scholarly journals Estimations of soil fertility in physically degraded soils through selective accounting of fine earth

2016 ◽  
Author(s):  
Mavinakoppa S. Nagaraja ◽  
Ajay Kumar Bhardwaj ◽  
G.V. Prabhakara Reddy ◽  
Chilakunda A. Srinivasamurthy ◽  
Sandeep Kumar

Abstract. Soil fertility and organic carbon (C) stock estimations are crucial to soil management especially that of degraded soils, for productive agricultural use and in soil C sequestration studies. Currently, estimations based on generalized soil mass (hectare-furrow basis) or bulk density (BD) basis are used which may be suitable for normal agricultural soils but not for degraded soils. We measured soil organic C, available nitrogen (N), available phosphorus (P) and available potassium (K), and estimated stocks using three methods: (i) generalized soil mass (GSM, 2 million kg ha−1 furrow soil), ii) bulk density based soil mass (BDSM) and (iii) the proportion of fine earth volume (FEV) method, for soils sampled from physically degraded lands in Eastern Dry Zone of Karnataka State in India. Comparative analyses using these methods revealed that the soil organic C, and N, P and K stocks determined by using BDSM were higher than those by GSM method. The soil organic C values were the lowest in the FEV method compared to the other two methods. The GSM method overestimated soil organic C, N, P and K by 9.3–72.1 %, 9.5–72.3 %, 7.1–66.6 % and 9.2–72.3 %, respectively, compared to FEV based estimations for physically degraded soils. The differences among the three methods of determinations were lower in soils with low gravel content and increased with increase in gravel volume. There was overestimation of soil organic C and soil fertility with GSM and BDSM methods. A reassessment of methods of estimation was, therefore, attempted to provide fair estimates for land development projects in degraded lands.

Solid Earth ◽  
2016 ◽  
Vol 7 (3) ◽  
pp. 897-903 ◽  
Author(s):  
Mavinakoppa S. Nagaraja ◽  
Ajay Kumar Bhardwaj ◽  
G. V. Prabhakara Reddy ◽  
Chilakunda A. Srinivasamurthy ◽  
Sandeep Kumar

Abstract. Soil fertility and organic carbon (C) stock estimations are crucial to soil management, especially that of degraded soils, for productive agricultural use and in soil C sequestration studies. Currently, estimations based on generalized soil mass (hectare furrow basis) or bulk density are used which may be suitable for normal agricultural soils, but not for degraded soils. In this study, soil organic C, available nitrogen (N), available phosphorus (P2O5) and available potassium (K2O), and their stocks were estimated using three methods: (i) generalized soil mass (GSM, 2 million kg ha−1 furrow soil), (ii) bulk-density-based soil mass (BDSM) and (iii) the proportion of fine earth volume (FEV) method, for soils sampled from physically degraded lands in the eastern dry zone of Karnataka State in India. Comparative analyses using these methods revealed that the soil organic C, N, P2O and K2O stocks determined by using BDSM were higher than those determined by the GSM method. The soil organic C values were the lowest in the FEV method. The GSM method overestimated soil organic C, N, P2O and K2O by 9.3–72.1, 9.5–72.3, 7.1–66.6 and 9.2–72.3 %, respectively, compared to FEV-based estimations for physically degraded soils. The differences among the three methods of estimation were lower in soils with low gravel content and increased with an increase in gravel volume. There was overestimation of soil organic C and soil fertility with GSM and BDSM methods. A reassessment of methods of estimation was, therefore, attempted to provide fair estimates for land development projects in degraded lands.


