Special Issue "Carbon, Nitrogen and Phosphorus Cycling in Cropland and Grassland Ecosystems"

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Soil and Plant Nutrition".

Deadline for manuscript submissions: closed (1 June 2020).

Special Issue Editor

Dr. Katja Klumpp
E-Mail Website
Guest Editor
INRA, VetAgro-Sup, UMR Ecosystème Prairial, 63000 Clermont-Ferrand, France
Interests: climate change studies; C and N cycling between plant-soil-atmosphere; C storage; GHG emissions; forage production; management effects

Special Issue Information

Dear Colleagues,

Biomass production for livestock and human needs has a great influence on nutrient cycles. Indeed, nutrient cycling in agro-ecosystems (croplands and grasslands) is often characterized by nutrient losses—partly due to the removal of agricultural products, but also due to inefficiencies in internal nutrient cycling and poor synchronization of nutrient availability with plant demand and nutrient supply. As a result, CNP cycling in agro-ecosystems is a perpetual coupling and uncoupling of nutrients, where carbon, nitrogen, and phosphorus cycles are more strongly coupled under grassland as compared to permanent cropping. An uncoupling of elemental cycles may occur through management intensification and during the transition from the soil-plant system to the animal. The geographic spread of grasslands and croplands, together with the diversity of vegetation cover (i.e., crops, forage grass, perennial cover) and management practices (tillage, fertilization, intercropping, as well as grazing and mowing), and the sometimes largely seasonally-restricted cycle of biomass production, complicates a detailed assessment of the carbon, nitrogen, and phosphor cycles and (greenhouse gas) balance, respectively. Relating production and environmental quality requires, thus, a detailed evaluation of emerging production systems and C–N–P cycles in agro-ecosystems. To improve this, we are inviting papers focusing on research on C–N–P cycles and balances in agro-ecosystems in this Special Issue.

Submissions on (but not limited to) the following topics are invited: (i) Plant–soil interactions that mediate CNP cycling (i.e., coupling and decoupling processes), (ii) C–N–P cycling in agro-ecosystems linked to management and climate (e.g., cropping systems, rotation, intensification, grazing vs. mowing), (iii) linking arable cropping and livestock production to improve CNP cycling (e.g., integrated system); (iv) advanced techniques for nutrient supply scheduling; and (v) decision support tools for nutrient diagnostics and modeling.

Dr. Katja Klumpp
Guest Editor

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Keywords

  • Management practices
  • Grazing strategies
  • Fertilization (types, quantities, application dates)
  • Cropping systems (rotation, crop type)
  • Integrated cropping systems (e.g., grass-ley)
  • Crop- and grassland models

Published Papers (11 papers)

