and in controls between 21.5–33.1% in 2017–2019. The Straw 2 decomposition varied between 26.3–51.3% in N treatments and in controls between 22.4–40.6%. Higher straw decomposition in 2019 was related to more rainy weather. The drought observed mainly in 2018 led to the decrease of straw decomposition and to the highest contents of residual mineral nitrogen in soils. The limited efficiency of N fertilisers on straw decomposition under drought showed a necessity of revision of current strategy of N treatments and reduction of N doses adequately according the actual weather conditions.


2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M F Furmenti ◽  
F Bert ◽  
M Rucci ◽  
U Fiandra ◽  
A Scarmozzino ◽  
...  

Abstract Background The ageing of the European population leads to an increasing demand for Long-Term Care services. The security and well-being of the elderly population hosted in nursing homes (NHs) needs an effective Risk Management policy, officially sanctioned in Italy by the so-called “Legge Gelli” n.24 (March 8th, 2017) and the Directive 2011/24/EU on the application of patients' rights in cross-border healthcare. In order to verify the effective application of common “best practices” in terms of Risk Management in NHs, a tool useful to analyse risk management attitudes in Northern Italy was conceived and applied in a sample of NHs. Methods The tool, developed in collaboration with the health insurance company SHAM Italia, is composed of 124 items (with a dichotomous answer -YES/NO) on topics related to various Risk Management practices. This tool was submitted in a face-to-face interview to several Directors (Health Directors or Nursing Coordinators) of NHs in the Piedmont Region. A list of randomly-chosen NHs was contacted: 4 of them were selected for the pilot study and compiled the questionnaire. Answers were gathered and analyzed through Microsoft Excel. Results Only the 25% of NHs has a Risk Management plan with objectives and indicators of effectiveness and uses Risk Analysis instruments for a pre- and post-” risk detection. Only one has employees working mainly on Risk Management alone. The 75% of the reported events were “Adverse Events”, and all the NHs (100%) have a protocol for a patient voluntary departure or for fall prevention or for bedsores prevention; while 50% have a protocol for prevention of aggressions towards operators or for patients' suicide prevention. Conclusions This work provides a starting point to face new challenges that are looming on the European Health-care Systems: the care for the elderlies needs to be perfected to reduce inefficiencies, cut useless costs and improve safety of patients in the NHs setting. Key messages Despite safety of older patients in nursing homes is not only important but mandatory in Italy, risk management tools for this setting are lacking in literature. A new tool applied in Italian nursing homes showed that risk management needs to be implemented in practice and these results can be extended to European context.


1987 ◽  
Vol 67 (4) ◽  
pp. 825-834 ◽  
Author(s):  
M. S. AULAKH ◽  
D. A. RENNIE

The effects of wheat straw incorporation on denitrification, immobilization of N, and C mineralization were investigated at H2O contents of 60, 90 and 120% saturation. Incorporation of increasing levels of straw consistently increased the rate of denitrification for the first 4–8 d, followed by negligible N losses thereafter. In a total period of 96 d, the addition of 1.0% straw increased N losses from 2.5 to 10.1, and from 61.6 to 83.9 μg g−1 in the 60 and 120% water saturation treatments, respectively. The pattern of CO2-C evolved was practically identical to that of the denitrification rate for the initial period when sufficient [Formula: see text] was present. This study has confirmed that in flooded soils, high rates of denitrification will persist only when C is supplied by native or applied organic C sources, provided adequate [Formula: see text] is present. When [Formula: see text] was low, denitrification rates rapidly decreased, even with a sufficient supply of C. Immobilization of fertilizer N (50 μg N g−1 as K15NO3) was very rapid. Around 90% of the total immobilization of applied N occurred within 4 d. Incorporation of 1.0% straw increased the immobilization of fertilizer N from 8.4 to 42.8, and from 1.0 to 7.6% in the 60 and 120% water-saturated treatments, respectively. Remineralization of recently immobilized fertilizer N was observed after 32 d in the 60% saturation treatments only. Key words: Denitrification, wheat straw, mineralization of N


2021 ◽  
Vol 118 (39) ◽  
pp. e2106576118
Author(s):  
Yulong Yin ◽  
Rongfang Zhao ◽  
Yi Yang ◽  
Qingfeng Meng ◽  
Hao Ying ◽  
...  

Hundreds of millions of smallholders in emerging countries substantially overuse nitrogen (N) fertilizers, driving local environmental pollution and global climate change. Despite local demonstration-scale successes, widespread mobilization of smallholders to adopt precise N management practices remains a challenge, largely due to associated high costs and complicated sampling and calculations. Here, we propose a long-term steady-state N balance (SSNB) approach without these complications that is suitable for sustainable smallholder farming. The hypothesis underpinning the concept of SSNB is that an intensively cultivated soil–crop system with excessive N inputs and high N losses can be transformed into a steady-state system with minimal losses while maintaining high yields. Based on SSNB, we estimate the optimized N application range across 3,824 crop counties for the three staple crops in China. We evaluated SSNB first in ca. 18,000 researcher-managed on-farm trials followed by testing in on-farm trials with 13,760 smallholders who applied SSNB-optimized N rates under the guidance of local extension staff. Results showed that SSNB could significantly reduce N fertilizer use by 21 to 28% while maintaining or increasing yields by 6 to 7%, compared to current smallholder practices. The SSNB approach could become an effective tool contributing to the global N sustainability of smallholder agriculture.


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