Multi-criteria decision making methods to address rural land allocation problems: A systematic review

Land allocation has been an important issue in land use planning research studies. Land allocation involves different multifunctional activities of maximizing environmental, economic and social benefits. Multi-criteria decision making (MCDM) method is the most popular tool to optimize land allocation problems by considering decision variables, conflicting objectives, and criteria. Hence, decision-makers face problems on how to optimize the land allocation while minimizing the conflicting trade-offs existing in the decision analysis. With this review study, we aim at identifying and extracting information on MCDM methods to solve land allocation problems from English language articles published between 2000 and 2019 and indexed by four scientific literature databases (Web of Science, Science Direct, Scopus, Google scholar). To this end, we applied a systematic literature review approach, i.e. the Preferred Reporting Items for Systematic Reviews and Meta-Analysis procedure (Moher et al., 2009), with a structured database search expression. 120 articles were selected of which, after careful screening of title, keywords and abstract, 69 were retained for detailed review. This review study report compiles comprehensive information by classifying the papers into application area, optimization objectives, criteria used, decision techniques, publication year and study region. In summary, we found that in the last two decades, the use of the MCDM method has increased, particularly in Europe and China. AHP (analytical hierarchal process) is frequently used for multi-attribute land allocation problems with reference to ecotourism and ecosystem management. LP (linear programming) and SA (simulating annealing) methods are predominantly used to optimize multi-objectives complex agricultural and forest land allocation problems respectively.     

Clonal and seasonal differences in leaf osmotic potential and organic solutes of five hybrid poplar clones grown under field conditions

Leaf osmotic potential at full turgor (Psi(pio)) and the major solutes that contribute to osmotic potential were characterized in five hybrid poplar clones of Populus trichocarpa Torr. & Gray x P. deltoides Bartr. (TD) and P. deltoides x P. nigra L. (DN), growing under field conditions at two sites in eastern Washington and Oregon, USA. Trees were drip irrigated with 46, 76 or 137 cm of supplemental irrigation during each growing season. Trees at Wallula, WA, which were in their third growing season in 1994, were sampled twice a year for two years (1994 and 1995), and trees at Boardman, OR, which were in their second growing season in 1994, were sampled once a year for three years (1994-1996). At Wallula, the TD and DN clones exhibited lower predawn leaf water potentials in the 46-cm treatment than in the 137-cm treatment (-1.2 versus -0.7 MPa) during a hot, dry period in July 1994. Clone TD had a lower Psi(pio) than Clone DN (-1.67 versus -1.56 MPa) during the same period and the difference was also evident in 1995 (-1.81 versus -1.72 MPa) when trees were in their fourth growing season. There was also a significant treatment effect on Psi(pio) in Clone TD, with trees in the 46-cm treatment having lower Psi(pio) than trees in the 137-cm treatment in July 1994. At Boardman, Psi(pio) was generally high with no treatment differences during the 1994-96 samplings. The TD clones had significantly lower Psi(pio) than the DN clones in 1994 (-1.44 versus -1.36 MPa) and 1996 (-1.72 versus -1.54 MPa), but there was no difference between clones in 1995 (-1.40 versus -1.43 MPa). In 1995, at Wallula, osmotic adjustment in Clone TD was largely accounted for by an increase in sucrose, which constituted 70% of total organic solutes. Although the total concentration of free primary amino acids in this clone was 28% higher in trees in the 46-cm treatment than in trees in the 137-cm treatment, amino acids constituted only a small fraction of the total solute pool. Sixty-two percent of total solutes were inorganic ions in Clone TD compared to 52% in Clone DN, and potassium was the main ion constituting about 30% of total solutes and 50% of total ions. However, the clonal difference in Psi(pio) was not fully accounted for by the difference in solute concentration. Osmotic potential at full turgor declined over the growing season and with age. We conclude that, because the extent of osmotic adjustment exhibited by these clones was small, other drought resistance mechanisms contributed to the clonal differences in field performance.     

Osmotic potential of several hardwood species as affected by manipulation of throughfall precipitation in an upland oak forest during a dry year

