Gravimetric Soil Moisture Content Research Articles

Spatial mapping of soil moisture content using very-high resolution UAV-based multispectral image analytics

Assessing soil moisture content (SMC) is necessary for managing water at a spatial scale. Remote sensing technologies provide a robust approach for detecting the spatial-temporal fluctuations of SMC. The aim of this study was to estimate SMC at different soil depths using very high-resolution unmanned aerial vehicle (UAV)-based multispectral (MS) images and machine learning algorithms and generate spatial maps of SMC using the best-performed machine learning (ML) algorithm. The UAV-based multispectral images of bare soil were captured at 40 m altitude with a very high spatial resolution (2.89 cm) during the rabi 2021/22 season. At the same time, the soil samples were collected from different soil depths, and the gravimetric SMC was measured. Five machine-learning algorithms (Linear Regression (LR), K-Nearest Neighbors (KNN), Random Forest (RF), Decision Tree (DT), and Support Vector Regression (SVR)) were used to train the model between SMC and MS data (MS band reflectance and vegetation indices). The soil with high SMC has low spectral reflectance and soil with low SMC shows high spectral reflectance. For the prediction of surface SMC, the linear regression (R2 = 0.89; RMSE = 2.80 %) and 5 cm depth SMC, the SVR (R2 = 0.64; RMSE = 3.03 %) were performed well compared to other ML algorithms. For surface SMC, blue band reflectance, and 5 cm depth SMC, the Ratio Vegetation Index (RVI) correlated well compared to others. All models failed to predict the SMC at the deeper soil depths. The spatial SMC mapping described the visual color variations in SMC within the field. Crop irrigation scheduling can be significantly improved through the insights this spatial SMC estimation approach provides, making it a valuable tool for farmers and irrigation planners.

Topsoil and Vegetation Dynamics 14 Years after Eucalyptus grandis Removal in Eastern Cape Province of South Africa.

A great deal of effort has been made to clear invasive alien plants in South Africa, yet it remains unclear if the clearing efforts are yielding positive soil and vegetation recovery trajectories. A few short-term studies have been conducted to monitor soil and vegetation recovery after alien plant removal in South Africa, but convincing, long-term monitoring studies are scarce yet needed. We investigated topsoil and vegetation recovery following Eucalyptus grandis removal 14 years ago by Working for Water in Makhanda, Eastern Cape province of South Africa. The detailed topsoil and vegetation surveys were conducted on forty 10 m × 10 m plots that were in paired cleared and natural sites. The results show no significant differences for the measured soil pH, total N, total C, K, Ca, and Na between the cleared and natural sites, an indication that the two sites are becoming similar. Similarly, the gravimetric soil moisture content shows no significant differences between the two sites, although monthly variations are observed. The topsoils in the cleared sites are hydrophobic as compared to those in the natural sites, which are wettable. We observed no significant vegetation diversity differences between the two sites, with native woody species, such as Crassula pellucida and Helichrysum petiolare, frequently occurring in the cleared sites. We recorded low reinvasion by E. grandis and other secondary invaders like Acacia mearnsii and Rubus cuneifolius in the cleared sites. Based on these results, we conclude that 14 years after E. grandis clearing, both topsoil and vegetation recovery are following a positive trajectory towards the natural sites. However, both reinvasion and secondary invasion have the potential to slow down soil and native vegetation recovery. Recommendations such as timeous follow-up clearing and incorporating restoration monitoring in the WfW clearing programme are discussed.

Spatial variability of dendrometric parameters in a native tree Mabea fistulifera Mart. and its relationship with soil physical properties

