Nutrient Leaching Research Articles

Altitudinal Patterns of Foliar Nutrients in Dominant Tree Species: Are Central Himalayan Forests Nutrient Stressed?

In forest ecosystems nutrient availability is one of the most important drivers of tree growth and ecosystem function. We studied changes in soil and foliar nutrients (N, P & K) and leaf N and P stoichiometry in eight dominant canopy and sub-canopy forest tree species of Central Himalayan forests occurring between 300 and 2200 m asl. Nutrient (N, P & K) concentration in leaves at bud break, mature and senescent stage varied significantly across the tree species. The nutrient resorption efficiency (NRE) varied significantly across the species and found ranging for N from 48.7 - 76.8%. Both the nitrogen resorption efficiency (NRE) and phosphorus resorption efficiency (PRE) increased linearly with altitude (R2= 0.647 for NRE significant at p< 0.05; and R2 for PRE= 0.525; NS) pointing out that trees growing in temperate climate conserve nutrients more efficiently to withstand the slow mineralization due to cold climate. With the increasing altitude leaf life-span increases significantly (R2= 0.0025; p< 0.0074). ANOVA indicates that the foliar N and P and altitude were unrelated. The low N: P ratio, a measure of nutrient status of forest ecosystems at senescent leaf stage, found ranging from 9.97 in Q. floribunda to 18.8 in P. roxburghii points out that forests of the study region are nutrient stressed, partly due to low P mineralization in temperate climate, leaching of nutrients due to heavy monsoon rain, and poorly developed underlying geology. Thus, the Central Himalayan forests are characterized by high NRE and low growth rate with increasing altitude. Winter season warming might help improve the nutrient availability in the forest floor and nutrient uptake to enhance nutrient cycling and biomass productivity in these forests.

Sentinel-2-based predictions of soil depth to inform water and nutrient retention strategies in dryland wheat

The thickness or depth of fine-textured soil (zf) dominates water storage capacity and exerts a control on nutrient leaching in semi-arid agroecosystems. At small pixel sizes (< 1 m; ‘fine resolution’), the normalized difference vegetation index (NDVI) of cereal crops during senescence (Zadoks Growth Stages [ZGS] 90–93) offers a promising alternative to destructive sampling of zf using soil pits. However, it is unclear whether correlations between zf and NDVI exist (a) at larger pixel sizes (1–10 m; ‘intermediate resolution’) and (b) across field boundaries. The relationship of zf to NDVI of wheat (Triticum aestivum L.) was tested using images from a combination of multispectral sensors and fields in central Montana. NDVI was derived for one field using sensors of fine and intermediate spatial resolution and for three fields using intermediate resolution sensors only. Among images acquired during crop senescence, zf was correlated with NDVI (p < 0.05) independent of sensor (p = 0.22) and field (p = 0.94). The zf relationship to NDVI was highly dependent on acquisition day (p < 0.05), but only when pre-senescence (ZGS ≤ 89) images were included in the analysis. Results indicate that cereal crop NDVI of intermediate resolution can be used to characterize zf across field boundaries if image acquisition occurs during crop senescence. Based on these findings, an empirical index was derived from multi-temporal Sentinel-2 imagery to estimate zf on fields in and beyond the study area.

Effect of Nitrogen, Calcium and Nano Fertilizers on Growth Yield and Quality of Strawberry (Fragaria × ananassa Duch.): A Review

