Increased Soil Acidity Research Articles

Use of environmental indicators to assess the state of forest ecosystems

The purpose of the study was to comprehensively analyse the effectiveness of environmental indicators in determining the state of forest ecosystems and their ability to reflect changes in the ecological balance. During the study, the influence of anthropogenic factors on biomass, soil acidity, and species diversity of forest ecosystems in the Sumy Oblast of Ukraine was evaluated. Field studies were conducted to determine the soil acidity, the biomass of plants and animals in anthropogenic and natural forest areas, followed by statistical analysis of the data. The degree of degradation of forest areas as a result of human activity was determined and the environmental consequences of these changes for natural systems were evaluated. The results showed that anthropogenically modified areas have reduced biomass (100 t/ha) and species diversity (20 plant species), increased soil acidity (pH 6.5-7) and high concentrations of nitrates and phosphates, compared to mixed forests, where biomass reaches 200 t/ha, species diversity – 50 species of flora, and soil acidity varies from moderately acidic to neutral (pH 5.5-6). These data confirmed the negative impact of human activity on ecosystems, in particular on biomass and soil acidity. It was established that environmental indicators allow forming a comprehensive picture of the state of ecosystems, which is necessary for making informed management decisions aimed at preserving and restoring ecosystems, and at effective management of natural resources. The results obtained demonstrated serious environmental problems as a result of anthropogenic impact on forest ecosystems. A decrease in biomass and species diversity, and an increase in soil acidity in anthropogenic zones indicate the need for urgent implementation of measures for the conservation and restoration of natural forests. The study will be useful in the context of long-term monitoring of ecosystems, which would allow a more detailed investigation of the dynamics of their changes

VARIABILITY OF FLUCTUATING ASYMMETRY OF BETULA PENDULA ROTH LEAVES DEPENDING ON GROWING CONDITIONS

In the work, the relationship (FA) of the leaves of the hanging birch Betula pendula Roth with atmospheric pollution, climatic indicators and soil characteristics was determined. We analyzed data obtained from 10 sites located in the main geographical directions from the city of Ukhta (Komi Republic, Russia). FA was based on 5 morphological parameters (n=100). In the soil, we determined the pH (water and salt extracts), the content of organic matter and mobile forms of metals. Information on air pollution and climate parameters was obtained from open sources. We established high FA of B. pendula at all sites (0.064-0.076). It was shown that this is not related to the geographical location of the birch growing area. There was no excess of standards of pollutants in the air and soil at the sites. Correlation analysis showed that FA increases in response to a decrease in the proportion of organic matter in the soil and an increase in soil acidity (r is -0.49 and -0.42, respectively). Also, the increase in FA is associated with the content of mobile forms of Pb, Mn, Cu (r is 0.6, 0.36, 0.35, respectively). We found no effect of the content of mobile Zn, Fe, Cd in the soil on the FA level of the leaves. Thus, it is shown that soil characteristics affect the asymmetry of the bioindicator plant, including within environmental regulations. This fact should be taken into account when interpreting the results of the assessment of the ecological state of the territories.

Plant functional traits modulate the effects of soil acidification on above- and belowground biomass

Abstract. Atmospheric sulfur (S) deposition has been increasingly recognized as a major driver of soil acidification. However, little is known about how soil acidification influences above- and belowground biomass by altering leaf and root traits. We conducted a 3-year S-addition experiment to simulate soil acidification in a meadow. Grass (Leymus chinensis (Trin.) Tzvelev) and sedge (Carex duriuscula C.A.Mey) species were chosen to evaluate the linkage between plant traits and biomass. Sulfur addition led to soil acidification and nutrient imbalances. Soil acidification decreased specific leaf area (SLA) but increased leaf dry-matter content (LDMC) in L. chinensis, showing a conservative strategy and thus suppressing aboveground instead of belowground biomass. However, in C. duriuscula, soil acidification increased plant height and root nutrients (N, P, S, and Mn), favoring competition for natural resources through enhanced above- and belowground biomass, i.e., adoption of an acquisitive strategy. Increased soil acidity resulted in an overall reduction in aboveground community biomass by 3 %–33 %, but it led to an increase in community root biomass by 11 %–22 % due to upregulation as a result of higher soil nutrient availability. Our results demonstrate that both above- and belowground plant biomass is affected by S-induced acidification. Understanding the linkage between plant biomass and functional traits contributes to a better understanding of plant–soil feedback in grassland ecosystems.

Effect of Cd(II) adsorption onto rice roots on its uptake by different indica and japonica rice varieties and toxicity effect of Cd(II) under acidic conditions.