Mabea fistulifera Mart. (common name: canudo-de-pito) belongs to the Euphorbiaceae family and is a native tree species in Brazil showing a high potential to recover degraded lands. This study aimed to evaluate the distribution and spatial correlation between the dendrometric parameters of the M. fistulifera plants and the physical attributes of the soil through geostatistics. The study was carried out at the Paulista State University (UNESP), in the city of Selvíria, MS, Brazil, in a typical dystrophic Red Oxisol with a clayey texture. The following properties were analyzed: for soil, penetration resistance, gravimetric moisture, particle density, and, for plants, circumference and diameter at breast height (measured at 130 cm above the ground), tree height, and total volume of the tree. An experiment grid was introduced with 35 sample points spaced 13 m x 13 m. Two soil samples were taken at each point, at 0.00 - 0.10 m and 0.10 - 0.20 m depth. Descriptive data analysis and spatial dependence analysis were carried out through semivariogram adjustments and kriging maps. The dendrometric properties of the species M. fistulifera and the soil gravimetric moisture content showed spatial dependence. The spherical semivariogram model best explained the spatial structure of circumference at breast height, diameter at breast height, tree volume, and soil gravimetric moisture. There was an emphasis on the correlation between the total volume of the tree as a function of the diameter at breast height, showing a moderate spatial dependence. Furthermore, the tree diameter at breast height proved to be a good indicator for determining the total height of the M. fistulifera tree.

Evaluation of pedotransfer functions to estimate some of soil hydraulic characteristics in North Africa: A case study from Morocco

Soil hydraulic properties are an important factor to optimize and adapt water management for a given crop. Pedotransfer functions (PTFs) present a solution to predict soil variables such as hydraulic properties, using fundamental soil properties. In this research, we compared two sources of soil information: iSDAsoil data and field data, in four regions in Morocco. We then used this data to evaluate published data and developed new PTFs using soil information to estimate soil gravimetric moisture content at saturation (w0), field capacity (w330) and permanent wilting point (w15000). A total of 331 samples were collected from four regions: Doukkala, Gharb-Loukous, Moulouya and Tadla. The data was divided into calibration and validation datasets. For development of different PTFs, we used simple linear regression, multiple linear regression, regression tree, Cubist algorithm, and random forest approaches. PTFs developed by Dijkerman (Geoderma, 1988, 42, 29–49) presented the best performance, showing lower RMSE, Bias and MAE compared to other PTFs. Using multiple linear regression to develop PTFs, models based on clay, silt and soil organic matter as input variables showed the best performance after calibration (R2 of 0.590, 0.785, 0.786 for w0, w330, and w15000, respectively). Regarding the techniques based on machine learning, random forest showed the best performance after calibration compared with other algorithms (R2 of 0.930, 0.955, 0.954 for w0, w330, and w15000, respectively). PTFs represent a low cost and easy technique to estimate soil hydraulic properties, to improve water management efficiency for the farmers.

Effect of Different Mulches and Planting Beds On Growth and Yield of Bitter Gourd in Coastal Saline Soils

A field experiment was carried out in coastal saline soils of Bangladesh in 2018, 2019 and 2020 to evaluate the effect of different kinds of mulches and planting beds to reduce salt accumulation in the soil and to increase the yield of bitter gourd. The experiment was laid out in a factional randomized complete block design having two kinds of mulches: viz. rice straw mulch and polythene mulch along with no mulch control and three kinds of planting beds: viz. convex bed, flat bed and concave bed. The polythene mulch treatment had highest fruit yield of 21.86, 27.20 and 20.49 t ha-1, respectively followed by rice straw mulch and no mulch control treatment in 2018, 2019 and 2020, respectively. Polythene mulch reduced electrical conductivity of soil by 31% and soil sodium content by 42% compared to no mulch treatment. Polythene mulch also increased soil temperature and gravimetric soil moisture content which promoted plant growth. The convex bed method produced highest mean fruit yield of 18.37, 20.06 and 15.18 t ha-1 followed by the flat bed and concave bed method in the year 2018, 2019 and 2020, respectively. Combined use of polythene mulch and convex bed planting could provide greatest benefit to the farmers. The polythene mulch along with convex bed planting is therefore, recommended to get higher yield of bitter gourd and to reduce detrimental effect of salt on crop in coastal saline soils. Bangladesh J. Agril. Res. 46(1): 71-87, March 2021