Strawberry cultivation represents a significant sector within the agriculture industry. The use of nitrogen (N), calcium (Ca), and nano fertilizers has emerged as an essential practice to improve both the yield and quality of strawberries. This comprehensive review aims to explore the multifaceted influence of these fertilizers on Fragaria × ananassa Duch, encompassing growth, quality, and environmental considerations. The study begins with an examination of historical perspectives and existing research, identifying gaps in the literature. The methodology includes a rigorous selection process for studies, with data extraction, quality assessment, and statistical analysis. The effects of N, Ca, and nano fertilizers on growth yield are thoroughly examined, considering their combined and individual contributions. The quality of strawberries is assessed based on physical appearance, nutritional content, and sensory characteristics, highlighting the role of these nutrients in color development, size, texture, vitamin content, sugar-acid balance, flavor, and aroma. The environmental impact is another critical aspect, exploring the effect on soil quality, including nutrient leaching, soil structure, microbial activity, and long-term health. The impact on surrounding ecosystems considers aquatic and terrestrial effects, biodiversity considerations, and the associated sustainability considerations. These encompass resource efficiency, environmental compliance, life cycle analysis, and integration with sustainable agricultural practices. Findings indicate that while N, Ca, and nano fertilizers significantly enhance growth and quality, careful management is essential to mitigate potential environmental concerns. The application of nano fertilizers presents promising opportunities for precise nutrient delivery, promoting efficiency, and sustainability. The review concludes by emphasizing the importance of continued research, innovation, and responsible management of these fertilizers in achieving a harmonious balance between productivity, quality, and environmental stewardship. The insights provided in this review contribute valuable knowledge to both scientific and agricultural communities, offering guidance for future research and best practices in strawberry cultivation.

Soil properties affect crop yield changes under conservation agriculture: A systematic analysis

AbstractConservation agriculture (CA) has the potential to sustain soil productivity and benefit agroecosystems, yet it is not fully understood how yield responses of different cropping systems are affected by inherent soil characteristics, for example, texture and dynamic soil properties, such as aggregation, nutrients and erosion. In this study, we conducted a systematic review to compare crop yield from cropland with conventional management versus different CA practices, specifically reduced‐ or no‐tillage, agroforestry, organic farming and cover crops. The data were first analysed for different climatic regions, soil textures and cash crop types. We then quantified how yield responses correlated with soil properties change under different CA practices. The results showed that CA practices were associated with an overall mean crop yield increase of 12%. This response was primarily driven by corn, which had a mean yield increase of almost 41% after CA implementation, whereas other cash crops did not have significant yield responses or showed slight decreases, as rotation with mixtures of multiple cash crops had a mean decrease of 6% when using CA. The increase in corn yield after CA may be related to the enhanced ability of that crop to absorb nutrient elements (e.g. nitrogen) and reduce nutrient leaching. Agroforestry increased crop yield by 66% and cover cropping increased yield by 11%, likely due to increases in soil water content and nutrient availability and decreases in erosion and surface runoff. However, other agricultural systems showed no significant increase after CA compared with conventional row cropping practices. Using CA practices had the greatest yield benefit in tropical climates and when farming in coarse‐textured soils. In addition, legumes and grass‐legume mixtures resulted in significant cash crop yield increases, possibly because legumes promoted the increase of soil nitrogen and depleted soil moisture less compared with other cover crops. The results provide new insight into how interactions between soil properties and CA practices affect crop yield and at the same time can help guide the development of practical, evidence‐based guidelines for using conservation practices to improve yield in corn and other cash crops.

Cereal Rye Among the Best Cover Crops at Weed Suppression

AbstractCereal rye, as a fall‐planted and winter‐grown cover crop, offers many benefits. It tolerates both frigid winter temperatures and warm springs. It also tolerates both the wet conditions and drought. It reduces soil erosion, enhances soil organic matter, improves soil water retention, and reduces nutrient leaching. But, it’s not a panacea, of course. This article will discuss some of the benefits, challenges, and considerations of using cereal rye as a cover crop. Earn 0.5 CEUs in Integrated Pest Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

Effects of Douglas fir cultivation in German forests on soil seepage water quantity and quality

