scholarly journals Assessing the impacts of agricultural managements on soil carbon stocks, nitrogen loss and crop production — a modelling study in Eastern Africa

2022 ◽  
Author(s):  
Jianyong Ma ◽  
Sam S. Rabin ◽  
Peter Anthoni ◽  
Anita D. Bayer ◽  
Sylvia S. Nyawira ◽  
...  

Abstract. Improved agricultural management plays a vital role in protecting soils from degradation in Eastern Africa. Changing practices such as reducing tillage, fertilizer use or cover crops are expected to enhance soil organic carbon (SOC) storage, with climate change mitigation co-benefits, while increasing crop production. However, the quantification of cropland managements’ effects on agricultural ecosystems remains inadequate in this region. Here, we explored seven management practices and their potential effects on soil carbon (C) pools, nitrogen (N) losses, and crop yields under different climate scenarios, using the dynamic vegetation model LPJ-GUESS. The model performance is evaluated against observations from two long-term maize field trials in western Kenya and reported estimates from published sources. LPJ-GUESS generally produces soil C stocks and maize productivity comparable with measurements, and mostly captures the SOC decline under some management practices that is observed in the field experiments. We found that for large parts of Kenya and Ethiopia, an integrated conservation agriculture practice (no-tillage, residue and manure application, and cover crops) increases SOC levels in the long term (+11 % on average), accompanied by increased crop yields (+22 %) in comparison to the standard management. Planting nitrogen-fixing cover crops in our simulations is also identified as a promising individual practice in Eastern Africa to increase soil C storage (+4 %) and crop production (+18 %), with low environmental cost of N losses (+24 %). These management impacts are also sustained in simulations of three future climate pathways. This study highlights the possibilities of conservation agriculture when targeting long-term environmental sustainability and food security in crop ecosystems, particularly for those with poor soil conditions in tropical climates.

2018 ◽  
Author(s):  
Carmen Emmel ◽  
Annina Winkler ◽  
Lukas Hörtnagl ◽  
Andrew Revill ◽  
Christof Ammann ◽  
...  

Abstract. Croplands are involved in the exchange of carbon dioxide (CO2) between the atmosphere and the biosphere. Further- more, soil carbon (C) stocks play an important role in soil fertility. It is, thus, of great interest to know whether croplands act as a net source or sink of atmospheric CO2, and if soil C stocks are preserved over long timescales. The FLUXNET site CH-Oe2 in Oensingen, Switzerland has been operational since the end of 2003. This cropland is managed under the Swiss framework of the Proof of Ecological Performance (PEP, a variant of integrated management) with a crop rotation centred on winter wheat, which also includes winter barley, winter rapeseed, peas, potato and intermediate cover crops. In addition to eddy covariance measurements, meteorological and soil measurements were available along with information on C imports and exports from organic fertilisation, sowing and harvesting. This study investigates cropland C budgets over 13 years and assesses whether the PEP regulations resulted in a balanced C budget. Strongest CO2 uptake was observed during cereal seasons. C export through harvest, however, offset the strong uptake of the cereal crops. The largest net CO2 emissions to the atmosphere were observed during pea and cover crop seasons. Net biome production, representing the overall C budget, typically ranged between close to C neutral to C losses of up to 407 g C m−2 per season, with peas being the largest source. Overall, the field lost 1674 g C m−2 over thirteen years (129 g C m−2 yr−1), which was confirmed by soil C stock measurements at the beginning and the end of the study period. Although managing the field under the regulations of PEP did not result in an overall C sink, model simulations showed that the use of cover crops reduced the C losses compared to leaving the field bare. The use of solid manure improved the C budget by importing substantial amounts of C into the soil while liquid manure had only a small effect. We thus conclude that additional efforts are needed to bring Swiss management practices closer to the goal of preserving soil C in the long-term.


2018 ◽  
Vol 15 (17) ◽  
pp. 5377-5393 ◽  
Author(s):  
Carmen Emmel ◽  
Annina Winkler ◽  
Lukas Hörtnagl ◽  
Andrew Revill ◽  
Christof Ammann ◽  
...  