Higher density swards have a higher load bearing capacity

AbstractIncreasing the water table is an important pathway to reduce greenhouse gas emissions from peaty soils. In order to continue utilizing grasslands on these soils, methods to increase load bearing capacity at a higher water table are sought. The objective of this study was to assess the effect of sward density on load bearing capacity, measured as both penetration resistance and the newly developed method measuring load bearing capacity through impact depth. Simultaneously, a new method to measure load bearing capacity through impact depth was developed. The study was conducted between 2018 and 2020 on 14 different farms in the western peat meadow district in the Netherlands, where the sward density measured with the point quadrat method ranged from 24% to 92%. Swards with a higher sward density showed a higher load bearing capacity than swards with a lower density. In a modelling approach an increase from 30% sward density to 90% sward density could result in a lengthening of the grazing season between three (11%) and six weeks (22%), depending on the soil moisture conditions. Load bearing capacity was also highly correlated with gravimetric soil moisture content as wetter conditions lowered load bearing capacity. In order to capture load bearing capacity more accurately a new measurement device was constructed which represents treading cattle. Both output (impact depth) and method (resembles cow hoof) are close to practice, which makes it a very suitable method allowing for easy interpretation by farmers.

Impact of wildfire on soil carbon and nitrogen storage and vegetation succession in the Nanweng'he National Natural Wetlands Reserve, Northeast China

In boreal regions, wildfires have a major impact on vegetation and permafrost. The ecosystem-protected Xing’an permafrost is sensitive to warming climate and wildfires, particularly on the southern margin of boreal coniferous forest and patchy permafrost zone. However, it remains unclear how fire disturbances are linked with changes in ecosystem composition and soil nutrients in the permafrost zones of Northeast China. Here, 13 years after the fire in the Yile’huli mountain knots, we investigated the parameters like vegetation cover, ground temperatures, active layer thickness, and soil carbon and nitrogen storage at burned and unburned sites of shrub wetlands. The fire resulted in ground warming of 0.1–5.0 °C at depths of 1.0–20.0 m and active layer deepening of 0.5 m, and gravimetric soil moisture content increasing of 26%-266%. Fire also increased the number of herbs and tall shrubs. After the fire, graminoids and tall shrubs increased significantly, and the species of herbs increased by five species. However, dwarf shrubs like Ledum palustre and Vaccinium uliginosum were missing from the burned site. A massive loss of total organic carbon (TOC) (248.40 t C/hm2) and nitrogen (TN) (11.87 t N/hm2) was observed by comparing their storage at burned and unburned sites. These results highlighted that the post-fire responses of vegetation cover and TOC and TN storage were dependent on the thermal regimes of near-surface permafrost and active layer, recovery of vegetation and organic layer, and soil moisture content. This study can provide an important reference for carbon storage and emission in boreal shrub wetlands under a warming climate and increasing fire disturbances.

Development of Electronic Wetting Front Detector for irrigation scheduling

Water is an important for plants growth, development and generating good crop yield. The rate of consumption of water by the crops depends on the type of crop, stage, soil characteristics and local climatic conditions. Irrigation scheduling takes care of when and how much water is to be applied to a crop during the entire the growing period. This calls for optimal water management, equipment, and labor in developing countries. An Electronic Wetting Front Detector was developed for irrigation scheduling by estimating the optimum soil moisture content present at the root-zone depth of the crops. The device measures the volumetric water content using electrical resistance of the soil and alarms the growers for the need of irrigation through its LED indicator installed in the device. The device was further calibrated and validated in the laboratory as well as in the farmer's field near Central University of Jharkhand, Ranchi, India. The device was tested and calibrated in the laboratory with the soil present in a container along with the Tensiometer fixed in the same container of soil and the data of the gravimetric soil moisture content was compared for accuracy by using regression analysis. Similarly, validation was also performed in the farmer's field and the result showed that it has a higher accuracy for measuring the soil water content. The developed device interprets readings from the sensors and alarms the farmer of overirrigation or underirrigation based on the sensors data. The EWFD developed is new intervention since the device could be easily used by farmer to understand the soil water content and schedule irrigation with respect to crop needs by alarming the farming. Therefore, the device may prove a valuable contribution to the list of other scientific instruments used for measuring the soil water content. The device can be used perfectly for scheduling irrigation.

