Changes In Soil Quality Research Articles

Changes in Soil Health with Remediation of Petroleum Hydrocarbon Contaminated Soils Using Two Different Remediation Technologies

For sustainable soil management, there is an increasing demand for soil quality, resilience, and health assessment. After remediation of petroleum hydrocarbon (PHC)-contaminated soils, changes in the physicochemical and ecological characteristics of the soil were investigated. Two kinds of remediation technologies were applied to contaminated soils: land farming (LF) and high temperature thermal desorption (HTTD). As a result of total petroleum hydrocarbons (TPH), PHC-contaminated soils were efficiently remediated by LF and HTTD. The soil health could not be completely recovered after the removal of pollutants due to adverse changes in the soil properties, especially in soil enzyme activities. Therefore, monitoring is necessary for accurate estimation of soil ecotoxicity and effective remediation, and additional soil management, such as fertilizer application or organic amendments, is needed to restore soil heath. In the case of HTTD, soil ecological properties are severely changed during the remediation process. The decision to reuse or recycle remediated soils should reflect changes in soil quality. HTTD is a harsh remediation method that results in deterioration of soil fertility and ecological functions. Alternatives, such as low-temperature thermal desorption or additional soil management using fertilizer or organic amendments, for example, are needed.

Soil organic carbon stocks maintained despite intensification of shifting cultivation

Shifting cultivation systems of Southeast Asia are rapidly intensifying, especially through shortening of the fallow periods. It is typically assumed that intensification will result in a depletion of soil organic carbon (SOC) stocks, but existing estimates of carbon stocks in these systems are variable, and there is little certainty about the carbon outcomes of intensification. We investigated the effects of intensification on SOC stocks of a shifting cultivation system in northern Laos. Volume-specific soil samples were collected from 20 sites representing: i) various rotation intensities (fallow periods of 3–4 years and 7–10 years), ii) various stages of the rotation cycle (fallows and active fields) and iii) reference plots (old regrowth of 25–30 years). Samples were analyzed for SOC, soil texture, pH, Total Nitrogen and permanganate oxidizable carbon (POXC) – an active carbon fraction that has been suggested as an easily measured early indicator of land use induced changes in soil quality and SOC. There were no significant differences between SOC concentrations or stocks of any of the sites under shifting cultivation and the reference sites. However, the SOC stock under fallows in the intensive rotation category was significantly larger than the SOC stock under fallows in the extensive rotation category. This is likely because inputs of dead root biomass from the slashed vegetation provides an important input to the SOC pool. Fallow sites under intensive rotation had significantly higher contents of POXC in the topsoil than the active fields, which suggests that POXC captures the immediate effect of the decreased input of litter to the topsoil during the cultivation period. We conclude that in this study there is no evidence that intensification of shifting cultivation leads to a decline in total soil carbon stock, or to a decline in the more active carbon fraction measured by POXC. Therefore, narratives of shifting cultivation leading to a decline in soil carbon stocks need to be revisited, and land use policies related to the system should not uncritically be based on this incorrect assumption.

Soil Organic Carbon and Labile Carbon Pools Attributed by Tillage, Crop Residue and Crop Rotation Management in Sweet Sorghum Cropping System

Labile organic carbon (LOC) fractions are considered as sensitive indicators of change in soil quality and can serve as proxies for soil organic carbon (SOC). Although the impact of tillage, crop rotation and crop residue management on soil quality is well known, less is known about LOC and SOC dynamics in the sweet sorghum production systems in South Africa. This short-term study tested two tillage levels: no-till and conventional-tillage, two crop rotations: sweet-sorghum/winter grazing vetch/sweet sorghum and sweet-sorghum/winter fallow/sweet sorghum rotations and three crop residue retention levels: 30%, 15% and 0%. Tillage was the main factor to influence SOC and LOC fractions under the sweet sorghum cropping system in South Africa. NT increased SOC and all LOC fractions compared to CT, which concurs with previous findings. Cold water extractable organic carbon (CWEOC) and hot water extractable organic carbon (HWEOC) were found to be more sensitive to tillage and strongly positively correlated to SOC. An increase in residue retention led to an increase in microbial biomass carbon (MBC). This study concludes that CWEOC and HWEOC can serve as sensitive early indicators of change in soil quality and are an ideal proxy for SOC in the sweet-sorghum cropping system in South Africa.

