Terrace Soil Research Articles

Effects of Phytoremediation Treatment on Bacterial Community Structure and Diversity in Different Petroleum-Contaminated Soils.

Increased exploitation and use of petroleum resources is leading to increased risk of petroleum contamination of soil and groundwater. Although phytoremediation is a widely-used and cost-effective method for rehabilitating soils polluted by petroleum, bacterial community structure and diversity in soils undergoing phytoremediation is poorly understood. We investigate bacterial community response to phytoremediation in two distinct petroleum-contaminated soils (add prepared petroleum-contaminated soils) from northwest China, Weihe Terrace soil and silty loam from loess tableland. High-throughput sequencing technology was used to compare the bacterial communities in 24 different samples, yielding 18,670 operational taxonomic units (OTUs). The dominant bacterial groups, Proteobacteria (31.92%), Actinobacteria (16.67%), Acidobacteria (13.29%) and Bacteroidetes (6.58%), increased with increasing petroleum concentration from 3000 mg/kg–10,000 mg/kg, while Crenarchaeota (13.58%) and Chloroflexi (4.7%) decreased. At the order level, RB41, Actinomycetales, Cytophagales, envOPS12, Rhodospirillales, MND1 and Xanthomonadales, except Nitrososphaerales, were dominant in Weihe Terrace soil. Bacterial community structure and diversity in the two soils were significantly different at similar petroleum concentrations. In addition, the dominant genera were affected by available nitrogen, which is strongly associated with the plants used for remediation. Overall, the bacterial community structure and diversity were markedly different in the two soils, depending on the species of plants used and the petroleum concentration.

Effects of zinc and boron on yield, nodulation and nutrient contents of fieldpea in terrace soils

An experiment was conducted for two consecutive years (2014-15 and 2015-16) in the field of Pulses Research Sub-Station, BARI, Gazipur during rabi (winter) season to evaluate the effect of zinc (Zn) and boron (B) application on the yield, nodulation and nutrient content of fieldpea (Pisum sativum L.). There were 16 treatment combinations comprising four levels each of zinc (0, 1, 2 and 3 kg ha-1) and boron (0, 1, 1.5 and 2 kg ha-1) along with a blanket dose of N12 P18 K30 S10 kg ha-1 over the treatments. The experiment was laid out in a split-plot design with three replications. Zinc (Zn) as ZnSO4.7H2O and boron (B) as H3BO3 were applied to the crop (cv. BARI Fieldpea-1). Results showed that the combination of Zn3B1.5 kg ha-1 produced the highest seed yield (1582 kg ha-1) in the 1st year and the Zn3B2 kg ha-1 gave the highest yield (1702 kg ha-1) in the 2nd year.The lowest seed yield was found in the control (Zn0B0). The Zn3B2 demonstrated the highest nodulation and nutrient and protein contents. The results suggest that the application of Zn3B2 kg ha-1 along with N12 P18 K30 S10 kg ha-1 can support the higher yield of fieldpea in terrace soils of Bangladesh.Bangladesh J. Agril. Res. 43(3): 441-451, September 2018

Assessing Soil Erosion by Agricultural and Forestry Production and Proposing Solutions to Mitigate: A Case Study in Son La Province, Vietnam

Son La is a province in the Northwest region of Vietnam; this province has diverse terrains with elevation ranging from 100 m to 2,900 m. Due to lack of cultivating lands, farmers still cultivate lands with steep slope, even above 25o. Consequently, the soil erosion has occurred hugely and the time for productive cultivation has been shortened. Therefore, it is necessary to assess the actual soil erosion, analyzing causes and proposing solutions to mitigate soil loss in the Son La province. Application of GIS technology and the Universal Soil Loss Equation (USLE) to predict soil erosion showed that the soil eroded at a very low level (0–1 ton·ha−1·year−1) accounted for the largest proportion with 56.49% of the area. Low level (1–5 ton·ha−1·year−1), medium level (5–10 ton·ha−1·year−1), and high level (10–50 ton·ha−1·year−1) eroded areas account for 8.52%, 7.88%, and 1.41%, respectively, of the area. Soil is eroded in very high level (>50 ton·ha−1·year−1), accounting for 25.7% of the study area. Research on solutions to mitigate soil erosion in Mai Son district showed that, for the cultivation of perennial crops (coffee), when planting on following contour lines, the amount of soil lost annually due to erosion is 63.37 ton·ha−1, while the cultivation following level top bench terrace soil loss is 39.55 ton·ha−1. If more grass strips were planted, the amount of soil lost annually due to erosion was reduced by 71% compared to traditional solutions. For this solution, when intercropping soybean, the soil erosion was reduced by 63–76% compared to the traditional methods. For cultivation of annual crops (maize) where the traditional methods of cultivation, namely, burning, ploughing, and seeding, are followed, the average loss of soil annually is 64.06 ton·ha−1. This value was 45.04 ton·ha−1 and 41.96 ton·ha−1, respectively, as the minimum soil tillage measure and no-tillage measure were used. When using the stems of maize after harvesting to cover lands following contour lines and terraces, soil erosion decreased by 38–59% compared to traditional solutions, while intercropping with legumes, soil loss due to erosion decreased 50–68% compared to traditional measures.

