Site-specific Management Approach Research Articles

Identification of functional traits responsible for environmental vulnerability of Cedrus deodara in temperate forests of Western Himalaya

Climate change is impacting forest tree species adversely and making the ecological system vulnerable. The present study attempts to assess the internal vulnerability of Cedrus deodara occurring in nine sub-types of temperate forests in Western Himalaya, India via a plant functional trait-based approach. Internal vulnerability was assessed based on sensitivity and adaptive capacity through proposing an index using IPCC framework. Sensitivity was determined based on various traits (indicators) of light harvesting, carbon assimilation, nutrient content, and water budget, whereas adaptability was defined based on light harvesting efficiency, water use efficiency, resource use efficiency, and nutrient limitation. Sensitivity was maximum in Dry Deodar Forest (0.51) and Low-Level Blue Pine Forest (0.51) and minimum in Western Mixed Coniferous Forest (o.38), however adaptability was maximum in Kharsu Oak Forest (0.65) and Moist Deodar Forest-II (0.65) with minimum adaptability for Ban Oak Forest (0.53). In Ban Oak Forest, Low-Level Blue Pine Forest and Moist Deodar Forest-II high stomatal conductance compensates the low chlorophyll achieving homeostasis state for photosynthesis. Negative minimum temperature (-6.95 to −2.04 °C) in winters followed by high monsoon rainfall (417.74 to 1256.13 mm) causes high sensitivity amongst the C. deodara population in Low Level Blue Pine Forest, Dry Deodar Forest and Moist Deodar Forest-II; and adaptability was majorly affected by water availability i.e., excessive monsoon rainfall in Ban Oak Forest (1962.45 mm) and least rainfall in Neoza Pine Forest (349.50 mm). Overall, the vulnerability was high in Low Level Blue Pine Forest (0.46), Ban Oak Forest (0.45) and Dry Deodar Forest (0.45). Present study identified key traits for species vulnerability therefore management intervention should orient towards those silvicultural operations which may reduce relative water use of the species and may also facilitate for improved photosynthesis i.e., through water provision and density management of the C. deodara dominated forests in Himalayan region. The study concludes that a unified approach for managing species of the forest may be disadvantageous and detrimental to forest conservation. Rather site-specific management approach, which led to incremental response to the identified traits may support the conservation of species.

Impacts of varying precipitation regimes upon the structure, spatial patterns, and productivity of Nothofagus pumilio-dominated old-growth forests in Patagonia

Climate is a critical variable in determining the productivity and structural complexity of forest ecosystems. Under similar temperature regimes and other site conditions, precipitation becomes fundamental for forest regeneration and growth, and eventually for the development of structural complexity and patterns in forest productivity. Empirical quantification for this expected response to varying precipitation is needed, especially to provide conservation and management strategies under current and future climate change impacts. To address this need, we evaluated the effects of varying annual precipitation regimes (dry, mesic, and humid sites; all with similar temperature regimes) on three key forest attributes and processes; 1) size and age structure, 2) tree spatial point patterns, and 3) forest stand productivity based on the normalized difference vegetation index (NDVI), in three old-growth lenga (Nothofagus pumilio) forests in western Patagonia. Tree-size and age structure were irregular in the humid and mesic sites, and regular (unimodal) in the dry site (based on Weibull probability function). The relationship between tree diameter and age was strongest in the humid site (r2 = 0.86), and weakest in the dry site (r2 = 0.36). Forest stand productivity was significantly higher in the humid site (mean NDVI = 0.73, vs. 0.68 and 0.63 in the mesic and dry sites, respectively). Univariate spatial-point patterns showed that the humid site had the strongest clumped pattern for live trees along all distances analyzed (i.e., 20 m), while the dry site had a fully random pattern for live and dead trees along all distances analyzed. Collectively, these results illustrate different challenges for silviculture in these forests: 1) The multi-aged structure, plus clumped spatial patterns of small trees (following partial overstory disturbance) in the humid and mesic sites, reflect a gap-based regeneration mode, which consequently suggests the feasibility of implementing uneven-aged silviculture in these sites; 2) Dry sites, close to the forest-steppe ecotone (dry, cool and windy) may require a focus on silviculture for adaptation to cope with expected declines in precipitation and to potentially avoid the loss of these ecosystems to woodlands; 3) Dieback of larger trees in mesic sites (presumably due to xylem cavitation) is a reflection of climate change impacts and a warning to implement strategies that may adapt these forests to new climate conditions (transition to dry condition). Consideration of the great variation in structure and productivity in Patagonian lenga forests due to differences in precipitation regimes, is urgently needed to guide the development of site-specific management approaches for this forest type, particularly given expected future declines in precipitation.

