Soil Fertility Patterns Research Articles

Spatial Pattern of Soil Fertility and its Influencing Factors in Longquan Mountain Urban Forest Park, Chengdu City

Exploring the spatial pattern and impact factors of soil fertility in Longquan Mountain Urban Forest Park can better guide the planning and management of the park, and provide scientific basis for ecological restoration and landscape configuration in this area. In this study, the spatial pattern of soil fertility in Longquan Mountain Urban Forest Park and its influencing factors were investigated and analyzed by sampling grid distribution points and combining the modified Nemerow formula as a quantitative calculation model of soil fertility. Our results were as follows: (1) The average content of available P was at the first level of the soil nutrient classification standard in the second national soil survey of China, while the average content of available K reached the forth level. The average content of soil organic matter and alkali-hydrolyzable nitrogen were both at the fifth level. (2) From the spatial pattern, the regions with good soil fertility were mainly distributed in the north of the study area, while that the poor soil fertility was mainly distributed in the central and southern part of the park. (3) The order of the soil comprehensive fertility index of different topography and land use types was plain > hill > low mountain, flat slope > gentle slope>slope > steep slope; for slope, the order was northwest > west > east > south > north > southwest > northwest > no slope direction > southeast; for slope position, the order was lower > middle=upper > valley department > the ground > the back; for land uses pattern, the order was cultivated land > orchard > bamboo land > mixed forest > pure forest > abandoned land > homestead land. Based on the soil comprehensive soil fertility status of Longquan Mountain Urban Forest Park, the areas with the soil fertility index of “good” should be protected, the areas with the soil fertility index of “medium” should be monitored and the natural restoration ability should be improved, the areas with the soil fertility index of “poor” should be mightily improved.

High C-and N-based soil fertility and microbial associations sustain the plant biodiversity of the campo rupestre in Brazil

The campo rupestre vegetation in the Serra do Rola Moça State Park (PESRM) grows on ironstone outcrops, forming vegetation islands where plant species establish belowground interactions. This area is circumscribed by several mining companies and, for mined land rehabilitation purpose, we assessed plant species composition, plat-microbial associations, and soil fertility patterns in a preserved campo rupestre. Aside from high plant biodiversity, we found elevated soil fertility in relation to soil CEC (~18 cmol/dm3), organic matter (~115 g/Kg), soil C (~ 53.3 g/Kg), humic (~12.5 g/Kg) and fulvic (~8.9 g/Kg) acids, soil N (~4 g/kg) and a low C:N ratio (~12). The overall nutrient levels were higher than or comparable to those of other preserved sites in Brazil. The prevalent legume Mimosa calodendron, hosting N-fixing and plant growth-promoting bacteria in its nodules, was considered an N source to the soil, as evidenced by the elevated leaf N content and the greater depletion of leaf δ15N compared to other families. However, leaf N was parsimoniously distributed among biogeochemical islands and within different plant species and families, which was attributed to a common mycorrhizal network (CMN) formed by arbuscular (AMF) and orchid mycorrhizal fungi (OMF), suggested by general root mycorrhizal colonisation and soil phospholipid fatty acid (PLFA) analyses. We revealed that a high C- and N-based soil fertility constitutes a natural pattern of fertility, which is maintained by below-ground associations and is sufficient to sustain plant biodiversity. For rehabilitation purposes, this natural soil fertility of preserved sites should be maintained by integrating the biogeochemical relations involving plant communities and microbial associations.

Which factor determines the spatial variance of soil fertility on uninhabited islands?

Uninhabited islands serve as a natural and unique laboratory for the study of soil fertility under varying natural conditions and potential anthropogenic influences, and how the soil fertility spatially varies and which factor determines the spatial variance remain to be studied. In this study, a total of 15 uninhabited islands in Miaodao Archipelago, a typical archipelago in northern China, were selected to demonstrate the study. The soil fertility was represented by seven soil factors and a composite index, namely, soil fertility indicator (SFI). Different environmental factors that covered natural and anthropogenic aspects were identified at island and local scales, and the spatial pattern of soil fertility responding to the environmental factors was analyzed. Then, the influences of different environmental factors on the spatial variances of soil fertility at the dual scales were quantified. Results revealed that the soils in the study area had considerably higher values of total carbon, total nitrogen, organic matter, available phosphorus, and available potassium compared with the soils on other China’s islands, the recognized standards, and the national and regional mean values, indicating the extremely high fertility. Great spatial differences in the soil fertility were observed among different islands and sampling sites. At island scale, the island isolation, which was represented by the distance to the inhabited islands and the mainland (DTI), determined the spatial variance of soil fertility. The SFI distinctly increased with the increase in DTI, which could be explained partly by the isolation from human activities and the vegetation condition at island scale, and partly by the cross-scale influence from altitude (Al). At local scale, Shannon-Wiener index (H’), Al, slope (Sl), and distance to the shoreline (DTS) showed clear positive correlations with SFI. The Al and DTS determined the spatial variance of soil fertility under the cross-scale influences from island area and DTI, while H’ and Sl didn’t involve cross-scale influences.

