Marginal Soils Research Articles

Growth performances of maize (Zea mays L.) intercropping with soybean (Glycine max (L.) Merrill.) in the legowo row system applied with bokashi plus fertilizer on marginal soils

The research aims to determine the growth response of maize intercropped with soybeans in a legowo row system with bokashi plus fertilizer on marginal land. It was carried out in Lamaeo Village, from May to August 2021, utilizing a randomized block design with a single factor and the dose of bokashi plus fertilizer, consisting of four levels, namely 0, 3, 6, and 9 t ha-1. Every therapy was replicated in four periods to obtain a total of 16 experimental plots. The legowo row system involved four rows of soybeans spaced 30 cm x 30 cm, with rows of corn spaced 120 cm x 40 cm. Plant height (cm), the number of leaves (strands), stem diameter (cm), leaf area (cm2), leaf area index (LAI), net assimilation rate, and relative growth rate were variables observed at 14, 28, 42, and 56 days after planting (DAP). The results of the research showed that bokashi plus fertilizer had a positive impact on the performance of corn intercropped with soybeans in the legowo row system on marginal land. The best outcome in terms of plant height, the number of leaves, stem diameter and leaf site were observed at 14, 28, 42, and 56 DAP, as well as leaf area index, net assimilation rate, and relative growth rate. The highest yields of corn and soybeans were obtained at a dose of 9 t ha-1, which amounted to 6.3 and 2.1 t ha-1, respectively, indicating better response on organic fertilizer.

Yield of Elymus elongatus and Secale cereanum on marginal soils in Central Europe

Yield of Elymus elongatus and Secale cereanum on marginal soils in Central Europe

Pengaruh Pemberian Berbagai Pupuk Organik pada Media Tanam Pasir Terhadap Pertumbuhan Tanaman Pakcoy (Brassica Rapa)

Organic fertilizers are materials derived from plant residues, and animal waste, both those that have undergone decomposition and those that are undergoing a decomposition process that functions to add nutrients. Substantially organic fertilizers are composed of humus and non-humus materials so that they can improve marginal soils and sand-dominated soils. The purpose of this study was to determine the effect of various organic fertilizers on sand planting media, and to determine the growth response of pakcoy on various types of organic fertilizers. The research was conducted at the Field Laboratory I Experimental Garden and Agrotechnology Laboratory of the Faculty of Agriculture, Halu Oleo University, the research took place from September to November 2020. This study was arranged in a randomized group design (RAK) with the treatment of various organic fertilizers, which were divided into; no organic fertilizer/control (B0), cow manure (B1), chicken manure (B2), comba-sheep green manure (B3), calopogonium green manure (B4). Each treatment was repeated four times as a group, resulting in 20 experimental units. Each experimental unit consisted of six polybags, resulting in a total of 120 polybags of pakcoy plants. The variables observed were plant height, number of leaves, fresh weight and dry weight of pakcoy plants. The results showed that organic fertilizer had a very significant effect on all observed growth variables of pakcoy plants. Cow manure treatment in the first and second week plant height variables showed the highest value (5.04 cm, and 6.71 cm). But in general, in the third to fifth week, the average chicken manure gave the highest growth response on the variable of plant height, number of leaves, fresh weight and dry weight of pakcoy plants.

The Effect of Compost and Liquid Fertilizer Application on the Growth and Production of Corn (Zea Mays L.) in Red Yellow Podzolic Land