Humidity-Sensitive PMMA Fiber Bragg Grating Sensor Probe for Soil Temperature and Moisture Measurement Based on Its Intrinsic Water Affinity.

Soil moisture measurement is very important for soil system monitoring. Compared to the traditional thermo-gravimetric technique, which is time-consuming and can be only performed in labs, the optic-fiber technique has unique advantages, such as small size, remote application in fields, fast response time and immunity to electromagnetic fields. In this paper, the soil moisture is measured by using a polymer optical fiber Bragg grating (POFBG) probe with a packaged dimension of 40 mm × 15 mm × 8 mm. Due to the intrinsic water-absorbing property of poly (methyl methacrylate) (PMMA), optical fiber Bragg gratings based on PMMA have been widely investigated for humidity measurement. Taking advantage of this, a sensor based on the POFBG is investigated to verify the soil condition. The POFBG is protectively integrated inside a stainless-steel package. A window is opened with a thin polypropylene mat as a filter, which allows the air to go through but prevents the soil from going inside to pollute the POFBG. The sensor probe is embedded in soils with different gravimetric soil moisture contents (SMCs) ranging from 0% to 40% and, then, insulated by polyethylene films to minimize the impact from the external environment, showing an average temperature cross sensitivity of −0.080 nm/°C. For a constant temperature, an exponential relationship between the Bragg wavelength and the SMC is obtained. For the SMCs between 8% and 24%, linear relationships are presented showing a temperature-corresponded sensitivity between 0.011 nm/% and 0.018 nm/%. The maximal sensitivity is calculated to be 0.018 nm/% at 20 °C, which is 28 times as high as that in the previous work. For the SMC over 24%, the sensor becomes insensitive because of humidity saturation in the cavity of the sensor probe. Though temperature cross sensitivity is problematic for SMC measurement, the influence could be eliminated by integrating another humidity-insensitive temperature sensor, such as a silica FBG temperature sensor.

Flood‐Induced Recharge of Matrix Water in a Vertic Forest Soil

AbstractVertisols shrink and swell with changes in soil moisture, influencing hydraulic properties. Vertisols are often in floodplains, yet the importance of flooding as a source of soil moisture remains poorly understood. We used blue dye and deuterated water as tracers to determine the role of the macropore network in matrix recharge under artificial flood durations of 3 and 31 days in large soil monoliths extracted from a forested soil. Gravimetric soil moisture content increased by 47% in the first three days, then increased only 3.5% from day 3–31. Post‐flood moisture content was greatest in the organic‐rich, top 10 cm and was lower at 10–75 cm where organic matter was less. Deuterium concentration revealed that soil moisture in the top 10 cm was quickly dominated by artificial flood water, but at depth remained <80% floodwater even after 31 days. Pervasive dye staining of ped surfaces in the top 4 cm indicated connectivity to flood waters but staining at depth was less and highly variable. The isotopic composition of soil water at depth continued to shift toward flood water despite no differences in dye staining between days 3 and 31. Results indicate flooding initially but incompletely recharges matrix water via macropores and suggest the importance of flooding as a source of matrix recharge in vertic floodplain soils may depend more on flood frequency than duration. Isotopic composition of matrix water in vertic soils depends on both advective and diffusional processes, with diffusion becoming more dominant as porosity decreases.

Effect of soil moisture on soil compaction during skidding operations in poplar plantation

ABSTRACT Poplar plantations have been widely practiced in the coastal area of the Caspian Sea in northern Iran. In this research, soil compaction following logging operations carried out by wheeled cable skidder was investigated in two poplar plantations with different characteristics including moist soil and dry soil. The soil gravimetric moisture content (MC) in the dry site ranged from 13% to 14.4%, while in the moist site it ranged from 30.5% to 34.6%. The mineral soil samples were collected from the skid trails in both sites. The impact of skidding operations on soil layers (soil depth, SD) was examined by measuring rut depth (RD), penetration resistance (PR), bulk density (BD), and total porosity (TP) at five traffic intensities (TI). Results indicated that MC and TI had a significant effect on RD, PR, BD, and TP; however, SD had a significant effect on PR and BD. The values of BD were significantly higher in the moist site than in the dry site, while the values of PR and TP were significantly higher in the dry site than in the moist site. The RD in the moist site (11.7 cm) was 1.65 times more than RD in the dry site (7.1 cm) after one pass where a pass was defined as one empty and one loaded trip over a spot. The differences between BD after 10 and 15 passes were not significant on the dry site, but significant in the moist site. We concluded that skidding operations should be conducted when soil conditions are dry.