Soil properties and understory herbaceous biomass in forests of three species of Quercus in Northeast Portugal

Aim of study: This paper aims to characterize some soil properties within the first 25 cm of the soil profile and the herbaceous biomass in Quercus forests, and the possible relationships between soil properties and understory standing biomass.Area of study: Three monoespecific Quercus forests (Q. suber L., Q. ilex subsp. rotundifolia Lam. and Q. pyrenaica Willd) in NE Portugal.Material and methods: During 1999 and 2000 soil properties (pH-KCl, total soil nitrogen (N), soil organic carbon (SOC), C/N ratio, available phosphorus (P), and available potassium (K)) and herbaceous biomass production of three forest types: Quercus suber L., Quercus ilex subsp. rotundifolia Lam. and Quercus pyrenaica Willd were studied.Main results: The results showed a different pattern of soil fertility (N, SOC, P, K) in Quercus forests in NE of Portugal. The C/N ratio and the herbaceous biomass confirmed this pattern. Research highlights: There is a pattern of Quercus sp. distribution that correlates with different soil characteristics by soil characteristics in NE Portugal. Q. pyrenaica ecosystems were found in more favoured areas (mesic conditions); Q. rotundifolia developed in nutrient-poor soils (oligotrophic conditions); and Q. suber were found in intermediate zones.Keywords: fertility; biomass; C/N ratio; cork oak; holm oak; pyrenean oak.

Land-use legacies: multi-centuries years-old management control of between-stands variability at the landscape scale in Mediterranean mountain forests, France

Traditional land use has shaped the Mediterranean region for a long time and has resulted in present-day complex landscapes. The land abandonment dating from the 19<sup>th</sup> century at a site located in the southwestern Alps (France) makes it possible to analyse how present-day forest stands inherit from past land uses. Tree composition and tree age structure were analysed in three stands resulting from different former land uses, i.e. ancient coppice, formerly grazed area and formerly tilled area. The ancient coppice contains the densest tree cover and is dominated by Fagus sylvatica, whereas the formerly ploughed and  grazed areas are less dense, both dominated by Pinus sylvestris. Forest stand in the ancient coppice is older than in the formerly grazed area, and forest stand is the youngest in the formerly ploughed area. These stand differences are largely explained by former land use and the abandonment process. Albeit strong changes result from the land abandonment, these landscapes inherit aspects of their land use during the 19<sup>th</sup>century at least and the dynamics does not match the expected pattern of soil fertility.  

Precipitation, soils, NPP, and biodiversity: resurrection of Albrecht's curve

Climate and soils are widely recognized as major drivers of virtually all properties of ecosystems and communities. However, despite major advances in the understanding of soil formation and ecosystem dynamics, the effects of climate on soil properties are not widely appreciated. Understanding the effects of water availability on the rates of chemical and biological processes that affect soil formation can help clarify the global patterns of soil fertility, which affect agricultural and forest productivity, as well as biodiversity. Empirical tests of Albrecht's conceptual model of soil development and degradation using global climate and soil data sets and soil chronosequences confirm that soil total exchangeable bases (TEB), phosphorus, nitrogen, and other components of soil fertility, along with plant productivity generally decline on older soils and under wetter conditions as precipitation exceeds potential evapotranspiration. The basic pattern of soil fertility in relation to water availability is a unimodal curve, with a maximum near or below a water balance of zero (annual precipitation minus annual potential evapotranspiration). Analysis of global data by subregions reveals significant differences between temperate and tropical soil fertility distributions, as well as significant differences between continents. The low levels of soil nutrients (e.g., TEB, P, N) and plant productivity found on ancient soils or highly weathered soils in regions with high precipitation suggest that the positive effects of low productivity on plant diversity that have been observed at local and regional scales may also occur at the global scale.