Norway spruce (Picea abies L.) has been a key tree species and timber source in European forests the last centuries and is increasingly suffering from drought and bark beetle infestations due to climate warming. Current management options include replacing of Norway spruce monocultures with pure and mixed stands of European beech (Fagus sylvatica) that is the naturally dominating tree species in Central Europe. Additionally, Douglas fir (Psudotsuga menziesii), a tree species with high water use efficiency and drought tolerance, is being increasingly cultivated to increase the resilience of European forests and meet the future demand of conifer timber in a warming climate. We studied the seepage water quantity and quality with a particular focus on the nitrate (NO3–) concentration and N leaching under pure and mixed stands of Douglas fir, Norway spruce, and European beech at seven sites in Germany. Additionally, we investigated seepage water concentrations of SO4-S, Ca, Mg, K, Al and hydrological variables (interception, canopy throughfall, transpiration). Looking at the seepage water quantity and quality, the best management option is the cultivation of pure beech stands. However, this is associated with the well-known risk of monocultures concerning ecosystem disturbance. Beech stands showed the highest seepage water quantities and the lowest seepage water concentrations of major cations and anions, including NO3–. Seepage water quantity was the smallest under pure Douglas fir compared to spruce and beech stands. The composition effects of stand tree species on seepage water quality and nutrient leaching were site-dependent. At N-rich sites, pure Douglas fir stands showed higher seepage water NO3– concentrations than spruce and beech stands, whereas the tree species effects were small at N-poor sites. With respect to seepage water quantity and quality, cultivation of mixed Douglas fir–beech stands is a promising option for producing conifer timber and at the same time avoiding increased disturbance risks of mono-species forests under a warmer climate. Our results support the recommendation of mixed Douglas fir–beech stands based on soil quality, ecosystem resilience, and forest economic studies.

Analysis of Organic Mulching on Soil Fertility and the Productivity of Sweet Corn (Zea mays saccharata Sturt L.)

One of the causes of the low productivity of sweet corn is decreased soil productivity due to the leaching of nutrients by rainwater, tillage, and continuous application of inorganic fertilizers. The function of mulching is to increase soil moisture, suppress weed growth, and prevent soil erosion to create optimal soil conditions for plant growth. This study aimed to determine the effect of organic mulching on soil fertility and the productivity of sweet corn (Zea mays saccharata Sturt). This study used a Split Plot Design consisting of two factors, Tillage (P) and Organic Mulch (M) which had 6 levels, M0 = No Mulch, M1 = Plastic Mulch, M2 = Rice Straw Mulch, M3 =Cocopeat Mulch, M4 = Sawdust Mulch, M5 = Rice Husk Mulch. The results show that the M2 treatment of Rice Straw Mulch tended to increase soil fertility and had a significant effect on the productivity of sweet corn.

Investigating the reasons behind the choice to promote crop diversification practices through the new CAP reform in Europe

The present study investigates the factors that might contribute influencing Member States decision to promote the adoption of crop diversification practices through their provisional National Strategic Plans for implementing the 2023–2027 Common Agricultural Policy. The Qualitative Comparative Analysis method is used to explore the link between key agricultural land uses and land use pressure indicators and the choice of funding the adoption of diversification practices and of imposing restrictions to access subsidies for their adoption. Results highlight that the choice of financing the adoption of diversification practices is associated with: the diffusion of cereal crops (share of cereals crops on the arable land above the median value of 20%), the diffusion of large farms (share of agricultural land for farms above 100 ha on the UAA above the median value of 10%) and the poor diffusion of grasslands (share of agricultural land cultivated with permanent grassland below the median value of 30%), mainly for eastern European countries, and with biodiversity pressures (share of biodiversity pressure indicators above the median value of 0.36), mainly for central European countries. Conversely, the choice of imposing high restrictions on the adoption of diversification practices is mainly associated with different form of land use pressures (nutrient leaching, biodiversity losses and soil erosion), mainly for southern European countries. Lack of financing and lack of restrictions remains unexplained for some MS (i.e., this is particularly evident for Sweeden and Finalnd) and apparently contradictory choices are highlighted for some others (i.e., financing the adoption of diversification practices with limited restrictions, which was addressed for France, Austria, Slovenia and Lithuania). The paper concludes providing a summary of the main findings, some policy recommendations to cope with existing shortcomings in current plans, due to excess flexibility and lack of coherence with existing priorities and highlighting the limits of the approach used and some proposal for further investigation.

Эффективная удобрительная утилизация бесподстилочного навоза на сенокосах и пастбищах при сохранении плодородия почвы и обеспечении экологической безопасности (к 85-летию В.Г. Дикарева)

