scholarly journals The effect of crop residues, cover crops, manures and nitrogen fertilization on soil organic carbon changes in agroecosystems: a synthesis of reviews

2020 ◽  
Vol 25 (6) ◽  
pp. 929-952
Author(s):  
Martin A. Bolinder ◽  
Felicity Crotty ◽  
Annemie Elsen ◽  
Magdalena Frac ◽  
Tamás Kismányoky ◽  
...  

Abstract International initiatives are emphasizing the capture of atmospheric CO2 in soil organic C (SOC) to reduce the climatic footprint from agroecosystems. One approach to quantify the contribution of management practices towards that goal is through analysis of long-term experiments (LTEs). Our objectives were to analyze knowledge gained in literature reviews on SOC changes in LTEs, to evaluate the results regarding interactions with pedo-climatological factors, and to discuss disparities among reviews in data selection criteria. We summarized mean response ratios (RRs) and stock change rate (SCR) effect size indices from twenty reviews using paired comparisons (N). The highest RRs were found with manure applications (30%, N = 418), followed by aboveground crop residue retention and the use of cover crops (9–10%, N = 995 and 129), while the effect of nitrogen fertilization was lowest (6%, N = 846). SCR for nitrogen fertilization exceeded that for aboveground crop residue retention (233 versus 117 kg C ha−1 year−1, N = 183 and 279) and was highest for manure applications and cover crops (409 and 331 kg C ha−1 year−1, N = 217 and 176). When data allows, we recommend calculating both RR and SCR because it improves the interpretation. Our synthesis shows that results are not always consistent among reviews and that interaction with texture and climate remain inconclusive. Selection criteria for study durations are highly variable, resulting in irregular conclusions for the effect of time on changes in SOC. We also discuss the relationships of SOC changes with yield and cropping systems, as well as conceptual problems when scaling-up results obtained from field studies to regional levels.

Soil Research ◽  
2019 ◽  
Vol 57 (2) ◽  
pp. 200 ◽  
Author(s):  
J. Somasundaram ◽  
M. Salikram ◽  
N. K. Sinha ◽  
M. Mohanty ◽  
R. S. Chaudhary ◽  
...  

Conservation agriculture (CA) including reduced or no-tillage and crop residue retention, is known to be a self–sustainable system as well as an alternative to residue burning. The present study evaluated the effect of reduced tillage coupled with residue retention under different cropping systems on soil properties and crop yields in a Vertisol of a semiarid region of central India. Two tillage systems – conventional tillage (CT) with residue removed, and reduced tillage (RT) with residue retained – and six major cropping systems of this region were examined after 3 years of experimentation. Results demonstrated that soil moisture content, mean weight diameter, percent water stable aggregates (>0.25mm) for the 0–15cm soil layer were significantly (Pmoderately labile>less labile. At the 0–15cm depth, the contributions of moderately labile, less labile and non-labile C fractions to total organic C were 39.3%, 10.3% and 50.4% respectively in RT and corresponding values for CT were 38.9%, 11.7% and 49.4%. Significant differences in different C fractions were observed between RT and CT. Soil microbial biomass C concentration was significantly higher in RT than CT at 0–15cm depth. The maize–chickpea cropping system had significantly (P–1 followed by soybean+pigeon pea (2:1) intercropping (3.50 t ha–1) and soybean–wheat cropping systems (2.97 t ha–1). Thus, CA practices could be sustainable management practices for improving soil health and crop yields of rainfed Vertisols in these semiarid regions.


Author(s):  
R. K. Naresh ◽  
S. S. Dhaliwal ◽  
M. S. Chandra ◽  
S. K. Malhotra ◽  
J. Harish ◽  
...  

Residues of various crops are considered nuisance but they can be helpful in increasing organic matter in soil and better cycling of nutrients in soil if managed properly. Better management and utilization of crop residues (CR) is necessary for better productivity and quality of crops. Sowing into loose residues is the major issue in adapting the drill sowing method. Apart from the higher quantity of rice (192.82 mt) and wheat residue (120.70 mt), the residue of sorghum, maize, barley, chickpea, groundnut, rapeseed, mustard, sugarcane trash, potato, soybean, sunflower and some other minor cereals also contribute substantially towards total amount of about 462.93 million tonnes in India in 1997-98. Three quarters of the total residue is produced by rice, wheat and oil seed crops with remaining quarter coming from sugarcane and sorghum. Crop residue is important component of low external input for sustainable agriculture without sacrificing productivity. The crop residues left behind is considered as burden forcing farmers to burn them as cheap and easiest method with mistaken belief that it enhances the soil fertility and helps in controlling weeds, insects and pests. Different studies revealed that burning of residues causes air pollution and nutrient loss in soil. Improvements in soil properties and the sustainability in crop productivity could be achieved if CR are proper managed. Long-term field studies at sites carefully selected with variations in temperature, moisture, soil mineralogy and management of agricultural residues representing various cropping systems across regions should be identified and sustained. The possible benefits of crop residues for the improvement of degrading soil fertility would be completely understood only then. Owing to the competing requirements for such biomass for feed, fuel or building material, smallholder farmers typically find it difficult to maintain a soil cover for crop residue or a cover crop.