INVESTIGATING COMPONENT SPECIES PROPORTIONS IN A CEREAL-LEGUME COVER CROP MIXTURE UNDER ORGANIC MANAGEMENT

ISHS XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Organic Horticulture: Productivity and Sustainability INVESTIGATING COMPONENT SPECIES PROPORTIONS IN A CEREAL-LEGUME COVER CROP MIXTURE UNDER ORGANIC MANAGEMENT

A STUDY OF USING QUEFTS MODEL FOR ESTABLISHING SITE SPECIFIC FERTILIZER RECOMMENDATION IN MAIZE ON THE BASIS OF FARMER FIELDS

Nutrient Use Efficiency (NUE) of Maize is considered low. There are two important factors responsible for this condition: (a) uniform fertilizer recommendation, (b) lack of consideration on soil variability, Indigenous Nutrient Supply and plant nutrient needs. A method for studying low NUE and the capability of studying these two factors are urgently required. This study used Quantitative Evaluation of Fertility on Tropical Soils (QUEFTS) model. The main aim of this study was to employ and evaluate QUEFTS model for establishing site specific fertilizer recommendation in maize on the basis of farmer fields. Due to a unique characteristic of farmer field, it may be interesting to observe the pattern of soil fertility in relation to yields. Six farmer's fields and thirty soil samples were taken and analysed in the laboratory. The results showed that QUEFTS model was a valuable tool to make fertilizer recommendation by using yields as an integrated indicator. The results also showed that QUEFTS model was a promising method for establishing fertilizer recommendation for maize. The merits of model for determining Indigenous Nutrient Supply, nutrient yield limiting factors, balanced fertilizer recommendation show that QUEFTS model is a valuable tool for site specific fertilizer recommendation. Keywords : QUEFTS, recommendation, site specific, yield

Nutrient Flows in Perennial Crop-Based Farming Systems in the Humid Forests of Cameroon

A study was conducted in some perennial crop-based farms in the humid forests of South West Cameroon, to better understand their soil fertility patterns and management and identify factors that contribute most to nutrient depletion trends in such multi-storey farmholdings. The main perennial crops were the para rubber tree (Hevea brasiliensis), cocoa (Theobroma cacao) and oil palm (Eleais guineensis) whose ages ranged from immature to very old (senescence). Data were collected over a two-year period (2007 and 2008) and modelled using the farm NUTrient MONitoring (NUTMON) tool. Results showed that the farming systems played key roles in the overall exploitation strategies. Plantain and cassava (annual crops) and cocoa (perennial) were the most associated crops, accounting for more than half of intercropped frequencies. Whereas nutrient flows within and between farm units were confirmed, the net loss in soil N, P and K nutrient balances differed with the main perennial crop - being highest for the oil palm and lowest for the rubber tree. The average nutrient balance of each farm was markedly negative for N but positive for P and K. Partial nutrient balance (ignoring biophysical flows like N-fixation, leaching and erosion) was positive for the three nutrients indicating therefore that the biophysical flows accounted more for N depletion. Nitrogen loss was mainly due to, leaching (~70%), volatilization (~20%), and exported crops and their residues.

Landscape dysfunction and reduced spatial heterogeneity in soil resources and fertility in semi‐arid succulent thicket, South Africa

Abstract Succulent thicket in the Eastern Cape of South Africa is one of many rangeland ecosystems in the world that displays evidence of unsustainable grazing pressure. Widespread transformation of succulent thicket has resulted in the replacement of the typical two‐phase perennial vegetation patches with a structurally simple field layer of ephemeral and weakly perennial grasses and forbs. We hypothesized that (i) transformation of succulent thicket leads to a switch from a spatially heterogeneous landscape to a homogenous and relatively infertile state; and (ii) that this loss of fertility is associated with a breakdown in the processes that conserve resources and promote water use efficiency. We tested these hypotheses at five fenceline contrast sites in Sundays River Thicket, an arid form of succulent thicket. We compared soil fertility (organic carbon, available nitrogen and phosphorus), texture, matric potential, and surface microtopography in the two main microhabitats on either side of the fencelines using a nested anova. Our results show that intact Sundays River thicket has a distinct spatial pattern of soil fertility where nutrients and organic carbon are concentrated under the patches of perennial shrubs, compared with under canopy trees. Transformation results in a significant homogenization of this pattern and an overall reduction in the fertility of the landscape. The proportion of the landscape surface that promotes infiltration due to a distinct litter layer decreases from 60% to 0.6%. Soil moisture retention (matric potential) also decreases with transformation. We interpret these patterns within the framework of semi‐arid landscape functionality.