Corn production in society is currently still low due to one of them, namely due to reduced soil fertility. The purpose of this study was to see the effect of applying compost with liquid fertilizer on the growth and production of corn plants. The materials used in this study were compost enriched with Trichoderma sp, liquid fertilizer, bran, goat manure, water, corn, sugar and marginal soil media while the tools used are polybags measuring 30x40 cm, buckets, shovels, hoes, scales, seedling houses, rulers, plastic sheeting, calipers and writing implements. This research method is arranged in a factorial form consisting of two factors, namely the first factor is the application of compost which consists of three levels and the second factor is the application of liquid fertilizer which consists of four levels. The parameters observed in this study were plant height (cm), number of leaves (strands), stem diameter (cm), weight of corn fruit (grams), weight of cobs (grams), total weight of seeds per cob (grams), and root weight. (m3), the results showed that the combination treatment of compost from EM4 and without liquid fertilizer gave the best results for plant height 225.00 cm, stem diameter 1.32cm, fruit weight 110.50g, seed weight 70.17g, cob weight 21.83 g, and root weight 32.67 g, while the combination of treatment with terichoderma sp compost and liquid fertilizer enriched with 2% NPK gave the best results for the number of leaves 12.83. The results showed that the combination of compost from EM4 and without liquid fertilizer gave the best results for the growth and production of corn plants.

Hidroponik Wick System Sebagai Alternatif Budidaya Sayur-Sayuran di Wilayah Pesisir Desa Laikang Kabupaten Takalar

Laikang village is the villages on the coast with a sandy and marginal soil environment, so it is not suitable for vegetable cultivation. The hydroponic wick system technology allows people in Laikang Village to be able to cultivate vegetables in their own yard. This community service aims to provide training on vegetable cultivation and how to make a hydroponic wick system by utilizing plastic bottle waste. This activity is carried out in 3 stages, namely the survey and socialization stage, the training stage, and the monitoring and evaluation stage. From the evaluation, there is an increase in the knowledge and skills of the participants regarding the theme of the activity. The evaluation results also showed that the implementation of this activity was in accordance with community expectations, with the level of satisfaction of training participants at 87%, participants' interest in the training theme at 89%, and the level of conformity with community expectations at 82%. The results of monitoring activities also show the continuity of cultivation activities that are still occupied by the people of Laikang Village to this day.

Influence of Sulphur and Foliar Application of Iron on Growth and Yield of Lentil (Lens culinaris L.)

Lentil (Lens culinaris L.) is typically cultivated in marginal soil with low fertility status. It is an important rabi season pulse crop in North India. The crop responds well to exogenous application of Sulphur and Iron. Considering the above, a field experiment was conducted during Rabi 2022 at the Crop Research Farm, Department of Agronomy, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, (U.P) India to study the influence of Sulphur and foliar application of Iron on Growth and Yield of Lentil. The experiment was laid out in Randomized Block Design comprising of two factors viz., Sulphur (20, 30, 40 kg/ha), Iron (control, 0.3%, 0.5%) and Control (20-40-20 NPK kg/ha). There were 10 treatments each replicated thrice. The soil of experimental plot was sandy loam in texture, nearly neutral in soil reaction (pH 6.9), organic carbon (0.112%), available N (278.93 kg/ha), available P (10.8 kg/ha), and available K (206.4 kg/ha). Application of Sulphur and foliar application of Iron significantly influenced the growth parameters, yield attributes and yield over control. Results revealed that at 60DAS the higher plant height (26.5 cm), more number of nodules per plant (26.7), maximum plant dry weight (7.31 g/plant), maximum crop growth rate (9.88 g/m2/day), more no of pods per plant (162.40), more no of seeds per pod (2.53), higher seed yield (1556.19 kg/ha) and higher stover yield (2868.3 kg/ha) were recorded with application of Sulphur 40 kg/ha + Iron 0.5% in lentil.

Heritage genetics for adaptation to marginal soils in barley.

Future crops need to be sustainable in the face of climate change. Modern barley varieties have been bred for high productivity and quality; however, they have suffered considerable genetic erosion, losing crucial genetic diversity. This renders modern cultivars vulnerable to climate change and stressful environments. We highlight the potential to tailor crops to a specific environment by utilising diversity inherent in an adapted landrace population. Tapping into natural biodiversity, while incorporating information about local environmental and climatic conditions, allows targeting of key traits and genotypes, enabling crop production in marginal soils. We outline future directions for the utilisation of genetic resources maintained in landrace collections to support sustainable agriculture through germplasm development via the use of genomics technologies and big data.

