Soil Management Options Research Articles

Variability of soil chemical properties and rice productivity in salt-affected soil in the north coastal rice field of Central Java, Indonesia

A coastal rice field is generally characterized by salt-affected soil and low soil quality for rice cultivation. Identifying soil chemical properties in these areas is necessary to determine soil management options for rice production. Therefore, soil samples were collected from 33 sampling points in the Wedung Sub-district of Demak Regency in the late dry season of 2021 to evaluate the variation among soil chemical characteristics in a coastline rice field. Soil samples were obtained beneath the topsoil (0-20 cm soil depth) and observed for electrical conductivity, exchangeable potassium, sodium, calcium, magnesium, and cation exchange capacity. Soils in the research field were categorized as slightly salty (0.75-2 dS m-1) to lightly salty (2.0-4.0 dS m-1) with very high sodium (>2 cmol(+) kg-1). Exchangeable potassium was dominated by moderate (0.3-0.7 cmol(+) kg-1) and low categories (0.2-0.3 cmol(+) kg-1). Based on soil calcium-to-magnesium ratios, around 6% of all samples were classified as calcium-deficient. The range of soil cation exchange capacity was 22-30 cmol(+) kg-1 and classified as high soil cation exchange capacity. Rice productivity in the salt-affected soil was around 4 t ha-1. Strategies for soil and controlling plants, such as soil amelioration and salt-tolerant rice cultivars, should be pursued to support plant growth and enhance rice productivity in the salt-affected soil, particularly in the coastal area.

Calibration and Evaluation of CERES-Maize and CROPGRO-Dry Bean Crop Simulation Models of the DSSAT in the Great Rift Valley Region of Ethiopia

Maize (Zea mays L.) is one of the most principal cereal crops ranking first in production in Ethiopia, predominantly produced and consumed directly by the smallholder farmers in the Great Rift Valley (GRV) of Ethiopia. Common bean (Phaseolus vulgaris) is also the most important legume crops as the source of protein and export commodity in the GRV. However, the average maize and common bean yields in Ethiopia are still low due to abiotic, biotic and socioeconomic constraints. In this regard, Crop simulation models (CSMs) are used in predicting growth and yield of crops and associated yield gaps under various management options and changing climatic parameters that are profitable with minimal unwanted impacts on the environment. Before using the CSMs, it is necessary to specify model parameters and understand the uncertainties associated with simulating variables that are needed for decision-making. Therefore, the research objective of this study was to calibrate and evaluate the performance of the CERES-Maize and CROPGRO-Dry bean CSMs of the Decision Support System for Agrotechnology Transfer (DSSAT) in the GRV of Ethiopia. The generalized likelihood uncertainty estimation (GLUE) method was used to estimate the genetic parameters of the CSM-CERES-Maize and CROPGRO-Dry bean models. Root mean squared error (RMSE) and Index of agreement (I) were used to evaluate the performance of the models. The DSSAT model reasonably reproduced observations for days to anthesis, days to physiological maturity, and grain yields, with values for the index of agreement of 0.97, 0.88 and 0.61 for CERES-Maize and 0.84, 0.75 and 0.51 for CROPGRO-Dry bean. Similarly, root mean square errors were moderate for days to anthesis (1.2 and 1.2 days), maturity (4.1 and 1.6 days), and yield (0.8 and 1.1 t/ha) for CERES-Maize and CROPGRO-Dry bean, respectively. The model has been successfully calibrated and evaluated for maize and common bean crop varieties and can now it can be taken for further applications in evaluating various crop and soil management options including climate smart agriculture technologies and climate change impact studies.

Degree of compaction, aeration, and soil water retention indices of a sugarcane field without soil disturbance after initial tillage