Identifying coastal saline soil management practices to reduce land degradation and increase crop production in Bangladesh

A consecutive three year duration field experiment was carried out to identify which of a suitable mulch material and a planting bed or their combinations potentially reduce salt accumulation in soil and increase snake gourd yield in coastal saline soils. There were nine treatment combinations having three kinds of mulch materials: no mulch (control), rice straw mulch and plastic mulch, and three kinds of planting beds: convex bed, flat bed and concave bed. Plastic mulch reduced electrical conductivity of soil by 32% and increased soil temperature by 23% and gravimetric soil moisture content by 25% over control treatment. Plastic mulch had a fruit yield of 30.73, 28.06 and 26.32 t ha-1, which was 72, 237 and 268 % higher than control treatment in 2018, 2019 and 2020, respectively. The convex bed planting had significantly higher fruit yield than flat bed and concave bed planting. Plastic mulching and convex bed planting may therefore be recommended for reducing soil salinity and improving snake gourd yield in coastal saline regions.
 Journal of Bangladesh Academy of Sciences, Vol. 44, No. 2, 145-159, 2020

Influence of Recurrent Rolling/Crimping on Cover Crop Termination, Soil Strength and Yield in No-Till Cotton

Rollers/crimpers have been used to terminate cover crops typically with supplemental herbicide application to speed-up termination. Due to environmental concerns, there is a need to reduce herbicide use. In the Southern USA, the cash crop is typically planted three weeks after a rolled cover crop reaches more than 90% kill rate which eliminates competition with the cash crop for water and nutrients. A three-year replicated field experiment was initiated in the fall of 2014 to determine the effects of recurring rolling by experimental rollers/crimpers in terminating a cereal rye cover crop in central Alabama and how multiple rolling affected soil strength. Experimental 2-stage (one smooth drum and one crimping drum), 4-stage (one smooth drum and three crimping drums), spiral, and smooth rollers were tested to roll rye 1, 2, and 3 times (conducted at the same day). A smooth roller with mounted spray boom applying glyphosate rolling once was also evaluated, and untreated rye was the control. Rye was terminated at the milk growth stage and was evaluated one, two and three weeks after rolling. At one week after rolling, the highest rye kill rate was obtained with rolling three times by the 4-stage (96%), 2-stage (92%), spiral roller (81%); rolling once by the smooth roller with glyphosate (94%) compared to the untreated rye at 37%. At two weeks after rolling no differences among rollers were found (91% to 98%); the untreated rye was 54%. Similarly, at three weeks after rolling no differences were detected among rollers (99% to 100%); the untreated rye was 86%. Rolling 2 or 3 times compared with rolling one time did not cause soil compaction. However, at the 15 cm depth cone index (CI) did exceed 2 MPa (a critical value of root penetration restriction); although this CI increase was solely related to decrease in gravimetric soil moisture content (GMC). In addition, over three growing seasons, the seed cotton yield was not affected by rolling treatments with the average yield of 3601 kg ha−1 (1512 kg ha−1 of cotton lint).