Components of dehydration tolerance, including osmotic potential at full turgor (Psi(pio)) and osmotic adjustment (lowering of Psi(pio)), of several deciduous species were investigated in a mature, upland oak forest in eastern Tennessee. Beginning July 1993, the trees were subjected to one of three throughfall precipitation treatments: ambient, ambient minus 33% (dry treatment), and ambient plus 33% (wet treatment). During the dry 1995 growing season, leaf water potentials of all species declined to between -2.5 and -3.1 MPa in the dry treatment. There was considerable variation in Psi(pio) among species (-1.0 to -2.0 MPa). Based on Psi(pio) values, American beech (Fagus grandifolia Ehrh.), dogwood (Cornus florida L.), and sugar maple (Acer saccharum Marsh.) were least dehydration tolerant, red maple (A. rubrum L.) was intermediate in tolerance, and white oak (Quercus alba L.) and chestnut oak (Quercus prinus L.) were most tolerant. During severe drought, overstory chestnut oak and understory dogwood, red maple and chestnut oak displayed osmotic adjustment (-0.12 to -0.20 MPa) in the dry treatment relative to the wet treatment. (No osmotic adjustment was evident in understory red maple and chestnut oak during the previous wet year.) Osmotic potential at full turgor was generally correlated with leaf water potential, with both declining over the growing season, especially in species that displayed osmotic adjustment. However, osmotic adjustment was not restricted to species considered dehydration tolerant; for example, dogwood typically maintained high Psi(pio) and displayed osmotic adjustment to drought, but had the highest mortality rates of the species studied. Understory saplings tended to have higher Psi(pio) than overstory trees when water availability was high, but Psi(pio) of understory trees declined to values observed for overstory trees during severe drought. We conclude that Psi(pio) varies among deciduous hardwood species and is dependent on canopy position and soil water potential in the rooting zone.     

Drought resistance of two hybrid Populus clones grown in a large-scale plantation

Poplar hybrids were grown with irrigation in a large-scale plantation to investigate the mechanisms underlying clonal differences in drought resistance. Beginning in spring 1992, Populus trichocarpa x P. deltoides (TD) and P. deltoides x P. nigra (DN) cuttings received 46, 76, or 137 cm year(-1) of irrigation to supplement the 18-20 cm of annual precipitation, and all trees received the same fertilization regime. Stem volume, assessed as the square of stem diameter at breast height times tree height (D(2)H), and water relations of the trees were studied from the end of their second growing season until the end of their fifth growing season. By the end of the second growing season, stem volume of Clone TD was 40-146% larger than that of Clone DN, but stem volume growth was independent of irrigation in excess of 46 cm year(-1) in both clones. During the third growing season, stem volume growth of both clones was limited by both the 46- and 76-cm irrigation treatments, so that by the end of the third growing season trees in the 46-cm irrigation treatment were only half the size of trees in the 137-cm irrigation treatment. These treatment differences were maintained through the fifth growing season. Although stem volumes of Clone TD trees in the 76- and 137-cm irrigation treatments were larger than the corresponding values for Clone DN trees at the end of the third growing season (1994), these clonal differences gradually decreased in subsequent years and were not detectable after 5 years, because stem volume relative growth rate of Clone DN was greater than that of Clone TD in all treatments. Although both clones exhibited similar predawn leaf water potentials, Clone DN typically maintained higher midday leaf water potentials, suggesting better stomatal control of water loss. Clonal and treatment differences in osmotic potential at full turgor were minimal and could not explain the clonal differences in drought resistance. Root density and root density to stem volume ratio increased more in response to moderate drought in Clone DN than in Clone TD, resulting in enhanced drought resistance (high stem volume growth rate under moderate drought conditions) and an increased capacity to withdraw water from the soil. We conclude that the greater drought resistance of Clone DN compared with Clone TD was the result of the maintenance of a more favorable water balance by stomatal regulation and greater carbon allocation to roots during the early stages of drought. However, the low root density to stem volume ratio in Clone DN growing in the 46-cm irrigation treatment suggests that severe water limitation restricted the preferential allocation of carbon to belowground tissues, so that both root and shoot growth were constrained by severe drought.     

Solute accumulation of chestnut oak and dogwood leaves in response to throughfall manipulation of an upland oak forest