2018 ◽  
Author(s):  
Jacqueline R. England ◽  
Raphael Armando Viscarra Rossel

Abstract. Maintaining or increasing soil organic carbon (C) is important for securing food production, and for mitigating greenhouse gas (GHG) emissions, climate change and land degradation. Some land management practices in cropping, grazing, horticultural and mixed farming systems can be used to increase organic C in soil, but to assess their effectiveness, we need accurate and cost-efficient methods for measuring and monitoring the change. To determine the stock of organic C in soil, one needs measurements of soil organic C concentration, bulk density and gravel content, but using conventional laboratory-based analytical methods is expensive. Our aim here is to review the current state of proximal sensing for the development of new soil C accounting methods for emissions reporting and in emissions reduction schemes. We evaluated sensing techniques in terms of their rapidity, cost, accuracy, safety, readiness and their state of development. The most suitable technique for measuring soil organic C concentrations appears to be vis–NIR spectroscopy and for bulk density active gamma-ray attenuation. Sensors for measuring gravel have not been developed, but an interim solution with rapid wet-sieving and automated measurement appears useful. Field-deployable, multi-sensor systems are needed for cost-efficient soil C accounting. Proximal sensing can be used for soil organic C accounting, but the methods need to be standardised and procedural guidelines need to be developed to ensure proficient measurement and accurate reporting and verification. This is particularly important if the schemes use financial incentives for landholders to adopt management practices to sequester soil organic C. We list and discuss the requirements for the development of new soil C accounting methods that are based on proximal sensing, including requirements for recording, verification and auditing.


Author(s):  
H. Haruna

Land use changes from forest into cultivated ecosystems result in negative impact on soil structure and quality. The purpose of this study was to determine effect of land use on soil quality in Afaka forest northern guinea savannah of Nigeria. Land use systems, including natural forest and cultivated land were identified. Eighteen (18) composite disturbed and undisturbed samples were collected from depth of 0-5 and 5-10 cm for analysis of pertinent soil properties in the laboratory using grid procedure. Most physical and chemical properties show relative variations in response to land use types and geomorphic positions. Results  indicate  that the soils had  high degree of weathering potentials, low  to moderate  bulk density at 0-5cm depth values between 1.42 to 1.49 Mg m-3 in  forest and  cultivated land, bulk density of  1.34 and 1.46 1.Mg m-3at 5 -1ocm depth   for forest and  cultivated land respectively. The soil water at 0-5cm depth is from 4.20 to 2.63 cm3/cm3, while at 5-10 cm depth these values vary from 4.32 to 2.13 cm3/cm3 under forest and cultivation land use. The pH (H2O) is 6.9 to 7.16 with low electrical conductivity of 0.13 dS/m(forest) and 0.12 dS/m (cultivation). The CEC of soils is recorded as 8.60 cmol kg-1 (forest) to 8.54 cmol kg-1 (cultivated)whereas  total nitrogen content of 1.21 g kg-1 and 1.11 g kg-1 and available phosphorus of 8.78 mg kg-1 (cultivated) and 5.47 mg kg-1 (forest).. Results indicate that soil fertility parameters were moderate to low for cultivated land and at all slope positions, suggesting that soil fertility management is required in order to make agriculture sustainable on Afaka area.


2018 ◽  
Vol 7 (2) ◽  
pp. 30 ◽  
Author(s):  
Theobald Bizuhoraho ◽  
Alexis Kayiranga ◽  
Noel Manirakiza ◽  
Khaldoon A. Mourad

Land use change has a significant impact on the ecosystem. In this paper the effects of land use change on the physicochemical properties of the soil in Rulindo District, Rwanda have been studied. Three different land use types were selected; forestland, cattle farmland and cultivated land. A randomised complete block research design was used to carry out this research. Nine soil samples were collected and then analysed. The distributed samples were analysed in the Soil Laboratory of University of Rwanda-Busogo campus, while the undisturbed samples were analysed in-situ. Eight physicochemical properties were measured: pH, Organic Matter (OM), available nitrogen, available phosphorus, exchangeable potassium, soil bulk density, moisture content and porosity. The results showed that changing land use from forest or farm to cultivated land reduced the organic matter, available nitrogen, soil moisture and porosity while bulk density and pH were significantly increasing. On the other hand, the exchangeable potassium and exchangeable phosphorus did not change significantly for the both land use changes. Hence, the reduction of forestland and farmland are highly sensible to erosion and will decline soil fertility. The paper proposed few steps and recommendations to be the base for a new sustainable land use management in Rwanda.