The rapid increase in soil acidity coupled with the deleterious effects of cadmium (Cd) toxicity had led to a decline in worldwide agricultural production. Rice absorbs and accumulates Cd(II) from polluted paddy soils, increasing human health risks throughout the food chain. A 35-day hydroponic experiment with four japonica and four indica (two each of them tolerant and sensitive cultivars) was conducted in this study to investigate the adsorption and absorption of Cd(II) by rice roots as related with surface chemical properties of the roots. The results showed that the three chemical forms of exchangeable, complexed, and precipitated Cd(II) increased with the increase in Cd(II) concentration for all rice cultivars. The roots of indica rice cultivars carried more negative charges and had greater functional groups and thus adsorbed more exchangeable and complexed Cd(II) than those of japonica rice cultivars. This led to more absorption of Cd(II) by the roots and greater toxicity of Cd(II) to the roots of indica rice cultivars and more inhibition of Cd(II) stress on the growth of the roots and whole plants of indica rice cultivars compared with japonica rice cultivars, which was one of the main reasons for more declines in the biomass and length of indica rice roots and shoots than japonica rice cultivars. Cd(II) stress showed more toxicity to the sensitive rice cultivars and thus greater inhibition on the growth of the cultivars due to more exchangeable and complexed Cd(II) adsorbed by their roots induced by more negative charges and functional groups on the roots compared with tolerant rice cultivar for both indica and japonica, which resulted in greater decreases in the biomass and length of roots and shoots as well as chlorophyll contents of the sensitive cultivars than the tolerant cultivars. The roots of sensitive rice cultivars also absorbed more Cd(II) than tolerant rice cultivars due to the same reasons as above. These findings will provide useful references for the safe utilization and health risk prevention of Cd-contaminated paddy fields.

Unlocking water potential in drylands: Quicklime and fly ash enhance soil microbiome structure, ecological networks and function in acid mine drainage water-irrigated agriculture

In water-stressed regions, treated acid mine drainage (AMD) water for irrigated agriculture is a potential solution to address freshwater scarcity. However, a significant knowledge gap exists on the short and long-term effects of treated AMD water on soil health. This study used high-throughput Illumina sequencing and predictive metagenomic profiling to investigate the impact of untreated AMD (AMD), quicklime- (A1Q and A2Q) and quicklime and fly ash-treated AMD water (AFQ) irrigation on soil bacterial diversity, co-occurrence networks and function. Results showed that untreated AMD water significantly increased soil acidity, electrical conductivity (EC), sulfate (SO42−), and heavy metals (HM), including reduced microbial diversity, disrupted interaction networks, and functional capacity. pH, EC, Cu, and Pb were identified as key environmental factors shaping soil microbial diversity and structure. Predominantly, Pseudomonas, Ralstonia picketti, Methylotenera KB913035, Brevundimonas vesicularis, and Methylobacteriumoryzae, known for their adaptability to acidic conditions and metal resistance, were abundant in AMD soils. However, soils irrigated with treated AMD water exhibited significantly reduced acidity (pH > 6.5), HM and SO42− levels, with an enrichment of a balanced bacterial taxa associated with diverse functions related to soil health and agricultural productivity. These taxa included Sphingomonas, Pseudoxanthomonas, Achromobacter, Microbacterium, Rhodobacter, Clostridium, Massillia, Rhizobium, Paenibacillus, and Hyphomicrobium. Moreover, treated AMD water contributed to higher connectivity and balance within soil bacterial co-occurrence networks compared to untreated AMD water. These results show that quicklime/fly ash treatments can help lessen impacts of AMD water on soil microbiome and health, suggesting its potential for irrigated agriculture in water-scarce regions.

Quantitative analysis of soil degradation in response to land use change in the Guinea savanna zone of Ghana