European beech leads to more bioactive humus forms but stronger mineral soil acidification as Norway spruce and Scots pine – Results of a repeated site assessment after 63 and 82 years of forest conversion in Central Germany

To reduce the effects of extended coniferous monoculture plantations on forest floor and topsoil processes, like amplified acidification or nutrient immobilization in organic layers, small interspersed groups of European beech were planted at the beginning of the 20th century amid large coniferous stands (CS) in Central Germany. Today, these so-called “Green Eyes” (GE) are 82-year old. In our study we focused on two different timelines to investigate the effects of forest conversion on vegetation composition, forest floor and mineral soil properties, encompassing a long-term (>80 year) comparison from tree planting in the 1930s to 2018 and a shorter timeframe nearly spanning 20 years (1999–2018). Since long-term forest conversion experiments (>60 years) across sites sharing a common forest land-use history are scarce, our study allows to contribute to a better evaluation of the long-term effects on changes in soil properties. We linked standard methods assessing soil pH, organic C and total N concentrations as well as stocks as indicators of soil quality changes in forest floor and mineral soil (down to 40 cm depth) to patterns in ground vegetation dynamics (most GE were characterized only by a few herbaceous species). Our results exhibited an effect of forest conversion on the activation in forest floor turnover resulting in increased turnover rates in the GE (GE contain only half of the forest floor OM of CS), hence forming more bioactive humus forms (mull, moder) and a noticeable higher forest floor pH (+0.6 units) compared to CS. The OC translocation from the forest floor into the topsoil is higher under GE (+0.7% OC content), probably building up a stable SOC pool hence contributing to C sequestration. The positive effects of European beech on forest floor quality are related to a stronger acidification of the subsoil during the past 20 years (-0.5 pH units). The base pump effect (uptake of Ca2+, Mg2+, K+ and assimilation into tree biomass in exchange release of H+) in GE led to more acidic conditions (-0.2 pH units) in the deeper mineral soil compared to CS. This bio-acidification may serve as one reason for subsoil acidification, as observed in our study, pointing out that mineral soil acidification is still an important issue in central European forests. Future restoration of soil base cation pools will still depend on the rate of bio-acidification, on the amount of acidifying air pollutant (and base cation) depositions and on forest management practices (e.g. intensity of biomass removal, soil regeneration-oriented liming).

Integrated watershed management on soil quality, crop productivity and climate change adaptation, dry highland of Northeast Ethiopia

Miyo-Hadi watershed in the northeast dry highland of Ethiopia is known for the excessive degradation of natural resources and recurrent drought. To avert the problem soil and water conservation practices (SWCPs) were exhaustively implemented by governmental and non-governmental organizations based on the integrated watershed management approach. Although many studies have been conducted in the wet highlands of Ethiopia to assess the role of SWCPs on soil physical and chemical properties, carbon stock and grain yield, studies in the dry highlands of northeast Ethiopia are limited. Thus, this research is aimed to (i) investigate the impacts of SWCPs on soil physical and chemical properties, (ii) quantify the carbon stock trapped by the SWCPs, (iii) assess barley grain yield and (iv) evaluate farmers' perception on climate change adaptive strategies. Field experiment, observation, socio-economic survey were conducted for data collection. SPSS was used for data analysis. The result shows that soil and water conservation practices positively influenced the physico-chemical properties of the soil and barley grain yield. The quality of soil physico-chemical properties and barley grain yield in the treated farms/fields were better than the untreated farms. Similarly, the quality of soil physico-chemical properties and barley grain yield were found to be high in farms with lower slope gradients than the higher slope gradients. Almost all of the interviewed households (93%) perceived the existence of climate change in the area; and recurrent drought, pest and disease were among the events. About 65% of the households perceived that the implemented strategies (SWCPs, infrastructure, credit & saving, and capacity building) were helpful to adapt climate related shocks. Therefore, it can be concluded that integrated watershed management as a holistic approach, and SWCPs as specific technologies have meaningful roles in terms of minimizing land degradation, improving soil quality, increasing barley yield, and reducing climate change.