Soil Research ◽  
2007 ◽  
Vol 45 (1) ◽  
pp. 13 ◽  
Author(s):  
Fiona A. Robertson ◽  
Peter J. Thorburn

The Australian sugar industry is moving away from the practice of burning the crop before harvest to a system of green cane trash blanketing (GCTB). Since the residues that would have been lost in the fire are returned to the soil, nutrients and organic matter may be accumulating under trash blanketing. There is a need to know if this is the case, to better manage fertiliser inputs and maintain soil fertility. The objective of this work was to determine whether conversion from a burning to a GCTB trash management system is likely to affect soil fertility in terms of C and N. Indicators of short- and long-term soil C and N cycling were measured in 5 field experiments in contrasting climatic conditions. The effects of GCTB varied among experiments. Experiments that had been running for 1–2 years (Harwood) showed no significant trash management effects. In experiments that had been running for 3–6 years (Mackay and Tully), soil organic C and total N were up to 21% greater under trash blanketing than under burning, to 0.10 or 0.25 m depth (most of this effect being in the top 50 mm). Soil microbial activity (CO2 production) and soil microbial biomass also increased under GCTB, presumably as a consequence of the improved C availability. Most of the trash C was respired by the microbial biomass and lost from the system as CO2. The stimulation of microbial activity in these relatively short-term GCTB systems was not accompanied by increased net mineralisation of soil N, probably because of the greatly increased net immobilisation of N. It was calculated that, with standard fertiliser applications, the entire trash blanket could be decomposed without compromising the supply of N to the crop. Calculations of possible long-term effects of converting from a burnt to a GCTB production system suggested that, at the sites studied, soil organic C could increase by 8–15%, total soil N could increase by 9–24%, and inorganic soil N could increase by 37 kg/ha.year, and that it would take 20–30 years for the soils to approach this new equilibrium. The results suggest that fertiliser N application should not be reduced in the first 6 years after adoption of GCTB, but small reductions may be possible in the longer term (>15 years).


2017 ◽  
Vol 9 (4) ◽  
pp. 2315-2326
Author(s):  
T. V. Jyothi ◽  
N. S. Hebsur

Field studies were conducted at farmer’s fields in Jodalli (Kalghatgi taluk) and Pale (Hubballi taluk) villages in 2012-13 and 2013-14, respectively to investigate the effect of NPK fertilizers on uptake of nutrients by Bt cotton and soil fertility status at harvest in Alfisol. Among the different treatment combinations, the application of 150:50:75 kg N:P2O5:K2O ha-1 (N3P1K2) recorded significantly (P=0.05) higher nitrogen (132.63 kg ha-1), phosphorus (31.26 kg ha-1) and potassium (128.94 kg ha-1) uptake by cotton. The interaction effect with respect to total micronutrients (Zn, Fe, Mn and Cu) uptake remained non significant at all the growth stages. Graded levels of fertilizers failed to exert significant impact on pH and electrical conductivity, soil organic carbon and available micronutrients during both the years of experimentation. The application of 100:50:50 kgN:P2O5:K2O ha-1 (N1P1K1) recorded significantly (P=0.05) highest available nitrogen (150.39 kg ha-1), available phosphorus (37.98 kg ha-1) and available potassium (230.99 kg ha-1) compared to rest of the treatments. The lowest available nitrogen (134.92 kg ha-1), available phosphorus (31.65 kg ha-1) and available potassium (217.63 kg ha-1) were recorded in treatment receiving 150:50:75 kg N:P2O5:K2O ha-1 (N3P1K2).


BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9303-9323
Author(s):  
Zhihui Wang ◽  
Dawei Yin ◽  
Hongyi Wang ◽  
Changjiang Zhao ◽  
Zuotong Li

Saline-alkali soils of northern China are prone to waterlogging after degradation caused by overuse. The effects of biochar (40 t/ha) were tested relative to the physico-chemical properties of maize rhizosphere soil, the composition and function of the soil bacterial community, and its response to sudden waterlogging. Biochar treatment decreased the pH and bulk density of the soil and increased soil organic carbon (SOC), available nitrogen (AN), and available phosphorus (AP). The relative abundance of bacteria (Proteobacteria, Actinobacteria, Bacteroidetes, and Nitrospirae) also increased, along with the activities of soil enzymes, such as dehydrogenase, β-glucosidase, and alkaline phosphomonoester. The response of soil microbial enzymes to biochar addition was induced by changes in the soil physical properties (pH, soil moisture content, and soil respiration (BR)). Changes in the bacterial community structure were driven by soil nutrients and physical characteristics (AN, AP, SOC, pH, moisture, water-stable aggregate stability rate, BR, and bulk density). After waterlogging, soil with biochar demonstrated high water permeability and improved soil respiration. The relative abundance of soil bacteria and enzyme activities remained higher in the biochar plot than in the no-biochar plot. Biochar maintained the growth and vitality of maize roots in unfavorable environmental conditions, thus ensuring high yields.