2016 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Joy L. Barsotti ◽  
Upendra M. Sainju ◽  
Andrew W. Lenssen ◽  
Zach J. Miller ◽  
Patrick G. Hatfield

Sheep (<em>Ovis aries </em>L<em>.</em>) grazing, a cost-effective method of weed control compared with herbicide application and tillage, may influence soil C fractions by consuming crop residue and weeds and returning C through feces and urine to the soil. We examined the effect of three weed management practices (sheep grazing, herbicide application, and tillage) and two cropping sequences (continuous spring wheat [<em>Triticum aestivum </em>L.] [CSW] and spring wheat-pea [<em>Pisum sativum </em>L.]/barley [<em>Hordeum vulgare </em>L.] mixture hay-fallow [W-P/B-F]) on soil microbial biomass C (MBC), potential C mineralization (PCM), and particulate organic C (POC) in relation to soil organic C (SOC) at the 0- to 30-cm depth from 2009 to 2011 in southwestern Montana. The MBC at 0 to 5 cm was greater with tillage on CSW than tillage on W-P/B-F in 2009 and 2011, but was greater with herbicide application on CSW than tillage on CSW in 2010. The POC at 0 to 5 cm and 15 to 30 cm was greater with sheep grazing than herbicide application on CSW and W-P/B-F, but at 5 to 15 cm was greater with grazing on CSW. The MBC, PCM, and POC at all depths decreased from 2009 to 2011. Crop residue incorporation into the soil increased MBC with tillage on CSW. Lower proportions of labile than nonlabile organic matter through feces and urine probably reduced MBC at the soil surface, but increased POC with sheep grazing compared with herbicide application on CSW and W-P/B-F. Sheep grazing may increase coarse soil organic matter compared with microbial biomass in dryland cropping systems.


2001 ◽  
Vol 81 (1) ◽  
pp. 21-31 ◽  
Author(s):  
E G Gregorich ◽  
C F Drury ◽  
J A Baldock

Legume-based cropping systems could help to increase crop productivity and soil organic matter levels, thereby enhancing soil quality, as well as having the additional benefit of sequestering atmospheric C. To evaluate the effects of 35 yr of maize monoculture and legume-based cropping on soil C levels and residue retention, we measured organic C and 13C natural abundance in soils under: fertilized and unfertilized maize (Zea mays L.), both in monoculture and legume-based [maize-oat (Avena sativa L.)-alfalfa (Medicago sativa L.)-alfalfa] rotations; fertilized and unfertilized systems of continuous grass (Poa pratensis L.); and under forest. Solid state 13C nuclear magnetic resonance (NMR) was used to chemically characterize the organic matter in plant residues and soils. Soils (70-cm depth) under maize cropping had about 30-40% less C, and those under continuous grass had about 16% less C, than those under adjacent forest. Qualitative differences in crop residues were important in these systems, because quantitative differences in net primary productivity and C inputs in the different agroecosystems did not account for observed differences in total soil C. Cropping sequence (i.e., rotation or monoculture) had a greater effect on soil C levels than application of fertilizer. The difference in soil C levels between rotation and monoculture maize systems was about 20 Mg C ha-1. The effects of fertilization on soil C were small (~6 Mg C ha-1), and differences were observed only in the monoculture system. The NMR results suggest that the chemical composition of organic matter was little affected by the nature of crop residues returned to the soil. The total quantity of maize-derived soil C was different in each system, because the quantity of maize residue returned to the soil was different; hence the maize-derived soil C ranged from 23 Mg ha-1 in the fertilized and 14 Mg ha-1 in the unfertilized monoculture soils (i.e., after 35 maize crops) to 6-7 Mg ha-1 in both the fertilized and unfertilized legume-based rotation soils (i.e., after eight maize crops). The proportion of maize residue C returned to the soil and retained as soil organic C (i.e., Mg maize-derived soil C/Mg maize residue) was about 14% for all maize cropping systems. The quantity of C3-C below the plow layer in legume-based rotation was 40% greater than that in monoculture and about the same as that under either continuous grass or forest. The soil organic matter below the plow layer in soil under the legume-based rotation appeared to be in a more biologically resistant form (i.e., higher aromatic C content) compared with that under monoculture. The retention of maize residue C as soil organic matter was four to five times greater below the plow layer than that within the plow layer. We conclude that residue quality plays a key role in increasing the retention of soil C in agroecosystems and that soils under legume-based rotation tend to be more “preservative” of residue C inputs, particularly from root inputs, than soils under monoculture. Key words: Soil carbon, 13C natural abundance, 13C nuclear magnetic resonance, maize cropping, legumes, root carbon


Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 120-126 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Louis J. Molnar ◽  
C. Wayne Lindwall

Field studies were conducted from 1993 through 1995 to determine potential reductions in herbicide use and associated cost savings by utilizing a weed-sensing sprayer, named Detectspray, to control weeds throughout the fallow season and to control perennial weeds after crop harvest. The Detectspray system gave comparable weed control to conventional broadcast spraying on 80% of the application dates and reduced glyphosate/dicamba use over the fallow season by 19 to 60%. This reduced herbicide use resulted in cost savings of $6 to $32 ha−1. A fallow treatment that combined two herbicide applications with the Detectsprayer plus one to two wide-blade tillage operations was less costly than conventional tillage at two of 11 sites and at all sites retained more surface crop residues to reduce the risk of erosion. Postharvest glyphosate use on quackgrass with the Detectsprayer was reduced 50 to 78% compared to broadcast applications and resulted in cost savings of $16 to $25 ha−1. Clopyralid use on Canada thistle with the Detectsprayer was reduced 71 to 80%, with cost savings of $44 to $50 ha−1. The Detectspray system is a useful tool to effectively manage weeds in conservation fallow and reduced tillage cropping systems.


2021 ◽  
Vol 42 (4) ◽  
pp. 1053-1061
Author(s):  
M. Kumar ◽  
◽  
S. Mitra ◽  
A. Bera ◽  
M.R. Naik ◽  
...  

Aim: Assessment of energy input output relationship, greenhouse gases emission and carbon footprint of diversified jute-rice cropping systems under different nutrients and crop residue management practices. Methodology: The inventory was prepared for all inputs required for crop cultivation and outputs of crops in cropping systems. These inputs and outputs were converted into energy by multiplying with energy equivalent coefficient and CO2 emission coefficient following standard procedure. Results: Jute-rice-baby corn cropping system recorded significantly higher net energy (324 GJ ha-1) and energy use efficiency (8.02). Among different nutrient and crop management (NCRM) practices, significantly higher energy output (336.9 GJ ha-1) and net energy (291.4 GJ ha-1) recorded 100% NPK with crop residue. The highest carbon footprint recorded with rice-rice (0.44 kg COe kg-1 economic yield) and the lowestwith jute-rice-pea (0.29 kg COe kg-1 economic yield) cropping system. Among different NCRM practices, higher carbon footprint was (0.38 kg COe kg-1 economic yield) recorded with 100% NPK with crop residue. Interpretation: The energy efficient and low input required cropping systems which include legume crops like garden pea and mungbean should be considered for cultivation for diversifying the existing rice-rice cropping system in Eastern India.


Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 539 ◽  
Author(s):  
R. Michael Lehman ◽  
Shannon L. Osborne ◽  
Kimberly McGraw

Linking agricultural management tactics to quantifiable changes in soil health-related properties is a key objective for increasing adoption of the most favorable management practices. We used two long-term, no-till cropping studies to illustrate the variable patterns of response of soil structure indices and microbial activity to additional management tactics, including crop rotational diversity, residue management and cover cropping. We found that observable effects of management tactics on soil properties were often dependent on the current crop phase sampled, even though the treatments were well-established. In some cases, a single additional management tactic produced a response, two tactics each produced a response and sometimes there were interactions between tactics. However, importantly, we never observed a negative effect for any of the response variables when stacking soil health building practices in no-till cropping systems. The collective results from the two field studies illustrate that soil health improvements with stacking management tactics are not always simply additive and are affected by temporal relationships inherent to the treatments. We conclude that the implementation of multiple positive management tactics increases the likelihood that improvements in soil properties can be documented with one or more of the proxy measures for soil health.


Weed Science ◽  
2013 ◽  
Vol 61 (3) ◽  
pp. 403-409 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
Seth B. Abugho

Crop residues acting as mulches can influence weed seedling emergence and weed biomass. A field study was conducted to evaluate the effect of rice residue amounts (0, 3, and 6 t ha−1) on seedling emergence of eight weed species in zero-till dry-seeded rice. The highest seedling emergence of spiny amaranth, southern crabgrass, crowfootgrass, junglerice, eclipta, goosegrass, and Chinese sprangletop was observed in the absence of residue. Seedling emergence of these weeds declined with increasing residue amounts; however, the greatest and most substantial reductions in emergence occurred with 6 t ha−1of residue. The presence of residue also resulted in less weed biomass than with the no-residue treatment. The emergence and biomass of threelobe morningglory seedlings, however, were not influenced by residue amounts. The use of residue also increased the time taken to reach 50% of maximum emergence for some species, for example, spiny amaranth and Chinese sprangletop. The results of our study suggest that the use of residue at high rates can help suppress seedling emergence and growth of many weeds. However, there is a need to integrate other weed management strategies with residue retention to achieve season-long weed control.


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