Effects of restorative agroecosystems on soil characteristics and plant production on a degraded soil in the Georgia Piedmont, USA

2009 ◽  
Vol 24 (3) ◽  
pp. 186-196 ◽  
Author(s):  
K.L. Jacobsen ◽  
C.F. Jordan

AbstractThis work presents the results of a three-year field study of agroecosystems designed to restore soil organic matter (SOM) to degraded soils of the Georgia Piedmont. The systems combine a suite of management practices previously demonstrated to increase SOM when studied individually, and examine the effects of these techniques when used in combination in a cropping systems context on soil characteristics, crop production and weed biomass. The systems' components include organic management, alley cropping with perennial legumes, conservation tillage, use of winter cover crops, straw mulch and two compost application rates. Vegetable crops grown were a rotation of okra, hot pepper and a corn and winter squash intercrop. The systems were not able to maintain soil C or N without the addition of compost. Systems incorporating alley cropping, organic management, conservation tillage and compost maintained soil C, and increased in soil C when mulch was not applied. In organic, conservation tillage without alley cropping, soil C did not change significantly, even with annual 44.8 Mg ha−1 of compost additions. Patterns for soil N followed those of soil C. The study demonstrated that alley cropping can maintain and sequester soil C and N beyond organic conservation tillage alone, and more than conventionally tilled, chemically fertilized treatments. Crop yields did not vary by treatment due to high variation within treatments. Winter cover crop residue provided an effective weed barrier for 4 to 6 weeks in the spring, but additional hand weeding was required throughout the summer. The results of this systems-level study demonstrated interactions between management practices when used in combination that would not have been observed when studied individually. It also demonstrates that agroforestry techniques, conservation tillage and compost applications can increase soil C in degraded, clayey soils while they are in cultivation.

2021 ◽  
Author(s):  
Xenia Bischel ◽  
Marife D. Corre ◽  
Marcus Schmidt ◽  
Edzo Veldkamp

<p>Monoculture croplands are commonly associated with deleterious environmental effects due to high fertilization rates. Agroforestry (alternate alleys of trees and crops or alley cropping) has the potential to mitigate the negative environmental effects from agriculture. Understanding the soil-N cycling aids in assessing how the soil function of nutrient cycling is impacted when monoculture system is converted into agroforestry. Currently, there is no systematic comparison in soil-N cycling rates between monoculture and agroforestry croplands in Western Europe. Our study aimed to investigate gross rates of soil-N cycling between agroforestry and monoculture croplands. We measured gross rates of soil-N cycling, using 15N isotopic pool dilution in May-June 2017, at three sites in Germany (Wendhausen, Dornburg, and Forst with Vertic Cambisol, Calcaric Phaeozem, Gleyic Cambisol soils, respectively); each site has paired monoculture and agroforestry systems (established in 2008, 2007, and 2010 at the respective sites). In each management system at each site, we had four replicate plots; for agroforestry system, we conducted measurements in the tree row and within the crop row at 1 m, 4 m, and 7 m from the tree row. The crop management practices in agroforestry crop row and monoculture were the same at each site.</p><p>For gross rates of ammonium cycling, differences were observed between agroforestry tree row, crop row and monoculture at the site with Vertic Cambisol soil. Higher gross N mineralization rates were observed in monoculture than agroforestry tree row whilst agroforestry tree row exhibited higher gross NH<sub>4</sub><sup>+</sup> immobilization rates than agroforestry crop row (P < 0.02). This was correlated to higher soil C/N ratio and higher water-filled pore space in the tree row. Tree rows also tend to have higher microbial biomass at all sites. Gross rates of nitrate cycling were higher in the tree row than in the crop row and monoculture at the site with Calcaric Phaeozem soil. This showed a similar pattern with the gene abundance of ammonium oxidizing archeae (AOA), supporting a niche differentiation of AOA by utilizing ammonium mineralized from soil organic matter rather than from fertilizer source. At the site with Vertic Cambisol soil, dissimilatory nitrate reduction to ammonium was very high in the tree row. These changes in soil-N cycling and AOA gene abundance in the tree rows suggest that trees in sites with older agroforestry systems had enhanced the cycling of N in the soil.</p>