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Research

Article
Plant Functional Diversity, Climate and Grazer Type Regulate Soil Activity in Natural Grasslands
Agronomy 2020, 10(9), 1291; https://doi.org/10.3390/agronomy10091291 - 31 Aug 2020
Cited by 2 | Viewed by 684
Abstract
Global change modifies vegetation composition in grasslands with shifts in plant functional types (PFT). Although changes in plant community composition imply changes in soil function, this relationship is not well understood. We investigated the relative importance of environmental (climatic, management and soil) variables [...] Read more.
Global change modifies vegetation composition in grasslands with shifts in plant functional types (PFT). Although changes in plant community composition imply changes in soil function, this relationship is not well understood. We investigated the relative importance of environmental (climatic, management and soil) variables and plant functional diversity (PFT composition and interactions) on soil activity and fertility along a climatic gradient. We collected samples of soil and PFT biomass (grasses, legumes, and non-legume forbs) in six extensively managed grasslands along a climatic gradient in the Northern Iberian Peninsula. Variation Partitioning Analysis showed that abiotic and management variables explained most of the global variability (96.5%) in soil activity and fertility; soil moisture and grazer type being the best predictors. PFT diversity accounted for 27% of the total variability, mostly in interaction with environmental factors. Diversity-Interaction models applied on each response variable revealed that PFT-evenness and pairwise interactions affected particularly the nitrogen cycle, enhancing microbial biomass nitrogen, dissolved organic nitrogen, total nitrogen, urease, phosphatase, and nitrification potential. Thus, soil activity and fertility were not only regulated by environmental variables, but also enhanced by PFT diversity. We underline that climate change-induced shifts in vegetation composition can alter greenhouse gas—related soil processes and eventually the feedback of the soil to the atmosphere. Full article
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Article
Carbon Budget of an Agroforestry System after Being Converted from a Poplar Short Rotation Coppice
Agronomy 2020, 10(9), 1251; https://doi.org/10.3390/agronomy10091251 - 25 Aug 2020
Viewed by 585
Abstract
Poplar (Populus L. spp.) Short Rotation Coppice systems (SRCs) for bioenergy production are being converted back to arable land. Transitioning to Alley Cropping Systems (ACSs) could be a suitable strategy for integrating former tree rows and arable crops. A field trial (Pisa, [...] Read more.
Poplar (Populus L. spp.) Short Rotation Coppice systems (SRCs) for bioenergy production are being converted back to arable land. Transitioning to Alley Cropping Systems (ACSs) could be a suitable strategy for integrating former tree rows and arable crops. A field trial (Pisa, Central Italy) was set up with the aim of assessing the C storage of an ACS system based on hybrid poplar and sorghum (Sorghum bicolor L. Moench) and comparing it with that of an SRC cultivation system. The carbon budget at the agroecosystem scale was assessed in the first year of the transition using the net biome production (NBP) approach with a simplified method. The overall NBP for the SRC was positive (96 ± 40 g C m−2 year−1), highlighting that the system was a net carbon sink (i.e., NBP > 0). However, the ACS registered a net C loss (i.e., NBP < 0), since the NBP was −93 ± 56 g C m−2 year−1. In the first year of the transition, converting the SRC into an ACS counteracted the potential beneficial effect of C storage in tree belowground biomass due to the high heterotrophic respiration rate recorded in the ACS, which was fostered by the incorporation of residues and tillage disturbance in the alley. Additional years of heterotrophic respiration measurements could allow for an estimate of the speed and extent of C losses. Full article
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Article
Tradeoff between the Conservation of Soil C Stocks and Vegetation Productivity in Temperate Grasslands
Agronomy 2020, 10(7), 1024; https://doi.org/10.3390/agronomy10071024 - 16 Jul 2020
Viewed by 517
Abstract
Grassland management affects ecosystem services such as the conservation of C stocks. The aim of this study was to analyze the relation between vegetation production and soil C stocks for a set of seven temperate grasslands of various productivity levels. We estimated vegetation [...] Read more.
