scholarly journals Soil Chemical Characteristics of Organic and Conventional Agriculture

2017 ◽  
Vol 21 (1) ◽  
pp. 19
Author(s):  
Muhammad Abdul Aziz ◽  
Fahrizal Hazra ◽  
Selly Salma ◽  
Dedi Nursyamsi Nursyamsi

Use of chemical fertilizers and pesticides on intensive land of both lowland and upland food crops have been shown to increase agricultural productivity significantly. Research aimed to study soil chemical characteristics and soil pesticide residues at some crops of organic and conventional farms. The research was carried out in  Laboratory of Soil Chemistry, Indonesian Soil Research Institute and in Laboratory of Agrochemical Residue, Indonesian Agricultural Environment Research Institute, Bogor from February to July 2015. Soil samples at 0-10 cm depth were taken compositely from broccoli (Brassica oleracea), carrots (Daucus carota), maize (Zea mays), and tomatoes (Solanum lycopersicum) farms in Bogor Regency as well as from rice field in Tasikmalaya Regency at both organic and conventional farms. Soil chemical characteristics were analyzed include: soil organic-C (Walkey and Black), total-N (Kjeldahl), potential-P (HCl 25%), available-P (Olsen), potential-K (HCl 25%), available-K (NH4OAc 1 N pH 7), CEC (NH4OAc 1 N pH 7), and pH (soil : water = 1: 5), while pesticide residues included levels of organochlorine (lindane, aldrin, heptaklor, dieldrin, DDT, endosulfan); organophosphates (diazinon, fenitrotin, metidation, paration, profenofos); and carbamates (carbofuran, MIPC, BPMC) in the soil by using Gas Chromatography method. Results showed that levels of soil organic-C, total-N, potential and available-P, potential and available-K, CEC, pH  at organic farms were higher than those at conventional farms. Some pesticide residues compound (organochlorines, organophosphates, and carbamates) were detected at conventional farm, while those at organic farm were not detected (trace).Keywords: Conventional farm, organic farm, pesticide residues, soil properties. [How to Cite: Muhammad AA, F Hazra, S Salma and D Nursyamsi. 2016. Soil Chemical Characteristics of Organic and Conventional Agriculture. J Trop Soils 21: 19-25. Doi: 10.5400/jts.2016.21.1.19] 

2021 ◽  
Vol 8 (2) ◽  
pp. 333-340
Author(s):  
Renaldi Sambo Eka Saputra ◽  
Syahrul Kurniawan

Agricultural practices, especially land clearing by burning in peat-land, usually causes land-fire and result in nutrient degradation of peat-land. The research was aimed to assess nutrient content (i.e. C, N, P) in oil palm plantation within peatlands post land fire. The study was conducted on Tulang Bawang regency, Lampung Province. Soil samples were collected from two locations with different intensity of land fire, i.e. field with low intensity of land fire (land A) and land with high intensity of land fire (land B). In each land, the soil was taken from two depths (i.e. 0-10 cm and 10-30 cm) in three different zones of oil palm plantation, named as fertilization area, frond stack, and harvested path, with three replications of each. The variable measured including soil organic C, total N, and available P. Prior to statistical analysis, the data were tested normality. The result showed that the location with low intensity of land fire (land A) had higher soil organic C, total N, and available P at 0-10 cm and 10-30 cm depths of soil as compared to the area with high land fire intensity (land B). Application of N fertilizer and liming resulted in a higher total N at 0-10 cm depth of soil and available P (in the land A) in fertilization area as compared to frond stack and harvest path areas, both in land A and land B. Available P in land B at 0-10 cm and 10-30 cm soil depth in the fertilization area was lower than harvest path and frond stack areas, and this was probably due to the high losses through leaching and/or uptake by palm oil.


2001 ◽  
Vol 31 (12) ◽  
pp. 2225-2236 ◽  
Author(s):  
Peter S Homann ◽  
Bruce A Caldwell ◽  
H N Chappell ◽  
Phillip Sollins ◽  
Chris W Swanston

Chemical and microbial soil properties were assessed in paired unfertilized and urea fertilized (>89 g N·m–2) plots in 13 second-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands distributed throughout western Washington and Oregon. A decade following the termination of fertilization, fertilized plots averaged 28% higher total N in the O layer than unfertilized plots, 24% higher total N in surface (0–5 cm) mineral soil, and up to four times the amount of extractable ammonium and nitrate. Decreased pH (0.2 pH units) caused by fertilization may have been due to nitrification or enhanced cation uptake. In some soil layers, fertilization decreased cellulase activity and soil respiration but increased wood decomposition. There was no effect of fertilization on concentrations of light and heavy fractions, labile carbohydrates, and phosphatase and xylanase activities. No increase in soil organic C was detected, although variability precluded observing an increase of less than ~15%. Lack of a regionwide fertilization influence on soil organic C contrasts with several site-specific forest and agricultural studies that have shown C increases resulting from fertilization. Overall, the results indicate a substantial residual influence on soil N a decade after urea fertilization but much more limited influence on soil C processes and pools.