Soil compaction after initial soil tillage for crop establishment has been a major problem in crop fields because of its deleterious effects on soil functioning and crop performance. Therefore, the study aimed to determine the degree of compaction, soil air capacity, near-surface optimum ratios, and water retention characteristics in a sandy loam. Dystrophic Paleudalf initially under different tillage methods for sugarcane crop but without tillage for two seasons in southern Brazil. Initial soil tillage systems consisted of no-tillage (NT), compacted no-tillage (NTC), conventional tillage, and chiseling of no-tillage (Ch). Disturbed and undisturbed soil was sampled from 0 to 10, 10 to 20, 20 to 40, and 40 to 60 cm layers to determine degree of compaction, air capacity, near-surface optimum ratios, soil water retention characteristics, and soil physical quality index S. Initially, NT treatment had the significantly ( p < 0.05) lowest degree of compaction (87%), highest soil air capacity (0.104 cm3 cm−3), air capacity/total porosity ratio (0.261), and better water retention characteristics in the surface layer. Over time, Ch had improved the structure of the subsurface soil layers with the lowest degree of compaction (≈88%) and highest air capacity (≈0.140 cm3 cm−3), while the measured indices were poor in NTC. Irrespective of tillage, the surface layer showed resilience during the years without soil disturbance with low degree of compaction, increased water retention, and air capacity. NT could be a good soil management option for sugarcane production, while mechanical chiseling is advocated for ameliorating compacted soils.

A global indicator of soil macroinvertebrate community composition, abundance and diversity

Macroinvertebrate communities are highly sensitive indicators of physical and chemical soil qualities. Their evaluation in field conditions is rather simple and could serve as proxy for soil-based ecosystem services that farmers and field technicians could use. We tested the hypothesis that an indicator of soil macroinvertebrate communities, with 14 taxonomic groups characterized at the order level, could be used in any region of the world to assess these communities. A synthetic indicator was calculated using data from 9 reference sites from tropical, subtropical and temperate regions, a set of 3694 data of the open access Macrofauna database and a new site for validation. Invertebrates were extracted with the standard ISO/TSBF methodology and characterized with a set of 14 large taxonomic units, plus an index of taxonomic richness and total density. At each of the 9 reference sites, 27 to 252 sample points, representing different types of plant covers and/or soil management options, were considered and compared with their respective local synthetic GISQ indicator values. These indicators, elaborated from Principal Component Analysis of the sample points data, are set to vary from 0.1 to 1.0 according to the composition, diversity and abundance of the community. Analyses showed great similarities among sites, with Factors 1 (from 21.9 to 36.9 % variance explained) expressing the overall abundance and diversity of the communities and Factors 2 (8.9 to 15.83 %) opposing sites with dominant soil ecosystem engineer populations (Earthworms, Ants, Termites and some Coleoptera) to sites dominated by litter transformer populations (Diplopoda, Isopoda and others). Indicator formulae were designed based on PCA analyses of each data set and a global formula was established with the Macrofauna database. Very high correlations (>0.95) were obtained among values calculated with local data set and the general formula calculated with data of the Macrofauna database, in 8 of 9 sites and in the validation site. We discuss the importance of having a single formula to transform data obtained with a simple standard field method in the building of public policies for soil-based ecosystem services payment.

The Implication of Soil Acidity and Management Options for Sustainable Crop Production in Africa

Acidic soils are widespread in Africa and present a major crop production challenge in a region faced with multiple climatic and soil constraints. Effective management recommendations in line with the 4Rs of lime management (Right Source, Rate, Time, and Place) are necessary for optimizing the agronomic and economic benefits of lime at the farm-level. In addition, policies and incentives are needed to develop viable lime supply chains.

The Impacts of Salt Affected Soil on Soil and Plant Growth and Management Options with Organic and Inorganic Amendments A: Reviewv

The Impacts of Salt Affected Soil on Soil and Plant Growth and Management Options with Organic and Inorganic Amendments A: Reviewv

Salt-affected soils in Tanzanian agricultural lands: Type of soils and extent of the problem

Salt-affected soils are a global challenge, affecting 1 billion ha of land, with 200 million ha found in Africa. The challenge brings adverse impacts on agricultural productivity, food security, environmental sustainability, and food security. In Tanzania, more than 2 million ha of land are salt-affected, of which 1.7 million ha are saline soil and 0.3 million ha are sodic soil. To cope with this threat, it is necessary to have a thorough understanding of its extent (coverage), existing types, and available management strategies. This review presents a comprehensive account of the challenges and opportunities of salt-affected soils in Tanzania and examines management options that have been observed to increase agricultural productivity in rice-growing areas. A systematic review of relevant articles published in databases was carried out using PRISMA guidelines and flowcharts. This review highlights the origin, extent, types, and various techniques for alleviating salt-affected soil problems. It also emphasize on the use of inorganic and organic amendments, salt-tolerant varieties, irrigation water quality, and drainage infrastructure. We revealed that farmers, use burned and unburned rice husks, sawdust, gypsum, and farm yard manure (FYM) as copping mechanisms. Furthermore, there have been continuing efforts to develop salt-tolerant rice varieties, coupled with maintenance of irrigation infrastructure and site-specific soil management options, as appropriate solutions to tackle salt issues. Given the light of existing data, the review recommends using RS and GIS for updating information on salt-affected soils, particularly in irrigated areas, as an essential component of sustainable management and preventing further loss of agricultural land.