PROPIEDADES FISICOQUÍMICAS Y MICROBIOLÓGICAS DE SUELOS CON CAÑA DE AZÚCAR Y MAÍZ BAJO CONDICIONES DE RIEGO Y TEMPORAL

<p><strong>Background</strong>: Sugarcane and maize are two main crops in Mexico, and the soil characteristics are important for their proper grow. Soil suitability is assessed through indicators which are chemical, physical and biological. <strong>Objective</strong>: We compared physical, chemical and microbiological soil properties in two agroecosystems, one with sugarcane and one with maize, under irrigation and rainfed conditions, so as to detect soil quality changes in each condition. <strong>Methodology</strong>: Soil samples were evaluated for pH, N, P, K, Ca, Mg, Na, organic matter, cationic exchange and texture, based on the NOM-021-RECNAT-2000. The number of microorganisms was quantified in each agroecosystem, using four culture media. Data was examined with an analysis of variance and Tukey mean test (P ≤ 0.05). <strong>Results</strong>: Soil quality was low in localities with maize, and there were not statistical differences among them; but it was better in sugarcane under rainy season-based cropping system than under irrigation. More microorganism colonies were found in maize under irrigation and sugarcane under rainy season-based cropping system. <strong>Implications</strong>: It is important to establish conservation measures that allow buffering and preserving soil and nutrient losses to maintain their productive capacity, especially in soils with more years of production. <strong>Conclusions</strong>: Soils under rainy season-based cropping system, with both agroecosystems, presented better nutritional contents in comparison with those under irrigation. The largest number of microorganisms in corn under irrigation and sugarcane under rainfed conditions could be because the pH was higher than the other two agroecosystems.</p>

Changes of soil quality induced by different vegetation restoration in the collapsing gully erosion areas of southern China

Understanding the influence of collapsing gully management restoration on soil quality and function is essential to the protection of the regional ecological environment in the collapsing gully erosion area. The primary objective of this study was to construct soil quality index (SQI) to assess the influence of different vegetation restoration types on soil quality in collapsing gully restoration. The influence of five vegetation restoration types on soil properties was investigated by using a path analysis, a comprehensive soil quality index (SQI), and a general linear model (GLM). Vegetation restoration was shown to significantly increase the saturated hydraulic conductivity (Ks), mainly due to the effect of the physical parameters of bulk density, soil cohesion, and soil water content. Meanwhile, pH, Ks, soil organic matter (OM), and sand content were revealed as reasonable indicators to evaluate the influence of vegetation restoration on soil quality. Moreover, vegetation restoration was found to significantly improve the soil quality, with the highest SQI value for natural restoration mixed forest (NF), followed by replanted arboreal forest (RA) and replanted scrubland (RS), which were all significantly higher than the SQI value of the erosion area (EA) in the collapsing gully. Additionally, vegetation type explained the most substantial proportion of total variability (46.41%), and restoration time showed a positive correlation with SQI. The results of this study can provide a reference for the restoration and protection of the regional ecological environment in the collapsing gully area.

Comparison of the Effects of Different Crop Production Systems on Soil Physico-Chemical Properties and Microbial Activity under Winter Wheat

In many areas, organic crop production systems have been shown to contribute to maintaining good soil condition. The organic production system has been recommended as an alternative to conventional agriculture. However, in order to recommend this practice in new regions, it is necessary to obtain information about its effects and consequences in local environmental conditions. The research was completed during 2016–2018 in Osiny (Lublin region, Poland) on a field experiment established 26 years previously in a Haplic Luvisol soil. The research was aimed at comparing the effects of long-term use of tilled soil with organic (ORG) and conventional (CON) crop production systems with those in non-tilled soil under permanent grass (PRG) as a control. This comparison was done on the basis of changes in the values of soil properties as follows: Total porosity (TP), total organic matter (OM), particulate organic matter (POM), humic substances (HS), water-extractable carbon (WEC), microbial biomass carbon pool (MBC) and dehydrogenase activity (DH). Soil samples were collected from experimental fields (each treatment 1 ha) under winter wheat and permanent grass each year from 0–5, 5–10, 15–20 and 30–35 cm depths. Over the three year study period, it was found that permanent grass and the organic crop production system contributed to increased soil OM, POM, HS, WEC and MBC contents and DH activity compared to the CON system, especially in the top soil layer, 0–5 cm. To obtain a clearer picture of soil quality change our study examined for the first time the metabolic potential index (MPI) as a ratio of dehydrogenase activity to the soluble organic carbon content. The MPI values confirmed the increase of metabolism in ORG soil as a consequence of management practices compared with CON soil. The obtained correlations showed strong mutual relationships within properties of the heterogeneous soil complex. The results show the positive effects of the ORG management system causing soil condition improvement which is based on organic fertilization, enriching the soil with a large amount of plant residues in creating positive changes in the soil quality in contrast to the CON system.