Management of Nuisance Geese on School Properties and Public Spaces

Abstract Conflicts with Canada geese (Branta canadensis) (Linnaeus, 1758, Anseriformes, Anatidae) have increased during the past three decades. Goose conflicts included feces on turf areas and paved surfaces, slippage on athletic fields and playing surfaces, overgrazing of turfgrass, and noise or aggression near nesting sites. Geese also negatively impacted community relations putting stakeholders at odds with each other. Geese using school grounds, local parks, golf courses, and other public properties require site-specific management approaches because these birds often use several properties, and effective management necessitates a community-wide approach. Our case study illustrated that management options to reduce goose conflicts must be customized to the resources and time that staff managing school grounds have available, and there is no one approach that will work in most situations.

Site-specific management of salt affected soils: A case study from Egypt

In Egypt all agricultural practices are generally applied uniformly without taking spatial variability into consideration, which is not efficient and may be more expensive than site-specific management approach. This is based on accurate assessment of within-field variation and on field delineation into homogeneous zones to be submitted to differential management. Multivariate geostatistics allows to assess and model the spatial variation of a set of soil attributes influencing management. The objective of this paper was to propose an approach for determining spatially variable rate application (VRA) of leaching water, to control soil salinity, and of fertilizer to improve productivity while reducing environmental impact. The research was conducted in an experimental 3.1-ha field in Egypt and the following soil attributes were measured: electrical conductivity (ECe), available nitrogen (N), available phosphorus (P), available potassium (K) and organic matter content (OM). Ordinary cokriging was applied to produce thematic maps of soil attributes and the appropriateness of the linear model of coregionalization was evaluated with cross-validation. Spatial maps of the five soil variables were classified into three isofrequencies classes and the mean values were calculated for each class. These values were then compared with critical reference values to assess the local soil requirements for reducing soil salinity and/or improving soil fertility. The results showed that the estimations of soil attributes were unbiased and accurate. Only for ECe and available nitrogen site-specific management would be preferable because it would reduce the agricultural costs for both soil reclamation (saving water used to leach salts) and improvement of soil N fertility in comparison with the traditional uniform methods.The proposed approach, though producing encouraging results, would require improvements in the determination of the threshold values used to plan salt leaching and soil fertilization.

Spray droplet size and carrier volume effect on dicamba and glufosinate efficacy.

Pesticide applications using a specific droplet size and carrier volume could maximize herbicide efficacy while mitigating particle drift in a precise and efficient manner. The objectives of this study were to investigate the influence of spray droplet size and carrier volume on dicamba and glufosinate efficacy, and to determine the plausibility of droplet-size based site-specific weed management strategies. Generally, across herbicides and carrier volumes, as droplet size increased, weed control decreased. Increased carrier volume (187 L ha-1 ) buffered this droplet size effect, thus greater droplet sizes could be used to mitigate drift potential while maintaining sufficient levels of weed control. To mitigate drift potential and achieve satisfactory weed control (≥ 90% of maximum observed control), a 900 µm (Ultra Coarse) droplet size paired with 187 L ha-1 carrier volume is recommended for dicamba applications and a 605 µm (Extremely Coarse) droplet size across carrier volumes is recommended for glufosinate applications. Although general droplet size recommendations were created, optimum droplet sizes for weed control varied significantly across site-years. Convoluted interactions occur between droplet size, carrier volume, and other application parameters. Recommendations for optimizing herbicide applications based on droplet size should be based on a site-specific management approach to better account for these interactions. © 2018 Society of Chemical Industry.