Nutrient management on the growth and yield of black cumin (Nigella sativa L.)

A field experiment was carried out at the research field of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, during rabi (winter) season of 2016-17 to evaluate the effects of fertilizer treatments on black cumin (BARI Kalozira-1). The field belongs to Shallow red-brown terrace soil of Salna series under AEZ-28 (Madhupur Tract). The experiment was laid out in randomized complete block design (RCBD) with three replications. Results showed that the application of nutrient elements had positive effect on plant height, branches per plant, capsule setting, umbels per plant, capsules per plant, capsule size, seeds per capsule, 1000-seed weight and seed yield of black cumin. The highest seed yield (1277 kg ha-1) was obtained from 75% RDCF + 25% cowdung-N treatment followed by 100% RDCF (N80P45K50S20Zn5B2 kg ha-1) and the lowest seed yield (420 kg ha-1) was recorded with 50% RDCF. Thus, the IPNS treatment 75% RDCF + 25% cowdung-N appeared to be the best suitable package for black cumin cultivation in this location.Bangladesh J. Agril. Res. 43(2): 205-210, June 2018

Minimal soil disturbance and increased residue retention increase soil carbon in rice-based cropping systems on the Eastern Gangetic Plain

The adoption of conservation agriculture (CA) in the intensive triple-cropping, rice-based systems of the Eastern Gangetic Plain (EGP) alters the dynamics of carbon (C) in the soil, but the nature of these changes is poorly understood. Our aim was to determine whether CA in these systems involving non-puddled transplanting of wetland rice and strip planting of dryland crops plus increased residue retention would increase the C storage in soils relative to conventional crop establishment practices. Long-term field experiments were studied in two locations of northwestern Bangladesh to determine C turnover as well as examining C cycling under three levels of soil disturbance (conventional tillage (CT), strip planting (SP) and bed planting (BP)) in combination with low residue (straw) retention (LR, the current practice) and increased residue retention (HR) in Calcareous Brown Floodplain soil (Alipur) and Grey Terrace soil (Digram). The total nitrogen (N), organic C, microbial biomass C (MBC) and water-soluble C (WSC) values were measured in soil samples from 0 to 10 cm depth collected at different stages during the growth of the 13th and 14th crops at Alipur and the 12th and 13th crops at Digram since the treatments commenced. At each location, SP and BP with either LR or HR retained more soil organic C (0–10 cm) from C inputs than CT with HR and LR. In general, the CO2 emissions relative to the stored soil organic C in the soils (0–10 cm) under SP with LR and HR were approximately 13 to 59% lower than those under CT and BP with LR and HR. The higher levels of C mineralization were associated with higher WSC contents in the soil. In contrast, the MBC contents in the HR treatments followed the order SPHR > BPHR > CTHR. Similarly, in SPLR and SPHR, the potentially mineralizable C (PMC) was higher, while the decay rate constant was lower. Increased residue retention with minimal soil disturbance practices (SP and non-puddled transplanting) after 14 crops at Alipur and 13 crops at Digram modified the C cycle by decreasing C emissions and increasing the levels of total organic C in the soil. The application of both minimal soil disturbance and increased residue retention enhanced soil organic C (0–10 cm) concentrations in the two soils under intensive rice-based cropping systems on the EGP.