Soil degradation (SD) poses a significant challenge to tropical agricultural production systems due to its role in depleting soil nutrients. Recently, SD has threatened population growth by causing hunger and poverty among smallholder farmers in the Guinea savanna agro-ecological zone of Ghana. However, SD cannot be directly measured. Instead, assessment and modelling efforts rely on biological and physico-chemical indicators. This study sought to: (i) select a minimum dataset (MDS) using a multivariate statistical technique; (ii) identify SD processes, and evaluate the extent of degradation; and (iii) suggest strategies to monitor SD in the study area. Soil samples were collected using the Land Degradation Surveillance Framework (LDSF), specifically designed for sub-plot level (1000 m2) sampling. This scheme aligns well with the typical farm structure of smallholder farmers (<10 acres). Soil samples, taken from a depth of 0–20 cm, were analyzed to assess their physico-chemical properties. Principal component analysis (PCA) identified seven key SD processes: soil texture, pH, organic carbon (OC), total nitrogen (TN), available phosphorus (Av. P), base saturation (BS) and Effective Cation Exchange Capacity (ECEC). These identified processes lead to the loss of OC, deterioration of soil texture, reduction in soil nutrients, and increased soil acidity. There was a strong positive correlation (r = 0.70, p<0.05) between soil physical and chemical properties. PC1 explained 26.86% of the total variance, followed by PC2 at 15.31%, PC3 at 12.46%, and PC4 at 9.98%. Also, PC5, PC6, and PC7 accounted for 8.49%, 7.25% and 1.42% of the variance, respectively. The land-use systems we identified significantly affected the concentration of soil nutrients (p<0.001). In our computed Composite Soil Degradation Index (CSDI), CEC emerged as the most significant SD indicator with a weight of 0.328, followed by Si:CL ratio at 0.187. The results indicate that soil management activities should focus on increasing organic matter. Soil nutrient depletion primarily occurs through several processes. Land clearing and burning of organic materials during land preparation are primary causes. Furthermore, a total crop removal during harvest, inadequate manure application, and subsequent leaching and erosion aggravates SD, leading to nutrient-depleted soils. We conclude that the loss of nutrients, specifically CEC, OC, Ex. K and Av. P is the primary contributor to chemical SD. Therefore, implementing integrated soil fertility management (ISFM) strategies, such as applying organic (e.g., animal-based manures, green manure, crop residues, compost) and inorganic fertilizers (e.g., NPK + micronutrients) is crucial for increasing soil nutrient availability, enhancing SOM content, and promoting carbon sequestration in these farming systems. This study establishes a baseline for comparing and evaluating the effectiveness of land management interventions at the landscape level in northern Ghana. Consequently, soil nutrient management should be tailored to site-specific conditions, focusing on increasing the efficiency of N, P, K and micronutrient uptake by plants. Adopting such site-specific management strategies could significantly contribute to the sustainable intensification of agricultural production systems in the Guinea Savanna agro-ecological zone of Ghana.

Carbon sequestration and nitrogen loss drive the evolution of French forest soils

The temporal change of soil chemistry in the forest floor and mineral soil down to a depth of 40 cm was assessed for the 102 permanent plots of the French Network for the Monitoring of Forest Ecosystems (RENECOFOR), over a 15-year period (from 1993–1995 to 2007–2012). In examining the separate and joint evolutions of a large set of parameters, many significant changes were detected reflecting the fact that French forest soils were not in a steady state. A significant increase in soil organic carbon (SOC) stocks was found, mainly in the surface soil (13.0% increase over the forest floor and the 0–10 cm layer). Conversely, the relative increase of the total nitrogen (Ntot) stocks was lower in the surface soil (4.8% increase), and a general and sharp decline of Ntot was detected between 10 and 40 cm depth (12.0% decrease). These results led to a substantial raise of C/N ratio over the whole soil profile. Another major finding is the difference in soil acidification recovery depending on the initial trophic level. In highly acidified contexts (top soil pH H2O &amp;lt; 4.5), increased soil acidification (pH and base saturation decrease, exchangeable Al increase) over the profile was observed while exchangeable base cation (Ca, Mg, K) pools increased. On the other hand, less acidic soils saw their global buffer capacity enhanced. These observations contrast with what is measured in other European inventories. While a previous study carried out on the same plots and over the same period highlighted SOC as a major driver of soil evolution in the top mineral soil, the possible mechanisms behind the large N decrease in the lower mineral soil remain to be confirmed.

Karakteristik Kimia Tanah pada Areal Kelapa Sawit dan Nilai Konservasi Tinggi (NKT) di Kabupaten Tapin, Provinsi Kalimantan Selatan