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).


2021 ◽  
Vol 18 (18) ◽  
pp. 5185-5202
Author(s):  
Juhwan Lee ◽  
Raphael A. Viscarra Rossel ◽  
Mingxi Zhang ◽  
Zhongkui Luo ◽  
Ying-Ping Wang

Abstract. Land use and management practices affect the response of soil organic carbon (C) to global change. Process-based models of soil C are useful tools to simulate C dynamics, but it is important to bridge any disconnect that exists between the data used to inform the models and the processes that they depict. To minimise that disconnect, we developed a consistent modelling framework that integrates new spatially explicit soil measurements and data with the Rothamsted carbon model (Roth C) and simulates the response of soil organic C to future climate change across Australia. We compiled publicly available continental-scale datasets and pre-processed, standardised and configured them to the required spatial and temporal resolutions. We then calibrated Roth C and ran simulations to estimate the baseline soil organic C stocks and composition in the 0–0.3 m layer at 4043 sites in cropping, modified grazing, native grazing and natural environments across Australia. We used data on the C fractions, the particulate, mineral-associated and resistant organic C (POC, MAOC and ROC, respectively) to represent the three main C pools in the Roth C model's structure. The model explained 97 %–98 % of the variation in measured total organic C in soils under cropping and grazing and 65 % in soils under natural environments. We optimised the model at each site and experimented with different amounts of C inputs to simulate the potential for C accumulation under constant climate in a 100-year simulation. With an annual increase of 1 Mg C ha−1 in C inputs, the model simulated a potential soil C increase of 13.58 (interquartile range 12.19–15.80), 14.21 (12.38–16.03) and 15.57 (12.07–17.82) Mg C ha−1 under cropping, modified grazing and native grazing and 3.52 (3.15–4.09) Mg C ha−1 under natural environments. With projected future changes in climate (+1.5, 2 and 5.0 ∘C) over 100 years, the simulations showed that soils under natural environments lost the most C, between 3.1 and 4.5 Mg C ha−1, while soils under native grazing lost the least, between 0.4 and 0.7 Mg C ha−1. Soil under cropping lost between 1 and 2.7 Mg C ha−1, while those under modified grazing showed a slight increase with temperature increases of 1.5 ∘C, but with further increases of 2 and 5 ∘C the median loss of TOC was 0.28 and 3.4 Mg C ha−1, respectively. For the different land uses, the changes in the C fractions varied with changes in climate. An empirical assessment of the controls on the C change showed that climate, pH, total N, the C : N ratio and cropping were the most important controls on POC change. Clay content and climate were dominant controls on MAOC change. Consistent and explicit soil organic C simulations improve confidence in the model's estimations, facilitating the development of sustainable soil management under global change.


1986 ◽  
Vol 8 (1) ◽  
pp. 11 ◽  
Author(s):  
RB Hacker

An earthy sand supporting a mulga shrubland community in the arid winter rainfall zone in Western Australia is characterized in terms of its chemical and physical properties. In this study, changes in these properties with overgrazing were investigated. Nutrient levels were low in relation to some soils supporting mulga communities elsewhere in Australia. Marked accumulations of total N, organic C and exchangeable Ca occurred in the hummocks of wind blown material surrounding surface obstructions. Improved water relationships are probably responsible for the abundance of ephemeral growth on such areas, and for their subsequent chemical enrichment. Changes in chemical properties with depth were evident for pH, total N, organic C, available P and exchangeable Mg with values decreasing from the 0-2 cm layer to the 2-10 cm layer in all cases. Chemical changes associated with overgrazing were restricted to the 0-2 cm layer. Some trends towards lower levels of organic C, total N, and available P could be distinguished, particularly for organic C and total N in hummock surfaces, but chemical parameters generally did not provide a sensitive measure of grazing impact. Sorptivity varied between the sandy and crusted phases of the soil mosaic and was reduced on sites in very poor condition. Sorptivity changes under grazing were apparently mediated partly by changes in the structural properties of the soil crust. There was no significant effect of overgrazing on either the bulk density of the surface (sub-crust) soil or on summer surface temperatures.