Grassland management affects ecosystem services such as the conservation of C stocks. The aim of this study was to analyze the relation between vegetation production and soil C stocks for a set of seven temperate grasslands of various productivity levels. We estimated vegetation production directly through measurements of aboveground biomass (>5 cm), stubble and root biomass, and indirectly via plant community functioning. Soil C stocks were measured for bulk soil (organic C, SOC) and hot-water-extractable C (HWC) of topsoil. Plant community functioning was characterized by community-weighted mean (CWM) traits and functional diversity index. Results show a negative relation between biomass production and SOCstock. The tradeoff between productivity and SOCstock could be linked to plant community functioning and particularly Leaf Dry Matter content (LDMCCWM) which appeared to be the most relevant descriptor of plant community functioning. High SOCstock could be associated to low productivity, conservative strategy (high LDMCCWM), low soil labile C content and grassland age. Our results show a strong direct effect of management and grassland age on plant community, which in turn affects plant tissue quality and subsequent organic matter mineralization. Old permanent grasslands appeared less productive but represent an occasion for C storage and thus global change mitigation. Full article
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Article
The Contribution of Root Turnover on Biological Nitrification Inhibition and Its Impact on the Ammonia-Oxidizing Archaea under Brachiaria Cultivations
Agronomy 2020, 10(7), 1003; https://doi.org/10.3390/agronomy10071003 - 13 Jul 2020
Cited by 3 | Viewed by 603
Abstract
Aims: Biological nitrification inhibition (BNI) has been reported as an emerging technology to control soil nitrifier activity for effective N-utilization in cropping systems. Brachiaria have been reported to suppress nitrifier populations by releasing nitrification inhibitors from roots through exudation. Substantial BNI activity has [...] Read more.
Aims: Biological nitrification inhibition (BNI) has been reported as an emerging technology to control soil nitrifier activity for effective N-utilization in cropping systems. Brachiaria have been reported to suppress nitrifier populations by releasing nitrification inhibitors from roots through exudation. Substantial BNI activity has been reported to be present in the root tissues of Brachiaria grasses; however, BNI contribution, such as root turnover, has not been addressed in previous studies. The present study aimed to clarify the contribution of root turnover on BNI under Brachiaria cultivations and its impact on nitrifier populations. Methods: We monitored root growth, changes in ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) numbers, nitrification rate, and available nitrogen (N) content under seven germplasm lines of Brachiaria, for 18 months with seasonal profile sampling. Results: Brachiaria cultivation increased soil NH4+-N, available N, and total soil carbon levels. Though we did not find any correlation between the changes in AOB populations and potential nitrification, the potential nitrification rate decreased when AOA populations decreased. Multiple regression analysis indicated that BNI substances from root tissue turnover had a significant contribution to the BNI function in the field. Conclusion Results indicated that the inhibitory effect of BNI was mostly evident in AOA, and not in AOB, in this study. Brachiaria cvs. ‘Marandu’, ‘Mulato’, and ‘Tupy’ had the most substantial BNI effect among the seven cultivars evaluated. The estimated total BNI activities and available N content of root tissue explained the observed nitrification inhibition. In conclusion, the release of BNI substances through plant decomposition contributes to the decrease in the abundance of AOA, and thus the inhibition of nitrification under Brachiaria cultivation. Full article
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Article
Proposed Techniques to Supplement the Loss in Nutrient Cycling for Replanted Coffee Plantations in Vietnam
Agronomy 2020, 10(6), 905; https://doi.org/10.3390/agronomy10060905 - 25 Jun 2020
Viewed by 639
Abstract
Nutrient cycling of the coffee ecosystem is often characterized by nutrient losses during the harvest, tree’s growth, leaching and erosion. The “Coffee Rejuvenation Strategies in Vietnam” has risked not being complete on schedule, with the low survival rate of seedlings on replanted soil, [...] Read more.
