Abstract: Composting is one of the conventional techniques adopted for organic waste management but the practice is very limited in emerging cities despite that most of the waste generated is organic. This paper aims to examine the viability of composting for organic waste management in the emerging city of Addis Ababa, Ethiopia by addressing the composting practice, quality of compost and application of compost in urban agriculture. The study collects data using compost laboratory testing and urban farm households’ survey and uses descriptive analysis on the state of compost production and application, physicochemical analysis of the compost samples, and regression analysis on the urban farmer’s willingness to pay for compost. The findings of the study indicated that there is composting practice at a small scale, most of the producers use unsorted feedstock materials, aerobic composting is dominantly used and the maturation period ranged from four to 10 weeks. The carbon content of the compost ranges from 30.8 to 277.1 due to the type of feedstock applied and this surpasses the ideal proportions for C:N ratio. The total nitrogen, pH, organic matter and moisture content are relatively optimal. The levels of heavy metals measured for Mn, Cu, Pb, Cd and Cr6+ in the compost samples are also insignificant. In the urban agriculture sector, chemical fertilizer is the dominant type of soil input in crop productions but vegetable producers use a combination of both fertilizer and other organic inputs including compost. The willingness to pay for compost depends on income, household size, gender, type of soil inputs, monitoring soil fertility, the main product of the farm, farming method and farm ownership. Finally, this study recommends the need for collaboration among stakeholders along the value chain of waste, awareness creation on the benefits of composting and addressing challenges faced by both compost producers and users.
Abstract: This study aims to characterize the physicochemical aspects of the soils of southeastern Chapada Diamantina - Bahia related to the phytophysiognomies of this area, rupestrian field, small savanna (savanna fields), small dense savanna (savanna fields), savanna (Cerrado), dry thorny forest (Caatinga), dry thorny forest/savanna, scrub (Carrasco - ecotone), forest island (seasonal semi-deciduous forest - Capão) and seasonal semi-deciduous forest. To achieve the research objective, soil samples were collected in each plant formation and analyzed in the soil laboratory of ESALQ - USP in order to identify soil fertility through the determination of pH, organic matter, phosphorus, potassium, calcium, magnesium, potential acidity, sum of bases, cation exchange capacity and base saturation. The composition of soil particles was also checked; that is, the texture, step made in the terrestrial ecosystems laboratory of the Department of Ecology of USP and in the soil laboratory of ESALQ. Another important factor also studied was to show the variations in the vegetation cover in the region as a function of soil moisture in the different existing physiographic environments. Another study carried out was a comparison between the average soil moisture data with precipitation data from three locations with very different phytophysiognomies. The soils found in this part of Bahia can be classified into 5 classes, with a predominance of oxisols. All of these classes have a great diversity of physical and chemical properties, as can be seen in photographs and in particle size and fertility analyzes. The deepest soils are located in the Central Pediplano of Chapada Diamantina where the dirty field, the clean field, the executioner and the semideciduous seasonal forest (Capão) are located, and the shallower soils were found in the rupestrian field, dry thorny forest, and savanna fields, the latter located on a hillside. As for the variations in water in the region's soil, the data indicate that there were large spatial variations in humidity in both the rainy and dry periods.
Abstract: Aggregate soil carbon distribution and stock in the soil in the form of a carbon pool is important for soil fertility and sequestration. The amount of carbon pool and other nutrients statues of the soil are to benefit plants, animal and the environment in the long run. This study was carried out at Akure North and South Local Government; the study area is one of the 18 Local Government Areas of Ondo State in the Southwest geo-political zone of Nigeria. The sites were divided into Map Grids and geo-referenced with Global Positioning System (GPS). Horizons were designated and morphological description carried out on the field. Pedons were characterized and classified according to USDA soil taxonomy. The local government area shares boundaries with; Ikere Local Government (LG) in the North, Ise Orun LG in the northwest, Ifedore LG in the northeast Akure South LG in the East, Ose LG in the South East, and Owo LG in the South. SOC-pool at Federal College of Agriculture topsoil horizon A2 is significantly higher than all horizons, 67.83 th⁻¹. The chemical properties of the pedons have shown that the soil is very strongly acidic to neutral reaction (4.68 – 6.73). The nutrients status of the soil topsoil A1 and A2 generally indicates that the soils have a low potential for retaining plant nutrients, and therefore call for adequate soil management.
