Soil Science, Environmental Soils Science, Another Soil and Environmental Sciences are possible

Buku ini digunakan sebagai Diktat Kuliah di Program Studi S1 Manajemen Sumberdaya Lahan (Ilmu Tanah), di Departemen Ilmu Tanah dan Sumberdaya Lahan, Fakultas Pertanian, IPB.  Diktat ini lebih ditujukan untuk proses pembelajaran di internal IPB.  Dalam pelaksanaan proses pembelajaran, materi dari diktat ini diperkaya dengan materi terkini, khususnya dari penelitian yang dilakukan oleh penulis.

Soil is a complex ecosystem comprised of several and mutually interacting components, both abiotic (organo-mineral associations) and biotic (microbial and pedofaunal populations and plants), where a single parameter depends on other factors and affects the same and other factors, so that a network of influences among organisms coexists with the reciprocal actions between organisms and their environment. Therefore, it is difficult to undoubtedly determine what is the cause and what the effect within relationships between factors and processes. Soil is commonly studied through the evaluation and measurement of single parameters (e.g. the content of soil organic matter (SOM), microbial biomass, enzyme activities, pH, etc.), events (e.g. soil erosion, compaction, etc.) and processes (e.g. soil respiration, carbon fluxes, nitrification/denitrification, etc.), often carried out in laboratory conditions in order to limit the number of factors acting within the ecosystem under study, but missing the information about the global soil environment that way. In the last decade, several scientists have proposed and suggested the need for a holistic approach to soil ecosystems in different contexts. Recently, we have applied a sensing system developed in the last decades and capable of analysing complex mixtures of gases and volatiles (odours or aromas) in atmospheres, namely called electronic nose (EN). Typically, ENs are devices consisting of an array of differentially and partially specific, despite selective, sensors upon diverse coatings of sensitive films, i.e. interacting with single analytes of the same chemical class, despite not highly specific for a single substance, only, but showing also lower extent of cross-selectivity towards compounds of other chemical classes. ENs can be used in the classifications of odours by processing the collected responses of all sensors in the array through pattern recognition analyses, in order to obtain a chemical fingerprint (olfactory fingerprint) typical of the analysed air sample. Due to these features, we decided to apply such a sensing technology to the analyses of soil atmospheres, because several processes in soil, both abiotic and biotic, result in gas and/or volatile production and the dynamics of such releases may also be affected by several additional environmental factors, such as soil moisture, temperature, gas exchange rates with outer atmosphere, adsorption/desorption processes, etc. Then, the analysis of soil atmosphere may provide information about global soil conditions (e.g. soil quality and health), according to a holistic approach, where several factors are contemporarily taken into account. At the same time, the use of such a technology, if adequately trained on purpose, can supply information about a single or a pool of processes sharing similar features, which occur in soil over a certain period of time and mostly affecting soil atmosphere. According to these premises and hypotheses, we demonstrated that EN is an useful technology to measure soil microbial activity, through its correlation to specific metabolic activities occurring in soil (i.e. global and specific respiration and some enzyme activities), but also soil microbial biomass. On the basis of such evidences, we also were able to use this technology to assess the quality and health conditions of soil ecosystems in terms of metabolic indices previously identified, according to some metabolic parameters and biomass quantification of microbial populations. In other studies, we also applied EN technology, despite using a different set of sensors in the array, to analyse the atmosphere of soil ecosystems in order to assess their environmental conditions after contamination with polycyclic aromatic hydrocarbons (PAHs) (i.e. semivolatile - SVOCs - organic pollutants). In this case, EN technology resulted capable of distinguishing between contaminated and uncontaminated soils, according to the differences in a list of substances, occurring in the atmospheres of differently treated soils, which were identified through SPME-GC/MS analyses and then suggested to be responsible for the different classification. Analysing the EN responses, it was also possible to follow the degradation process of pollutants by resident microbial populations over time, on the basis of the contemporary decrease of contaminant and the increased release of CO2. Then, we suggest that EN technology may be usefully employed in the analyses of soil ecosystems in order to both supply information about global soil environment, according to the holistic approach, and about specific processes occurring therein. Furthermore, since EN technology resulted to be effective and successful in detecting processes in soil, in both natural and perturbed conditions, involving microbial populations, which are commonly considered as the most sensitive and responsive to soil environmental modifications, we suggest it might be reasonably employed in analyses concerning the assessment of soil quality and health. Consequently, such a technology may also be used to study several processes involving soil ecosystems, such as soil management practices, soil restoration, soil contamination and remediation, soil fertility, etc.