Impact of Drip Irrigation and Nitrogen Fertilization on Soil Microbial Diversity of Spring Maize.

Given the shortage of water resources and excessive application of nitrogen fertilizers in irrigated areas, we explored the effect of water−nitrogen coupling on soil microbial diversity in maize fields irrigated using shallow buried droppers. A field experiment (split-plot design) was used with irrigation amounts set at 40%, 50%, and 60% of the conventional amount; furthermore, 13 water and nitrogen coupling treatments were designed. The secondary area was the nitrogen application level, corresponding to 50%, 70%, and the original conventional application amounts. The results showed that the effect of irrigation amount on bacterial community composition was greater than that of nitrogen, whereas the effect of nitrogen on fungi was greater than that on bacteria. No significant difference was detected in the α diversity index or species richness of bacteria and fungi. Available phosphorus and organic carbon contents significantly correlated with the community structure of soil bacteria (p < 0.05). The relative abundances of bacteria and fungi were stable with the decrease of nitrogen application rate at the irrigation rate of 2000 m3 ha−1. With the decrease of irrigation amount, the relative abundance of bacteria and fungi was stable under the treatment of 210 kg ha−1 nitrogen fertilizer. Moreover, the relative abundance of nitrogen-fixing bacteria related to the nitrogen cycle was increased by irrigation of 2000 m3 ha−1 and nitrogen application of 210 kg ha−1. Moderate reduction of subsequent N supply should be as a prior soil management option in a high N input agroecosystem.

Soil Autotrophic Bacterial Community Structure and Carbon Utilization Are Regulated by Soil Disturbance—The Case of a 19-Year Field Study

The roles of bacterial communities in the health of soil microenvironments can be more adequately defined through longer-term soil management options. Carbon dioxide (CO2) fixation by autotrophic bacteria is a principal factor in soil carbon cycles. However, the information is limited to how conservation tillage practices alter soil physiochemical properties, autotrophic bacterial communities, and microbial catabolic diversity. In this study, we determined the changes in autotrophic bacterial communities and carbon substrate utilization in response to different soil management practices. A replicated field study was established in 2001, with the following soil treatments arranged in a randomized complete block: conventional tillage with crop residue removed (T), conventional tillage with residue incorporated into the soil (TS), no tillage with crop residue removed (NT), and no tillage with residue remaining on the soil surface (NTS). Soils were sampled in 2019 and microbial DNA was analyzed using high-throughput sequencing. After the 19-year (2001–2019) treatments, the soils with conservation tillage (NTS and NT) increased the soil’s microbial biomass carbon by 13%, organic carbon by 5%, and total nitrogen by 16% compared to conventional tillage (T and TS). The NTS treatment increased the abundance of the cbbL gene by 53% in the soil compared with the other soil treatments. The cbbL-carrying bacterial community was mainly affiliated with the phylum Proteobacteria and Actinobacteria, accounting for 56–85% of the community. Retaining crop residue in the field (NTS and TS) enhanced community-level physiological profiles by 31% and carbon substrate utilization by 32% compared to those without residue retention (T and NT). The 19 years of soil management lead to the conclusion that minimal soil disturbance, coupled with crop residue retention, shaped autotrophic bacterial phylogenetics, modified soil physicochemical properties, and created a microenvironment that favored CO2-fixing activity and increased soil productivity.