Using portable OSL reader to obtain a time scale for soil accumulation and erosion in archaeological terraces, the Judean Highlands, Israel

Abstract Current conventions on the fate of agricultural bench terraces in the mountainous Mediterranean climatic zones, assume that after abandonment terraces undergo rapid degradation and soil loss. First walls crumble, followed by soil washed out of breaches in the walls by runoff, resulting in rapid erosion of soil from the slopes downhill into the streams. Additionally, soil erosion may explain why previous optically stimulated luminescence (OSL) dating of terrace soils in the Judean Highlands, Israel, found mostly young soils dating to the past 700 years, and only occasionally were older ages obtained for soils at the very base of these terraces. In contrast, observations made in the same region show that slopes with degraded terraces appear to still retain much soil even though only faint remains of the terraces exist. To test if terraces and soils indeed erode entirely and how long this might take, a relatively smooth hill slope showing remains of highly degraded sets of terraces was studied. Samples were collected from excavated pits for full OSL dating, in addition to samples densely collected for OSL measurements using a portable OSL reader (PR). Air-born photogrammetry was used to obtain high spatial resolution Digital Elevation Model. Results show that the main body of terraces was first built ∼800 years ago and maintained until 175-100 years age when they were abandoned and subsequently degraded. Since then 30–45% of soil volume was lost to erosion, however steady-state was reached at a relatively high slope of 65%, with stabilization by vegetation. The thick soil present on most of the slope suggests that after the first stage of rapid degradation the slopes reache equilibrium, most likely due to vegetation that reduces direct soil erosion, so most of the soil is retained on the slope. Finally, the PR allows for a much more nuanced understanding of terrace soil history.

Response of strawberry to NPKS on yield in terrace soil

Strawberry (Fragaria X annanassa Duch.) is highly exhaustive and responsive to chemical fertilizers. An experiment on strawberry was conducted in fruits research field of Horticulture Research Centre, BARI, Gazipur over three consecutive years, 2009-2010, 2010-2011 and 2011-2012 to find out the suitable combination of nitrogen (N), phosphorus (P), potassium (K) and sulphur (S) for yield maximization of strawberry. Fourteen treatment combinations were tested in this trial comprising four levels each of N (0, 90, 115 and 140 kg ha-1), P (0, 20, 40 and 60 kg ha-1), K (0, 85, 110 and 135 kg ha-1) and S (0, 15, 25 and 35 kg ha-1) with blanket dose of 4 kg Zn ha-1, 2 kg B ha-1 and 10 t cowdung ha-1. The experiment was set up in randomized completely block design with three replications. Results showed that treatment combination N115P40K110S25 (underscript represent kg ha-1) produced higher strawberry fruit yield (9.59 t ha-1) followed by N90P40K110S25 kg ha-1 and N140P40K110S25 kg ha-1 treatment combinations. The lowest fruit yield (6.05 t ha-1) was found in control (N0P0K0S0) treatment. Therefore, the combination of N115P40K110S25 kg ha-1 may be considered as suitable dose for strawberry cultivation in terrace soils of Bangladesh.Bangladesh J. Agril. Res. 43(1): 89-97, March 2018

Effect of urea super granule and prilled urea on the growth and yield of broccoli

A field experiment was conducted at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur during the period from 2012-13 to verify the effectiveness of urea super granule (USG) and prilled urea (PU)on growth, yield and yield attributes of broccoli in Shallow Red-Brown Terrace Soil under Madhupur Tract (AEZ-28). The experiment was laid out in a Randomized Complete Block Design with three replications having 5 treatments constituted with different levels of USG and PU as- T1: Control, T2: USG-N140 (140 kg N as USG), T3: USG-N160 (160 kg N as USG), T4: USG-N180 (180 kg N as USG), T5: PU-N180 (180 kg N as PU). Performance of USG was better than PU and the treatment USG-N160 gave the highest yield (13.49 ton ha-1) which was followed by USG-N180 (12.43 ton ha-1) and PU-N180(12.05 ton ha-1) having significant difference among these. Higher but statistically identical number of lateral head 5.103 and 5.38 was produced by USG-N160 and USG-N180 treatments, respectively in comparison with PU-N180 (5.04). But higher lateral head yields (6.05 and 5.03 ton ha-1) were found in USG-N180 treatments followed by PU-N180. All the yield contributing characters and the economic profitability were favorably correlated with these high yield performing treatments with the highest MRR (3336.67%) obtained from USG-N160 which indicated that USG @ 160 kg N ha-1 (USG-N160) is the most economically viable N dose in terms of yield and economics for broccoli production. Therefore, USG @ 160 kg N ha-1 (USG-N160) with other recommended fertilizer could be suggested as USG based fertilizer recommendation for better broccoli production in terms of yield and economics in Silty Clay Loam Soil of Madhupur Tract.Bangladesh J. Agril. Res. 43(1): 53-69, March 2018