Comparison of wheat yield under uniform and variable rates of fertilizer on spatially‐eroded land

Field studies were made to determine the yield and quality of wheat at different landscape positions managed with uniform vs. variable rates of nitrogen (N). A moderately‐eroded wheat farm near Thana (Swat) was divided into four parallel transects which were further divided into two strips each. On one strip, fertilizer was applied at a uniform rate of 120 kg N ha‐1, and along the other strip, three different rates of N (80, 110, and 125 kg N ha‐1) were applied to match the crop productivity patterns. A basal dose of 90 kg P2O5 and 60 kg K2O ha‐1 was applied to the whole field. Soil profiles were described for the three different zones, i.e., low, medium, and high productivity zones. Soil in Zone I was Pirsabak, moderately deep variant, and in Zones II and III, Badwan soil series. Although uniformly fertilized strip (120 kg N ha‐1) received 40 and 10 kg N ha1 more than Zone I and Zone II (variable management strategy), there were no significant differences in yield. The differences in three fertilizer management zones were due to differences in moisture content at sowing, infiltration rate, lime content, steepness, and soil depth. Test weight of wheat grains was not significantly affected. Protein content of wheat was significantly higher in variably fertilized strips than in uniformly treated strips. Based on these results, it is suggested that farms with spatially‐variable soils should be fertilized according to the crop productivity and soil fertility patterns.

Sandstone vegetation pattern in the Jim Jim Falls region, Northern Territory, Australia

AbstractAnalysis of 58 floristic quadrats from two areas near Jim Jim Falls on the Arnhem Land Plateau revealed seven plant communities: wetland; monsoon forest; Allosyncarpia forest; broadleaf woodland; shrubby Eucalyptus woodland; Eucalyptus arnhemensis woodland; and sandstone scrub. The communities inter‐grade with each other and form a complex mosaic. The patterning of vegetation is related to topography, rockiness, degree of fire protection and moisture supply. Surface soil nutrient concentrations were similar in all the communities with the exception of the monsoon forest which was substantially more fertile. We suggest that moisture supply is the primary determinant of vegetation and soil fertility patterns. Fire in the preceding dry season stimulated some herbaceous species, while a long unburnt shrubby Eucalyptus woodland was invaded by some monsoon forest seedlings. Conservation of the present mosaic of vegetation presents a major challenge to land managers because of this variable impact of fire.

The Distribution of Evergreen and Deciduous Trees Relative to Soil Type: An Example from the Sierra Madre, Mexico, and a General Model

An example of the association of evergreen plants with nutrient—poor soils is described from the Sierra Occidental of northwestern Mexico. At elevations from 600 to 1100 m in this mountain range, distinct patches of evergreen—oak woodland are surrounded by subtropical deciduous forest in a mosaic pattern. To quantify the vegetation pattern and examine its environmental basis, vegetation and soil samples were taken throughout the elevational range of the mosaic. Analysis of the samples indicated that the patches of evergreen vegetation occur on extremely acid, infertile soils (derived from hydrothermally altered rock), while deciduous vegetation dominates on less acid, more fertile soil (derived from unaltered volcanic rock). The two community types have very little floristic overlap, and the deciduous forest has much higher density of woody plants and greater species richness. The actual location of boundaries between patches of the two community types can be more abrupt than can be accounted for by soil change. At higher elevations (above 1100 m) evergreen woodland is not restricted to acid soils and occurs on all soil types. These data are discussed in terms of a general model to account for the association of evergreen plants with nutrient—poor soils in the Sierra Madre as well as in other areas with similar growth form soil fertility patterns. I propose that evergreen plants would grow and survive at least as well on fertile soils as on infertile soils in isolation, but are unable to establish in dense, productive vegetation because of low growth rates associated with high carbon costs and low photosynthetic rates of evergreen leaves.

Regional soil fertility patterns in wheatgrowing areas of Victoria

Soil fertility patterns in the wheatgrowing areas of Victoria were examined. The three major patterns identified from the protein content of wheat delivered to 113 silos over the period 1946-74 showed a marked regional grouping encompassing the Wimmera (type 3), Western Mallee (type 2) and the Eastern Mallee, Northern and North-East Districts (type 1). Using 107 P x N wheat fertilizer experiments, four major patterns were identified. Only one of these (low P, nil N yield response) showed any regional grouping (with the Wimmera region); the other three (moderate P, moderate N; high P, small N ; and high P, nil N yield responses) occurred at random throughout the wheat belt. Possible reasons for these patterns and their implications are discussed.