Nutrient cycling of the coffee ecosystem is often characterized by nutrient losses during the harvest, tree’s growth, leaching and erosion. The “Coffee Rejuvenation Strategies in Vietnam” has risked not being complete on schedule, with the low survival rate of seedlings on replanted soil, due to the nutrient loss and imbalance supplements after a long-term of monoculture and intensive cultivation. In this study, measures, including biochemical and organic treatments were applied to replanted coffee farm, in order to supplement the loss of nutrient cycling. Survival rate, growth indicators, and soil properties from the controls and treatments, were monitored and compared during the experimental periods. The results suggested the optimal tillage model as follow: Remove old coffee trees with their stumps and roots; liming 1.5 tons/ha; dry tillage soil for the first 6 months; Intercrop Mexican marigold (Tagetes erecta) with new coffee plants for the next 6 months; From the second year, apply 5 kg of microbial organic fertilizer /hole/year; bury 30 kg of green manure/hole/2–3 years; apply NPK fertilizers according to the governmental recommended procedure. This would be a proposed integrating tillage method to supplement the lost nutrients and restore the fertility of replanted coffee soil in Vietnam. Full article
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Article
Spatial Heterogeneity of Vegetation Structure, Plant N Pools and Soil N Content in Relation to Grassland Management
Agronomy 2020, 10(5), 716; https://doi.org/10.3390/agronomy10050716 - 16 May 2020
Viewed by 691
Abstract
Spatial heterogeneity in plant and soil properties plays a key role for biogeochemical cycling, nutrient losses and ecosystem function. Different management practices are expected to induce varying levels of spatial heterogeneity in agroecosystems, but the effects of contrasting biomass removal regimes and herbivore [...] Read more.
Spatial heterogeneity in plant and soil properties plays a key role for biogeochemical cycling, nutrient losses and ecosystem function. Different management practices are expected to induce varying levels of spatial heterogeneity in agroecosystems, but the effects of contrasting biomass removal regimes and herbivore species on grassland variability and spatial pattern have faced little attention. We carried out a spatially-explicit sampling campaign and geostatistical analyses to quantify the spatial heterogeneity of the biomass and N in plants and soil for three management treatments (mowing, cattle grazing and sheep grazing) within a long-term grassland experiment. All plant and soil properties showed within-site variation, irrespective of management treatment. Within-site variation in plant variables could be ranked as grazing > mowing. Cattle grazing increased variability in vegetation structure, soil mineral N and soil C:N compared with sheep grazing. In addition, the cattle-grazed field had a higher degree of spatial structure and a more coarse-grained pattern of spatial heterogeneity in plant properties than the sheep-grazed field. However, both grazing treatments showed spatial asynchrony in above- and below-ground responses to grazing. These results demonstrate the importance of herbivore species identity as a driver of grassland spatial heterogeneity, with implications for spatial uncoupling of nutrient cycles at the field scale. Full article
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Article
Spatial and Temporal Distribution of Cattle Dung and Nutrient Cycling in Integrated Crop–Livestock Systems
Agronomy 2020, 10(5), 672; https://doi.org/10.3390/agronomy10050672 - 11 May 2020
Cited by 1 | Viewed by 775
Abstract
Residue decomposition from cattle dung is crucial in the nutrient cycling process in Integrated Crop–Livestock Systems (ICLS). It also involves the impact of the presence of trees exerted on excreta distribution, as well as nutrient cycling. The objectives of this research included (i) [...] Read more.
Residue decomposition from cattle dung is crucial in the nutrient cycling process in Integrated Crop–Livestock Systems (ICLS). It also involves the impact of the presence of trees exerted on excreta distribution, as well as nutrient cycling. The objectives of this research included (i) mapping the distribution of cattle dung in two ICLS, i.e., with and without trees, CLT and CL, respectively, and (ii) quantification of dry matter decomposition and nutrient release (nitrogen—N, phosphorus—P, potassium—K, and sulphur—S) from cattle dung in both systems. The cattle dung excluded boxes were set out from July 2018 to October 2018 (pasture phase), and retrieved after 1, 7, 14, 21, 28, 56 and 84 days (during the grazing period). The initial concentrations of N (~19 g kg−1), P (~9 g kg−1), K (~16 g kg−1), and S (~8 g kg−1) in the cattle dung showed no differences. The total N, P, K and S released from the cattle dung residues were less in the CLT system (2.2 kg ha−1 of N; 0.7 kg ha−1 of P; 2.2 kg ha−1 of K and 0.6 kg ha−1 of S), compared to the CL (4.2 kg ha−1 of N; 1.4 kg ha−1 of P; 3.6 kg ha−1 of K and 1.1 kg ha−1 of S). Lesser quantities of cattle dung were observed in the CLT (1810) compared to the CL (2652), caused by the lower stocking rate, on average, in this system (721 in the CL vs. 393 kg ha−1 in the CLT) because of the reduced amount of pasture in the CLT systems (−41%), probably due to light reduction (−42%). The density of the excreta was determined using the Thiessen polygon area. The CL system revealed a higher concentration of faeces at locations near the water points, gate and fences. The CLT affects the spatial distribution of the dung, causing uniformity. Therefore, these results strengthen the need to understand the nutrient release patterns from cattle dung to progress fertilisation management. Full article