Response of hybrid tomato varieties to boron application

A field experiment was carried out in Grey Terrace Soil of Joydebpur and Non Calcareous Grey Floodplain Soil of Agricultural Research Station, Burirhat, Rangpur during the rabi season of 2010-2011 and 2011-2012. The objectives were to evaluate the effect of boron on the yield and yield attributes of BARI Hybrid Tomato-5 as well as to determine an optimum rate of boron application for maximizing yield. Three varieties of BARI Hybrid Tomato-5 viz., Epoch, NS 815 and BARI Hybrid-5 and five levels of boron (0, 0.5, 1.0, 1.5 and 2.0 kgB ha-1) along with a blanket dose of N220 P60 K120 S40 Zn4.0 kg ha-1 and cow dung 5 t ha-1 were used in the study. Results revealed that NS 815 performed the best with 1.5 kg B ha-1 that produced 79.7 t ha-1 at Joydevpur whereas at Burirhat Epoch performed best (101 t/ha). The said combination increased 31.7% and 57.8% yield over the control at Joydevpur and Burirhat, respectively. However, from regression analysis, a positive but quadratic relationship was observed between yield and boron levels. The optimum dose of boron was appeared to be as 1.37 kg and 1.54 kg B ha-1 for Joydevpur and Burirhat, respectively.Bangladesh J. Agril. Res. 42(4): 707-714, December 2017

Soils of the Southwestern Part of the Pacific Coast of Russia

The diversity of soils in the southwestern part of the Pacific coast of Russia (Primorie region) is discussed. Overall, 17 soil types belonging to 8 soil orders have been described in this region, and their morphology and properties have been studied. The diversity of plant communities, geomorphic conditions, and parent materials and relatively mild (as compared with other parts of the Far East region of Russia) specify the great variability of soil cover patterns. Low sea terraces are occupied by various peat, organo-accumulative, and gley soils; poorly drained medium-high terraces are the areas of various dark-humus and darkhumus gleyed soils. Typical and gleyic dark-humus podbels, dark-humus, and dark-humus gleyed soils formed on the high sea terraces. Residual elevations are occupied by brown forest (burozemic) soils, including typical burozems, dark-humus burozems, and gleyic dark-humus burozems and by dark-humus podbels. Various alluvial, gleyic gray-humus, and mucky gley soils are developed on riverine plains. On general, darkhumus soils with the high (>10%) humus content predominate; the area of dark-humus podbels us estimated at about 20%, and the area of dark-humus burozems is about 12%. All the soils in this region are specified by increased acidity values. The exchangeable sodium content is often high in the upper soil horizons with maximum values (0.71–1.19 cmol(c)/kg) in the peat gleyzems, peaty dark-humus soils, mucky-gley soils, and eutrophic peat soils of sea terraces. The grouping of the soils with respect to their physicochemical and agrochemical properties is suggested.

Effect of Different Levels of Urea Super Granule and Prilled Urea on the Crop Quality, Nutrient Uptake and Soil Nutrient Status of Broccoli