2021 ◽  
Vol 9 (5) ◽  
pp. 983
Author(s):  
Cristina Lazcano ◽  
Xia Zhu-Barker ◽  
Charlotte Decock

The use of organic fertilizers constitutes a sustainable strategy to recycle nutrients, increase soil carbon (C) stocks and mitigate climate change. Yet, this depends largely on balance between soil C sequestration and the emissions of the potent greenhouse gas nitrous oxide (N2O). Organic fertilizers strongly influence the microbial processes leading to the release of N2O. The magnitude and pattern of N2O emissions are different from the emissions observed from inorganic fertilizers and difficult to predict, which hinders developing best management practices specific to organic fertilizers. Currently, we lack a comprehensive evaluation of the effects of OFs on the function and structure of the N cycling microbial communities. Focusing on animal manures, here we provide an overview of the effects of these organic fertilizers on the community structure and function of nitrifying and denitrifying microorganisms in upland soils. Unprocessed manure with high moisture, high available nitrogen (N) and C content can shift the structure of the microbial community, increasing the abundance and activity of nitrifying and denitrifying microorganisms. Processed manure, such as digestate, compost, vermicompost and biochar, can also stimulate nitrifying and denitrifying microorganisms, although the effects on the soil microbial community structure are different, and N2O emissions are comparatively lower than raw manure. We propose a framework of best management practices to minimize the negative environmental impacts of organic fertilizers and maximize their benefits in improving soil health and sustaining food production systems. Long-term application of composted manure and the buildup of soil C stocks may contribute to N retention as microbial or stabilized organic N in the soil while increasing the abundance of denitrifying microorganisms and thus reduce the emissions of N2O by favoring the completion of denitrification to produce dinitrogen gas. Future research using multi-omics approaches can be used to establish key biochemical pathways and microbial taxa responsible for N2O production under organic fertilization.


Soil Research ◽  
2012 ◽  
Vol 50 (2) ◽  
pp. 83 ◽  
Author(s):  
W. E. Cotching

Soil carbon (C) stocks were calculated for Tasmanian soil orders to 0.3 and 1.0 m depth from existing datasets. Tasmanian soils have C stocks of 49–117 Mg C/ha in the upper 0.3 m, with Ferrosols having the largest soil C stocks. Mean soil C stocks in agricultural soils were significantly lower under intensive cropping than under irrigated pasture. The range in soil C within soil orders indicates that it is critical to determine initial soil C stocks at individual sites and farms for C accounting and trading purposes, because the initial soil C content will determine if current or changed management practices are likely to result in soil C sequestration or emission. The distribution of C within the profile was significantly different between agricultural and forested land, with agricultural soils having two-thirds of their soil C in the upper 0.3 m, compared with half for forested soils. The difference in this proportion between agricultural and forested land was largest in Dermosols (0.72 v. 0.47). The total amount of soil C in a soil to 1.0 m depth may not change with a change in land use, but the distribution can and any change in soil C deeper in the profile might affect how soil C can be managed for sequestration. Tasmanian soil C stocks are significantly greater than those in mainland states of Australia, reflecting the lower mean annual temperature and higher precipitation in Tasmania, which result in less oxidation of soil organic matter.