Abstract: Peri-urban agriculture in Jos Nigeria serves as a major means of livelihood for both urban and peri-urban poor, and constitutes huge commercial inclination with a target market that has spanned beyond Plateau State. Yet, the sustainability of this sector is threatened by intensive application of urban refuse ash contaminated with heavy metals, as a result of the highly heterogeneous materials used in ash production. Hence, this research aimed to understand the current fertilizer employed by farmers, their perception and acceptability in utilization of household sewage sludge for agricultural purposes and their capacity in mitigating risks associated with such practice. Mixed methods approach was adopted, and data collection tools used include survey questionnaire, focus group discussion with farmers, participants and field observation. The study identified that farmers maintain a complex mixture of organic and chemical fertilizers, with mixture composition that is dependent on fertilizer availability and affordability. Also, farmers have decreased the rate of utilization of urban refuse ash due to labor and increased logistic cost and are keen to utilize household sewage sludge for soil fertility improvement but are mainly constrained by accessibility of this waste product. Nevertheless, farmers near to sewage disposal points have commenced utilization of household sewage sludge for improving soil fertility. Farmers were knowledgeable on composting but find their strategic method of dewatering and sun drying more convenient. Irrigation farmers were not enthusiastic for treatment, as they desired both water and sludge. Secondly, household sewage sludge observed in the field is heterogeneous due to nearness between its disposal point and that of urban refuse, which raises concern for possible cross-contamination of pollutants and also portrays lack of extension guidance as regards to treatment and management of household sewage sludge for agricultural purposes. Hence, farmers concerns need to be addressed, particularly in providing extension advice and establishment of decentralized household sewage sludge collection centers, for continuous availability of liquid and concentrated sludge. Urgent need is also required for the Federal Government of Nigeria to increase commitment towards empowering her subsidiaries for efficient discharge of corporate responsibilities.
Abstract: Municipal Solid Waste (MSW), being a rich source of organic materials, can be used for agricultural applications as an important source of nutrients for soil and plants. This is also an alternative beneficial management practice for MSW generated in developing countries. In the present study, MSW treated soil samples from last four to six years at farmer’s field in Rohtak and Gurgaon states (Haryana, India) were collected. The samples were analyzed for all-important agricultural parameters and compared with the control untreated soil samples. The treated soil at farmer’s field showed increase in total N by 48 to 68%, P by 45.7 to 51.3%, and K by 60 to 67% compared to untreated soil samples. Application of sewage sludge at different sites led to increase in microbial biomass C by 60 to 68% compared to untreated soil. There was significant increase in total Cu, Cr, Ni, Fe, Pb, and Zn in all sewage sludge amended soil samples; however, concentration of all the metals were still below the current permitted (EU) limits. To study the adverse effect of heavy metals accumulation on various soil microbial activities, the sewage sludge samples (from wastewater treatment plant at Gurgaon) were artificially contaminated with heavy metal concentration above the EU limits. They were then applied to soil samples with different rates (0.5 to 4.0%) and incubated for 90 days under laboratory conditions. The samples were drawn at different intervals and analyzed for various parameters like pH, EC, total N, P, K, microbial biomass C, carbon mineralization, and diethylenetriaminepentaacetic acid (DTPA) exactable heavy metals. The results were compared to the uncontaminated sewage sludge. The increasing level of sewage sludge from 0.5 to 4% led to build of organic C and total N, P and K content at the early stages of incubation. But, organic C was decreased after 90 days because of decomposition of organic matter. Biomass production was significantly increased in both contaminated and uncontaminated sewage soil samples, but also led to slight increases in metal accumulation and their bioavailability in soil. The maximum metal concentrations were found in treatment with 4% of contaminated sewage sludge amendment.