Pertumbuhan Semai Salam (Syzygium polyanthum) Terhadap Pemberian Pupuk Kandang Sapi dan Arang Sekam pada Tanah Tercemar Oli Bekas

Salam plant (Syzygium polyanthum) can grow in marginal soils, such as soil contaminated with used oil. The planting of salam with the application of cow manure and husk charcoal is expected to reduce the bad impact of used engine oil pollution. This study aims to analyze the response to the growth of salam and to obtain information on the optimal dose to increase the growth of salam to the application of cow manure and husk charcoal on soil contaminated used engine oil with a concentration of 60 ml/1 kg of soil. The study used a factorial completely randomized design with two factors and soil analysis test. The result showed that the application of cow manure and its interaction with husk charcoal significantly affected the root shoot ratio (NPA) parameter. The combination of 60 grams of cow manure and 60 grams husk charcoal had the best NPA value of 3,11. The high growth of salam tended to be optimal in the K4A0 treatment (dose of 120 gram of cow manure and 0 gram of husk charcoal). The application of treatment can reduce the Al, Zn, and Mn content in the contaminated with used engine oil.
 Keywords: cow manure, husk charcoal, root shoot ratio, Syzygium polyanthum, used engine oil

Use of Bioinoculants Affects Variation in Snap Bean Yield Grown under Deficit Irrigation

The use of beneficial microorganisms, such as plant growth promoting rhizobacteria (PGPR) and mycorrhizal fungi, for organic farming could improve the productivity and the resilience of vegetable crops. Both PGPR and PGPF are allowed for organic farming, and they represent new important tools for regenerating poor and marginal soils in transition to environmentally friendly farming. In the experiment, the effects of PGPM-based products were evaluated on snap bean in combination with two irrigation regimes. The experimental design adopted was split-plot, with the main plot represented by the irrigation regime (reintegration of 100 and 60% of the ETc), the sub-plot by the microbial consortia, and finally the sub-sub-plot by genotype (‘Domino’ and ‘Maxi’). Seeds were sown in a cold greenhouse and the growing cycle finished after 86 days from sowing. The results showed a significant increase of the yield due to the application of PGPM compared to the control. The deficit irrigation applied (ETc 60%) affected plants growth in the two genotypes and their related production differently (in average 2.20 kg m−2 for Domino and 3.63 kg m−2 for Maxi), showing a positive effect of PGPM on yield (in average 2.47 kg m−2 without PGPM and 3.36 kg m−2 with PGPM) and product quality. Furthermore, an interesting negative correlation between the number of nodules and the yield was also observed, as a consequence of their early outcome which increased plant productivity in relation to the experimental factors.

Molecular mechanism of saline-alkali stress tolerance in the green manure crop Sophora alopecuroides

Selecting suitable plants as green manures is essential for improving marginal soil fertility and sustainable agroecosystems. Sophora alopecuroides is a highly salt- and alkali-tolerant leguminous plant that is often used as green manure. However, the molecular mechanism underlying saline-alkali tolerance in S. alopecuroides remains largely unclear. In this study, we investigated the molecular mechanisms underlying saline-alkali stress tolerance through physiological and transcriptomic analyses in S. alopecuroides seedlings. Comparative transcriptome analysis revealed that saline-alkali stress induced the expression of genes involved in cell wall modification, thereby increasing the contents of pectin and hemicellulose in roots and improving saline-alkali stress tolerance. The expression of genes related to the glycolysis pathway was induced, whereas genes involved in the TCA cycle and primary nitrogen metabolism were downregulated under salt and alkali stresses, indicating that S. alopecuroides plants modulate carbon flow to provide energy and ultimately regulate saline-alkali stress adaptation. Saline-alkali stress also modulated phytohormone signaling pathways in S. alopecuroides. Moreover, the leaves of seedlings under salt and alkali stresses contained elevated potassium, zinc and manganese contents, and the roots of seedlings under salt stress contained higher iron content. Taken together, these adaptive mechanisms to saline-alkali stress provide a physiological basis for the coordinated nutrient cycling of S. alopecuroides green manure. These results provide a molecular basis for the phytoremediation and utilization of saline-alkali soil, enabling the design of an integrated nutrient cycling system and optimization of the cultivation and field management of S. alopecuroides green manure.