2021 ◽  
Author(s):  
Sylvia Vetter ◽  
Michael Martin ◽  
Pete Smith

<p>Reducing greenhouse gas (GHG) emissions in to the atmosphere to limit global warming is the big challenge of the coming decades. The focus lies on negative emission technologies to remove GHGs from the atmosphere from different sectors. Agriculture produces around a quarter of all the anthropogenic GHGs globally (including land use change and afforestation). Reducing these net emissions can be achieved through techniques that increase the soil organic carbon (SOC) stocks. These techniques include improved management practices in agriculture and grassland systems, which increase the organic carbon (C) input or reduce soil disturbances. The C sequestration potential differs among soils depending on climate, soil properties and management, with the highest potential for poor soils (SOC stock farthest from saturation).</p><p>Modelling can be used to estimate the technical potential to sequester C of agricultural land under different mitigation practices for the next decades under different climate scenarios. The ECOSSE model was developed to simulate soil C dynamics and GHG emissions in mineral and organic soils. A spatial version of the model (GlobalECOSSE) was adapted to simulate agricultural soils around the world to calculate the SOC change under changing management and climate.</p><p>Practices like different tillage management, crop rotations and residue incorporation showed regional differences and the importance of adapting mitigation practices under an increased changing climate. A fast adoption of practices that increase SOC has its own challenges, as the potential to sequester C is high until the soil reached a new C equilibrium. Therefore, the potential to use soil C sequestration to reduce overall GHG emissions is limited. The results showed a high potential to sequester C until 2050 but much lower rates in the second half of the century, highlighting the importance of using soil C sequestration in the coming decades to reach net zero by 2050.</p>


2007 ◽  
Vol 22 (3) ◽  
pp. 157-167 ◽  
Author(s):  
H. Mason ◽  
A. Navabi ◽  
B. Frick ◽  
J. O'Donovan ◽  
D. Niziol ◽  
...  

AbstractCanadian Western Hard Red Spring (CWRS) wheat is recognized as premium quality wheat, ideal for breadmaking due to its superior milling qualities, baking characteristics and protein content. Organic wheat production is becoming more prevalent in Canada, due to increasing consumer demand for organic wheat products. Differences may exist in the baking and milling quality of wheat grown under conventional and organic management, a result of the dissimilarity between organic and conventional soil and crop management practices. Five CWRS cultivars released from 1885 to 1997 were grown under conventional and organic management and were assessed for their breadmaking potential. Several traits were investigated, including test weight, protein content, flour yield, kernel hardness and several mixograph parameters. Test weight was higher under conventional management, while no differences in protein content were observed between organic and conventionally grown wheat. Higher sodium dodecyl sulfate sedimentation (SDSS) volume, a reflection of gluten strength, was observed under conventional management, while there was a trend towards higher dough strength under organic management. Cultivars differed in grain protein, flour yield, kernel hardness and mixograph parameters, with Park and McKenzie superior to the others, particularly Red Fife, a much older cultivar. Management×cultivar interaction effects suggest that cultivars exhibit somewhat different baking characteristics when grown in the two management systems. There was no evidence that older cultivars (developed prior to the widespread use of pesticides and fertilizers) are better suited, in terms of breadmaking quality, for organic production.


2018 ◽  
Author(s):  
Jacqueline R. England ◽  
Raphael Armando Viscarra Rossel

Abstract. Maintaining or increasing soil organic carbon (C) is important for securing food production, and for mitigating greenhouse gas (GHG) emissions, climate change and land degradation. Some land management practices in cropping, grazing, horticultural and mixed farming systems can be used to increase organic C in soil, but to assess their effectiveness, we need accurate and cost-efficient methods for measuring and monitoring the change. To determine the stock of organic C in soil, one needs measurements of soil organic C concentration, bulk density and gravel content, but using conventional laboratory-based analytical methods is expensive. Our aim here is to review the current state of proximal sensing for the development of new soil C accounting methods for emissions reporting and in emissions reduction schemes. We evaluated sensing techniques in terms of their rapidity, cost, accuracy, safety, readiness and their state of development. The most suitable technique for measuring soil organic C concentrations appears to be vis–NIR spectroscopy and for bulk density active gamma-ray attenuation. Sensors for measuring gravel have not been developed, but an interim solution with rapid wet-sieving and automated measurement appears useful. Field-deployable, multi-sensor systems are needed for cost-efficient soil C accounting. Proximal sensing can be used for soil organic C accounting, but the methods need to be standardised and procedural guidelines need to be developed to ensure proficient measurement and accurate reporting and verification. This is particularly important if the schemes use financial incentives for landholders to adopt management practices to sequester soil organic C. We list and discuss the requirements for the development of new soil C accounting methods that are based on proximal sensing, including requirements for recording, verification and auditing.