Soil erosion risk assessment and treatment priority classification: A case study on guder watersheds, Abay river basin, Oromia, Ethiopia

Soil erosion is the most persistent environmental problem in the Upper Blue Nile River (UBNR) basin of Ethiopia. Guder River is one of thetributaries of UBNR basin which critically required soil conservation practices. The main objective of this particular research article was to appraise soil erosion hazard priority classification with an easy and uncomplicated erosion modelling tool, the universal soil loss equation (USLE) using GIS software and RS data. Remote Sensing data such as annual mean precipitation, land-use land-cover, and soil map, digital elevation model map were used to determine the USLE factor values. The average annual rainfall data was derived from the widely used climate dataset CRU TS (Climatic Research Unit gridded Time Series) and converted to rainfall erosivity factor. Soil Erodibility Factor Soil (K) was calculated from FAO soil data “Digital Soil Map of the World - ESRI shapefile format”. Topographic Factor (LS) was delineated from a 30m digital elevation model. Cover Factor (C) and Support Practice Factor (P) were estimated from a 20m Ethiopia Sentinel2 Land-use Land-cover year, 2016. The study classified the Guder watersheds into different kinds of severity classes for prioritization of soil and water management options and conservation strategy. The mean annual soil eroded for the whole sub-basin was estimated at 25.23 tha−1y−1. The study output outcomes demonstrated that about 0.1% (426ha) 6.9% (46764 ha), 8.9% (60055 ha), and 19.8 % (134320ha) have been under Catastrophic, very severe, severe, high erosion severity class respectively. About half of the Guder sub-basin has been underneath a very slight erosion. Nevertheless, the area covered by very severe erosion was 6.9%, and the annual percent of sum-total soil erosion accounted for was 46.86%. The second and third in magnitude soil lost annually from the sub-basin with regards to per cent of total soil loss were severe (26.53%), and high (21.53%) respectively. In only 7% of the area under investigation, soil erosion estimated was to go beyond 100 t/ha/yr. erosion rate. District wise erosion affected and hotspot areas were identified: Middle of Steep slopes Mountainous parts of Ginde Beret, Jeldu, Ifata, Ambo, parts Ababo and Horo Guduru located in the study area borderline, Toke Kutaye, along the boundary of Midakegn and Cheliya were found in severe to very severe erosion. Finally, the study proposed that the government, policymakers, and soil and water management agents plan and implement the conservation measures and give awareness to stakeholders for optimum use of limited precious resources.

Soil quality and its implication for brackishwater pond soil management option in East Java Province, Indonesia

East Java Province has a vast area for brackishwater pond culture, but its pond production is still low, one of the reasons is that soil management is not optimal. This study was conducted in brackishwater ponds in Sidoarjo Regency and used the previous data from the Tuban, Gresik, Lamongan, Pasuruan, and Probolinggo Regencies to obtain information about pond soil quality and offer the option of pond soil management. The variable of soil quality measured and analyzed in this study included: pH, macronutrients, micronutrients, and texture. Before data were descriptively analyzed, data analysis was previously done to detect outlier. The result of the study showed that pond soil in East Java Province belonged to volcanic soil which is characterized by neutral pH soil yet slightly acid at certain places in Pasuruan and Probolinggo Regencies, relatively low N and C content, and relatively high PO4 content and C: N ratio. Microelement content, such as Al and Fe is relatively low. Soil texture is relatively varied but generally classified as coarse. The soil management option offered is liming with agricultural lime at a dose up to 1,500 kg/ha and application of urea fertilizer at the dose of 100-150 kg/ha. The use of PO4 solubilizing bacteria is recommended to increase PO4 availability in pond soil, followed by the application of SP-35 fertilizer at the dose of 75-100 kg/ha. The use of organic fertilizer up to 2,500 kg/ha could increase organic C content and improve the soil structure of brackishwater pond, particularly in Sidoarjo, Tuban, and Probolinggo Regencies.

A review of the Current State of Soil Infertility and Management Options in Kenya: The Case of Maize Growing Regions

Inappropriate soil fertility management has caused fertility to decline considerably over the years leading to low maize yields despite the growing human population with high food demand in Kenya. Despite high nutrient mining, fertilizer use and adoption of soil fertility improvement practices have remained low among maize farmers in the country. At the current yield levels, maize crops extract over 40, 8, 40.6, and 5.4 kg of N, P, K, and S per growing season, respectively. These extracted nutrients must be replaced to avoid nutrient depletion. Maize crop response to secondary macronutrients (S, Ca, and Mg) and micronutrients (Zn and B) is evidenced, signifying that these nutrients have also reached critical levels in Kenya soils. The rate of replenishing these lost nutrients is still low, farmers apply an average of 43.25 kg of fertilizer per hectare per season. The situation is worsened further by increasing soil acidity- currently below pH 5.5 in most maize-growing regions. Poor agronomic practices applied by farmers directly reduce yields and facilitate other factors leading to nutrient losses. For example, farmers across the country recycle seeds, apply low fertility rates, and rarely keep their fields weed-free. These practices lower the capacity of the crops to tolerate the impact of other production constraints including infertility. To realize yield improvement and return on investments, farmers must adapt and adopt crucial practices under integrated soil fertility management. Managing soil acidity should be the first approach to unlocking fixed nutrients. Fertilizer application should follow the right rate, right source, right time, and right placement approach. Also, improved cropping systems such as maize-legume rotation and intercropping should be considered for sustainable soil fertility management and crop production.