2021 ◽  
Vol 8 (2) ◽  
pp. 95-98
Author(s):  
LAKKIMSETTI K PRASAD ◽  
J POORNA BINDU ◽  
D DAMODAR REDDY ◽  
C CHANDRASEKHARA RAO ◽  
H RAVISANKAR

An assessment of soil fertility of Northern Light Soil area of FCV tobacco was carried out to study the status of soil macro and micronutrients. Soils of the study area are mostly moderately acidic in nature with low organic carbon and available nitrogen with a mean value of 0.29 % & 110 kg ha-1, respectively. Available phosphorus was high (88% samples) with a mean value of 92.6 kg ha-1. While the average available potassium content was 297 kg ha-1 with 48 % samples in medium class. Among available micronutrients, the available zinc content in 73 % of samples was very low – low (0.0 to 0.6 ppm).  Whereas the availability of copper in 25 % samples was very low to low as per the fertility class (0.0 - 0.30 ppm).  Available iron (18.8 -35.03 ppm) and manganese (17.03-21.5 ppm) contents were high in the region. Nutrient index of available nitrogen was 1.00 (Low) while, NI was 2.83 (High) & 2.36 (Medium) for available phosphorus and available potassium, respectively.


Solid Earth ◽  
2016 ◽  
Vol 7 (1) ◽  
pp. 1-9 ◽  
Author(s):  
A. Cruz-Ruíz ◽  
E. Cruz-Ruíz ◽  
R. Vaca ◽  
P. Del Aguila ◽  
J. Lugo

Abstract. Mexico is the world's fourth most important maize producer; hence, there is a need to maintain soil quality for sustainable production in the upcoming years. Pumice mining is a superficial operation that modifies large areas in central Mexico. The main aim was to assess the present state of agricultural soils differing in elapsed time since pumice mining (0–15 years) in a representative area of the Calimaya region in the State of Mexico. The study sites in 0, 1, 4, 10, and 15 year old reclaimed soils were compared with an adjacent undisturbed site. Our results indicate that gravimetric moisture content, water hold capacity, bulk density, available phosphorus, total nitrogen, soil organic carbon, microbial biomass carbon and phosphatase and urease activity were greatly impacted by disturbance. A general trend of recovery towards the undisturbed condition with reclamation age was found after disturbance, the recovery of soil total N being faster than soil organic C. The soil quality indicators were selected using principal component analysis (PCA), correlations and multiple linear regressions. The first three components gathered explain 76.4 % of the total variability. The obtained results revealed that the most appropriate indicators to diagnose the quality of the soils were urease, available phosphorus and bulk density and minor total nitrogen. According to linear score analysis and the additive index, the soils showed a recuperation starting from 4 years of pumice extraction.


2021 ◽  
Vol 13 (10) ◽  
pp. 5332
Author(s):  
Dianpeng Li ◽  
Jianqin Zhou ◽  
Yuxin Zhang ◽  
Tao Sun ◽  
Shuqing An ◽  
...  

In arid regions, decreased soil fertility has adversely affected agricultural sustainability. The effects of different amendments in alleviating these issues and increasing soil fertility remain unclear. Herein, a two-year field experiment was conducted to evaluate the properties of grey desert soil and soil respiration (SR) dynamics under six different treatment groups: biochar (BC), leonardite (LD), anionic polyacrylamide (PAM−), cationic polyacrylamide (PAM+) powder, anionic polyacrylamide solution in water (PAM−W), and control (CK). We observed that the BC and LD amendments significantly altered soil pH, organic matter, available nitrogen, available phosphorus, cation exchange capacity, and SR. PAM amendment increased the SR as compared to the control, except in autumn, but PAM did not affect the soil properties. SR under different amendments showed strong seasonal patterns, the highest and lowest SR rates were observed in June and January, respectively. Amendments and seasonal dynamics significantly affected SR, but no interaction was observed between these factors. Temporal variation of SR was substantially influenced by soil temperature at 15 cm of soil depth. Temperature sensitivity of SR (Q10) increased with soil depth and decreased with amendment addition. SR was significantly affected by soil temperature, moisture, air temperature, and their interactions. The outcomes of this study suggested that the BC and LD amendments improved soil fertility and negated the net carbon accumulation by increasing the SR and Q10 in arid agriculture soil.


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