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Article
Land-Use Effect on Soil Carbon and Nitrogen Stock in a Seasonally Dry Tropical Forest
Agronomy 2020, 10(2), 158; https://doi.org/10.3390/agronomy10020158 - 22 Jan 2020
Cited by 1 | Viewed by 703
Abstract
Total organic carbon (TOC) and total nitrogen (TN) concentration in the soil are an indicator of soil degradation. To understand how land-use may impact these concentrations in seasonally dry tropical forests (SDTF), we analyzed the effect of four land-uses on TOC stocks (STK.TOC) [...] Read more.
Total organic carbon (TOC) and total nitrogen (TN) concentration in the soil are an indicator of soil degradation. To understand how land-use may impact these concentrations in seasonally dry tropical forests (SDTF), we analyzed the effect of four land-uses on TOC stocks (STK.TOC) and TN stocks (STK.TN) in a semi-arid region of Brazil. Soil samples were collected in 12 trenches (three sites × four land-uses—dense caatinga (DC), open caatinga (OC), pasture (PA) and agriculture (AG)), in the 0–10; 10–20 and 20–30 cm layers or as far as the bedrock. The data were compared by the Kruskal–Wallis test (p ≤ 0.05) and similarity investigated by cluster analysis. STK.TOC and STK.TN the surface layer (0–10 cm) showed no significant difference (p ≤ 0.05) between the DC; OC and PA land-uses. The similarity in STK.TOC and STK.TN values between DC, OC and PA, indicate that it is possible to explore SDTF to produce biomass and protein by adopting open caatinga and pasture land uses on Neosols with very low TOC stocks. The greatest reduction in STK.TOC and STK.TN in the agriculture land-use may lead to soil degradation and contribute to the addition of CO2 to the atmosphere. Full article
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Article
Effects of Cowpea-Amaranth Intercropping and Fertiliser Application on Soil Phosphatase Activities, Available Soil Phosphorus, and Crop Growth Response
Agronomy 2020, 10(1), 79; https://doi.org/10.3390/agronomy10010079 - 06 Jan 2020
Cited by 4 | Viewed by 1044
Abstract
Low available soil phosphorus (P) is associated with its immobility, which renders it unavailable for plant uptake. In addition, farmers normally apply inorganic fertilisers to legumes to activate soil-bound phosphorus using root exudates. Sufficient soil mineral nutrition is key to sustainable crop production, [...] Read more.
Low available soil phosphorus (P) is associated with its immobility, which renders it unavailable for plant uptake. In addition, farmers normally apply inorganic fertilisers to legumes to activate soil-bound phosphorus using root exudates. Sufficient soil mineral nutrition is key to sustainable crop production, and hence food and nutritional security. The aim of this study was to quantify the acid and alkaline phosphatase activity as an indicator of P supply and availability under varying levels of nitrogen, phosphorus and potassium (NPK) fertilization and different cropping systems. An intercropping (cowpea and amaranth) and fertiliser (control, 25%, 50%, and 100% of the recommended NPK levels) field trial was laid out in a 2 × 4 factorial treatment structure in a completely randomized design (CRD) with four replications. There was higher acid and alkaline phosphatase activity in the rhizosphere of cowpea and amaranth grown as sole crops compared to those from intercropping. The cowpea and amaranth plants grown without fertiliser or 25% NPK had the highest rhizospheric phosphatase activity, while 100% NPK application exhibited the least. The markedly higher phosphatase activity from the low fertiliser application treatments indicates the possible stimulation of microbial activity to supplement P demands for the crops. The study revealed that the application of lower rates inorganic fertilisers in a legume intercrop stimulates the activity of the phosphatase enzymes, which can subsequently liberate soil-bound phosphorus. Plant tissue phosphorus concentration of cowpea and amaranth plants increased proportionately to the increase in fertiliser application up to 50% of the recommended NPK level. The land equivalent ratio (LER) was greater than 1, indicating that it is more beneficial to intercrop cowpea and amaranth as opposed to growing them as sole crops. Overall, the application of NPK fertilizer to amounts of up to 50%, based on the results of this study, appear to be better than 100% in terms of biomass accumulation and phosphate activity. Full article