In the practice of oil palm plantation management, land clearing and cultivation using heavy equipment will change soil conditions from anaerobic to aerobic. This condition will cause sulfide compounds contained in the soil, or commonly referred to as pyrite (FeS2) to undergo an oxidation process that can cause the formation of sulfuric acid compounds (H2SO4) which when dissociated will release H+ ions in the soil solution, thus increasing soil acidity. In addition, improved drainage will also lead to a high likelihood of plant nutrients being leached from the soil. On the other hand, the HCV areas will be left unmanaged by maintaining the original vegetation adjacent to the oil palm plantations. So there are two different land management systems between oil palm land and HCV areas which in theory will have different land characteristics, one of which can be seen from differences in soil chemical characteristics. The purpose of this study was to determine the differences in the characteristics of several soil chemical properties including pH, C-organic, Al-dd and P-available in oil palm land and HCV areas. This research is a field research using survey method. Sampling in the field was carried out by purposive sampling at PT Kharisma Inti Usaha, Tapin Regency, South Kalimantan Province. Soil samples used in this study were soil samples at a depth of 0-30 cm and 30-60 cm on oil palm land and HCV areas where each land was taken as many as 10 sampling points, so that the total sample points amounted to 40 sampling points. The results showed that the characteristics of soil acidity (pH), carbon (C-organic), aluminum (Al-dd) and phosphorus (P-available) on oil palm land were lower than HCV areas in PT Kharisma Inti Usaha Tapin Regency.

Effect of Different Factors on the Soil Quality of Typic Ustipsamments of State Kerala, in India

Aims: Assessment of soil quality of selected panchayaths of sandy plains (Typic Ustipsamments ) of Kerala based on various soil attributes and to work out soil quality index (SQI).&#x0D; Study Design: A study was conducted in the selected panchayaths of sandy plains of Kerala (AEU 3) and 100 representative georeferenced surface soil samples were collected from various land uses. These soil samples were characterized for important physical, chemical, and biological properties.&#x0D; Place and Duration of Study: Onattukara Regional Agricultural Research Station, Kayamkulam between April 2021 and May 2022.&#x0D; Methodology: Hundred geo-referenced surface soil samples were collected from various land uses of selected panchayaths of sandy plains of Kerala and characterized for various physical (texture, bulk density, particle density, porosity, aggregate analysis, soil moisture, and WHC), chemical (pH, EC, organic carbon and available macro and micronutrients and biological attributes (acid phosphatase and dehydrogenase activity). Principal component analysis was used to set up the minimum data set of the indicators to compute the soil quality index. Seven principal components were extracted from which nine indicators that highly influenced the soil quality were identified. Scores and weights were assigned to each indicator, and they were aggregated to compute the soil quality index. The relative soil quality index of the soils was also found.&#x0D; Results: Increased soil acidity and low levels of nutrients like nitrogen, potassium, magnesium, sulfur, and boron were noticed in these soils. The available P content of the soil was high. Mg, S, and B were deficient in 100 percent of the samples, whereas, Fe and Mn remained sufficient. Ca, Zn, and Cu exhibited 72.9, 24.3, and 21.7 percent deficiency, respectively. The majority of the soils belonged to medium soil quality (78.6 percent), followed by poor (12.8 percent) and good (8.6 percent) quality.&#x0D; Conclusion: The majority of soils of selected panchayaths of sandy plains of Kerala fell into the medium soil quality class. However, there are several soil fertility issues in these soils. Hence site-specific and crop-specific management strategies have to be followed for the profitable cultivation of the crops and soil test-based fertilizer application has to be followed. It is mandatory to maintain the fertility of the soil for the sustainability of the environment.

Physiological and Proteomic Changes in Camellia semiserrata in Response to Aluminum Stress.

Camellia semiserrata is an important woody edible oil tree species in southern China that is characterized by large fruits and seed kernels with high oil contents. Increasing soil acidification due to increased use of fossil fuels, misuse of acidic fertilizers, and irrational farming practices has led to leaching of aluminum (Al) in the form of free Al3+, Al(OH)2+, and Al(OH)2+, which inhibits the growth and development of C. semiserrata in South China. To investigate the mechanism underlying C. semiserrata responses to Al stress, we determined the changes in photosynthetic parameters, antioxidant enzyme activities, and osmoregulatory substance contents of C. semiserrata leaves under different concentrations of Al stress treatments (0, 1, 2, 3, and 4 mmol/L Alcl3) using a combination of physiological and proteomics approaches. In addition, we identified the differentially expressed proteins (DEPs) under 0 (CK or GNR0), 2 mmol/L (GNR2), and 4 mmol/L (GNR4) Al stress using a 4D-label-free technique. With increasing stress concentration, the photosynthetic indexes of C. semiserrata leaves, peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), soluble protein (SP), and soluble sugar (SS) showed an overall trend of increasing and then decreasing, and proline (Pro) and malondialdehyde (MDA) contents tended to continuously increase overall. Compared with the control group, we identified 124 and 192 DEPs in GNR2 and GNR4, respectively, which were mainly involved in metabolic processes such as photosynthesis, flavonoid metabolism, oxidative stress response, energy and carbohydrate metabolism, and signal transduction. At 2 mmol/L Al stress, carbon metabolism, amino sugar and nucleotide sugar metabolism, and flavonoid metabolism-related proteins were significantly changed, and when the stress was increased to 4 mmol/L Al, the cells accumulated reactive oxygen species (ROS) at a rate exceeding the antioxidant system scavenging capacity. To deal with this change, C. semiserrata leaves enhanced their glutathione metabolism, drug metabolism-cytochrome P450, metabolism of xenobiotics by cytochrome P450, and other metabolic processes to counteract peroxidative damage to the cytoplasmic membrane caused by stress. In addition, we found that C. semiserrata resisted aluminum toxicity mainly by synthesizing anthocyanidins under 2 mmol/L stress, whereas proanthocyanidins were alleviated by the generation of proanthocyanidins under 4 mmol/L stress, which may be a special mechanism by which C. semiserrata responds to different concentrations of aluminum stress.