The Effects of Land Use and Landscape Position on Soil Physicochemical Properties in a Semiarid Watershed, Northern Ethiopia

Understanding topography effects and assessing the soil properties in different land use is an essential first step for sustainable soil management. Hence, land use type and altitudinal gradient on selected soil parameters were studied in Ayiba watershed, northern Ethiopia. Thirty composite soil samples were collected from 0 to 30 cm of soil depth under four land use types across three altitudinal gradients and were analyzed for selected soil parameters following the standard procedures. A significant main effect of land use and altitudinal gradient on the content of the soil particles was noted. Results also indicated that the bulk density (BD), total porosity (TP), and Pav of the soil are significantly different ( p &lt; 0.05) in the watershed because of land use type and altitudinal gradient. Barren land and higher altitude landscapes have the highest BD, and the lowest TP, and grassland and lower altitude landscapes have the lowest BD and high TP. Intensive cultivation accompanied by natural land conversion and erosion due to the rugged landscape nature caused high BD and low TP. Analysis of variance results also shows the significant interaction effect of land use type and altitudinal gradient on EC, SOM, SOC ( p &lt; 0.001), and pH-water (1:2.5), and TN ( p &lt; 0.01). The Pearson correlation of SOM with TP, TN, MC, and clay content showed a strong positive relationship. But, SOC, TN, and clay content were negatively correlated with BD. Soils of the study watershed are found in low to optimum rating levels in their selected physicochemical properties. Overall, the results show that land use and topography gradient significantly affected soil physicochemical properties in the study watershed. Therefore, soil management options should focus on scenarios that could improve the soil conditions to enhance crop production on a sustainable basis.

Sustainable Soil Management for Food Security in South Asia

The soils of South Asia provide food to almost 1.8 billion people but are prone to many sustainability issues. The ever-increasing population has put enormous pressure on the available natural resources (land/soil and water), which is threatening future food security. The fertile farmlands are being encroached by urbanzation. Declining groundwater levels, increasing micronutrient deficiencies, the use of fertile soil for brick making, degrading soil structure, and global warming are serious sustainability issues in South Asia. The extensive production of cereals and conventional soil management practices are increasing soil erosion; depleting soil organic matter, soil fertility, water resources, and increasing salinization. The restoration and management of soil organic matter, rainwater harvesting, and the efficient use of water and sustainable nutrient management are essential to sustain the long-term productivity of agricultural soils. Diversification of monocropping systems and the adoption of conservation agriculture may enhance the sequestration of soil carbon and increase biodiversity. However, site-specific technologies must be identified and made available to farmers. Prime agricultural land must be protected against urban encroachment. Communication and collaboration between scientists, farmers, and policymakers are needed to manage soils for ensuring food security in South Asia. The objective of this review is to deliberate the causes of soil degradation in South Asia and suggest soil management options to reverse the degradation trends and ensure long-term food security in the region.

Quantitative Evaluation of Spatial and Temporal Variation of Soil Salinization Risk Using GIS-Based Geostatistical Method