Influence of soil moisture content on pullout properties of Hippophae rhamnoides Linn. roots

Plant root system plays an important role in preventing soil erosion and improving slope stability. However, its performance is significantly affected by soil moisture content, and the role of soil moisture in root reinforcement is not fully understood. In this study, the influence of soil moisture on root pullout properties was studied by experiments. Vertical in-situ pullout tests under four different levels of soil matric suction (12 kPa, 18 kPa, 24 kPa, 30 kPa) were carried out on roots of sea buckthorn plants (Hippophae rhamnoides Linn.) which were artificially cultivated for 7 months. Diameter and length of the root system of sea buckthorn were investigated. The results showed that a very significant correlation was observed between root diameter (D) and root length (L) (P<0.01), and root diameter decreased with soil depth. When soil bulk density was constant, peak pullout force (F) and friction coefficient of root-soil interface (μ) decreased with increasing gravimetric soil moisture content in power functions. Soil moisture content significantly affected root pullout resistance because the increase of soil moisture content decreased the friction coefficient between the roots and soil. Root diameter at breakage point (Db) and length of root segment left in soil (Lb) were increased with soil moisture content. In addition, peak pullout force of the roots increased in a power function with root diameter at the soil surface (Do) and in a linear function with total root length (L). The results provided an experimental basis for quantifying the effects of soil moisture content on soil reinforcement by plant roots.

Untangling the influence of soil moisture on root pullout property of alfafa plant

Root pullout property of plants was of key importance to the soil reinforcement and the improvement of slope stability. To investigate the influence of soil moisture on root pullout resistance and failure modes in soil reinforcement process, we conducted pullout tests on alfalfa (Medicago sativa L.) roots at five levels (40, 30, 20, 10 and 6 kPa) of soil matric suction, corresponding to respectively 7.84%, 9.66%, 13.02%, 19.35% and 27.06% gravimetric soil moisture contents. Results showed that the maximal root pullout force of M. sativa decreased in a power function with increasing soil moisture content from 7.84% to 27.06%. Root slippage rate increased and breakage rate decreased with increasing soil moisture content. At 9.66% soil moisture content, root slippage rate and breakage rate was 56.41% and 43.58%, respectively. The threshold value of soil moisture content was about 9.00% for alfalfa roots in the loess soil. The maximal pullout force of M. sativa increased with root diameter in a power function. The threshold value of root diameter was 1.15 mm, because root slipping force was greater than root breaking force when diameter >1.15 mm, while diameter ≤1.15 mm, root slipping force tended to be less than root breaking force. No significant difference in pullout forces was observed between slipping roots and breaking roots when they had similar diameters. More easily obtained root tensile force (strength) is suggested to be used in root reinforcement models under the condition that the effect of root diameter is excluded as the pullout force of breaking roots measured in pullout tests is similar to the root tensile force obtained by tensile tests.

Assessment of Spatial Variability of Physico-chemical Properties of Soil at Crop, Soil and Pest Management Research Farm, FUTA

Soil is an important natural resource for growing plants and the suitability of the soil for crop production is based on the quality of the soil’s physical, chemical and biological properties. The objectives of the study were to determine the soil physical and chemical properties and characterize the spatial variability of soil physico-chemical properties across the study area. The study was conducted at Crop, Soil and Pest Management Research Farm, Futa. Soil samples were collected from six sampling depths between 0-60 cm at an interval of 10 cm at different 20 points across the field while coordinates of the soil sampling points were determined using Global Positioning System (GPS) procedures. The test for variance was carried out on the physical properties of %sand, %silt, %clay, bulk density (g/cm3), %porosity, %water holding capacity (WHC) and soil hydraulic conductivity and chemical properties on pH, organic matter content (%), total nitrogen (%), available phosphorus (ppm), calcium, magnesium, sodium and potassium (cmol/kg), and effective cation exchange capacity (cmol/kg). The laboratory analysis (soil textural analysis) revealed that the soil types at the site were predominantly Sandy Clay Loam. Gravimetric soil moisture content and the water holding capacity (WHC) in all the 20 sampling spots at the topsoil has a mean value of 9.13% ± 1.90 and 52.43%±2.45 respectively. The minimum and maximum hydraulic conductivity (K) value at the distribution show a moderately skewed distribution of the K data and the distribution is positively skewed. The mean pH value of the soil in the study site was found to be slightly acidic and the soils were low in soil OM. The CEC, Mg2+, OC, TEB and TN indicated a significant difference for soil chemical properties. The physical and chemical properties of the study were found to be optimal for crop production, fertility assessment and land use management practices for crop productions and drip irrigation is suitable for the study area. Keywords: Spatial variability, Soil physico-chemical property, GPS procedures, Sampling point, Land use management practices, fertility assessment