A field experiment was conducted at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur during the period 2010-2011 to assess the effect of urea super granule (USG) and prilled urea (PU) on the quality attributes (Compactness coefficient, Vitamin C, β-carotene and chlorophyll contents) of broccoli, to assess the comparative performance of USG and PU on nutrient uptake and uptake efficiency of broccoli plant, to assess the effect of different forms and levels of urea N on the post harvest soil nutrient status of broccoli field and to select the better doses of USG and PU for quality broccoli production in Shallow Red-Brown Terrace Soil under Madhupur Tract (AEZ-28). The experiment was laid out in a randomized complete block design with three replications having 17 treatments constituted with different levels of urea super granule (USG) and prilled urea (PU) as- T1: N-control, T2: PU-N80, T3: PU-N100, T4: PU-N120, T5: PU-N140, T6: PU-N160, T7: PU-N180, T8: PU-N200, T9: PU-N220, T10: USG-N80, T11: USG-N100, T12: USG-N120, T13: USG-N140, T14: USG-N160, T15: USG-N180, T16: USG-N200, T17 and USG-N220 kg ha-1. Results revealed that the comparative performance of USG in relation to head quality (compactness coefficient, ascorbic acid, β-carotene and chlorophyll content), nutrient (NPKS) uptake and N uptake efficiency was found better as compared to PU. The compactness coefficient, β-carotene and chlorophyll contents were increased with increasing rate of N as well as USG and PU, but ascorbic acid content was slightly decreased with increasing rate of USG and PU. The maximum compactness coefficient (18.61) was found from the treatment USG-N180 that was followed by USG-N160 (18.24) and the highest β-carotene content (0.401 mg/100gFW) was found from USG-N160 followed by PU-N180 (0.40 mg/100gFW). Similarly the highest chlorophyll-a content (0.818 mg/100gFW) was found from USG-N180 followed by USG-N160 (0.814 mg/100gFW) and the highest chlorophyll-b content (1.141mg/100g FW) was recorded from USG-N180. The higher nutrient uptake and N uptake efficiency (108.531%) was obtained from USG treated plots over that of the PU. But N uptake efficiency was decreased with increasing rates of N fertilizer. But post harvest soil nitrogen status did not show any systematic trend although it was found higher in USG over PU. Similarly no remarkable changes were observed in post harvest soil P, K, S and B status for the crop. However, USG @ 160 kg N ha-1 (USG-N160) followed by USG-N140 and PU @ 180 kg N ha-1 (PU-N180) with other recommended doses of fertilizer could be suggested as USG and PU based fertilizer recommendation for a good quality broccoli production in terms of yield and quality in Silty Clay Loam Soil of Madhupur Tract.The Agriculturists 2017; 15(2) 24-39

Soils of Agricultural Terraces with Retaining Walls in the Mountains of Dagestan

Soil-archeological studies of agricultural terraces with retaining walls in the area of construction of the Gotsatlinskaya Hydroelectric Power Station in Khunzakh district of the Republic of Dagestan have been performed. The morphogenetic and chemical properties of the anthropogenic soils (Anthrosols) in different parts of the terrace complex are analyzed. It is argued that slope terracing in the mountains ensures the development of thicker soil profiles with pronounced genetic horizons. The soils of agricultural terraces store important information of the paleoenvironmental history and land use. A characteristic feature of the Anthrosols of agricultural terraces is a relatively even distribution of gravelly material of up to 5 cm in diameter in the plow layer. The soils of terraces are characterized by the high variability in their properties within the entire terrace complex and within the particular terraces.

Impact of forest conversion to agricultural plantation on soil erosion

Agriculture in Malaysia makes up to twelve percent of the nation’s GDP and is supplying one-third of the world rubber export. Ambitious agriculture demand increases the intensity of forest conversion which is driven to the soil erosion. Thus, this study is to measure and analyse the impact of forest conversion on soil erosion relate to some manipulated variables such as slope, bulk density, soil moisture, canopy openness and ground cover, where rainfall and soil type are constant within the sites. Two different land-uses of High Conservation Value Forest (HCVF) and Mature Rubber Plantation of Timber Latex Clone (MRP) were selected around Kelantan state, due to the high land conversion compared to the other states of West Malaysia. Ground height change was monitored by using Modified Laser Erosion Bridge (MLEB) in between 17 to 48 transects. The result found that the annual soil erosion rate was 76.12 t.ha-1.yr-1 for HCVF is higher compared to the MRP was 6.37 t.ha-1.yr-1. Terrace soil conservation technique is practiced for MRP helps in reducing soil movement resulted significant low erosion rate compared to the HCVF. The results indicate that even a relatively limited forest conversion can be assumed to have a significant effect on regional soil erosion rate.

Tunnelling on terrace soil deposits: Characterization and experiences on the Bogota-Villavicencio road

Terrace deposits are often encountered in portal areas and tunnels with low overburden. They are challenging to excavate considering their great mechanical and spatial heterogeneity and a very high stiffness contrast within the ground. Terrace deposits are difficult to characterize, considering that samples for laboratory testing are almost unfeasible to obtain, and laboratory tests may not be representative due to scale effects. This paper presents the approach taken for their characterization during the design stage and their posterior validation performed during construction. Lessons learned from several tunnels excavated on terrace deposits on the Bogota-Villavicencio road (central-east Colombia), suggest that based on numerical simulations, laboratory testing and tunnel system behaviour monitoring, an observational approach allows engineers to optimize the excavation and support methods for the encountered ground conditions, resulting in a more economic and safe construction.