Large livestock farms and complexes accumulate large amounts of liquid manure of varying degrees of dilution with water — semi-liquid, liquid, manure effluents. The most effective method of utilization of liquid manure is its widespread use for fertilizing meadow grass stands. The effectiveness of the use of manure effluents depends on the doses and timing of their application, the type of soil, its mechanical composition. Viktor Grigoryevich Dikarev paid considerable attention to the issues of effective and environmentally safe use of various types of organic fertilizers, their combination with mineral fertilizers on reclaimed hayfields and pastures in his research. He is a Candidate of Agricultural Sciences, senior researcher at the Laboratory of Irrigated Meadow Farming and Lysimetric Research at the V.R. Williams Institute of Feed in 1976–2010. He studied various types of cattle manure, the timing of its application, its use as the main fertilizer and top dressing during the growing season of herbs, its various combinations with mineral fertilizers (according to the timing and doses of application). He also studied the leaching of nutrients from the soil, in order to achieve environmental safety of the methods used to intensify grassland farming. On the basis of long-term studies on sod-podzolic medium loamy soil with low potassium and high phosphorus, the highest productivity (116.1 centner/ha of dry matter) of grass with the dominance of the awnless brome was obtained when manure drains were applied at a dose of N300R60K200 at the rate of 1/3 for the first mowing in autumn and 1/3 for the second and third mowing during the vegetation of grasses. 30% N, 70% P2O5, 100% K2O were introduced with effluents. At the same time, the collection of crude protein was 16.1 centner/ha. 30% N, 70% P2O5, 100% K2O were introduced with effluents. At the same time, the collection of crude protein was 16.1 centner/ha.

Residue Management and Nutrient Dynamics in Conservation Agriculture: A Review

Conservation tillage significantly influence the physico-chemical properties of soil that makes microclimate conducive for crop growth and productivity. The use of chemical fertilizers alone to sustain high crop yield has not been successful due to its effects on soil acidity, nutrient leaching, degradation of soil’s physical properties and organic matter. Higher levels of soil organic carbon, microbial biomass of carbon and nitrogen, nitrogen mineralization, total nitrogen and extractable phosphorus are directly related to crop residues under conservation tillage management. Conservation agriculture (minimum or no tillage with residue retention and crop rotation) practices has potential for increasing the nutrient supply to crops through changes in the mineralization and immobilization of nutrients by microbial biomass and provide an eco-protective environment for sustainable production. Conservation agriculture reduces nutrient percolation/leaching from the soil profile, can redistribute the soil profiles thus affects nutrient supply, and its storage. Entire soil-plant continuum changes after the conversion from conventional agriculture to conservation agriculture. The review therefore highlights the nutrient dynamics under crop residue management with no or minimum tillage.

Sustainability of High-Density Olive Orchards: Hints for Irrigation Management and Agroecological Approaches

The production of olive oil in Portugal and other countries of the Mediterranean region has greatly increased in recent years. Intensification efforts have focused on the growth of the planted area, but also on the increase of the orchards density and the implementation of irrigation systems. Concerns about possible negative impacts of modern olive orchard production have arisen in the last years, questioning the trade-offs between the production benefits and the environmental costs. Therefore, it is of great importance to review the research progress made regarding agronomic options that preserve ecosystem services in high-density irrigated olive orchards. In this literature review, a keywords-based search of academic databases was performed using, as primary keywords, irrigated olive orchards, high density/intensive/hedgerow olive orchards/groves, irrigation strategies, and soil management. Aside from 42 general databases, disseminated research, and concept-framing publications, 112 specific studies were retrieved. The olive orchards were classified as either traditional (TD) (50–200 trees ha−1), medium-density (MD) (201–400 trees ha−1), high-density (HD) (401–1500 trees ha−1), or super-high-density (SHD) orchards (1501–2500 trees ha−1). For olive crops, the ETc ranged from 0.65 to 0.70, and could fall as low as 0.45 in the summer without a significant decrease in oil productivity. Several studies have reported that intermediate irrigation levels linked with the adoption of deficit irrigation strategies, like regulated deficit irrigation (RDI) or partial rootzone drying (PRD), can be effective options. With irrigation, it is possible to implement agroecosystems with cover crops, non-tillage, and recycling of pruning residues. These practices reduce the soil erosion and nutrient leaching and improve the soil organic carbon by 2 to 3 t C ha−1 year−1. In this situation, in general, the biodiversity of plants and animals also increases. We expect that this work will provide a reference for research works and resource planning focused on the improvement of the productive and environmental performance of dense irrigated olive orchards, thereby contributing to the overall enhancement of the sustainability of these expanding agroecosystems.