Ecophysiological difference in co-existing beech and oak saplings grown in different soil types under a free-air ozone exposure system

ABSTRACT To know effects of elevated ozone (eO3) response to beech (Fagus crenata) and oak (Quercus mongolica var. crispula) saplings, focusing on shoot elongation and leaf nutrient characteristics, beech and oak were grown in a free-air ozone-enrichment system (concentration: 35 ppb (aO3) vs. 75 ppb (eO3)) for two years under different soils (volcanic ash soil vs. brown forest soil). This treatment resulted in lower O3 tolerance in beech than in oak. The ratio of 2nd shoot flush showed a characteristic response to eO3 fumigation in beech and oak. For beech, the ratio was less than 0.5, while for oak, it ranged between 0.4 and 0.6. There was no difference in the photosynthetic rate of oak, although the photosynthetic rate of beech was slightly lower under elevated O3. Principal component analysis provided a good summary of the traits of beech and oak in response to O3 enrichment and soil combination, with O3-enriched beech characterized by higher Ca and lower N, P, K and A max in the 1st component and lower Mg and Mn in the 2nd component. O3 -treated oak in O3-enriched brown forest soils was characterized by high N, P, K and A max, while the influence of the 2nd component was small. Increased soil acidification will increase soil Mn and Al concentrations and may reduce the photosynthetic activity of beech saplings in eO3.

Growth and Yield of Broccoli Vegetables (Brassica oleracea var. botrytis L.) on Types and Dosages of Manure

Broccoli is a vegetable commodity that has high commercial value and prospects in Indonesia, because of its role in fulfilling food, feed, and industrial needs. In cultivating broccoli plants, they still face production problems due to nutrient availability problems. Farmers generally use chemical fertilizers continuously. Continuous use of chemical fertilizers will increase soil acidity, damage the physical condition of the soil, reduce organic matter, make plants vulnerable to pests and disease, and reduce soil microbial life. Many consumers are interested in organic broccoli. The use of organic fertilizer as an alternative to chemical (inorganic) fertilizer can reduce environmental pollution and create healthy broccoli (Brassica oleracea) vegetable products. One of the organic fertilizers is manure which is a waste product from domestic animals such as chickens, goats, and pigs which are generally found in Tomohon City. Manure can be used to add nutrients, and improve the physical and biological properties of soil. The quality of manure depends on the animal and greatly influences crop yields. The research objectives are: (1) Studying the effect of the interaction between the type and dose of manure on broccoli growth and yield, (2) Obtaining the type and dose of manure that provides the highest growth and yield of broccoli, and (3) Get semi-organic broccoli by using a 25% dose of compound nitrogen, phosphorus, potassium (NPK) fertilizer. To achieve the above objectives, this research used a Factorial Randomized Block Design (FRBD) with 2 treatment factors and 3 replications the first factor was the type of manure (A) which consisted of A1: Chicken manure, A2: Goat manure, A3: Pig manure. The second factor is the dose of manure (B) which consists of B0: 125 kg NPK/hectare, B1: 20 manure/hectare, B2: 30 kg/hectare. The observation variables include plant height, number of leaves, diameter of broccoli per plant, and wet weight of broccoli per plant. Data analysis uses Analysis of Variance (ANOVA). If the results of the analysis show that there is an effect of treatment, then continue with the BNT test at the 5% level. The results showed that the treatment with goat manure at a dose of 20 tons/hectare and without manure at half the recommended dose of nitrogen, phosphorus, and potassium gave the highest number of leaves (18.67 and 19.67 leaves). The best broccoli crop diameter was treated with goat manure at a dose of 20 and 30 tons/hectare. The weight of the best broccoli crop in goat and pig manure at a dose of 20 tons/hectare was 47.67 grams.