Evaluation of the Potential for Soil Organic Carbon Content Monitoring With Farmers

Increasing soil organic carbon (SOC) content is crucial for soil quality and climate change mitigation. SOC monitoring is indispensable to the corresponding policies and should provide results at farm scale to allow for incentives. In Switzerland farmers perform mandatory analyses of the SOC content of the 0-20 cm topsoil of every field, based on a composite sample, at least every ten years. The corresponding results are stored in a database in canton of Geneva. These data may be relevant for topsoil SOC monitoring, in particular for carbon sequestration policies, provided that they show appropriate quality, which is analyzed in this study. The minimum detectable change (MDC) of past results calculated based on the observed SOC changes was 0.013 % g g-1 at canton scale (2700 fields). Based on extended sampling of three representative fields different sampling strategies were simulated to determine the best future sampling guidelines for farmers. Collecting 20 aliquots with a gouge on the field diagonals was considered the best sampling compromise with field MDC of about 0.1 % g g-1 and a sampling duration of 20 mn. Compared to this procedure, former farmers’ sampling was not biased in average but showed a variance of 0.22% g g-1 due to smaller number of aliquots and varying sampling depths. Based on the best sampling results and assumptions on farm-scale SOC variance or SOC differences, the MDCs at farm scale ranged from 0.21 to 0.12 % g g-1 (5 fields) and 0.09 to 0.05 % g g-1 (30 fields), respectively. These MDCs are small compared to published monitoring networks MDCs, and allow determining SOC change rates at farm scale, thus offering perspectives for inexpensive and efficient monitoring in the frame of soil quality or climate mitigation incentives. For the latter, however, additional information with equivalent soil mass and deeper layers carbon content would be necessary.

Comparison among Different Rewetting Strategies of Degraded Agricultural Peaty Soils: Short-Term Effects on Chemical Properties and Ecoenzymatic Activities

In 2013, a pilot experimental field of about 15 ha was set up within the basin of Lake Massaciuccoli (Tuscany, Italy) in order to compare different management strategies—a paludicultural system (PCS), a constructed wetland system (CWS), a nearly-natural wetland system (NWS)—for peatland restoration after almost a century of drainage-based agricultural use (CS). After five years, changes in peat soil quality were investigated from a chemical, biochemical, and ecoenzymatic perspective. The soil in CS was mainly characterized by oxidant conditions, higher content of overall microbial activity, low levels of easily available phosphorus for vegetation, and medium total carbon content ranging from 25.0% to 30.7%. In PCS, the levels of total carbon and the content of bioavailable P were higher, while the oxidant conditions were lower compared to the other systems. As expected, the soils in CWS and NWS were characterized by the most reduced conditions and by the highest levels of arylsulphatase activity. It was noteworthy that soils in the NWS systems were characterized by the highest level of nonavailable P. Outputs from ecoenzymatic activity confirmed the physico-chemical and biochemical results.

Do Wildfires Cause Changes in Soil Quality in the Short Term?

Wildfires have high frequency and intensity in the Mediterranean ecosystems that deeply modify the soil abiotic (i.e., pH, contents of water, organic matter and elements) and biotic properties (i.e., biomass and activity). In 2017, an intense wildfire occurred inside the Vesuvius National Park (Southern Italy), destroying approximately 50% of the existing plant cover. So, the research aimed to evaluate the fire effects on soil quality through single soil abiotic and biotic indicators and through an integrated index (SQI). To achieve the aim, soil samples were collected inside the Vesuvius National Park at 12 sampling field points before fire (BF) and after fire (AF). The findings highlighted that in AF soil, the contents of water and total carbon, element availability, respiration and the dehydrogenase activity were lower than in BF soil; in contrast, pH and hydrolase activity were significantly higher in AF soil. The microbial biomass and activity were affected by Al, Cr and Cu availability in both BF and AF soils. Despite the variations in each investigated soil abiotic and biotic property that occurred in AF soil, the overall soil quality did not significantly differ as compared to that calculated for the BF soil. The findings provide a contribution to the baseline definition of the properties and quality of burnt soil and highlight the short-term effects of fire on volcanic soil in the Mediterranean area.