Abstract: Land-cover maps were important for many scientific, ecological and land management purposes and during the last decades, rapid decrease of soil fertility was observed to be due to land use practices such as rice cultivation. High-precision land-cover maps are not yet available in the area which is important in an economy management. To assure accurate mapping of land cover to provide information, remote sensing is a very suitable tool to carry out this task and automatic land use and cover detection. The study did not only provide high precision land cover maps but it also provides estimates of rice production area that had undergone chemical degradation due to fertility decline. Land-cover were delineated and classified into pre-defined classes to achieve proper detection features. After generation of Land-cover map, of high intensity of rice cultivation, soil fertility degradation assessment in rice production area due to fertility decline was created to assess the impact of soils used in agricultural production. Using Simple spatial analysis functions and ArcGIS, the Land-cover map of Municipality of Quezon in Nueva Ecija, Philippines was overlaid to the fertility decline maps from Land Degradation Assessment Philippines- Bureau of Soils and Water Management (LADA-Philippines-BSWM) to determine the area of rice crops that were most likely where nitrogen, phosphorus, zinc and sulfur deficiencies were induced by high dosage of urea and imbalance N:P fertilization. The result found out that 80.00 % of fallow and 99.81% of rice production area has high soil fertility decline.
Abstract: Environment-friendly organic wastes of Brewers' spent grain, a byproduct of the brewing process, have recently used as soil amendment to improve soil fertility and plant production. In this work, treatments of 1% (T1) and 2% (T2) of spent grains, 1% (C1) and 2% (C2) of compost and mix of both sources (C1T1) were used and compared to the control for growing Zea mays L. on sandy soil under arid Mediterranean climate. Soils were previously incubated at 65% saturation capacity for a month. The most relevant soil physical and chemical parameters were analysed. Water holding capacity and soil organic matter (OM) increased significantly along the treatments with the highest values in T2. Soil pH decreased along the treatments and the lowest pH was in C1T1. Bicarbonate decreased by 69% in C1T1 comparing to control. Total nitrogen (TN) and available P varied significantly among all treatments and T2, C1T1 and C2 treatments increased 25, 17 and 11 folds in TN and 1.2, 0.6 and 0.3 folds in P, respectively related to control. Available K showed the highest values in C1T1. Soil micronutrients increased significantly along all treatments with the highest values in T2. After corn germination, significant variation was observed in the velocity of germination coefficients (VGC) among all treatments in the order of C1T1>T2>T1>C2>C1>control. The highest records of final germination and germination index were in C1T1 and T2. The spent grains may compensate deficiencies of macro and micronutrients in newly reclaimed sandy soils without adverse effects to sustain crop production with a rider that excessive or continuous use need to be circumvented.
Abstract: Field experiments were conducted during 2013, 2014 and 2015 cropping seasons at Rufus Giwa Polytechnic, Owo, Ondo State, southwest Nigeria. The objective of the investigation was to determine the effect of Cocoa Pod Ash (CPA) and Poultry Manure (PM) applied solely and their combined form, as sources of fertilizers on soil properties, leaf nutrient composition, growth and yield of yam. Three soil amendments: CPA, PM (sole forms), CPA and PM (mixture), were applied at 20 t ha-1 with an inorganic fertilizer (NPK 15-15-15) at 400 kg ha-1 as a reference and a natural soil fertility, NSF (control). The five treatments were arranged in a randomized complete block design with three replications. The test soil was slightly acidic, low in organic carbon (OC), N, P, K, Ca and Mg. Results showed that soil amendments significantly increased (p = 0.05) tuber weights and growth of yam, soil and leaf N, P, K, Ca and Mg, soil pH and OC concentrations compared with the NSF (control). The mixture of CPA+PM treatment increased tuber weights of yam by 36%, compared with inorganic fertilizer (NPK) and 19%, compared with PM alone. Sole PM increased tuber weight of yam by 15%, compared with NPK. Sole or mixed forms of soil amendments showed remarkable improvement in soil physical properties, nutrient availability, compared with NPK and the NSF (control). Integrated application of CPA at 10 t ha-1 + PM at 10 t ha-1 was the most effective treatment in improving soil physical properties, increasing nutrient availability and yam performance than sole application of any of the fertilizer materials.