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Article
Species Interactions Improve Above-Ground Biomass and Land Use Efficiency in Intercropped Wheat and Chickpea under Low Soil Inputs
Agronomy 2019, 9(11), 765; https://doi.org/10.3390/agronomy9110765 - 16 Nov 2019
Cited by 3 | Viewed by 1043
Abstract
Little is known about how the performance of legumes symbiosis affects biomass and nutrient accumulation by intercropped cereals under the field condition. To assess the agricultural services of an intercropping system; durum wheat (Triticum turgidum durum L.cv. VITRON) and chickpea (Cicer [...] Read more.
Little is known about how the performance of legumes symbiosis affects biomass and nutrient accumulation by intercropped cereals under the field condition. To assess the agricultural services of an intercropping system; durum wheat (Triticum turgidum durum L.cv. VITRON) and chickpea (Cicer arietinum L.cv. FLIP 90/13 C) were cultivated as both intercrops and sole cropping during two growing seasons under the field trial, to compare plant biomass, nodulation, N and phosphorus (P) uptake, and N nutrition index. Both the above-ground biomass and grain yield and consequently, the amount of N taken up by intercropped durum wheat increased significantly (44%, 48%, and 30%, respectively) compared with sole cropping during the two seasons. However, intercropping decreased P uptake by both durum wheat and chickpea. The efficiency in use of rhizobial symbiosis (EURS) for intercropped chickpea was significantly higher than for chickpea grown as sole cropping. The intercropped chickpea considerably increased N (49%) and P (75%) availability in durum wheat rhizosphere. In the case of chickpea shoot, the N nutrition (defined by the ratio between actual and critical N uptake by crop) and acquisition were higher in intercropping during only the first year of cropping. Moreover, biomass, grin yield, and resource (N and P) use efficiency were significantly improved, as indicated by higher land equivalent ratio (LER > 1) in intercropping over sole cropping treatments. Our findings suggest that change in the intercropped chickpea rhizosphere-induced parameters facilitated P and N uptake, above-ground biomass, grain yield, and land use efficiency for wheat crop. Full article
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Article
Soil Nitrification Potential Influences the Performance of Nitrification Inhibitors DCD and DMPP in Cropped and Non-Cropped Soils
Agronomy 2019, 9(10), 599; https://doi.org/10.3390/agronomy9100599 - 29 Sep 2019
Cited by 2 | Viewed by 1048
Abstract
The application of nitrification inhibitors (NIs) shows promise in prolonging the ammonium presence in soil with beneficial effects for agriculture ecosystems and climate change mitigation. Although the inhibitory effect (IE) of NIs has been studied in the presence of various environmental and edaphic [...] Read more.
The application of nitrification inhibitors (NIs) shows promise in prolonging the ammonium presence in soil with beneficial effects for agriculture ecosystems and climate change mitigation. Although the inhibitory effect (IE) of NIs has been studied in the presence of various environmental and edaphic conditions, little is known about the effect of soil nitrification potential (NP) on the effectiveness of NIs. Here, laboratory-scale experiments were conducted to investigate the effect of the variation in soil NP rates, among land-use type and temperature, on the performance of two nitrification inhibitors, dicyandiamide (DCD) and 3,4-dimethypyrazole phosphate (DMPP), at four NI application rates imposed upon eight cropland and non-cropland soils. We found that the IE of DCD and DMPP were organized according to soil NP rates. Nevertheless, NP was lower in non-cropped soil than in cropped systems, and DMPP-based inhibition was higher than DCD. The IE of both NIs decreased with NP and the amount of NI required to achieve an IE ≈ 50%, was significantly reduced for soils that exhibited the lowest NP rates, especially for DMPP. However, the temperature did not appear to have a major influence on IE of both DCD and DMPP, demonstrating the potential of NIs to inhibit nitrification for a wider temperature range, dependent on the NI application rate. Our findings provide evidence that change in soil NP rate has important influences on the efficacy of NI which required great consideration for N-fertilizer optimization with the application of nitrification inhibitors. Full article
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