Lupin, a Unique Legume That Is Nodulated by Multiple Microsymbionts: The Role of Horizontal Gene Transfer

Lupin is a high-protein legume crop that grows in a wide range of edaphoclimatic conditions where other crops are not viable. Its unique seed nutrient profile can promote health benefits, and it has been proposed as a phytoremediation plant. Most rhizobia nodulating Lupinus species belong to the genus Bradyrhizobium, comprising strains that are phylogenetically related to B. cytisi, B. hipponenese, B. rifense, B. iriomotense/B. stylosanthis, B. diazoefficiens, B. japonicum, B. canariense/B. lupini, and B. retamae/B. valentinum. Lupins are also nodulated by fast-growing bacteria within the genera Microvirga, Ochrobactrum, Devosia, Phyllobacterium, Agrobacterium, Rhizobium, and Neorhizobium. Phylogenetic analyses of the nod and nif genes, involved in microbial colonization and symbiotic nitrogen fixation, respectively, suggest that fast-growing lupin-nodulating bacteria have acquired their symbiotic genes from rhizobial genera other than Bradyrhizobium. Horizontal transfer represents a key mechanism allowing lupin to form symbioses with bacteria that were previously considered as non-symbiotic or unable to nodulate lupin, which might favor lupin's adaptation to specific habitats. The characterization of yet-unstudied Lupinus species, including microsymbiont whole genome analyses, will most likely expand and modify the current lupin microsymbiont taxonomy, and provide additional knowledge that might help to further increase lupin's adaptability to marginal soils and climates.

Grain-cropping suitability for evaluating the agricultural land use change in Brazil

Mapping and monitoring tools are imperative in assessing agricultural systems and guiding future decision-making to safeguard food security. Since grain-croplands are the main occupation within the Brazilian croplands that has played a substantial role in the country's land use/land cover (LULC) dynamic, this study aims at proposing a grain-cropping suitability index (CroppingSI) to support the geographical analysis of LULC agricultural trends. The proposed approach considers detailed information on climate, soils, and terrain coupled with grain-crop simulations, soil quality indexing, and terrain restrictions evaluated at the highest available resolution. With historical LULC maps (2000 and 2020), we found that terrain was the most critical factor for cropland expansion, followed by climate and soil quality. The new croplands expanded towards regions with better climate and terrain conditions while neglecting the soil quality, mostly in the Cerrado and Amazon regions. In addition, the assessment of CroppingSI was instrumental in understanding that expanding new croplands over current cleared areas (i.e., pasturelands) may expose them to marginal soil and terrain conditions. This suggests a fragility of the current expansion trend of grain-cropping systems which can substantially put food security at risk, requiring alternative strategies for maintaining or improving food through crop intensification.

Reclamation effects of distinct volumes and concentrations of CaCl2-amended brackish ice in different saline-sodic soils

The proper usage of marginal soil and water resources has major implications for the sustainability of agriculture, such as brackish water and saline-sodic soils. The saline soils can be ameliorated though melting process of calcium-containing brackish ice, however, the optimum concentration and volume of brackish ice (water) for the reclamation of different saline-sodic soils remain to be determined. In this study, 108 soil columns representing four Ice salinity levels (16, 26, 36, 46 mmolc L−1) and three Pore Volumes (2/3, 1.5, 2.5 PV) of calcium-amended brackish ice were tested to reveal the reclaiming effect on a range of saline-sodic soils. The linear mixed model (LMM), multiple regression equation, and principal coordinate analysis (PCoA) were applied to calculate the amelioration effect in terms of three factors: Ice volume, Ice salinity and Column depth. Our results showed that the soil salinity and sodicity generally decreased with increasing Ice volume and Ice salinity, and the saline-sodic soils with low exchangeable sodium percentages (i.e. ESP 20) were more sensitive to Ice salinity, with high salinity (26–46 mmolc L−1) and large volume (2.5 PV) of brackish ice reaching a better amelioration effect. The effect of Ice volume became more dominant in medium and high ESP soils (ESP 40 and ESP 70), whereas the high salinity combined with low volume of brackish ice would lead to worse soil properties, especially at the bottom layers. Meanwhile, the Column depth factor had a considerable effect on the soil chemical properties, with the variance explained ranging from 18.6% to 36.0%. These results provide theoretical guidance in the rational use of calcium-amended brackish ice and highlight the necessity to take layer effect into consideration for reclaiming saline-sodic soils.