Abstract: An experiment was carried out for three consecutive years at Owo, southwest Nigeria. The objective of the investigation was to determine the effect of Cocoa Pod Ash (CPA) and Poultry Manure (PM) applied solely and their combined form, as sources of fertilizers on soil properties, leaf nutrient composition, growth and yield of cocoyam. Three soil amendments: CPA, PM (sole forms), CPA and PM (mixture), were applied at 7.5 t ha-1 with an inorganic fertilizer (NPK 15-15-15) at 400 kg ha-1 as a reference and a natural soil fertility, NSF (control), arranged in a randomized complete block design with three replications. Results showed that soil amendments significantly increased (p = 0.05) corm and cormel weights and growth of cocoyam, soil and leaf N, P, K, Ca and Mg, soil pH and organic carbon (OC) concentrations compared with the NSF (control). The mixture of CPA+PM treatment increased corm and cormel weights, plant height and leaf area of cocoyam by 40, 39, 42, and 48%, respectively, compared with inorganic fertilizer (NPK) and 13, 12, 15 and 7%, respectively, compared with PM alone. Sole or mixed forms of soil amendments showed remarkable improvement in soil physical properties compared with NPK and the NSF (control). The mixture of CPA+PM applied at 7.5 t ha-1 was the most effective treatment in improving cocoyam yield and growth parameters, soil and leaf nutrient composition.
Abstract: Application of biochar to arable soils represents a new
approach to restore soil health and quality. Many studies reported the
positive effect of biochar application on soil fertility and
development of soil microbial community. Moreover biochar may
affect the soil water retention, but this effect has not been sufficiently
described yet. Therefore this study deals with the influence of
biochar application on: microbial activities in soil, availability of
mineral nitrogen in soil for microorganisms, mineral nitrogen
retention and plant production. To demonstrate the effect of biochar
addition on the above parameters, the pot experiment was realized.
As a model crop, Lactuca sativa L. was used and cultivated from
December 10th 2014 till March 22th 2015 in climate chamber in
thoroughly homogenized arable soil with and without addition of
biochar. Five variants of experiment (V1 – V5) with different regime
of irrigation were prepared. Variants V1 – V2 were fertilized by
mineral nitrogen, V3 – V4 by biochar and V5 was a control. The
significant differences were found only in plant production and
mineral nitrogen retention. The highest content of mineral nitrogen
in soil was detected in V1 and V2, about 250 % in comparison with
the other variants. The positive effect of biochar application on soil
fertility, mineral nitrogen availability was not found. On the other
hand results of plant production indicate the possible positive effect
of biochar application on soil water retention.
Abstract: Compost can influence soil fertility and plant health. At the same time compost can play an important role in the nitrogen cycle and it can influence leaching of mineral nitrogen from soil to underground water.
This paper deals with the influence of compost addition and mineral nitrogen fertilizer on leaching of mineral nitrogen, nitrogen availability in microbial biomass and plant biomass production in the lysimetric experiment. Twenty one lysimeters were filed with topsoil and subsoil collected in the area of protection zone of underground source of drinking water - Březová nad Svitavou. The highest leaching of mineral nitrogen was detected in the variant fertilized only mineral nitrogen fertilizer (624.58 mg m-2), the lowest leaching was recorded in the variant with high addition of compost (315.51 mg m-2). On the other hand, losses of mineral nitrogen are not in connection with the losses of available form of nitrogen in microbial biomass. Because lost of mineral nitrogen was detected in variant with the least change in the availability of N in microbial biomass.
The leaching of mineral nitrogen, yields as well as the results concerning nitrogen availability from the first year of long term experiment suggest that compost can positive influence the leaching of nitrogen into underground water.