Comparative study on spatial variability of topsoil moisture content and carbon stocks as influenced by land use and soil and water conservation structures in the semi-arid Ethiopian highlands

ABSTRACT Land uses and soil and water conservation (SWC) structures affect topsoil moisture and carbon stocks, particularly in the water deficit semi-arid environment of the northern Ethiopian highlands. This study was undertaken to assess the effects of land use and SWC structures on topsoil moisture, biomass, and soil carbon. Soil moisture was measured manually using gravimetric methods and theta probes with data loggers. Vegetation was inventoried and soil samples collected to assess carbon stocks of biomass and soils of different land uses. Merebmiti catchment had higher average gravimetric soil moisture content (GSMC; 24%) in wetlands, with the lowest (13%) in exclosures, whereas Mayleba catchment had relatively higher GSMC (14%) in exclosures and the lowest (8%) in rangelands. In both catchments, GSMC was higher at sampling locations closer to SWC structures than farther away. Merebmiti had significantly more biomass carbon (28.9 Mg ha−1) than Mayleba (6.32 Mg C ha−1). Higher soil organic carbon stocks were found in exclosures (46.1 ± 2.20 Mg ha−1) and wetlands (62.1 ± 2.9 Mg ha−1) than in frequently cultivated croplands (24.3 ± 1.4 Mg ha−1). Effective management of land use and implementation of SWC structures remarkably improves topsoil moisture content and carbon stocks in these catchments.

Fifty years of recorded hillslope runoff on seasonally frozen ground: the Swift Current, Saskatchewan, Canada, dataset

Abstract. Long records of hillslope runoff and nutrient concentrations are rare – on seasonally frozen ground they are almost non-existent. The Swift Current hillslopes at the Swift Current Research and Development Centre on the Canadian Prairies provide such a long-term hydrological record. Runoff, runoff nutrient concentration, snowpack depth, density and water equivalent, soil moisture, and soil nutrient concentration were monitored on the three 5 ha hillslopes over a 50-year period (1962–2011). Digital elevation data are available for the three hillslopes at a 2 m horizontal resolution, and, for one of the hillslopes (Hillslope 2), at a 0.25 m horizontal resolution. Runoff from the hillslopes was generated episodically during snowmelt and occasional rainfall events. Hillslope runoff was measured with a 0.61 m H-flume. Daily runoff nutrient concentration data are available for nitrate–N (March 1971–April 2011), ammoniacal–N (February 1996–April 2011), and phosphate-P (March–April 1971; June 1991–April 2011). Snowpack data (snowpack depth, density, and water equivalent) were determined via manual snow surveys carried out several times each winter, between January and March, between 1965 and 2011. Gravimetric soil moisture content was measured in October and April each year between 1971 and 2011 at five depth intervals (0–15, 15–30, 30–60, 60–90, and 90–120 cm) at nine points on each hillslope. We provide these hillslope data in two publicly available repositories: (1) 1962–2011 data on runoff, runoff nutrients, snowpack, soil moisture, soil nutrients, and crop and tillage practices at https://doi.org/10.23684/hhn5-rz52 (McConkey and Thiagarajan, 2018); and (2) digital elevation data at https://doi.org/10.20383/101.0117 (Coles et al., 2018). Complete climate data recorded at a Environment and Climate Change Canada meteorological station located 390 m from the three hillslopes are publicly available at http://climate.weather.gc.ca/ (last access: 30 August 2019).