Effect of garden and park waste hydrochar and biochar in soil application: a comparative study

Thethermochemical treatments of biowaste yield alternative renewable carbon-rich materials, while achieving waste valorization. These technologies allow to reduce amount of biowaste and enhance its life span avoiding the landfill disposal. The agronomic application as a soil amendment strategy using fresh hydrochar (obtained via the hydrothermal treatment of garden and park waste (GPW) at 180 °C for 1 h), post-treated hydrochar (washed, aged, and thermally treated), and biochar (obtained via the pyrolysis of GPW at 900 °C for 90 min) has been studied and compared in order to stablish the best approach for its valorization. We evaluated the effects of mixing fresh hydrochar (1–5% on dry weight) with different peat-based growth substrates on the seed germination index as well as the fresh and dry weights of Arabidopsis thaliana, Chenopodium quinoa, and Solanum lycopersicum (tomato). We also performed a germination assay with marginal agricultural soil mixed with fresh and post-treated chars as well as biochar using the same doses. All carbonaceous materials complied with the European legal framework being categorized as a class A amendment and present a favorable chemical composition for their agronomic use, carbon sources with a low heavy-metal content, and a high mineral and organic matter content. Application of post-treated hydrochar to the agricultural marginal soil improved the germination index of tomato seeds (by 10–20%) at low dosages (< 3% on dry weight) when washed and thermally treated hydrochar was used. However, fresh hydrochar negatively affected seed germination and plant growth when applied to marginal soil and peat-based growth media, particularly sandy substrates. Washing improved the germination index (by approximately 18%), reduced 90% of the total volatile fatty acid content, and effectively removed furans, amines, amides, pyridines, pyrazines, benzoic compounds, and organic acids that can affect seed germination and plant growth. Because the use of hydrochar in soils for agricultural purposes requires post-treatment to alleviate germination and plant growth inhibition, washing is the most suitable option considering the energy and technological requirements.

In Vitro Assessment of Salinity Stress Impact on Early Growth in Ten Certified Palestinian Barley Cultivars (Hordeum vulgare L.) Potentially Suitable for Cultivation on Former Quarry Substrates