Soil salinization is one of the environmental threats affecting the sustainable development of arid oases in the northwest of China. Thus, it is necessary to assess the risk of soil salinity and analyze spatial and temporal changes. The objective of this paper is to develop a temporal and spatial soil salinity risk assessment method based on an integrated scoring method by combining the advantages of remote sensing and GIS technology. Based on correlation coefficient analysis to determine the weights of risk evaluation factors, a comprehensive scoring system for the risk of salinity in the dry and wet seasons was constructed for the Ebinur Lake Wetland National Nature Reserve (ELWNNR), and the risk of spatial variation of soil salinity in the study area was analyzed in the dry and wet seasons. The results show the following: (1) The risk of soil salinity during the wet season is mainly influenced by the plant senescence reflectance index (PSRI), deep soil water content (D_wat), and the effect of shallow soil salinity (SH_sal). The risk of soil salinity during the dry season is mainly influenced by shallow soil salinity (SH_sal), land use and land cover change (LUCC), and deep soil moisture content (D_wat). (2) The wet season was found to have a high risk of salinization, which is mainly characterized by moderate, high, and very high risks. However, in the dry season, the risk of salinity is mainly characterized by low and moderate risk of salinity. (3) In the ELWNNR, as the wet season changes to dry season (from May to August), moderate-risk area in the wet season easily shifts to low risk and risk-free, and the area of high risk in the wet season easily shifts to moderate risk. In general, the overall change in salinity risk of the ELWNNR showed a significant relationship with changes in lake water volume, indicating that changes in water volume play an important role in the risk of soil salinity occurrence. Ideally, the quantitative analysis of salinity risk proposed in this study, which takes into account temporal and spatial variations, can help decision makers to propose more targeted soil management options.

Generalized model for plantation production of Eucalyptus grandis and hybrids for genotype-site-management applications

The use of process-based modelling of wood production in forest plantation has increased in recent decades amongst researchers and forest companies. Although, such models are used by several plantation researchers and managers, improved options and sensitivity to soil characteristics, genotype, and management options are desirable. A new generation of forest productivity modelling needs to extend previous capabilities and incorporate modern software engineering technologies. Our objective was to develop and evaluate an Agricultural Production Systems sIMulator (APSIM) Next Generation model for simulating the growth of Eucalyptus grandis and hybrids with or of E. globulus and E. urophyylla. The model simulates stem, canopy and root development, resource capture and use (light, water, N), and C and N allocation as mediated by climate, soil, genotype physiological characteristics and management. Tree dimensions (stem diameter, height, volume) are calculated as empirical functions of above-ground biomass. Datasets used for model calibration or independent evaluation were from diverse conditions in Australia (5 sites) and Brazil (13 sites), and at several of these sites there were treatments for fertilizer, irrigation or genotype. For the calibration and evaluation datasets, model performance was very good for above-ground biomass (Nash Sutcliffe Efficiency, NSE = 0.96 and 0.84 respectively). Notwithstanding this general performance, and as an example, local calibration improved performance in one of the independent test datasets, suggesting that applications of the model for specific sites or clones may benefit from parameterization to local conditions. Simulation of management for weed cover, N fertilizer and genotype are also demonstrated. As the model performed well and has high flexibility, it warrants consideration by forest plantation managers and researchers for knowledge synthesis and operational productivity predictions of Eucalyptus and other plantation genotypes.

EVALUATING SELECTED SOIL PHYSICAL PROPERTIES UNDER DIFFERENT SOIL TILLAGE SYSTEMS IN ARID SOUTHEAST RAWALPINDI, PAKISTAN

Tillage is a critical soil management option that affect many soil physical, chemical and biological properties, which in turn may alter the soil environment and consequently impact on root growth and distribution, and crop yield. This study was carried out to evaluate the long-term effects of different soil tillage systems on some soil physical properties under both irrigated and rainfed wheat productions for nine consecutive wheat seasons (2011-12 and 2019-20) at Koont research farm, PMAS-Arid Agriculture University, Rawalpindi. Four soil tillage systems were performed i.e. conventional tillage system (S1), reduced tillage system-1 (S2), reduced tillage system-2 (S3) and no tillage system (S4). The results showed that soil moisture content measured at both soil depths (0-15 and 15-30 cm) was the maximum in direct sowing (S4) and lowest in conventional soil tillage system (S1). Bulk density and porosity were changes with tillage depth. Among studied tillage systems, bulk density and penetration resistance values were the maximum and porosity was lowest in direct wheat sowing system. Soil particle size distribution was affected by operations and agricultural machinery used in soil tillage systems. The aggregate size smaller than 1 mm showed higher fragmentation (42.25%) in S3. This study showed that soil physical properties were influenced by tillage systems in wheat production under irrigation and rainfed environment. Although the climate of the study area is semi-arid and direct sowing system provide maximum moisture but reduced tillage method can be used for better soil physical properties and highest crop yield.