Abstract: Although many factors play a significant role in agricultural production and productivity, the importance of soil fertility cannot be underestimated. The extent to which small farmers are able to manage the fertility of their farmlands is crucial in agricultural development particularly in sub-Saharan Africa (SSA). This paper assesses the nutrient status of selected farmers’ fields in relation to how government policy addresses the allocation of and access to agricultural inputs (e.g. chemical fertilizers) in a unique social-ecological environment of the Okavango Delta in northern Botswana. It also analyses small farmers and soil scientists’ perceptions about the political economy of integrated soil fertility management (ISFM) in the area. A multi-stage sampling procedure was used to elicit quantitative and qualitative information from 228 farmers and 9 soil researchers through the use of interview schedules and questionnaires, respectively. Knowledge validation workshops and focus group discussions (FGDs) were also used to collect qualitative data from farmers. Thirty-three composite soil samples were collected from 30 farmers’ plots in three farming communities of Makalamabedi, Nokaneng and Mohembo for laboratory analysis. While meeting points exist, farmers and scientists have divergent perspectives on soil fertility management. Laboratory analysis carried out shows that most soils in the wetland and the adjoining dry-land/upland surroundings are low in essential nutrients as well as in cation exchange capacity (CEC). Although results suggest the identification and use of appropriate inorganic fertilizers, the low CEC is an indication that holistic cultural practices, which are beyond mere chemical fertilizations, are critical and more desirable for improved soil health and sustainable livelihoods in the area. Farmers’ age (t= -0.728; p≤0.10); their perceptions about the political economy (t = -0.485; p≤0.01) of ISFM; and their preference for the use of local knowledge in soil fertility management (t = -10.254; p≤0.01) had a significant relationship with how they perceived their involvement in the implementation of ISFM.
Abstract: Soil tillage systems can be able to influence soil compaction, water dynamics, soil temperature and crop yield. These processes can be expressed as changes of soil microbiological activity, soil respiration and sustainability of agriculture. Objectives of this study were: 1 - to assess the effects of tillage systems (Conventional System (CS), Minimum Tillage (MT), No-Tillage (NT)) on soil compaction, soil temperature, soil moisture and soil respiration and 2- to establish the effect of the changes on the production of wheat, maize and soybean. Five treatments were installed: CS-plough; MT-paraplow, chisel, rotary grape; NT-direct sowing. The study was conducted on an Argic-Stagnic Faeoziom. The MT and NT applications reduce or completely eliminate the soil mobilization, due to this; soil is compacted in the first year of application. The degree of compaction is directly related to soil type and its state of degradation. The state of soil compaction diminished over time, tending toward a specific type of soil density. Soil moisture was higher in NT and MT at the time of sowing and in the early stages of vegetation and differences diminished over time. Moisture determinations showed statistically significant differences. The MT and NT applications reduced the thermal amplitude in the first 15cm of soil depth and increased the soil temperature by 0.5-2.20C. Water dynamics and soil temperature showed no differences on the effect of crop yields. The determinations confirm the effect of soil tillage system on soil respiration; the daily average was lower at NT (315-1914 mmoli m-2s-1) and followed by MT (318-2395 mmoli m-2s-1) and is higher in the CS (321-2480 mmol m-2s-1). Comparing with CS, all the four conservation tillage measures decreased soil respiration, with the best effects of no-tillage. Although wheat production at MT and NT applications, had no significant differences soybean production was significantly affected from MT and NT applications. The differences in crop yields are recorded at maize and can be a direct consequence of loosening, mineralization and intensive mobilization of soil fertility.
Abstract: Field study was conducted to determine the post field soil fertility status responses of pawpaw (Carica papaya L.) var. homestead selection and sunrise-solo orchards to organo-mineral fertilizer (OMF) rates applied at 10, 20 40 t/ha where both the zero t/ha OMF and NPK 15:15:15 at 50 g/plant/month served as control. The result showed that all pawpaw orchards treated with OMF rates recorded significantly (p≤0.01) higher % P, % K, Na and % organic matter in soil compared to applied NPK which recorded lower Na. However, while orchards plated with sole pawpaw were higher in soil bulk density (SBD), orchards with homestead mixture were lower in SBD and significantly lower % organic matter compared to obtainable under sunrise crop mixture which recorded lower Na and Mg. In conclusion, as a result of loosening effect on soil particles, the homestead pawpaw probably due to more rooting activities as well as the addition of organic fertilizer to soils both had significant influence leading to lower SBD.
Abstract: In order to evaluation the effects of natural, biological
and chemical fertilizers on grain yield and chickpea quality, field
experiments were carried out in 2007 and 2008 growing seasons. In
this research the effects of different organic, chemical and biological
fertilizers were investigated on grain yield and quality of chickpea.