Bioinoculants from-Azospirillum brasilense (Dobereiner, 1978), Bacillus megaterium (Ehrenberg, 1835) var. phosphaticum and Pseudomonas fluorescens (Migula, 1895) and its storability

Use of carrier based inoculum for crop growth and yield is wide practice among the conventional agriculture. Precision farming is a site specific management approach. Carrier based inoculum is not suitable for precision farming system due to clogging effect. Hence, liquid bioinoculant's was prepared using N fixer (Azospirillum brasilense), P solubilizer (Bacillus megaterium var. phosphaticum) and PGPR (Pseudomonas fluorescens). The results of the experiment convey that the inoculants supplemented with 10mM of phosphate buffer (pH 7) + 10% glycerol supported maximum survival of Azospirillum (0.17 x 1019 MPN/mL), Bacillus (25 x 1019 cfu/mL) and Pseudomonas (21 x 1019 cfu/mL) at room temperature.

PREDICTING THE VARIABILITY OF COPPER AND ZINC IN LEAF AND SOIL OF OIL PALM PLANTED ON A 12 HA LAND USING GEOSPATIAL INFORMATION SYSTEM TECHNOLOGY

Oil palm (Elaeis guineensis) is an important economic tree crops in the tropic. However, more than 95 % of oil palms grown in Southeast Asia are on acid, low fertility and highly weathered soils. Optimum value of micronutrients in the soil was required to enhance the efficiency of use of macro-nutrients. Hence, to observe and predict the fertility status of the oil palm plantation area, a 12 hectare study site was used and a total of 60 geo-referenced soil and leaf samples were collected for determinations of pH and selected micronutrients of Cu and Zn content. The data were explored and mapped using geostatistic and Geographic Information System (GIS). The study area had acidic type of soil with pH ranged from 3.25-5.85. The analysis showed that almost 78% of the study area had high content of Cu in soil, while another 22% of area was low to moderate in Cu. However, Cu content in leaf were categorized as insufficient as 100% of the area was observed to have Cu less than 3 ppm. About 80% of the study area showed a low to moderate content of Zn in soil, while another 20% of area showed a high content of Zn. Zinc content in leaf ranged from optimum to high categories. However, this value did not reach the excess level of Zn (50 ppm). These results suggest that, this plantation area need a site specific management approach in order to increase its crop productivity in regards to nutrient management. As a preliminary recommendation, a zone management practice would be applied in future as it is beneficial in term of protecting the environment from excessive fertilizer.

Data fusion techniques for delineation of site-specific management zones in a field in UK

Fusion of different data layers, such as data from soil analysis and proximal soil sensing, is essential to improve assessment of spatial variation in soil and yield. On-line visible and near infrared (Vis–NIR) spectroscopy have been proved to provide high resolution information about spatial variability of key soil properties. Multivariate geostatistics tools were successfully implemented for the delineation of management zones (MZs) for precision application of crop inputs. This research was conducted in a 18 ha field to delineate MZs, using a multi-source data set, which consisted of eight laboratory measured soil variables (pH, available phosphorus (P), cation exchange capacity, total nitrogen (TN), total carbon (TC), exchangeable potassium (K), sand, silt) and four on-line collected Vis–NIR spectra-based predicted soil variables (pH, P, K and moisture content). The latter set of data was predicted using the partial least squares regression (PLSR) technique. The quality of the calibration models was evaluated by cross-validation. Multi-collocated cokriging was applied to the soil and spectral data set to produce thematic spatial maps, whereas multi-collocated factor cokriging was applied to delineate MZ. The Vis–NIR predicted K was chosen as the exhaustive variable, because it was the most correlated with the soil variables. A yield map of barley was interpolated by means of the inverse distance weighting method and was then classified into 3 iso-frequency classes (low, medium and high). To assess the productivity potential of the different zones of the field, spatial association between MZs and yield classes was calculated. Results showed that the prediction performance of PLSR calibration models for pH, P, MC and K were of excellent to moderate quality. The geostatistical model revealed good performance. The estimates of the first regionalised factor produced three MZs of equal size in the studied field. The loading coefficients for TC, pH and TN of the first factor were highest and positive. This means that the first factor can be assumed as a synthetic indicator of soil fertility. The overall spatial association between the yield classes and MZs was about 40 %, which reveals that more than 50 % of the yield variation can be attributed to more dynamic factors than soil parameters, such as agro-meteorological conditions, plant diseases and nutrition stresses. Nevertheless, multivariate geostatistics proved to be an effective approach for site-specific management of agricultural fields.