Salinity is a major constraint for crop health and productivity, particularly on arid, semiarid, and otherwise marginal soils, such as quarry residue. Quarries are a main pillar of national income in Palestine but have a long-lasting toll on the environment. We examined barley (Hordeum vulgare L.), another pillar of the Palestinian economy and one of the most important crops in the world, in this regard for its tolerance to salinity stress. This study is the first to evaluate the impact of salinity (50, 85, 120, and 175 mM NaCl) on seed germination, early growth stage, and morpho-anatomy on ten pre-selected certified Palestinian barley cultivars (Baladi, Improved Baladi, Rihan, ICARDA 1, ICARDA 15, ACSAD 68, ACSAD 176, ACSAD 1417, ACSAD 1732, and ACSAD 1744) to assess their potential for a successful growth start under adverse saline conditions. In addition, soil samples from quarries in Hebron governorate were randomly selected and tested for salinity level, electrical conductivity, and total of soluble salts for a first rough overview of options for applying our results, since local data are often scarce or outdated. The examined soil samples reached electrical conductivity (EC) ranges of 1.81 × 10−4–9.071 × 10−4 dS m−1, which are below the normal EC (11–57 × 10−4 dS m−1). This result may contraindicate the hypothesis that quarry lands always suffer from salinity stress. Cultivars such as ACSAD 68 and Icarda 15 proved very sensitive to higher salinity stress with high G50 (time point when 50% of seeds have germinated) at 4.4 d, with 120 mM NaCl (ACSAD 68) or incalculable amounts (Icarda 15) and just 50 and 20% total germination, respectively. Concentrations of 175 mM NaCl were found in ACSAD 176 and Improved Baladi (no G50, 37 and 30% germination, respectively). Some cultivars showed a moderate to high resilience to salinity, such as ICARDA I, ACSAD 1417, and ACSAD 1744, which reached &gt; 80% seed germination at 120 mM NaCl and &gt;60% at 175 mM NaCl, and G50 within 1.5–2.2 days; the most resilient was ACSAD 1732 with G50 &lt; 2 days and germination still &gt;80% at 175 mM NaCl. This is strongly supported by the monitored growth parameters. In conclusion, ACSAD1732 and Icarda 1 cultivars are highly recommended for cultivation in areas of low precipitation and high salt accumulation. In addition, the land and/or soil of quarries, their landfills, and nearby areas in Palestine may be fit for barley cultivation with recommended cultivars regarding salinity stress.

Addressing Profitability With Conservation Programs

AbstractRepurposing underperforming cropland to improve environmental outcomes and increase producer profitability is possible. Transitioning these acres into conservation areas, utilizing farm bill programs, and partnering with organizations like Quail Forever and Cotton Inc. can provide guaranteed income from these marginal soils.

Effect of spatial scale of soil data on estimates of soil ecosystem services: Case study in 100 km2 area in France

AbstractOver the last decade, the ecosystem services (ESs) framework has been increasingly used to support mapping and assessment studies for sustainable land management purposes. Previous analysis of practical applications has revealed the significance of the spatial scale at which input data are obtained. This issue is particularly problematic with soil data that are often unavailable or available only at coarse scales or resolutions in various part of the world. In this context, four soil‐based ecosystem services, namely biomass provision, water provision, global climate regulation, and water quality regulation, are assessed using three conventional soil maps at the 1:1,000,000, 1:250,000 and 1:50,000 scales. The resulting individual and joint ES maps are then compared to examine the effects of changing the spatial scale of soil data on the ES levels and spatial patterns. ES levels are finally aggregated to landforms, land use, or administrative levels in order to try to identify the determinants of the sensitivity of ES levels to change in the scale of input soil data. Whereas the three soil maps turn out to be equally useful whenever ESs levels averaged over the whole 100 km2 territory are needed, the maps at the 1:1,000,000 and 1:250,000 induced biases in the assessment of ESs levels over spatial units smaller than 100 and 10 km2, respectively. The simplification of the diversity and spatial distribution of soils at the two coarsest scales indeed resulted in local differences in ES levels ranging from several 10 to several 100%. Identification of the optimal representation of soil diversity and distribution to obtain a reliable representation of ESs spatial distribution is not straightforward. The ESs sensitivity to scale effect is indeed context‐specific, variable among individual ESs, and not directly or simply linked with the soil typological diversity represented in soil maps. Forested and natural lands in the study area appear particularly sensitive to soil data scales as they occupy marginal soils showing very specific ESs signatures.

Classic Maya Settlement Systems Reveal Differential Land Use Patterns in the Upper Belize River Valley