Experimental units were arranged in split-split plots based on
randomized complete blocks with three replications. The highest
amounts of yield and yield components were obtained in G1×N5
interaction. Significant increasing of N, P, K, Fe and Mg content in
leaves and grains emphasized on superiority of mentioned treatment
because each one of these nutrients has an approved role in
chlorophyll synthesis and photosynthesis ability of the crop. The
combined application of compost, farmyard manure and chemical
phosphorus (N5) had the best grain quality due to high protein, starch
and total sugar contents, low crude fiber and reduced cooking time.
Abstract: Paddy being cultivated since about 10,000 years B.C in Ganga Valley in India, its production reached up to 99 million tons in the year 2012. BGA are of much ecological importance for maintaining the soil fertility and reclaiming the alkalinity. In present investigation attempts were made to identify the local cyanobacterial genera from the paddy fields, BGA application for green farming enabling the paddy to utilize more amount of nitrogen released and to examine its impact along with Urea upon growth and yield responses of the Paddy crop. It was observed that combined treatment of BGA with Urea proved better response in almost all growth parameters and yield attributes except number of tillers/ Plant and grains/ panicle as compared to application of either Urea or BGA alone. The Paddy growers should be encouraged to adopt BGA along with Urea as source of Nitrogen for Paddy cultivation.
Abstract: The acid rain causes change in pH level of soil it is
directly influence on root and leaf growth. Yield of the crop was
reduced if acidity of soil is more. Acid rain seeps into the earth and
poisons plants and trees by dissolving toxic substances in the soil,
such as aluminum, which get absorbed by the roots. In present
investigation, effect of acid rain on crop Vigna radiata was studied.
The effect of acid rain on change in soil fertility was detected in
which pH of control sample was 6.5 and pH of 1% H2SO4 and 1%
HNO3 were 3.5. Nitrogen nitrate in soil was high in 1% HNO3 treated
soil & Control sample. Ammonium nitrogen in soil was low in 1%
HNO3 & H2SO4 treated soil. Ammonium nitrogen was medium in
control and other samples. The effect of acid rain on seed
germination on 3rd day of germination control sample growth was
6.1cm with plumule 0.001% HNO3 & 0.001% H2SO4 was 5.5cm
with plumule and 8cm with plumule. On 10th day fungal growth was
observed in 1% and 0.1% H2SO4 concentrations when all plants were
dead. The effect of acid rain on crop productivity was investigated on
3rd day roots were developed in plants. On 12th day Vigna radiata
showed more growth in 0.1% HNO3 and 0.1% H2SO4 treated plants
as compare to control plants. On 20th day development of
discoloration of plant pigments were observed on acid treated plants
leaves. On 34th day Vigna radiata showed flower in 0.1% HNO3,
0.01% HNO3 and 0.01% H2SO4treated plants and no flowers were
observed on control plants. On 42th day 0.1% HNO3, 0.01% HNO
and 0.01% H2SO4 treated Vigna radiata variety and control plants
were showed seeds on plants. In Vigna radiate variety 0.1%, 0.01%
HNO3, 0.01% H2SO4treated plants were dead on 46th day and fungal
growth was observed. The toxicological study was carried out on
Vigna radiata plants exposed to 1% HNO3 cells were damaged more
than 1% H2SO4. Leaf sections exposed to 0.001% HNO3 & H2SO4
showed less damaged of cells and pigmentation observed in entire
slide when compare with control plant.
Abstract: Most agricultural crops cultivated in Brazil are highly
nutrient demanding. Brazilian soils are generally acidic with low base
saturation and available nutrients. Demand for fertilizer application
has increased because the national agricultural sector expansion. To
improve productivity without environmental impact, there is the need
for the utilization of novel procedures and techniques to optimize
fertilizer application. This includes the digital soil mapping and GIS
application applied to mapping in different scales. This paper is
based on research, realized during 2005 to 2010 by Brazilian
Corporation for Agricultural Research (EMBRAPA) and its partners.
The purpose was to map soil fertility in national and regional scales.
A soil profile data set in national scale (1:5,000,000) was constructed
from the soil archives of Embrapa Soils, Rio de Janeiro and in the
regional scale (1:250,000) from COMIGO Cooperative soil data set,
Rio Verde, Brazil. The mapping was doing using ArcGIS 9.1 tools
from ESRI.