Nutrient release from organic resources in Nitisols of the Central Highlands of Kenya

We carried out a litterbag experiment to assess the characteristics of animal manure and Tithonia diversifolia and their nutrient release dynamics in un-amended soils under different tillage systems. We conducted the study in Meru South and Kandara sub-Counties during short rains 2016 (SR16) and long rains 2017 (LR17) seasons. The treatments were; conventional tillage (ConvT) and minimum tillage (MinT). Litterbags were buried vertically in the soil to a depth of 8 cm at planting. T. diversifolia had high nitrogen concentration resulting in a significantly low C/N ratio. The recalcitrant pool (cellulose, lignin and polyphenols) was higher in animal manure compared with T. diversifolia. Nutrients (N and P) remaining from litterbags with animal manure were generally higher under MinT while in T. diversifolia they were lower under MinT in both sites. Nutrient content in both organic resources declined as the cropping season progressed. N and P release rate from animal manure was significantly higher under ConvT compared with MinT on the 8th week at Meru South site. Nutrients' release rates in T. diversifolia were significantly higher under ConvT by 57 and 48% for N and P, respectively, compared with MinT on the 6th week during SR16 season in Meru South. At Kandara site, N release rates from animal manure were significantly higher under ConvT by 60% on the 2nd week and 30% on the 8th week compared with MinT during SR16 season. The phosphorous release rate was significantly high under ConvT by 62% on the 2nd week, 43% on the 8th week and 25% on the 10th week during SR16 season. During LR17 season, N and P release rates in animal manure were significantly higher under ConvT by 54% compared with MinT on the 8th week at Kandara. Nitrogen release rates from T. diversifolia were significantly higher under ConvT by 40% on the 4th week, 30% on the 6th week and 42% on the 10th week during SR16 season. P release rate from T. diversifolia was significantly higher under ConvT by 41% on the 4th week and 32% on the 10th week compared with MinT. During LR17 season, N and P release rate from T. diversifolia was significantly higher under ConvT by 29 and 28% respectively, compared with MinT on the 8th week. Therefore, tillage, as a soil management option, influences nutrient availability from organic resources and should be considered in soil fertility management.

A Framework to Consider Soil Ecosystem Services in Territorial Planning

As a critical interface in the environment, soils can provide a wide range of ecosystem services (ES). However, while there is growing demand to assess soil ES from agricultural systems, considering them in land management strategies remains a challenge. Indeed, because of the difficulty in relating soil properties to ES, soil ES are still not fully considered in the territorial planning decision process. Through a comprehensive approach based on soil processes, an assessment framework is proposed to make soil ES understandable and usable by actors of territorial planning. This assessment framework is based on a conceptual model that is then developed into an operational framework. The conceptual model, which is supported by a literature review, relates agricultural soil ES to common socio-economic development challenges. The operational framework is based on the development of soil ES modelling and enables comparison of soil management options, which provides information to help choose among planning scenarios. This soil ES assessment framework, relating soil science to territorial governance, should improve integration of soil ES into decision making in a territorial planning context and support sustainable socio-economic development.

Identifying the position of the compacted layer by measuring soil penetration resistance in a dryland farming region in Northeast China

AbstractTopsoil is disturbed by ploughing, the effects of infiltration, the movement of fine particles from the topsoil to the subsoil, and direct pressure from agriculture machinery, all creating an abrupt delineation in the form of a compacted layer with very low permeability. Spatial variability of soil properties, such as soil structure and penetration resistance (PR), can help identify the compacted layer. However, there are no quantitative methods to describe this layer. In this study,PRwas used to survey different soil types. A Mann–Kendall (M‐K) test ofPRdata was used to identify the presence and position of the compacted layer in a dryland farming region of Northeast China. Our results demonstrated thatPRwas mainly affected by bulk density and soil water content. Compared with the topsoil,PRwas more significantly affected by water content in deeper soil layers. An M‐K test of thePRcurve can provide a more reliable and objective assessment of the thickness of the plough layer and location of the compacted layer than field observation. Our data indicated that there was a compacted layer in the soil profile in the study areas and the spatial variability of the compacted layer was heterogeneous. The plough layer was shallow, and the compacted layer was thicker in areas with frequent use of agricultural machinery. Moreover, frequent use of agricultural machinery resulted in aPRof the plough and compacted layers that was greater than that in other areas. Information on identifying the position and thickness of the compacted layer and the factors influencing their spatial distribution can be used to create effective soil management options and improve conditions for the development of plant roots in dryland farming regions.