Spatio-temporal dynamic of soil quality in the central Iranian desert modeled with machine learning and digital soil assessment techniques

Soil degradation reduces soil quality by a loss of organic matter, reduced soil fertility, and structural breakdown, erosion, undesirable changes in salinity, acidity or alkalinity and the effects of toxic chemicals, contaminants or excessive flooding. In this study, we investigated spatial and temporal changes of soil quality between 1986 and 2030 in the Central Iranian desert. 201 topsoil samples (0–20 cm) in Yazd-Ardakan plain of Iran were chosen with conditioned Latin hypercube sampling strategy and analysed for soil organic carbon, electrical conductivity, dry bulk density, aggregate stability, and soil heavy metals. A soil quality index was calculated using weighted index method. To predict the spatial distribution of the soil quality index, we implemented a random forest model based on a set of covariates with a coefficient of determination of 0.69 between soil quality index and covariates. The results of soil quality index changes from 1986 to 2030 show that during this period, the areal extent of the Very Low SQI Class (<0.4) increased by 78,242 ha (increase of 16.2%), while the extent of the Good SQI Class (>0.6) decreased by 366,018 ha (decrease of 75.8%). This indicates that the soil quality in the study area, over time, is progressively becoming poorer. The results of the study of soil quality changes can be used in land evaluation, environmental studies and integrated planning and management in order to properly and reasonably utilize natural resources and reduce future soil degradation.

Soil labile organic carbon fractions and soil enzyme activities after 10\xa0years of continuous fertilization and wheat residue incorporation

Labile organic carbon (LOC) fractions and related enzyme activities in soils are considered to be early and sensitive indicators of soil quality changes. We investigated the influences of fertilization and residue incorporation on LOC fractions, enzyme activities, and the carbon pool management index (CPMI) in a 10-year field experiment. The experiment was composed of three treatments: (1) no fertilization (control), (2) chemical fertilizer application alone (F), and (3) chemical fertilizer application combined with incorporation of wheat straw residues (F + R). Generally, the F + R treatment led to the highest concentrations of the LOC fractions. Compared to the control treatment, the F + R treatment markedly enhanced potential activities of cellulase (CL), β-glucosidase (BG), lignin peroxidase (LiP), and manganese peroxidase (MnP), but decreased laccase (LA) potential activity. Partial least squares regression analysis suggested that BG and MnP activities had a positive impact on the light-fraction organic carbon (LFOC), permanganate-oxidizable carbon (POXC), and dissolved organic carbon (DOC) fractions, whereas laccase activity had a negative correlation with those fractions. In addition, the F + R treatment significantly increased the CPMI compared to the F and control treatments. These results indicated that combining fertilization with crop residues stimulates production of LOC and could be a useful approach for maintaining sustainable production capacity in lime concretion black soils along the Huai River region of China.

Effect of long-term reclamation on soil quality in agricultural reclaimed coastal saline soil, Eastern China

The assessment of soil quality related to different reclamation years and land use/cover types is the key parameter to evaluate the success of reclamation activities in coastal saline soil. Soil samples were collected from natural bare flat and coastal wetlands that have been reclaimed for different times (7, 32, 40, and 63 years) to investigate the change in soil quality during the process of reclamation in this study. Soil quality was evaluated using a soil quality index (SQI), which was calculated by the selected minimum dataset (MDS) and the technique for order preference by similarity to ideal solution (TOPSIS) methods. Soil water content (SWC), bulk density (BD), electrical conductivity (EC), and pH were observed significantly decreased whereas soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), urease (URE), and acid and alkaline phosphatase (ACP and ALP) activities notably increased after 60 years of reclamation. However, amylase (AMY) activity increased first and then decreased, and dehydrogenase (DEH) activity showed weak differences within 60 years reclamation. Further, TN, EC, AMY, and ACP activity were in the MDS with 12 soil properties as soil quality indicators. The SQI values varied from 0.05 in the bare flat soils to 0.86 in the soils after 63 years of reclamation and improved with increasing reclamation years. In addition, the SQI values of different land use/cover types were in the order of bare flat (0.07 ± 0.03) < uncultivated land (0.22 ± 0.16) < Spartina alterniflora (0.25 ± 0.16) < fishpond (0.57 ± 0.10) ≈ wheat land (0.58 ± 0.08) ≈ broad bean land (0.58 ± 0.07) < rape land (0.73 ± 0.15). Soil quality improved with the increase of reclamation years. Additionally, low levels of TN and high concentrations of EC were the primary constraints restricting soil quality in bare flat and soil in the early stage of reclamation, whereas AMY activity was the main obstacle after 30 years of reclamation.