The influence of soil age and regional climate on clay mineralogy and cation exchange capacity of moist tropical soils: A case study from Late Quaternary chronosequences in Costa Rica

Tropical soils exhibit large differences across landscapes in many attributes, notably clay mineralogy (2:1 vs. 1:1 clays), bulk geochemistry (Ca, Al), pH, cation exchange capacity (CEC), organic matter and soil texture. In order to examine the factors controlling these variables, a series of three chronosequences (≤120ka) of tropical soils on uplifted terraces along the Pacific coast of Costa Rica were studied. The three study locations differ mainly as a function of soil moisture and leaching, with conditions ranging from 2700mm/yr mean annual precipitation (MAP) on the southern Nicoya Peninsula (4-month dry season), to 3200mm/yr in the Esterillos region (3-month dry season), and 4250mm/yr on the Osa Peninsula (no dry season). Analytical methods include X-ray diffraction (XRD), transmission-analytical electron microscopy (TEM-AEM), inductively coupled plasma optical emission and mass spectrometry (ICP-OES, ICP-MS), ammonium acetate extraction (1M NH4OAc, pH=7, for CEC) and C:N analysis.Soil weathering reactions and related decrease in CEC occur three-to-four times faster in a sequence of Inceptisol-to-Oxisol soils in the wettest climate (Osa) compared to the less-moist Esterillos area; in the even drier monsoon climate soils (Nicoya), this evolved, low-CEC (<10cmolc/kg) state does not occur, even after 120ka of soil formation, and rate of compositional alteration is approximately five to ten times slower than at Osa. The dominant exchangeable cation at all sites is Ca. Interlayer K and Al increase relative to Ca over time, resulting in interstratified K-S with smectite layers that become progressively more vermiculite-like and illite-like.The age-related evolution of tropical soils appears to be a predictable sequence in lowland tropical landscapes where periodic tectonism, erosion or volcanism produces unweathered parent material at the land surface. Empirical data from this project enables the extrapolation of simple equations applicable to tropical volcanic arc landscapes where presence of uplifted marine terrace soils facilitates determination of soil age. The two variables controlling soil composition can be combined into an effective age (ageeff) that takes into account soil age and weathering intensity (factoring in MAP and wet-dry months from climate data), and equations are of the form, e.g. ECEC=−18.1∗ln(ageeff)+77, with R2 values of 0.75 to 0.87. Greatest scatter occurs in the youngest soils. Given the apparent prevalence of this sequence and the systematic nature of its reaction progression, these results could be useful for modeling tropical soils.

High Temporal and Spatial Variability of Atmospheric-Methane Oxidation in Alpine Glacier Forefield Soils.

Glacier forefield soils can provide a substantial sink for atmospheric CH4, facilitated by aerobic methane-oxidizing bacteria (MOB). However, MOB activity, abundance, and community structure may be affected by soil age, MOB location in different forefield landforms, and temporal fluctuations in soil physical parameters. We assessed the spatial and temporal variability of atmospheric-CH4 oxidation in an Alpine glacier forefield during the snow-free season of 2013. We quantified CH4 flux in soils of increasing age and in different landforms (sandhill, terrace, and floodplain forms) by using soil gas profile and static flux chamber methods. To determine MOB abundance and community structure, we employed pmoA gene-based quantitative PCR and targeted amplicon sequencing. Uptake of CH4 increased in magnitude and decreased in variability with increasing soil age. Sandhill soils exhibited CH4 uptake rates ranging from -3.7 to -0.03 mg CH4 m-2 day-1 Floodplain and terrace soils exhibited lower uptake rates and even intermittent CH4 emissions. Linear mixed-effects models indicated that soil age and landform were the dominating factors shaping CH4 flux, followed by cumulative rainfall (weighted sum ≤4 days prior to sampling). Of 31 MOB operational taxonomic units retrieved, ∼30% were potentially novel, and ∼50% were affiliated with upland soil clusters gamma and alpha. The MOB community structures in floodplain and terrace soils were nearly identical but differed significantly from the highly variable sandhill soil communities. We concluded that soil age and landform modulate the soil CH4 sink strength in glacier forefields and that recent rainfall affects its short-term variability. This should be taken into account when including this environment in future CH4 inventories.IMPORTANCE Oxidation of methane (CH4) in well-drained, "upland" soils is an important mechanism for the removal of this potent greenhouse gas from the atmosphere. It is largely mediated by aerobic, methane-oxidizing bacteria (MOB). Whereas there is abundant information on atmospheric-CH4 oxidation in mature upland soils, little is known about this important function in young, developing soils, such as those found in glacier forefields, where new sediments are continuously exposed to the atmosphere as a result of glacial retreat. In this field-based study, we investigated the spatial and temporal variability of atmospheric-CH4 oxidation and associated MOB communities in Alpine glacier forefield soils, aiming at better understanding the factors that shape the sink for atmospheric CH4 in this young soil ecosystem. This study contributes to the knowledge on the dynamics of atmospheric-CH4 oxidation in developing upland soils and represents a further step toward the inclusion of Alpine glacier forefield soils in global CH4 inventories.