Abstract. Croplands are involved in the exchange of carbon dioxide (CO2) between the atmosphere and the biosphere. Furthermore, soil carbon (C) stocks play an important role in soil fertility. It is thus of great interest to know whether intensively managed croplands act as a net source or sink of atmospheric CO2 and if soil C stocks are preserved over long timescales. The FluxNet site CH-Oe2 in Oensingen, Switzerland, has been operational since the end of 2003. This cropland is managed under the Swiss framework of the Proof of Ecological Performance (PEP, a variant of integrated management) with a crop rotation centred on winter wheat, which also includes winter barley, winter rapeseed, peas, potato and intermediate cover crops. In addition to eddy covariance measurements, meteorological and soil measurements were available along with information on C imports and exports from organic fertilisation, sowing and harvesting. This study investigates cropland C budgets over 13 years and assesses whether the PEP regulations resulted in a balanced C budget. The strongest CO2 uptake was observed during cereal seasons. C export through harvest, however, offset the strong uptake of the cereal crops. The largest net CO2 emissions to the atmosphere were observed during pea and cover crop seasons. Net biome production, representing the overall C budget (assuming carbon leaching to groundwater to be negligible), typically ranged between close to C neutral to C losses of up to 407 g C m−2 per season, with peas being the largest source. Overall, the field lost 1674 g C m−2 over 13 years (129 g C m−2 yr−1), which was confirmed by soil C stock measurements at the beginning and the end of the study period. Although managing the field under the regulations of PEP did not result in an overall C sink, model simulations showed that the use of cover crops reduced the C losses compared to leaving the field bare. The use of solid manure improved the C budget by importing substantial amounts of C into the soil, while liquid manure had only a small effect. We thus conclude that additional efforts are needed to bring Swiss management practices closer to the goal of preserving soil C in the long term.


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):  
Beatriz Gómez‐Muñoz ◽  
Lars Stoumann Jensen ◽  
Lars Munkholm ◽  
Jørgen Eivind Olesen ◽  
Elly Møller Hansen ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yang Su ◽  
Benoit Gabrielle ◽  
Damien Beillouin ◽  
David Makowski

AbstractConservation agriculture (CA) has been promoted to mitigate climate change, reduce soil erosion, and provide a variety of ecosystem services. Yet, its impacts on crop yields remains controversial. To gain further insight, we mapped the probability of yield gain when switching from conventional tillage systems (CT) to CA worldwide. Relative yield changes were estimated with machine learning algorithms trained by 4403 paired yield observations on 8 crop species extracted from 413 publications. CA has better productive performance than no-till system (NT), and it stands a more than 50% chance to outperform CT in dryer regions of the world, especially with proper agricultural management practices. Residue retention has the largest positive impact on CA productivity comparing to other management practices. The variations in the productivity of CA and NT across geographical and climatical regions were illustrated on global maps. CA appears as a sustainable agricultural practice if targeted at specific climatic regions and crop species.


Weed Science ◽  
2009 ◽  
Vol 57 (4) ◽  
pp. 417-426 ◽  
Author(s):  
Vince M. Davis ◽  
Kevin D. Gibson ◽  
Thomas T. Bauman ◽  
Stephen C. Weller ◽  
William G. Johnson

Horseweed is an increasingly common and problematic weed in no-till soybean production in the eastern cornbelt due to the frequent occurrence of biotypes resistant to glyphosate. The objective of this study was to determine the influence of crop rotation, winter wheat cover crops (WWCC), residual non-glyphosate herbicides, and preplant application timing on the population dynamics of glyphosate-resistant (GR) horseweed and crop yield. A field study was conducted from 2003 to 2007 in a no-till field located at a site that contained a moderate infestation of GR horseweed (approximately 1 plant m−2). The experiment was a split-plot design with crop rotation (soybean–corn or soybean–soybean) as main plots and management systems as subplots. Management systems were evaluated by quantifying in-field horseweed plant density, seedbank density, and crop yield. Horseweed densities were collected at the time of postemergence applications, 1 mo after postemergence (MAP) applications, and at the time of crop harvest or 4 MAP. Viable seedbank densities were also evaluated from soil samples collected in the fall following seed rain. Soybean–corn crop rotation reduced in-field and seedbank horseweed densities vs. continuous soybean in the third and fourth yr of this experiment. Preplant herbicides applied in the spring were more effective at reducing horseweed plant densities than when applied in the previous fall. Spring-applied, residual herbicide systems were the most effective at reducing season-long in-field horseweed densities and protecting crop yields since the growth habit of horseweed in this region is primarily as a summer annual. Management systems also influenced the GR and glyphosate-susceptible (GS) biotype population structure after 4 yr of management. The most dramatic shift was from the initial GR : GS ratio of 3 : 1 to a ratio of 1 : 6 after 4 yr of residual preplant herbicide use followed by non-glyphosate postemergence herbicides.