Land use practices have had important implications for structuring household inequalities and broader political systems in the past. Our contribution examines settlement patterns in relation to political structure, household wealth, ecological productivity and agricultural techniques. Combining settlement pattern data with high–precision soils data, we examine the extent to which different trajectories of polity formation impact the settlement location and land use practices of intermediate elites and commoners. The Classic Maya (CE 250/300–900) polities of Baking Pot and Lower Dover in the Upper Belize River Valley serve as enlightening case studies because despite being situated near one another, the two centers emerged along very different trajectories. Whereas the polity of Baking Pot arose slowly, in tandem with surrounding demography, the neighboring polity of Lower Dover arose rapidly in the Late Classic period (CE 600–900) in an area which was already home to established local populations. Our analysis shows that while Baking Pot had substantial settlement clustering around its epicenter, populations at Lower Dover aggregated around secondary and tertiary centers farther away from the polity core. Analyses also demonstrate that most commoner and intermediate elite residences were situated on the most productive agricultural lands in the region, though some intermediate elite households were situated on hilltops or in border zones with marginal soil productivity for political and tactical reasons. Commoner households were situated on a range of productivity zones reflecting diverse land–use practices which had implications for household wealth. Our case study illustrates the importance of integrating land use practices into our reconstructions of ancient political hierarchies, especially in terms of understanding political strategies and household wealth.

A life cycle assessment of guar agriculture

Guar gum, the main product of the guar crop, is used widely in the USA as an emulsifier in the food industry and as fracturing fluid additive in the oil and gas industry. The USA is the number one global importer of guar, and interest has grown to domestically cultivate guar in the USA. Guar is an annual desert legume native to India and Pakistan. The goal of this study was to evaluate the environmental sustainability of growing guar in the USA via a life cycle analysis (LCA). The LCA helps identify the information gap for US agriculture and guide future field studies to optimize guar cultivation in the USA. This study concluded that in terms of environmental sustainability, irrigation, harvesting, and P-fertilization methods offer the most opportunity for improved guar agricultural sustainability. This is promising because one of guar’s prominent characteristics is its high water use efficiency and ability to grow in marginal soils. Lowering irrigation and water use can be implemented with simple management practice changes such as optimizing irrigation. In addition, this study shows that there is an opportunity for field trials to optimize fertilizer application rates to achieve the greatest yields. This study also found a knowledge gap with respect to carbon soil fluxes and field emissions of nitrogen and phosphorus from guar agriculture. As the USA considers adopting guar agriculture in the southwest, through research collaborations such as the USDA Sustainable Bioeconomy of Arid Regions Center of Excellence, it will be critical to evaluate irrigation to achieve maximum yields (e.g., drip, flood, sprinkler) and fill fertilizer and emissions knowledge gaps.

Experimental Warming of Typically Acidic and Nutrient-Poor Boreal Soils Does Not Affect Leaf-Litter Decomposition of Temperate Deciduous Tree Species

Ongoing rapid climatic changes are expected to modify the structure, composition, and functioning of forest ecosystems. Studying the influence of such changes on biogeochemical processes is thus crucial for a fuller understanding of forest response to climate change. In a temperate forest of Quebec, Canada, we emulated climate change by warming the acidic, nutrient-poor, and dry soils of two mixedwoods by 3 to 4 °C using heating cables. Leaf-litter mass loss of the local red maple, sugar maple, large-tooth aspen, and American beech were monitored to assess the ability of these tree species to condition boreal soils in the context of their northward migration under climate change. We hypothesized that decomposition rates of all leaf-litter types would be decreased equally by warming due to a drying effect of the soil and its surface, which is detrimental to microbial biomass and activity. Our results suggest differences in decomposition rates between tree species as follows: sugar maple &gt; red maple ≥ American beech = large-tooth aspen. There was no indication of a slower turnover in these marginal soils compared to other studies conducted on typical hardwood soils. Moreover, no difference in litter mass loss was detected between treatments, likely due to a drying effect of the soil warming treatment. Results imply that climate change has a marginal influence on leaf-litter dynamics of temperate tree species on soils that are typical of the boreal forest. However, some variables that could play an important role on litter decomposition in the context of climate change were not measured (e.g., plant phenology, understory composition and density, microbes) and thus, uncertainties remain. The soil drying effect by warming also needs to be further documented and modeled. The study year was characterized by significant periods of water stress but was not considered an exceptional year in that regard. It would be relevant to test for leaf-litter dynamics during dry and wet summers and verify again our initial hypothesis of decreased leaf-litter decomposition rates due to soil warming/drying.