SPATIO-TEMPORAL ASSESSMENT OF LAND USE/LAND COVER CHANGE AND ITS IMPLICATIONS ON DONGA RIVER BASIN, TARABA STATE, NIGERIA

Disturbances due to anthropogenic activities, especially Land use/ Land cover change; modifies runoff and sediment transport leading to adjustment in channel dimension. To this effect, the land use/land cover change of Donga River Basin was conducted with the aid of temporal satellite images of 1985, 2000 and 2020 downloaded from the United States Geological Survey (USGS) achieve. An unsupervised classification was carried out in ARCGIS 10.3 where seven classes were generated namely: built up area, cropland, forest, grassland, plantations, water body, woodland and bare surfaces. Descriptive statistics was further used to analyse the data. The analysis revealed that Built-Up Area, Cropland, Grassland, Woodland and Bare surfaces increased by +3.41, +12.37, +2.88, +3.05 and +3.75 respectively; while Forest, Plantation and Water Body decreased by -20.93, -2.47 and -2.1 respectively. The implications of such changes at basin scale are increase sediment generated during agricultural activities which are capable of entrainment by fluvial processes, siltation, flooding, cutoffs, narrowing of geomorphic threshold, loss of anchorage for bank materials making it prone to under cutting, bank collapse, channel widening and loss of life and properties. It was recommended that healthy agricultural practices should be encouraged so as to reduce the amount of sediments generated from farming activities especially on hill slopes. Overgrazing and annual bush burning should be check mated in order to reduce the effect of nutrient leaching and erosion of the top soil. There’s also need for land use plan that is in line with ecological principles of the study area.

Water footprint of paddy cultivation under controlled runoff conditions: A case study in Kurunagala district, Sri Lanka

Paddy cultivation is the largest global consumer of water, and it also significantly contributes to water pollution. Investigating the water footprint of paddy agriculture can provide insights into how pollutants affect the ecosystem. This study aimed to quantify the total water footprint for paddy grown in Sri Lanka's Low Country Intermediate Zone under supplementary irrigation. A lysimeter study was carried out to determine the amount of leached nutrients below the root zone. The experimental design was a Complete Randomized Block Design (CRBD) with two factors (cropping season and gradient) and two levels (Yala and Maha; upper and lower). The green and blue water footprints for both sites were estimated using the CROPWAT 8.0 model by crop water requirement option. The results revealed that the loss of NO3-N through leaching accounted for 8.61 ± 1.84 kg/ha (8%), and the leaching losses of PO43-- P were 0.49 ± 0.1 kg/ha (2%) under controlled runoff conditions during the experimental period. The nitrogen fertilizer-induced grey water footprint (WFgrey) for one tonne of rice produced was 193 ± 27 m3/t, and the phosphorous fertilizer-induced WFgrey was 61 ± 7 m3/t. The study identified nitrate as the critical element for water pollution. The estimated total water footprint (WFtotal), which was the sum of green, blue, and grey water footprint, was 1409 ± 95 m3/t under controlled runoff conditions, while the global average value is 1325 m3/t. The estimated value is about 6% higher than the global average value. Therefore, these findings demonstrate the need for further research.

Pre-activated biochar by fertilizers mitigates nutrient leaching and stimulates soil microbial activity

BackgroundPrevious studies have suggested that the targeted application of biochars in agricultural soils may benefit soil health and crop production. Physico-chemical properties of soils after biochar addition have been explored, but less is known about how microbial parameters respond. Therefore, impact of biochar (NB), mineral fertilizer-activated biochar (AB), or mineral fertilizer (MF) application on selected chemical and microbial parameters of lettuce-planted soil was evaluated in a pot experiment.ResultsIn comparison to the control, soil enzymes activities, related to carbon (C), nitrogen (N), and phosphorus (P) cycling, and their content in plant biomass, were significantly increased by the addition of mineral fertilizer with or without biochar (MF, NB + MF). Conversely, microbial respiration (basal and substrate induced) was highly responsive to the activated biochar amendment (AB) as compared to other treatments. N, P, and potassium (K) concentrations in soil pore water were stabilized by the mineral fertilizer-activated biochar, indicating reduced leaching and the likelihood of increased longevity of these nutrients in soils. Enhanced carbon acquisition and mitigated nitrogen acquisition in soil of the most experimental treatments were coupled with higher crop (lettuce) biomass.ConclusionsOur study demonstrates that the application of biochar both with and without mineral fertilizer has the potential to enhance microbial activity and fertility in the tested agricultural soil, but that leaching of fertilizer-borne nutrients may be mitigated by the activation process.Graphical