2017 ◽  
Vol 5 (1) ◽  
pp. 42-50
Author(s):  
Nabin Rawal ◽  
Rajan Ghimire ◽  
Devraj Chalise

Balanced nutrient supply is important for the sustainable crop production. We evaluated the effects of nutrient management practices on soil properties and crop yields in rice (Oryza sativa L.) - rice - wheat (Triticum aestivum L.) system in a long-term experiment established at National Wheat Research Program (NWRP), Bhairahawa, Nepal. The experiment was designed as a randomized complete block experiment with nine treatments and three replications. Treatments were applied as: T1- no nutrients added, T2- N added; T3- N and P added; T4- N and K added; T5- NPK added at recommended rate for all crops. Similarly, T6- only N added in rice and NPK in wheat at recommended rate; T7- half N; T8- half NP of recommended rate for both crops; and T9- farmyard manure (FYM) @10 Mg ha-1 for all crops in rotation. Results of the study revealed that rice and wheat yields were significantly greater under FYM than all other treatments. Treatments that did not receive P (T2, T3, T7, T8) and K (T2, T4) had considerably low wheat yield than treatments that received NPK (T5) and FYM (T9). The FYM lowered soil pH and improved soil organic matter (SOM), total nitrogen (TN), available phosphorus (P), and exchangeable potassium (K) contents than other treatments. Management practices that ensure nutrient supply can increase crop yield and improve soil fertility status.Int. J. Appl. Sci. Biotechnol. Vol 5(1): 42-50


2020 ◽  
Vol 13 (1) ◽  
pp. 41
Author(s):  
Anny Mulyani ◽  
Mamat Haris Suwanda

<p><strong>Abstrak</strong>. Wilayah Nusa Tenggara mempunyai lahan kering beriklim kering seluas 4,9 juta ha dengan curah hujan &lt;2.000 mm/tahun dan bulan kering 5-10 bulan, bersolum tanah dangkal dan berbatu. Sebagian lahan tersebut sudah dimanfaatkan menjadi lahan pertanian terutama jagung, akibatnya produktivitas tanaman jagung rendah dibandingkan potensi genetiknya, yaitu sekitar 2,5 ton/ha di NTT dan 5,3 ton/ha di NTB dibanding dengan potensi genetiknya 9 ton/ha. Sejak tahun 2010-2015, Badan Penelitian dan Pengembangan Pertanian telah mengembangkan inovasi teknologi pengelolaan lahan kering beriklim kering dan berbatu di beberapa kabupaten di NTT dan NTB, meliputi penyediaan sumberdaya air (dam parit, embung, tampung renteng mini, sumur dangkal), pengenalan varietas unggul baru dan budidaya tanaman pangan. Pembelajaran yang diperoleh menunjukkan bahwa penyediaan air menjadi titik ungkit untuk meningkatkan indeks pertanaman dan produktivitas tanaman. Inovasi teknologi yang dibutuhkan petani adalah, mudah diterapkan, biaya murah, dan efisien tenaga kerja mendorong berlanjutnya teknologi tersebut meskipun progam tersebut telah selesai. Pada tahun 2014-2018 telah dilaksanakan kegiatan pertanian konservasi melalui dana hibah barang dan jasa yang dikelola FAO. Prinsip dasar pertanian konservasi terdiri atas 3 pilar, yaitu olah tanah terbatas berupa lubang olah permanen, penutupan permukaan tanah, rotasi/tumpangsari. Lubang tanam tersebut diberi pupuk kandang atau kompos, dan ditanami jagung pada 4 penjuru lubang, dan ditumpangsarikan dengan berbagai kacang-kacangan atau tanaman merambat seperti labu kuning yang berfungsi sebagai penutup tanah dan penghasilan tambahan dari kacang-kacangan berumur pendek. Berdasarkan hasil analisis tanah sebelum dan sesudah implementasi pertanian konservasi menunjukkan bahwa pertanian konservasi dapat meningkatkan kesuburan tanah, retensi air dan meningkatkan produksi tanaman jagung.</p><p> </p><p><strong>Abstract</strong>. The Nusa Tenggara region has upland area with dry climate of 4.9 million ha, less than 2,000 mm annual rainfall, 5-10 dry months, shallow and rocky soils. Some of the land has been used for agricultural development, especially corn, resulting in low corn productivity of around 2.5 tons / ha in NTT and 5.3 tons / ha in NTB as compared to it genetic potential 9 tons /ha. Since 2010-2015, Indonesian Agency of Agricultural Research and Development has developed innovation of soil management technology for upland with dry climates and and rocky soils in several districts in NTT and NTB. The innovation includes the provision of water resources (dam trenches, reservoirs, mini catchments, and shallow wells), introduction of new high yielding varieties and cultivation crops. The lessons learned show that water supply is the initial point to increase cropping index and crop productivity. Technological innovations needed by farmers are easy to implement, low cost, and labor efficient thereby encourage the continuation of the technology even though the program has been completed. In 2014-2018, conservation agriculture activities were carried out through grants of goods and services managed by Food Agriculture Organization (FAO). The basic principle of conservation agriculture consists of 3 pillars, namely limited tillage in the form of permanent planting holes, cover crops, rotation / intercropping. The planting hole is given manure or compost, and planted with corn in 4 corners, and intercropped with various nuts or vines such as pumpkin that serves as a soil cover and additional income from short-lived beans. Based on the results of soil analysis before and after the implementation of conservation agriculture, it shows that conservation agriculture can increase soil fertility, water retention and increase corn crop production.</p>