Macronutrient Fertilization and Cadmium Absorption in Two Cocoa Clones

Soil Cd is absorbed by roots and accumulated in cocoa plants, which represents a problem in the commercialization of beans. In order to evaluate whether the exogenous application of macronutrients (N, N-P, N-P-K, N-P-K-S, N-P-K-S-Mg, and N-P-K-S-Mg-Ca) mitigates the absorption, translocation, and accumulation of Cd in plants, soil pH and electric conductivity, dry root and shoot biomass, leaf gas exchange, chlorophyll content, and macronutrient bioaccumulation were evaluated in two cocoa clones (CCN-51 and EET-103) grown in a greenhouse. An increase in macronutrients gradually increased the extraction capacity of Cd in both clones, with the highest Cd values being obtained with the application of N-P-K-S-Mg-Ca. Macronutrient fertilization did not affect leaf gas exchange; however, it caused significant reductions of 30, 40, and 60% in chlorophyll content, shoot, and root dry biomass, respectively. The greatest translocation of Cd from the root to the shoot was obtained with treatments that included N in clone EET-103 and Ca in clone CCN-51. Fertilization with macronutrients did not decrease the absorption and accumulation of Cd in the cocoa seedlings, because a greater removal force of Cd from the adsorption complex towards the soil solution was caused by the exogenous application of Ca and Mg and an increase in soil acidity.

Decreased soil pH weakens the positive rhizosphere effect on denitrification capacity

The stimulating effect of rhizosphere on denitrification is considered to be an unavoidable loss of soil nitrogen (N) and detrimental to crop N use efficiency, which is regulated by crop growth and soil properties. Soil acidification, occurring rapidly in many intensive farming lands, affects both crop growth and soil properties, thereby altering rhizosphere effect on denitrification. However, the mechanism by which soil acidification regulates rhizosphere denitrification still remains unclear. Here, we determined the denitrification capacity (DC) and associated community compositions of nirK- and nirS-type denitrifiers in maize rhizosphere and bulk soils at four acidity gradients (pH = 6.8, 6.1, 5.2, and 4.2). Results showed that the stimulating effect of rhizosphere on DC strongly depended on soil pH. Compared to bulk soil, rhizosphere soil had significantly higher DC at pH ≥ 5.2, but not at pH of 4.2. With increasing soil acidity, the stimulation of rhizosphere on DC (calculated as the difference in DC between rhizosphere and bulk soils) decreased from 8.01 to 0.01 mg N kg-1 d-1. Moreover, soil acidification significantly reduced the differences in dissolved organic carbon (DOC) and abundance of key nirK-type denitrifier taxa between rhizosphere and bulk soils, both of which were positively related to the stimulation of rhizosphere on DC. These findings demonstrated that soil acidification could weaken the positive rhizosphere effect on denitrification via regulated C availability and associated nirK-type denitrifier community, potentially reducing N loss risk in rhizosphere soil. The independent role of soil pH should be fully considered when modelling N behaviour in plant-soil systems.

Back to the future? Conservative grassland management can preserve soil health in the changing landscapes of Uruguay

Abstract. The “soils of the Anthropocene” are predominately agricultural. To understand them, we analyzed agri- and silvicultural intensification of Uruguayan grasslands (GLs) in a country-wide survey on fertility proxies, pH and trace metals in topsoils originating from different land uses across the whole country. Thus, our results reflect interactions of both the natural diversity of Uruguayan soil formation and the impacts of land use change. We observed a loss of nutrients, trace metals and organic matter from GLs, croplands and timber plantations (TPs). As an example, the cation exchange capacity was 160 % higher in native forests (NFs) compared to GLs and lowest in TPs, reaching only half of the cation exchange capacity (CEC) in GLs. Acidification of topsoils continues as three-fourths of all samples are “extremely acidic” and “very strongly acidic”. Topsoils of riverine forests accumulate more trace metals compared to the other uses. We assume an accumulation in the topsoils of riverine forests, where high levels of nutrients, trace metals and organic carbon (OC) are found. The translocation of nutrients and organic matter across the landscape to the erosion base depends on local land use trajectories. Increasing soil acidification is driving a positive feedback loop, and land use intensification has lead to degradation of local black soils within a few decades. Our data raise questions about the resilience and carrying capacity of Uruguayan soils with regard to currently implemented highly productive management forms, including the use of TPs for carbon sequestration, and supports more conservative forms of extensive management on the GL biome.