Pinpointing the distinctive impacts of ten cover crop species on the resident and active fractions of the soil microbiome

Cover crops are used in agriculture to minimize soil erosion, prevent nutrient leaching and increase soil organic matter content. Cover crops can also be grown to stimulate the soil microbial community to improve soil biological conditions. Despite their widespread use, little is known about the impact of different cover crop species on the composition and activity of the soil microbiome. Here we investigate the effect of distinct cover crop species on the rhizosphere microbiome and characterize both the resident (ribosomal (r)DNA-based) and the potentially active (rRNA-based) fractions of the bacterial, fungal, protist and metazoan communities in the cover crops rhizosphere. We conducted a field experiment using 70-l bottomless containers in which we grew ten monocultures of commonly used cover crop species belonging to five plant families, and an unplanted control treatment (fallow). The total DNA and RNA were extracted from soil and the bacterial, fungal, protistan and metazoan communities were characterized using Illumina MiSeq sequencing. We found that all cover crop species significantly impacted the resident and the potentially active microbial communities in their rhizospheres. Cover crops exerted distinct selection strengths on the native microbial communities. For individual cover crops, the impacts on the resident and the potentially active microbial communities differed while showing similar overall tendencies. Oilseed radish (Brassicaceae) was shown to provoke the strongest microbial shifts, in part attributable to a promotion of the bacterial family Pseudomonadaceae and a repression of Microascaceae in the rhizosphere. Lentil (Fabaceae) induced a widespread stimulation of fungal taxa, including Trichocomaceae and fungal members of the Glomerales order, whereas black oat and hybrid ryegrass (both Poaceae) gave rise to relatively mild changes in the soil microbial communities. Analyses of rRNA-based rhizobiome data revealed that, except for phacelia, all cover crops induced an increase in microbial network complexity as compared to the fallow control. Data presented here provide a broad baseline for the effects of cover crops on four organismal groups, which may facilitate future cover crop selection to advance soil health.

The importance of biomass in sustainable agricultural soil management

The importance of biomass in sustainable agricultural soil management

ENERGY- AND RESOURCE-SAVING PROCESSES INVOLVING THE POLYMER PHASE

The paper deals with the processes of application and production of various polymer materials. By coating the surface of mineral fertilizer granules with hydrophobic polymer films, fertilizers with controlled release of nutrient components were obtained. Such fertilizers can prevent the leaching of nutrients, prevent the negative impact on the environment and reduce fertilizer consumption. Methods for calculating the particle distribution function by the degree of coating characterizing the uniformity of coating on fluidized bed particles for stationary and non-stationary modes of operation of the apparatus are considered. The process of applying a thick composite coating to the surface of urea granules in a pan granulator was also investigated. A simple method for calculating the size distribution of the obtained granules with a composite shell is proposed. The actual problem of developing a method for predicting the kinetics of nutrient release from polymer-coated fertilizer granules based on a fairly simple mathematical model of the process has been solved. Studies of the combined polymerization and drying process in the synthesis of polyacrylamide and sodium methacrylate copolymer with methacrylic acid amide have shown that its use at the final stage of obtaining water-soluble acrylic polymers is very effective. This technique allows to reduce the total time of the technological cycle. The process of obtaining polyethylene powder by the method of elastic-deformation grinding of polymer gel and a two-stage process of solvent removal from polymer powder with the return of the solvent to the technological cycle has been developed. The rational technological parameters of the electrodialysis process of contaminated steam condensate of mineral fertilizers plant have been identified, which allows to obtain a more concentrated salt solution, which is used as a secondary raw material, as well as a desalinated solution used as process water. For citation: Lipin A.G., Lipin A.A. Energy- and resource-saving processes involving the polymer phase. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 7. P. 203-213. DOI: 10.6060/ivkkt.20236607. 6836j.