Dynamics in soil quality and crop physiology under poplar-agriculture tillage models in coastal areas of Jiangsu, China

The coastal area of northern Jiangsu is rich in land resources. Meanwhile, Poplar-Agricultural compound management is an efficient and ecological management mode. Thus, it is of great significance to explore the application of agroforestry in different specific soil types in the coastal areas of northern Jiangsu. This study was conducted to investigate the dynamics changes of soil quality and crop growth physiology in eight Poplar-Agricultural complex management mode (Poplar pure forest (CY), Populus L.+Arachis hypogaea (YH), Populus L.+Glycine max (YD), Populus L.+Ipomoea batatas (YS) under coastal silt soil and CY*, YH* YD*.YS* under desalted soil after initial fresh water treatment). The results indicate that under the same soil conditions, compared with pure forests, the effects of Poplar-Agricultural compound management on soil physical and chemical properties were more significant. The growth status of trees was generally better under the condition of desalted soil and the survival rate was 35%–40% higher than that of saline soil. However, the survival rate of trees under the combined management of forestry and agriculture was 5%–10% higher than that of pure forest under the same soil condition. The microenvironment and crop photosynthesis were significantly affected by site conditions. Specifically, microenvironment was more stable under the condition of desalted soil and the photosynthetic effect of crops was better than that of silt soil. Overall, desalinized soil was more suitable for the growth of poplar plantation than silt soil, and Poplar-Agricultural compound management improved soil and forest environment which was better than pure poplar plantation. The study demonstrates that Poplar-Agricultural compound management plays an important role in improving soil quality and crop photosynthesis, and the selection of suitable specific soil conditionals can provide fundamental information for the sustainable development and management of agroforestry model in costal mudflat reclaimed lands.

Changes in and evaluation of surface soil quality in Populus × xiaohei shelterbelts in midwestern Heilongjiang province, China

To examine changes in surface soil quality over time in Populus × xiaohei shelterbelts, we collected soil samples from five shelterbelts of different ages and also from former cropland left fallow for 25 years. Twenty-one surface soil (0–20 cm) properties were measured, and variation in soil quality was assessed using one-way ANOVAs and multiple comparison tests. Based on this analysis, 16 soil indexes were used in a model evaluating soil quality, with each index given weight as determined by the correlation coefficient. Compared with the control, the post-mature forest had greater soil moisture content but lower bulk density (P < 0.05). The mature forest also had higher soil pH, total organic carbon, alkali-hydrolyzed nitrogen, available phosphorus, and biomass nitrogen content, but reduced nitrate-nitrogen and total phosphorus content than the control (P < 0.05). Total porosity was highly positively correlated with aeration, nitrate-nitrogen, alkali-hydrolyzed nitrogen, available phosphorus, microbial biomass carbon and microbial biomass nitrogen. Soil total organic carbon, ammonium nitrogen, nitrate-nitrogen, alkali-hydrolyzed nitrogen, total nitrogen, available phosphorus, microbial biomass carbon and microbial biomass nitrogen were all strongly correlated. In the soil quality evaluation model, total organic carbon was assigned the highest weight and total potassium content the lowest. The soil quality index was lowest in the near-mature forest and greatest in the post-mature forest. Generally, soil quality in Populus × xiaohei shelterbelts varied with age and was higher in the 10–20 cm versus 0–10 cm soil layer. After a single forest generation, surface soil quality was significantly improved.

Sustainable soil quality management for enhancing crop productivity in tribal areas of central India: A case study

The objectives of current investigation are to assess soil quality and sustainable management of soils for enhancing crop productivity in the tribal districts (Jhabua, Alirajpur and Dhar) of central India. Field trials were conducted in ten farmers’ fields for two years. Soybean-wheat system was adopted in six farmers’ fields and maize-wheat system in four farmers’ fields. Treatments were integrated plant nutrient supply (IPNS); soil test based nutrient management (STNM); recommended doses of fertilizers (RDF) and farmers’ practices (FP). Initial and post experiment soil samples were collected and analyzed. Soil quality changes were also studied. IPNS and STNM practices improved crop yield, farm income and soil quality compared to RDF and FP. Low organic carbon and deficiency of N, S and P are the major soil constraints in the region. Therefore, IPNS and STNM could be practiced to enhance crop productivity, farm income and to maintain soil health in the region.