Conceptualization of Water Flow Pathways in Agricultural Terraced Landscapes

AbstractAgricultural terraces are often subject to degradation issues related to water movement. A better understanding of the main hydrological processes that govern surface and subsurface water flow pathways and that are responsible for terrace failure and dry‐stone wall collapse is essential for appropriate water resource management and rural landscape maintenance in terraced areas. However, a clear conceptualization of different hydrological functioning related to wall instability issues is still missing. In this study, we monitored a terrace system in a hilly site of central Italy cultivated with vineyards. We adopted a multidisciplinary approach based on soil analysis, different geophysical techniques, hydrological monitoring, high‐resolution grid terrain analysis and field experiments (infiltration and flooding tests) aiming to: (i) obtain new information of terrace soil and subsoil structure; (ii) test the hypothesis on wall instability based on the formation of preferential flow and water accumulation behind the wall; and (iii) develop a conceptual model of water circulation in agricultural terraces. Our results indicate that terrace soil was highly heterogeneous, including discontinuities and piping systems that facilitated a rapid infiltration and the development of fast subsurface flow. Groundwater rise did not occur, as observed in other terraced sites, but infiltrated water accumulated behind dry‐stone walls, increasing pore water pressure and inducing wall bulging and instability. Our findings provided new field evidences of water circulation and led to the definition of a novel paradigm of hydrological functioning of farming terraced systems for addressing more efficient management and maintenance issues in these vulnerable landscapes. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Characteristics and the Relationship of Nitrogen and Phosphorus in Soil and Water of Different Land Use Types of a Small Watershed in the Three Gorges Reservoir Area

Long-term field monitoring data was analyzed regarding the characteristics of nitrogen and phosphorus in the soil and shallow groundwater of different land use types in a typical small watershed of the Three Gorges Reservoir area. Furthermore, the relationships among soil nitrogen and phosphorus contents, concentrations of nitrogen and phosphorus in shallow groundwater, and slope surface runoff were analyzed. The results showed that the average contents of TN and NO3--N in terrace soil were significantly higher than those in sloping upland soil (P< 0.05), for which the average content of paddy terrace was highest (1.49 g·kg-1). The average contents of TP in the soil of sloping upland and mulberry-sloping upland were significantly higher than those in the soil of other land types. The average content of NO3--N in the soil of dryland terrace was highest of all land use types and its discrete degree was also largest. The slope land use type had greater impact on the concentrations of TN and NO3--N in shallow groundwater, but it had little influence on TP concentration. In addition, the shallow groundwater TN concentration and NO3--N concentration had significant positive correlation, and the average contribution rate of NO3--N to TN in five wells ranged from 67.82% to 78.51%. The monthly average concentration of TN and NO3--N in shallow groundwater changed little, only showing a significant upward trend after the fertilization stage of the two crops in spring and autumn. The average contents of TN and NO3--N in the slope soil were significantly correlated with the TN and NO3--N concentrations in the shallow groundwater, but there was no significant correlation between the TN and NO3--N concentrations in the surface runoff. When the slope surface runoff TP concentration was>0.1 mg·L-1, the average content of TP had a significant linear correlation with it. There was a significant power function relationship between the concentrations of TN and NO3--N in the surface runoff and concentrations of TN and NO3--N in the shallow groundwater, with higher correlation of NO3--N concentrations between surface runoff and shallow groundwater.