Effect of Seed Coating and Burkina Rock Phosphate on the Growth and Yield of Rice

Purpose: Coordinated soil richness management innovation fits into the position of resource for poor cultivating on an Afisol in the Guinea savannah zone of Ghana. The research was conducted to determine the effect of seed coating and Burkina rock phosphate on the growth and yield of rice at University for Development Studies in Nyankpala near Tamale in the Northern Region of Ghana. The study aimed is to determine the interaction of Burkina rock phosphate and Triple superphosphate on the growth and yield of rice.Research Method: The experiment was a 2x3 factorial laid in randomized complete block design replicated six times. Factor one consisted of two levels such as, coated rice seed and non-coated rice seed whilst factor two consisted of three levels of (P) phosphate; (Burkina rock phosphate, Triple superphosphate and Non-Phosphate (control) were all treatments). The research was design to determine the interaction of coated seed and Burkina rock phosphate on the growth and yield of rice. However, treatment 1, 2, 3, 4, 5, 7 and 8 were the main plot whiles treatment 6, 9 and 10 were the sub-plots. The parameters measured included plant height, gravimetric soil moisture content, tiller count, effective tiller count, chlorophyll content, days to 50% flowering, plant height at harvest, straw biomass and grain yield.Findings: The outcome of the results obtained on treatment 1 shows significant on moisture content when coated seed of rice recorded highest among the treatments (Figure 02). Besides, similar results were obtained on plant height when coated seed of rice was compared with non-coated seed of rice on week after planting which confirmed significantly on 3, 6 (WAP) week after planting on Burkina rock phosphate and Triple superphosphate whiles non-coated seed of rice, Burkina rock phosphate and Triple superphosphate were significant on 6, 9 (WAP) week after planting (Figure 03 and Figure 04). Moreover, the results obtained gave similar outcomes when coated seed plus non-coated seeds of rice on treatment 1 and 4 were compared which shows significant on Burkina rock phosphate and Triple superphosphate on grain yield and straw weight (Figure 10 and Figure 11). However, among the treatment applied on tiller count phosphate (P2O5) was significant whiles Burkina rock phosphate and Triple superphosphate were significant on effective tiller count with coated seed plus non-coated seed of rice (Figure 05 and Figure 06). Comparatively under Burkina rock phosphate, coated seed of rice was significant in chlorophyll content whiles coated seed of rice shows significant among treatments on chlorophyll content at harvest (Figure 07 and Figure 08). Overall, results obtained on coated seed plus non-coated seed of rice on days to 50% flowering was significant on Burkina rock phosphate (BRP) and phosphate (P2O5) (Figure 09).Research Limitation: Deficiency of Burkina rock phosphate and Triple superphosphate resulted on the growth and yield.Originality/ Value: The experiment should further be repeated for confirmation of results on effect of coated seed and Burkina rock phosphate on the growth and yield of rice in the lowland ecology.

Characterization of Biochars and Their Application Rates on Soil Moisture Retention in Light Textured Soil of Assam

“Biochar” is a relatively new term, yet it is not a new substance. Biochar, product of thermal decomposition or incomplete combustion of biomass or bio-wastes under limited oxygen supply, are fine-grained highly porous charcoal substances that are distinguished from other charcoals in its intended use as soil amendments. The state of Assam produces surplus quantities of biowastes and leaves behind bulk quantity of wastes soon after harvest of the main crop(s) remain unutilized annually and these farm wastes have the potential of further reutilization through production of biochar, which may effectively be used in sustainable production system. Characterization of biochar with respect to physico-chemical properties determines the suitability of biochar to conserve soil moisture, which is again regulated by kind and source of feed stock materials. Keeping these aspects in view, a study on characterization of biochars prepared from four different feed stocks, namely rice straw, rice husk, toria stover, and bamboo leaves was conducted at Assam Agricultural University during 2014-15 and 2015-16 to validate its efficiency to conserve soil moisture for longer time. After determining the physicochemical properties of the four biochars, a set of pot culture experiment in poly house taking toria as test crop was conducted with four biochars. Four hundred gram of soil (preferably light textured) in 500 g capacity of plastic pot replicated thrice was designed statistically (factorial CRD) with four doses of biochars (0, 0.5, 1.0, and 1.5% wt/wt). Initially, a moisture level at field capacity was maintained and periodical volumetric soil moisture content (upto 70 days) was monitored to evaluate their efficiency. Gravimetric soil moisture content decreased significantly with the progress in days of experimentation irrespective of types of biochar used. However, increase in biochar doses increased the soil moisture content significantly over the one where no biochar was applied. Highest efficiency to conserve soil moisture over the days of study period was due to the application of bamboo leaves biochar.