2021 ◽  
Vol 20 (1) ◽  
pp. 29-40
Author(s):  
T.E. Odunjo ◽  
E.Y. Thomas

The risk associated with the presence of heavy metals in soil is their potential toxicity and ability to enter the ecosystem through the food chain. Total heavy metal content of a soil is inadequate for predicting the toxicity of heavy metals in soil. Therefore, the current study was designed to determine the various forms in which the selected heavy metals: Chromium (Cr), Lead (Pb), Nickel (Ni), and Cadmium (Cd) exist in the soil to ascertain the available forms for plant uptake. Soils samples were randomly collected from selected organic and conventional farms in Akinyele local government, Ibadan, Oyo State, Nigeria, at different depths (0-15, 15-30 and 30-45 cm) using random sampling method. Routine analysis was carried out to determine the textural classes and chemical properties of soil samples. The total heavy metals of the soil samples were determined and their fractions were analysed using sequential extraction method. Cadmium was not detected in most of the soil samples. Residual fraction was predominant in all the analysed heavy metals. In addition, Cr was more associated with the oxidizable fraction having a range of 0.1 mg/kg from Ajibode organic farm (AO) at 30-45 cm depth. Pb and Ni were both more associated with reducible fraction with Pb having a range of 2.7 mg/kg in Ajibode conventional farm (AI) at 0-15 cm depth and 0.1 mg/kg in (AI) at 30-45 cm depth. Reducible values of Ni ranges from 4.3 mg/kg in AI at 0-15 cm to 1.4 mg/kg in AO at 30-45 cm. The apparent mobility and bioavailability for these heavy metals in the studied soils were in the order: Pb>Cr>Ni. The result showed that uptake of heavy metals by the plants would be low as the concentration of the exchangeable form of the heavy metals in the analysed soil sample has the least concentration when compared with the other forms.


2021 ◽  
Author(s):  
Raphael Viscarra Rossel ◽  
Juhwan Lee ◽  
Mingxi Zhang ◽  
Zhongkui Luo ◽  
YingPing Wang

<p>We simulated soil organic carbon (C) dynamics across Australia with the Rothamsted carbon model ({\sc Roth C}) by connecting new spatially-explicit soil measurements and data with the model. This helped us to bridge the disconnection that exists between datasets used to inform the model and the processes that it depicts. We compiled publicly available continental-scale datasets and pre-processed, standardised and configured them to the required spatial and temporal resolutions. We then calibrated {\sc Roth C} and run simulations to estimate the baseline soil organic C stocks and composition in the 0--0.3~m layer at 4,043 sites in cropping, modified grazing, native grazing, and natural environments across Australia. We used data on the C fractions, the particulate, mineral associated, and resistant organic C (POC, MAOC and ROC, respectively) to represent the three main C pools in the {\sc Roth C} model's structure.<span class="Apple-converted-space">  </span>The model explained 97--98\% of the variation in measured total organic C in soils under cropping and grazing, and 65\% in soils under natural environments. We optimised the model at each site and experimented with different amounts of C inputs to simulate the potential for C accumulation under constant and chainging climate in a 100-year simulation. Soils under native grazing were the most potentially vulnerable to C decomposition and loss, while soils under natural environments were the least vulnerable. An empirical assessment of the controls on the C change showed that climate, pH, total N, the C:N ratio, and cropping were the most important controls on POC change. Clay content and climate were dominant controls on MAOC change. Consistent and explicit soil organic C simulations improve confidence in the model's estimations, contributing to the development of sustainable soil management under global change.<span class="Apple-converted-space"> </span></p>


1995 ◽  
Vol 35 (7) ◽  
pp. 923 ◽  
Author(s):  
NA Fettell ◽  
HS Gill

Differences in soil organic carbon (C), total nitrogen (N), and pH resulting from 14 and 15 years of different tillage, stubble, and fertiliser N management practices were measured for a red-brown earth at Condobolin in western New South Wales. The 5 main treatments comprised stubble burning or retention in factorial combination with cultivation and direct drilling, and stubble incorporation combined with cultivation. Two rates of N fertiliser (0 and 40 or 50 kg/ha) were applied annually, and wheat was grown each year. There were no significant differences between tillage and stubble treatments for soil organic C, total N, or pH. Fertiliser N application caused small but significant increases in organic C and total N but decreased the pH of the surface 2.5 cm of soil by 0.4-0.5 units compared with the nil fertiliser rate. The study indicates that direct drilling and stubble retention with continuous wheat have had little long-term effect on soil organic C and total N in this low rainfall environment.


1986 ◽  
Vol 107 (3) ◽  
pp. 555-559
Author(s):  
P. M. Nimje ◽  
Jagdish Seth

SUMMARYThe effects of applying phosphorus, farmyard manure (FYM) and nitrogen on some soil properties were studied at the end of 2 years of field experimentation at New Delhi, India. Each year a crop of soya bean sown in the rainy season received phosphorus and farmyard manure and maize sown in winter received nitrogen fertilizer. Phosphorus was applied to soya bean at 0, 40 and 80 kg P2O5/ha, farmyard manure at 0 and 15 t/ha and nitrogen to maize at 0, 60 and 120 kg N/ha. Phosphorus application increased organic C, total N and available P status of the soil. It also improved bulk density and water-holding capacity of the soil. Farmyard manure increased organic C, total N, available P and K and pH of the soil, but decreased EC and bulk density of the soil. Water-holding capacity of the soil was increased by FYM. N fertilizer increased organic C and total N only.


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