“Insects as an Indicator for Environmental Pollution”

Bioindicators have been generating great interest in environmental pollution research. The main goal of research on bioindicators is to identify species that would reliably indicate disturbances in the environment as well as show the effects of those disturbances on other species or the overall biodiversity. Insects are especially useful to assess the effects of anthropogenic activities on the terrestrial ecosystem as well as aquatic system and atmosphere, because they are in close contact with toxic elements present in soil, water and air. In this article we have highlighted the importance of the insects as a beneficiary in monitoring of environmental pollution and assessment of pollutants. We have mainly focused on insects as important indicators of change in air, water and soil quality. Most insects like beetles, ants, honeybees, and butterflies are used as biological indicators in this study because they are sensitive to even a slight change in the environment and also used in monitoring of various pollutants in environment.

Changes in soil quality under conservation agriculture practices in West Nusa Tenggara, Indonesia

The main challenge for cultivating upland in semi arid environment as in West Nusa Tenggara, Indonesia is the limited availability of water resources and accelerated deterioration of soil quality. This study evaluated changes in selected soil properties and soil quality 4 years after the implementation of conservation agriculture (CA) practices. The study was conducted at the CA demonstation plots in Gunung Malang Village, Pringgabaya District, East Lombok Regency, West Nusa Tenggara Province. The surface soil texture was loam with slope ranging from 5 to 10%. Two CA Models and one farmer practice (LP) were compared. Within each model three sampling positions were sampled: within the corn planted area (Position A), 0-10 cm from the edge of the corn planted area (Position B), and 10 – 20 cm from the edge of the corn planted area (Position C). Intact soil samples (76 by 40 mm) were taken from the three positions at two depths (100-mm increments) to determine soil physical properties and bulk samples from the surface soil (0 – 15 cm) to determine soil chemical properties in the laboratory. The CA Model had significantly (&lt;em&gt;P&lt;/em&gt; &amp;lt; 0.01) lower bulk density (BD), and increase soil organic carbon (SOC) and available P (Av P), while Position had significantly affect only BD. The lowest BD (0.87 ± 0.07 Mg m-&lt;sup&gt;3&lt;/sup&gt;) and the highest SOC (1.51± 0.05%) and available pore water (AWC; 18.06 ± 0.76% vol) were found at Position A in CA with permanent pit (PIT). The highest soil quality index was found in Position A followed by Position B and the least was in C indicating that the crop rotation component in CA had relatively small effect on improving soil quality. These results suggested that there is a gradual improvement on soil quality after 4 years of the implementation of conservation agriculture and require longer time than 4 yr to achieve the best soil quality for this semi arid environment

Change in composition and function of microbial communities in an acid bamboo (Phyllostachys praecox) plantation soil with the addition of three different biochars

Biochar has been known as means to increase soil carbon (C) storage, and at the same time to ameliorate soil acidity and enhance plant growth. However, how biochar addition affects microbial community composition and metabolic function in subtropical plantation soils and their linkage with soil quality change is still poorly understood. We selected bamboo stick, corn straw and peel of Carya cathayensis as feedstocks to produce three biochars at 350 °C by slow pyrolysis, and added them to an acid bamboo (Phyllostachys praecox) plantation soil. Changes in soil nutrient and C availability, soil acidity, plant biomass, and microbial function in terms of C source utilization and soil enzyme activities were investigated after a three-month greenhouse trial. The results showed that the biochars from corn straw and peel significantly increased plant biomass, soil pH, organic C, total nitrogen (N) and dissolved organic N contents, while decreased exchangeable H+ and exchangeable Al3+ concentrations. The concentration of total phospholipid fatty acids (PLFAs) was increased significantly under biochars from corn straw and peel. The activities of β-D-cellobiosidase, N-acetylglucosaminidase and acid phosphatase were significantly increased by peel biochar. Soil basal respiration and microbial utilization rate of carbohydrates, carboxylic acids and amino acids compounds were significantly increased under the three biochars, suggesting a higher capacity of biochar-treated soil to catabolize C sources. Increased plant biomass was related to the increased N availability and decreased acidity. Our study suggests that biochar–induced changes in soil acidity and soil nutrient availability are key drivers shaping the composition of microbial communities and enhancing their catabolic capacity, but the effects on soil microbial function vary depending on feedstock origins.