2022 ◽  
pp. 112-120
Author(s):  
Jeffrey P. Mitchell ◽  
Anil Shrestha ◽  
Lynn Epstein ◽  
Jeffery A. Dahlberg ◽  
Teamrat Ghezzehei ◽  
...  

To meet the requirements of California's Sustainable Groundwater Management Act, there is a critical need for crop production strategies with less reliance on irrigation from surface and groundwater sources. One strategy for improving agricultural water use efficiency is reducing tillage and maintaining residues on the soil surface. We evaluated high residue no-till versus standard tillage in the San Joaquin Valley with and without cover crops on the yields of two crops, garbanzo and sorghum, for 4 years. The no-till treatment had no primary or secondary tillage. Sorghum yields were similar in no-till and standard tillage systems while no-till garbanzo yields matched or exceeded those of standard tillage, depending on the year. Cover crops had no effect on crop yields. Soil cover was highest under the no-till with cover crop system, averaging 97% versus 5% for the standard tillage without cover crop system. Our results suggest that garbanzos and sorghum can be grown under no-till practices in the San Joaquin Valley without loss of yield.


2021 ◽  
Author(s):  
Sara Minoli ◽  
Jonas Jägermeyr ◽  
Senthold Asseng ◽  
Christoph Müller

&lt;p&gt;Broad evidence is pointing at possible adverse impacts of climate change on crop yields. Due to scarce information about farming management practices, most global-scale studies, however, do not consider adaptation strategies.&lt;/p&gt;&lt;p&gt;Here we integrate models of farmers' decision making with crop biophysical modeling at the global scale to investigate how accounting for adaptation of crop phenology affects projections of future crop productivity under climate change. Farmers in each simulation unit are assumed to adapt crop growing periods by continuously selecting sowing dates and cultivars that match climatic conditions best. We compare counterfactual management scenarios, assuming crop calendars and cultivars to be either the same as in the reference climate &amp;#8211; as often assumed in previous climate impact assessments &amp;#8211; or adapted to future climate.&lt;/p&gt;&lt;p&gt;Based on crop model simulations, we find that the implementation of adapted growing periods can substantially increase (+15%) total crop production in 2080-2099 (RCP6.0). In general, summer crops are responsive to both sowing and harvest date adjustments, which result in overall longer growing periods and improved yields, compared to production systems without adaptation of growing periods. Winter wheat presents challenges in adapting to a warming climate and requires region-specific adjustments to pre and post winter conditions. We present a systematic evaluation of how local and climate-scenario specific adaptation strategies can enhance global crop productivity on current cropland. Our findings highlight the importance of further research on the readiness of required crop varieties.&lt;/p&gt;


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