Alfalfa: directions and results of breeding

Purpose. Generalization of the results of breeding work with alfalfa (Medisago L.) based on many years of foreign and domestic research. Methods. Monitoring, system analysis, economic-mathematical approach, statistical and monographic. Results. The main areas of breeding alfalfa are presented, including increasing seed productivity, nitrogen fixation, and resistance to adverse abiotic (wintering conditions, drought, increased soil acidity) and biotic (pathogens, diseases and pests) factors, improving feed quality, and creating transgenic plants. The results of the multi-year selection work carried out by the Institute of Feed Research and Agriculture of Podillia of NAAS on the creation of alfalfa seed varieties tolerant to increased soil acidity, have been concretized. The research results on the population variability of self-incompatibility of alfalfa plants evaluation are given, which made it possible to develop a plan for creating synthetic varieties with increased and stable level of heterosis of feed and seed productivity traits. Conclusions. Alfalfa is a valuable feed crop that occupies a leading position among perennial legumes. There are a number of challenges for this culture that need to be solved through breeding. Laboratory and field methods of evaluating alfalfa resistance to aluminum and increased soil acidity were developed due to which the Sinyuha and Radoslav alfalfa varieties were created and introduced into production. This technique contributes to: achieving a relatively high level of feed and seed productivity in combination with plant tolerance to increased soil acidity and other negative environmental factors; the expansion of the zone of optimal cultivation of alfalfa seeds in Ukraine significantly north of the previously defined limits; minimization or complete exclusion of specific negative factors, taking into account the biological and morphological features of the available starting material when creating alfalfa varieties and hybrids.

Effects of Different Kinds of Fertilizers on the Vegetative Growth, Antioxidative Defense System and Mineral Properties of Sunflower Plants

Long-term use of inorganic fertilizers can increase soil acidity, be harmful to the environment, and leaving bad effects on human health. Organic fertilizer application is one of the safer alternatives with numerous benefits, such as supplying nutrients for plant growth. Sunflower is one of the most important grown oilseed crops in the world. Sunflower plants need a supply of essential nutrients for their optimal growth. As a result, the aim of this research is to explore the effect and mechanism of two organic fertilizers from different sources (sugarcane bagasse ash (SBA), compost coupled with biofertilizer (CCB)) and NPK inorganic fertilizer as a control on enzyme activity, physiological traits, and the uptake of mineral contents and heavy metals in sunflower plant (Helianthus annuus L.). Fresh or dry mass (FM, DM), osmolytes and secondary metabolites, photosynthesis pigments, and enzymatic and non-enzymatic antioxidant molecules were all determined. Both sugarcane bagasse ash and compost coupled with biofertilizer resulted in a high value of fresh and dry mass, plant height, and chlorophyll content. The results revealed that the use of sugarcane bagasse ash (SBA) and compost coupled with biofertilizer increased osmolyte contents (soluble proteins and soluble sugars), antioxidants system enzyme/molecule (catalase, superoxide dismutase, peroxidase, and TGS) and secondary metabolites. However, the highest value of proline, total free amino acids, and phenolic compounds in sunflower plants was determined after NPK fertilizer application. On the contrary, it lowered Na, Na/K ratio, and Cd content. Data showed that organic fertilizers enhanced the accumulation of Cl, PO4, and SO4 content in sunflower plants. Generally, CCB and SBA treatments increased Cu, Zn, and Pb accumulation in sunflower plants. Using organic fertilizers with chemical NPK fertilizer can improve the chemical, physical, and biological soil properties.

Improving fertilizer response of crop yield through liming and targeting to landscape positions in tropical agricultural soils

Nutrient management research was conducted across locations to investigate the influence of landscape position (hill, mid-, and foot slope) in teff (Eragrostis tef) and wheat (Triticum aestivum) yield response to fertilizer application and liming in the 2018 and 2019 cropping seasons. The treatments included 1) NPS fertilizer as a control treatment (42 N + 10P + 4.2S kg ha−1 for teff and 65 N + 20P + 8.5S kg ha−1 for wheat); 2) NPS and potassium (73 N + 17P + 7.2S + 24 K kg ha−1 for teff and 103 N + 30P + 12.7S + 24 K kg ha−1 for wheat) and 3) NPSK and zinc (73 N + 17P + 7.2S + 24K + 5.3Zn kg ha−1 for teff and 103 N + 30P + 12.7S + 24K + 5,3Zn kg ha−1 for wheat) in acid soils with and without liming. Results showed that the highest teff and wheat grain yields of 1512 and 4252 kg ha−1 were obtained at the foot slope position, with the respective yield increments of 71% and 57% over the hillslope position. Yield response to fertilizer application significantly decreased with increasing slope owing to the decrease in soil organic carbon and soil water content and the increase in soil acidity. The application of lime with NPSK and NPSKZn fertilizer increased teff and wheat yields by 43–54% and 32–35%, respectively compared to the application of NPS fertilizer without liming where yield increments were associated with the application of N and P nutrients. Orthogonal contrasts revealed that landscape position, fertilizer application, and their interaction effects were significant on teff and wheat yields. Soil properties including soil pH, organic carbon, total N, and soil water content were increased down the slope, which might be attributed to sedimentation down the slope. However, available P is yet very low both in acidic and non-acidic soils. We conclude that crop response to applied nutrients could be enhanced by targeting nutrient management practices to agricultural landscape features and addressing other yield-limiting factors such as soil acidity and nutrient availability by conducting further research.