2021 ◽  
Vol 10 (19) ◽  
pp. 201-208
Author(s):  
Emilian Madoşă ◽  
Lavinia Sasu ◽  
Sorin Ciulca ◽  
Constantin Avădanei ◽  
Adriana Ciulca ◽  
...  

The aim of the research was to evaluate the variability value of the main characters that contribute to the achievement of plant production to a collection of hot pepper genotypes. The biological material was composed of 17 landraces of hot peppers collected from western Romania. The study was conducted for two years, with biometric measurements on the morphological characteristics of fruit production on the plant. Intra-population variability was assessed (mean, standard deviation of mean and coefficient of variability) and differences between populations for these characters. The results show that the variability within the collection is high. Within populations, fruit sizes (length, diameter) are uniform, but the number of fruits and their weight per plant show greater variability. Within the collection, variations in morphological characteristics are large, especially for fruit length, fruit weight, number and weight of fruit per plant. Among the landraces studied, some may be recommended for breeding programs, as parents or as material for the application of selection: for long fruits (Juliţa, Aldeşti I and Satchinez I), for short fruits (Satchinez III), but also the landraces Rieni III (17.07 g average weight of the fruit), Temerești II (89.82 fruits per plant), Aldești I (931.17 g fruits per plant).


2021 ◽  
Author(s):  
Jussi Heinonsalo ◽  
Anna-Reetta Salonen ◽  
Rashmi Shrestha ◽  
Subin Kalu ◽  
Outi-Maaria Sietiö ◽  
...  

<p>Soil C sequestration through improved agricultural management practices has been suggested to be a cost-efficient tool to mitigate climate change as increased soil C storage removes CO<sub>2</sub> from the atmosphere. In addition, improved soil organic carbon (SOC) content has positive impacts on farming though better soil structure and resilience against climate extremes through e.g. better water holding capacity. In some parts of the world, low SOC content is highly critical problem for overall cultivability of soils because under certain threshold levels of SOC, soil loses its ability to maintain essential ecosystem services for plant production. Soil organic amendments may increase soil C stocks, improve soil structure and boost soil microbial activities with potential benefits in plant growth and soil C sequestration. Additional organic substrates may stimulate microbial diversity that has been connected to higher SOC content and healthy soils.</p><p>We performed a two-year field experiment where the aim was to investigate whether different organic soil amendments have an impact on soil microbial parameters, soil structure and C sequestration.</p><p>The experiment was performed in Parainen in southern Finland on a clay field where oat (Avena sativa) was the cultivated crop. Four different organic soil amendments were used (two wood-based fiber products that were leftover side streams of pulp and paper industry; and two different wood-based biochars). Soil amendments were applied in 2016. Soil C/N analysis was performed in the autumns 2016-2018 and soil aggregate in the summer and autumn 2018, as well as measures to estimate soil microbial activity: microbial biomass, soil respiration, enzymatic assays, microbial community analysis with Biolog ®  EcoPlates and litter bag decomposition experiment. The relative share of bacteria and fungi was determined using qPCR from soil samples taken in the autumns 2016, 2017 and 2018.</p><p>Data on how the studied organic soil amendments influence soil structure and C content, as well as soil microbial parameters will be presented and discussed.</p>


1958 ◽  
Vol 38 (1) ◽  
pp. 36-43 ◽  
Author(s):  
H. B. McEwen ◽  
B. C. Matthews

The rate of release of non-exchangeable potassium, i.e. potassium-supplying power, of 41 Ontario soils was measured by a continuous percolation procedure. It was found that clay content of the soil was the predominant factor affecting potassium-supplying power (r = 0.978). Potassium fertilization or intensive cropping of the soil caused no change in the potassium-supplying power of the soil. As potassium-supplying power was found to be a constant characteristic of soil and not a function of previous management, potassium-supplying power measurements should not be necessary in routine soil testing. Knowledge of potassium-supplying power can be deduced from particle size distribution. Because soils of different texture have different potassium-supplying power, the interpretation of measured exchangeable potassium in terms of fertilizer requirement will be different for soils of different textural class.


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