Abstract: A passive system "Qanat" is collection of some
underground wells. A mother-well was dug in a place far from the
city where they could reach to the water table maybe 100 meters
underground, they dug other wells to direct water toward the city,
with minimum possible gradient. Using the slope of the earth they
could bring water close to the surface in the city. The source of water
or the appearance of Qanat, land slope and the ownership lines are
the important and effective factors in the formation of routes and the
segment division of lands to the extent that making use of Qanat as
the techniques of extracting underground waters creates a channel of
routes with an organic order and hierarchy coinciding the slope of
land and it also guides the Qanat waters in the tradition texture of salt
desert and border provinces of it. Qanats are excavated in a specified
distinction from each other. The quantity of water provided by
Qanats depends on the kind of land, distance from mountain,
geographical situation of them and the rate of water supply from the
underground land. The rate of underground waters, possibility of
Qanat excavation, number of Qanats and rate of their water supply
from one hand and the quantity of cultivable fertile lands from the
other hand are the important natural factors making the size of cities.
In the same manner the cities with several Qanats have multi central
textures. The location of cities is in direct relation with land quality,
soil fertility and possibility of using underground water by excavating
Qanats. Observing the allowable distance for Qanat watering is a
determining factor for distance between villages and cities.
Topography, land slope, soil quality, watering system, ownership,
kind of cultivation, etc. are the effective factors in directing Qanats
for excavation and guiding water toward the cultivable lands and it
also causes the formation of different textures in land division of
farming provinces. Several divisions such as orderly and wide, inorderly,
thin and long, comb like, etc. are the introduction to organic
order. And at the same time they are complete coincidence with
environmental conditions in the typical development of ecological
architecture and planning in the traditional cities and settlements
order.
Abstract: Acid rain occurs when sulphur dioxide (SO2) and
nitrogen oxides (Nox) gases react in the atmosphere with water,
oxygen, and other chemicals to form various acidic compounds. The
result is a mild solution of sulfuric acid and nitric acid. Soil has a
greater buffering capacity than aquatic systems. However excessive
amount of acids introduced by acid rains may disturb the entire soil
chemistry. Acidity and harmful action of toxic elements damage
vegetation while susceptible microbial species are eliminated. In
present study, the effects of simulated sulphuric acid and nitric acid
rains were investigated on crop Glycine max. The effect of acid rain
on change in soil fertility was detected in which pH of control sample
was 6.5 and pH of 1%H2SO4 and 1%HNO3 were 3.5. Nitrogen nitrate
in soil was high in 1% HNO3 treated soil & Control sample.
Ammonium nitrogen in soil was low in 1% HNO3 & H2SO4 treated
soil. Ammonium nitrogen was medium in control and other samples.
The effect of acid rain on seed germination on 3rd day of germination
control sample growth was 7 cm, 0.1% HNO3 was 8cm, and 0.001%
HNO3 & 0.001% H2SO4 was 6cm each. On 10th day fungal growth
was observed in 1% and 0.1%H2SO4 concentrations, when all plants
were dead. The effect of acid rain on crop productivity was
investigated on 3rd day roots were developed in plants. On12th day
Glycine max showed more growth in 0.1% HNO3, 0.001% HNO3 and
0.001% H2SO4 treated plants growth were same as compare to control
plants. On 20th day development of discoloration of plant pigments
were observed on acid treated plants leaves. On 38th day, 0.1, 0.001%
HNO3 and 0.1, 0.001% H2SO4 treated plants and control plants were
showing flower growth. On 42th day, acid treated Glycine max variety
and control plants were showed seeds on plants. In Glycine max
variety 0.1, 0.001% H2SO4, 0.1, 0.001% HNO3 treated plants were
dead on 46th day and fungal growth was observed. The toxicological
study was carried out on Glycine max plants exposed to 1% HNO3
cells were damaged more than 1% H2SO4. Leaf sections exposed to
0.001% HNO3 & H2SO4 showed less damaged of cells and
pigmentation observed in entire slide when compare with control
plant. The soil analysis was done to find microorganisms in HNO3 &
H2SO4 treated Glycine max and control plants. No microorganism
growth was observed in 1% HNO3 & H2SO4 but control plant showed
microbial growth.