Effect of Nitrogen, Phosphorus and Potassium Fertilizers on Yield and Yield Attributes of Marigold (&lt;i&gt;Tagetes patula&lt;/i&gt; L.)

An experiment was conducted at the research field of Horticulture Research Centre, BARI, Gazipur during Rabi season of 2012-13 to 2014-15 to evaluate the yield and yield attributes of Marigold (var. BARI Marigold-1) to different doses of N, P and K fertilizers and to find out the optimum and economic doses of NPK for maximizing flower yield. Eleven treatments as T1, T2, T3, ,T10 and T11 comprising with four levels of fertilizer nutrients each of N (0, 60, 90 and 120 kg ha-1), P (0, 30, 40 and 50 kg ha-1) and K (0, 60, 90 and 120 kg ha-1) along with a blanket dose of 2 kg B and 4 kg Zn ha-1. The experiment was conducted assigning the treatments in a randomized complete block design with three replications. Flower yield and yield attributes of marigold significantly increased with NPK fertilizer for all three years. The significantly highest flower yield (22.25, 27.38 and 25.15 ton ha-1) was obtained from T3 treatment applying the nutrients N90P40K90 kg ha-1 along with blanket dose of 2 Kg B and 4 kg Zn ha-1 for the years 2012-13, 2013-14 and 2014-15, respectively which was statistically identical with T4 treatment (N120P40K90 kg ha-1) for the year 2012-13, but significantly different from all other treatments for the years 2013-14 and 2014-15, respectively. Flower yields were increased in T3 treatment (N90P40K90 kg ha-1) by 81.34, 62.53 and 49.53%; 146.00, 119.39 and 108.84% and 121.20, 92.13 and 84.11% over their control in respect to the years 2012-13, 2013-14 and 2014-15. The highest benefit-cost ratio 7.14 was obtained from T3 (N90P40K90 kg ha-1) followed by T4 (6.53) treatment. From the quadratic regression equation averaging three years data the optimum and economic doses 103.75 and 102.44 kg N; 36.67 and 36.31 kg P and 90.10 and 88.43 kg K, respectively were found which could be recommended for marigold production in Grey Terrace Soil of Joydebpur under AEZ 28.The Agriculturists 2017; 15(1) 101-109

Effect of N, P and K fertilizer on the flower yield of Chrysanthemum

An experiment was conducted at the research field of Horticulture Research Centre, BARI, Gazipur during Rabi season of 2012-13 to 2014-15 to evaluate the response of different doses of N, P and K on the yield and yield attributes of chrysanthemum (var. BARI Chrysanthemum-1) and to find out the optimum and economic doses of NPK for maximizing yield of chrysanthemum. Treatments comprising four levels each of N (0, 100, 150 and 200 kg ha-1), P (0, 50, 75 and 100 kg ha-1) and K (0, 90, 135 and 180 kg ha-1) along with blanket dose of 2 kg B and 4 kg Zn ha-1 were used. The treatments were assigned in a randomized complete block design with three replications. The combined effect of NPK significantly increased yield and yield attributes of chrysanthemum for each of the yearly experiments as well as the average of three years results. Significantly, the highest flower yield (12.45, 11.47 and 11.96 t/ha) was obtained with the application of N150P75K135 kg ha-1 (T3) along with blanket dose of 2 kg B and 4 kg Zn ha-1 for the years of 2012-13, 2013-14 and 2014-15, respectively and it was statistically identical with T4 (N200P75K135 kg ha-1) treatment. Application of 150 kg N, 75 kg P and 135 kg K increased yield by 52.76, 42.29 and 36.51%, 152.08, 126.23 and 99.13% and 88.35, 51.30 and 60.75%, respectively, over their control in respect to the years. The highest benefit-cost ratio 5.54 followed by 5.14 was obtained from T3 (N150P75K135 kg ha-1) followed by T4 treatment, respectively. From the quadratic regression equation averaging three years data the optimum and economic doses 155 and 151.8 kg N, 79.3 and 77.68 kg P and 118.75 and 115.7 kg K, respectively were found which could be recommended for chrysanthemum production in Grey Terrace Soil of Joydebpur under AEZ 28.The Agriculturists 2017; 15(1) 58-67