To determine the biochemical basis of osmotic adjustment, seasonal and treatment differences in foliar water- soluble organic solutes and inorganic ions were investigated for two hardwood species that exhibited osmotic adjustment in a Throughfall Displacement Experiment at the Walker Branch Watershed near Oak Ridge, Tennessee. Leaf samples of overstory and understory chestnut oak (Quercus prinus L.) and understory dogwood (Cornus florida L.) were collected during the 1994 (wet) and 1995 (dry) growing seasons from each of three treatments: dry (-33% throughfall), ambient (control) and wet (+33% throughfall). Foliar soluble carbohydrates and organic acids were measured by gas chromatography-mass spectrometry. During May 1994, when the demand for sucrose was greatest, dogwood accumulated small amounts of glucose, quinic acid and Mg2+, offsetting a decline in nitrate concentration. As the mild drought continued and tree growth slowed, there was a significant accumulation of sucrose in dogwood in the dry treatment in June, and a trend toward increased K+. In overstory chestnut oak in the dry treatment over the same period, there were significant accumulations of fructose, glucose and K+, and a trend toward increased quinic acid accumulation. Sucrose did not become a key osmotically active compound in chestnut oak until August 1994. In 1995, with the exception of understory chestnut oak, there was no accumulation of K+ in either species. During the severe drought of 1995, monosaccharides, particularly glucose and fructose, accounted for most of the osmotic adjustment in both species. Among solutes, glucose constituted the largest accumulation in dogwood in the dry treatment in August 1995, followed by fructose and sucrose. There was only a moderate increase in solutes in chestnut oak trees in 1995, with fructose and glucose constituting over 50% of the predicted solute accumulation in July. Both species accumulated a wider array of solutes during the dry year than during the wet year, but treatment differences in solute accumulation in chestnut oak were partially limited by drought. The greater dehydration tolerance of chestnut oak than dogwood was evident in the higher baseline concentrations of organic solutes and the greater array of solutes accumulated in response to drought.     

Influence of rewatering and time of sampling on solute accumulation of two Populus deltoides clones

We investigated effects of rehydration and time of sampling on solute accumulation in plants of two greenhouse-grown Populus deltoides Bartr. clones (Ohio Red and Platte) subjected to multiple cycles of water stress. Osmotic potential of leaves at full turgor was measured at predawn on well-watered (control) and water-stressed (conditioned) plants that had been rewatered the previous afternoon. Water-soluble organic solutes (carbohydrates, phenolic glucosides and organic acids) were determined at both predawn and midday, before and after rewatering. Conditioning resulted in solute accumulation; however, rewatering of conditioned plants decreased the predawn concentration of glucose by 19-35% and the total solute concentration by 14-15%, relative to values before rewatering. There was a 52% increase in salicin concentration in response to rewatering in conditioned plants of the Platte clone. In conditioned plants of both clones, the concentration of glucose was generally lower at midday than at predawn (16-47%), whereas the concentration of sucrose was higher at midday than at predawn (46-133%). Time of sampling was an important factor in determining whether conditioning resulted in accumulation of glucose and fructose. Compared with control plants, there was a significant accumulation of glucose and fructose at predawn and either no accumulation or a significant reduction of these solutes at midday both before and after rewatering of conditioned plants. Sampling time also affected the amount of solute that accumulated in response to conditioning.     

Biomass and soil carbon stocks of Rhamnus prinoides based agroforestry practice with varied density in the drylands of Northern Ethiopia

Agroforestry Systems - Agroforestry plays a significant role in climate change mitigation through improved sequestration and storage of carbon in farmlands. However, quantitative information on...     

Genetic analysis of broad spectrum resistance to potyviruses using doubled haploid lines of pepper (Capsicum annuum L.)

Summary Genetic analysis of resistance to PVY in androgenetic doubled haploid lines, F1, F2 and backcross progenies of the Mexican pepper line, CM 334 (Capsicum annuum L.), was performed. Three reaction types were observed when seedlings were inoculated with several PVY strains of different pathotypes and with an American PeMV strain. Resistant genotypes never showed systemic symptoms although some individuals sporadically developed necrotic local lesions on inoculated cotyledons. Susceptible genotypes exhibited either a typical systemic mosaic or a systemic necrosis that caused the death of the inoculated seedlings. Segregation analyses indicated that resistance to pepper potyviruses in CM 334 is conferred by two genes. The first one, tentatively named Pr4, is dominant and confers the resistance to all now known pathotypes of PVY and to PeMV. The second one, tentatively named pr5, is recessive; it confers only the resistance to common strains of PVY. The systemic necrotic response is conferred by an independent dominant gene, tentatively named Pn1.     

Diversity between some Ethiopian farmer's varieties of barley and within these varieties among seed sources

Barley is one of Ethiopia's major crops. Cultivation is mostly by traditional varieties that are chosen by farmers for their suitability for end-use or their adaptation to specific farming systems. A collection of 155 barley lines was grouped in 13 varieties, according to the name given by the farmers. The collection was evaluated for simple agronomic traits and resistance to barley scald disease. A large level of diversity was found, mainly between varieties, but also within varieties between farms from which the samples originated. In spite of a certain degree of overlapping, these traditional farmer's varieties showed coherence for the characters measured. Earlier maturing varieties were found to be more susceptible to scald, but a number of accessions combined earliness with scald resistance. It is suggested that the traditional variety name be included, next to the physical characters of the collection site, as a parameter to explain the degree of diversity in Ethiopian barley germplasm evaluation. The cultivated area of a number of traditional barley varieties is declining rapidly and special collection missions are needed to preserve this germplasm.