A method to generate and use as-applied surfaces to evaluate variable-rate fertilizer applications

Variable-rate technology (VRT) has been used by farmers in an attempt to better match inputs to local growing conditions. In theory, VRT minimizes over- and under-application of inputs. However, the limitations and errors of this technology have not been well documented. Further, standard methods for quantifying the application accuracy using VRT do not currently exist, limiting practitioners’ knowledge on performance. Therefore, a spatial data model was developed to generate “as-applied” surfaces as a means to evaluate VRT performance of two applicators. The spatial data model uses geographic information system functionality to merge applicator descriptive patterns with a field application file to generate an ‘as-applied’ surface map representing not only the actual deposition of granular fertilizer but more importantly spatial distribution. Field data were collected and used to validate the spatial model. Comparisons between the actual and predicted application rates indicated moderate to good correlations (0.62 < R < 0.88) for two applicators. Longitudinal offset such as for a global positioning system receiver impacted model performance for one applicator but not the other. A comparison of the actual application rates to the prescription maps illustrated the inconsistency of VRT performance to deliver target rates. Both applicators were only within 10 % of the target rates a small percentage of time (<45 %) during field operation. Generated as-applied surface maps highlighted errors associated with VRT along with limitations of the technology within site-specific management (SSM). Thus, as-applied surface maps provide a means to properly evaluate VRT while enhancing researchers’ and practitioners’ abilities to compare and customize SSM approaches.

Forest management, restoration, and designer ecosystems: Integrating strategies for a crowded planet

As the global human population increases, the demand to conserve, restore, create, and sustainably manage ecosystems will increase as well. Forested ecosystems are of particular interest because of the biodiversity they support and their diverse values to people. Developments in conservation, restoration forestry, and in the study of designer ecosystems provide a diverse set of tools with which to pursue sustainable forestry goals. Nonetheless, we suggest that sustainable forestry can only be achieved by fully considering ecological, economic, and social needs in landscapes. This will require a clear realization of the trade-offs in site-specific management approaches and a multifaceted, landscape-scale perspective for evaluation of sustainability criteria. We propose collaborative creation of Sustainable Forestry Portfolios as a means to encourage the breadth of thinking required to guide sustainable forest management. We discuss 3 examples of Sustainable Forestry Portfolios with relevance to different settings in the future: 1) the Triad Approach, 2) Forest Landscape Restoration, and 3) Urban Forestry. In all settings, sustainable forestry is not solely a technical problem, but a challenge that must be met through a multidimensional perspective, interdisciplinary collaboration, and with active engagement of the people that live and work in the landscape.

Spatial Analysis of Maize Response to Nitrogen Fertilizer in Central New York

An increasing number of farmers are considering the use of site-specific nitrogen (N) applications to maize (Zea mays L.) as a way of maximizing yield potential while minimizing fertilizer cost. The objectives of this 3-years experiment were to evaluate the spatial structure of yield response to N fertilizer and investigate the potential for site-specific N management under maize production in New York. Four experimental N rates (50, 110, 160, or 220 kg ha∧1), two tillage systems (chisel till and zone-till) and two crop rotations (maize•maize and maize•soybean (Glycine max L.)) were superimposed over a 12 ha field in central New York State with a complex of Honeoye-Lima, Kendaia, and Lima soils ranging from moderately well to poorly drained soils. Pre-sidedress soil nitrate tests (PSNT) showed significant spatial structure but did not conform to that for crop N response, indicating that N fertilizer recommendations based on PSNT results cannot be simply applied in a site-specific management approach. Optimal N rate varied from 110 kg ha ∧1 for the dry years 1999 and 2000 to 220 kg ha∧1 for 1998, with a warm wet spring. Tillage treatments were generally comparable in N response. Spatial yield response analysis showed limited field-scale regionalization of both yield and profit response to N, suggesting that site-specific application of nitrogen is impractical. The greatest source of variability in N requirements was observed with the annual effects of weather, and presents a greater potential for precise N application than site-specific application. Annual variations in optimum N rate were not related to annual yield differences and yield potential itself does not appear to be a good predictor of N needs.