Pelatihan Pemanfaatan Limbah Sagu Sebagai Bahan Pembuatan Pupuk Organik dengan Bioreaktor Bsfl pada Kelompok Tani “Dwitrap” Kampung Tambat Kabupaten Merauke

The Dwitrap farmer group's sago processing industry in Tambat Village produces sago starch/sago flour products. Apart from producing its main product, the sago processing process also produces side products in the form of solid waste and liquid waste. Waste if not handled properly will have a negative impact on the environment. Solid waste from sago processing is in the form of sago dregs. Solid waste from the sago industry contains 56.86% cellulose and 37.70% lignin. Solid waste if disposed of and left unchecked will cause environmental problems such as odor and increased soil acidity (pH&lt;4) which has an impact on inhibiting growth and even causing death in plants. Therefore, proper handling and management of sago industrial waste is needed to reduce the impact on the environment. The content in sago pulp waste is very useful for various purposes such as animal feed and raw material for making organic fertilizer both solid and liquid. Sago solid waste organic fertilizer can be used by the community as a safe fertilizer for plants in community gardens and also BSF larvae can be used as livestock and fish feed. In addition, the purpose of this activity is to provide knowledge to the community about the impact of waste generated and to provide skills in utilizing waste to make it more economical. The method used to achieve this target is socialization about the impact of sago waste and its potential utilization, training or hands-on practice in making liquid organic fertilizer using black soldier fly larvae bioreactor, activity evaluation, and community assistance. The results of the socialization show that there is a transfer of knowledge to the community. This is indicated by the number of questions asked by the participants to the presenters. After the presentation, the presenter gave feedback questions about the material and training that had just been carried out and the participants were able to answer them appropriately. This indicates an increase in public knowledge about the importance of processing sago waste into organic fertilizer, both solid and liquid. This understanding is important so that awareness arises about the importance of preserving the environment and the sustainability of agriculture in the future. In addition, the training also added new skills to the community, namely that the community could produce both solid and liquid organic fertilizer from kitchen waste and solid sago waste with a simple method.

Effects of blended NPSB fertilizer rates on selected soil properties at Banshure Kebele, in Bedele District, South Western Ethiopia

Balanced fertilizer application is an important management practice to improve soil fertility and quality in the agricultural lands. In present study, we examined the effects of nine different rates of blended NPSB fertilizer rates on soil pH, soil organic carbon (SOC), total nitrogen, available sulphur (ava.S), available boron (ava.B) and available phosphorus (ava.P) in the plowed layer (0-20 cm). The results obtained from this study indicated that, the values of soil pH obtained from all treatments are lower than that of soil pH before fertilizer application. The application of fertilizer have remarkably improved soil organic carbon (SOC) and total nitrogen (TN) values compared with soil organic carbon (SOC) and total nitrogen (TN) recorded before fertilization. Except soil total nitrogen (TN) and soil organic carbon (SOC), application of different rates of blended NPSB fertilizer were highly significantly affected the values of soil pH, available phosphorus (ava.P), available sulphur (ava.S), and available boron (ava.B). The highest values of available phosphorus (ava.P), available sulphur (ava.S), and available boron (ava.B) were obtained from the plot treated with the highest (300kg/ha) fertilizer rate, were as the lowest was recorded from the control plot. Unlike available phosphorus (ava.P), available sulphur (ava.S), and available boron (ava.B), the values of soil pH recorded after fertilizer application becomes declined as the rate of fertilizer applied to the soil is increased dramatically. Thus, these indicated that, as the rate of blended NPSB fertilizer increased soil acidity becomes increased due to the presence of soil acidifying compounds such as nitrate, sulphate and boric acid in blended form.