Nutrient Leaching Losses from Continuous Application of Washed Rice Water on Three Contrasting Soil Textures

Washed rice water (WRW) is often used as liquid plant fertilizer. However, there is no study on nutrient leaching of soils due to frequent WRW application. Therefore, a column study was undertaken to evaluate the rate of nutrient leaching losses, nutrient retention, and recovery of elements in leachates of three different soil textures irrigated with WRW. The treatments were 3 soil textures and 2 water types. The treatments were evaluated for 8 weeks, and the soils and leachates were measured biweekly. Factorial and repeated measurements in a completely randomized design were therefore employed. Higher cumulative leaching of the elements was found in sandy clay loam soil with 666.29, 378.13, 138.51, 50.82, 44.61, and 27.30 mg L-1 of K, P, Mg, Ca, NH4+-N, and NO3--N, respectively. Higher percentages of elements recovery in leachate were found in the sandy clay loam soil with a range of increase by 37.8–283.1% than the other two soil textures. In contrast, after 8 weeks of WRW application, the clay and silt loam soils had a range of increase in nutrient retention by 0.43–1358.5% than the sandy clay loam, with P and NO3--N being the highest and the lowest elements retained, respectively, for all soil textures. This study showed that frequent WRW disposal on sandy textured soils risks higher environmental contamination, mainly due to the soil’s lower water retention and nutrients, leading to nutrient leaching. Therefore, organic amendments should be added to sandy textured soils.

Mechanisms of weed suppression by cereal rye cover crop: A review

AbstractCereal rye (Secale cereale L.) is an important cover crop species in the United States. It has the potential to minimize soil erosion, reduce nutrient leaching, decrease fertilizer inputs, improve soil water after termination, and enhance soil organic matter. Cereal rye is also an efficient tool for weed suppression (up to 100% under ideal conditions), which is achieved through several mechanisms. Reported biomass production estimates ranged from 0.9 to 20 ton ha−1 in different environments; weed suppression benefits were observed in all these scenarios, though the extent of suppression significantly differed across the studies, indicating the presence of multiple weed suppression mechanisms with cereal rye cover crops. These can be competitive (competition for space [i.e., mulching effect], water, nutrients, and light) or non‐competitive (allelopathy, reduction in soil temperature, and reduction in light quality). Such a variety of mechanisms make it an excellent tool for integrated weed management in both conventional and organic systems. In this review, we summarize and analyze published information on the mechanisms of weed suppression by cereal rye. First, we outline the physiological characteristics that make cereal rye an excellent cover crop species and the many benefits it can provide. Second, we review four competitive mechanisms of weed suppression, which are generally considered the leading ones. Third, we summarize three non‐competitive mechanisms, the applications of which are not yet fully understood in agricultural systems. Finally, we analyze the management implications of this information and identify knowledge gaps for directing future research on this topic.

Synergistic effect of zeolite and biochar on geotechnical and fertility properties of vegetation concrete prepared by sandy soil

The mechanical strength and fertility retention capacity of vegetation concrete (VC) are insufficient when prepared using sandy soil. Biochar (BC) has been used to improve the fertility retention capacity of VC; however, it negatively affects mechanical strength and is prone to aging. In this study, a novel method using the synergistic effects of zeolite (ZL) and BC was proposed. Four different ZL contents (0%, 1%, 2%, and 4% of the planting soil weight) were investigated to determine the influence of ZL on the physical, mechanical, chemical, and biological properties of sandy VC. The results reveal that the ZL not only alleviated the negative effect of the BC but also enhanced its positive effects. In particular, by adding ZL, the porosity, permeability, and nutrient (ammonium nitrogen and nitrate nitrogen) leaching loss rates of the sandy VC decreased, whereas the cohesion, internal friction angle, matric suction, dissolved organic carbon content, and microbial biomass increased. In addition, the secondary hydration reaction between the ZL and calcium hydroxide enhanced the mechanical properties of the VC, and the adsorption of aged broken small BC particles on the ZL prolonged the fertility retention of the BC. The secondary hydration reaction of ZL occurs first, and then the remaining ZL absorbs the small BC particles. Considering the effects and cost of ZL, the recommended amount of ZL to be mixed with sandy VC is 2–4 wt%.