SUMMARY Over the past three decades oil palm plantations (OPP) in Indonesia has been expanded also on peatland. Expansion of OPP is a large scale land use change and is having dynamics to the environments. In the perspective of national-level resource management and policy development regarding peatlands, understanding the historical expansion of OPP over peatland and explores the dynamics of above-ground biomass (AGB) during the land use changes is much needed. The study area consisted of two provinces in Indonesia, namely Riau and West Kalimantan. This study highlights the conversion of peat swamp forests (PSF) based on the status of primary or secondary forests. The study also reported on the transitions occurred in AGB in the peatlands that have been developed for OPP by distinguishing classes of peat thickness. Landsat imagery was used to visually interpret OPP followed by intersection with peat thickness and swamp forest maps to create province-wide maps; spanning three temporal periods spanning from 1990 to 2013. The AGB estimates reported in the scientific literature were used to assess the AGB loss associated with each land use change. The results show that in 1990, the two provinces collectively had approximately 0.31 M ha of OPP, which expanded to 3.04 Mha by 2013. The OPP grew at an approximately constant rate (11% yr –1). Only 0.94% (29,137 ha) of the OPP had been derived directly from primary peat swamp forest (PPSF), and 21.55% (0.67 M ha) of the OPP had been established on land previously covered with secondary peat swamp forest (SPSF) within the past 23 years (1990-2013) in Riau and West Kalimantan. Higher portion of SPSF converted to wet shrublands (WSL) leading to the greatest loss of AGB (85.5 M tons). Lower loss of AGB resulted by conversion from SPSF to OPP (47.5 M tons). Similarly, the loss of AGB from the conversion of PPSF to OPP (estimated to be only 4.39 M tons) was higher than for conversions from PPSF to WSL (3.44 M tons).

Agriculture is the mainstay of the economy of Ghana. The Government has given special attention to the sector to play a leading role in the economic development of the country. The role of the sector is an engine of economic development and depends upon other things on sustainable use of the land resource. This study was carried out in the Sudan Savannah (Bawku and Navrongo) and Guinea Savannah (Tolon kumbungu and Walewale) zone of Ghana to assess the effect of fertilizer subsidy on yield of crops among rural farmers. Data was collected from randomly selected households by administering questionnaire and a descriptive statistics consisting of simple percentages, frequencies, means and tables, were used to examine the socio- economic characteristics of farmers. The arithmetic mean was used to find the average farm size per acre and output per acre of beneficiaries and non-beneficiaries of the fertilizer subsidy program. Results of the analysis showed that 93% of the sampled farmers were men. Land ownership of the farmers was known to affect their farming activities. Evidence from this study reveals that (63%) of the farmers were sole owners, (13%) hired, (25%) family, 68% belong to farmers group and 32% do not belong to any association. The percentage of beneficiaries of the fertilizer subsidy program was 68% and that of the non-beneficiaries was 32%. The average output per acre of the beneficiaries of the fertilizer subsidy program were16.15kg/acre maize, 7kg/acre soybean, 41kg/acre rice and 8kg/acre groundnut and average output per acre for the non-beneficiaries of the fertilizer subsidy program were 12.38kg/acre maize, 2.25kg/acre soybean, 8.5kg/acre rice and 5kg/acre groundnut. The average output per acre of the beneficiaries before the fertilizer subsidy program were 16.15kg/acre maize, 7kg/acre soybean, 40.4kg/acre rice and 8kg/acre groundnut and that of the beneficiaries output per acre after the fertilizer subsidy program were 19.54kg/acre maize, 8kg/acre soybean, 29kg/acre rice and 4.2kg/acre groundnut. Majority 93% of the farmers were aware of the fertilizer subsidy program and few were unaware of the fertilizer subsidy program7%.

The influence of different forest species (Gleditsia amorphoides (Griseb.) Taub.; Patagonula americana L.; Chlorophora tinctoria L.; Gaud; & Astronium balansae Engl.) on the physical properties of soils are showed; selected forestal plots are located at the 'Reserva Natural Estricta' of Colonia Benítez, 17 km NE from the city of Resistencia (Province of the 'El Chaco', Argentina).

Soil erosion is one of the most important forms of land degradation that threatens continued and sustained agricultural production in Ghana. The most severely affected areas are the three northern regions especially Upper East Region, where large tracts of land have been destroyed by water erosion leading to soil depth reduction and decline in soil fertility. This study was carried out in Talensi Nabdam District of Upper East Region of Ghana to examine the adoption of soil conservation technologies of rural farmers in the district. A random sample of 350 household was selected from seven communities in the district. Questionnaires administered in the area provided primary data needed for analysis. Descriptive statistics were employed in describing the socio-economic characteristic of farmers. Mean was used to rank the constraints and perception indices were used to analyze for the perception of farmers on the various soil conservation technologies. Probit model was used in the analysis of factors that influenced farmer’s decision to adopt soil conservation technologies and among the eight variables fitted in the model, four were found to be significant for stonebunds, three for earthbunds, three for vertiver grass and three for manure. Farmer based organization, household size; extension contact and labour were significant for stonebunds. Education, household size and labour were significant for earthbunds. Gender, household size and extension contact were significant for vertiver grass. Gender, household size and extension contact were significant for manure. Age, marital status and credit have no significant effects on farmers adopting all the conservation technologies.