Peeyush Soni

Spatial assessment of climate change effects on crop suitability for major plantation crops in Sri Lanka

Climate change is the main global challenge of this century; it is therefore imperative to identify its effects on agriculture in developing countries. This research makes spatial assessment of climate change effect on major plantation crops in Sri Lanka, with emphasis on crop suitability of tea, rubber, and coconut. Geo-referenced maps of spatial and temporal changes in crop suitability and production potentials are generated and compared. Data pertaining to six agro-ecological zones under the study area are analyzed for a period of 1980–2007. Crop suitability maps are generated amalgamating yield maps and climatic factors maps using AHP in multi-criteria analysis under two time frames of 1980–1992 and 1993–2007. Percent change in crop suitability and crop yield classes is calculated based on five crop suitability and five crop yield classes during two time frames. Dynamics of climatic parameters and crop yield are recognized using geo-referenced maps. The suitability maps of the two time frames are compared to identify the changes with each crop in conjunction with changes in the prevailing climate and yield. Geographic shift of suitability, yield, and climate classes are examined. Net gain or loss in crop production is quantified. Long-term annual rainfall significantly decreased in mid-country wet zone, whereas the mean temperature of the study area increased by 1.4°C. Results clearly showed that the climate and yield can be meaningfully related to the crop suitability and management.

Automatic Non-destructive Quality Inspection System for Oil Palm Fruits

Abstract In this research a non-destructive, rapid and cost effective examination machine for the estimation of the ripeness fraction, oil content and free fatty acid level in oil palm fresh fruits bunch was developed. The automatic machine-vision based inspection system provided consistency, rapid estimation and acceptable accuracy results in non-destructive manner. Fresh fruits bunch samples from Tenera cultivar (7 to 20 years trees) were taken from Cimulang plantation, Bogor, Indonesia. Two statistical analysis methods were used: a forward stepwise multiple linear regression analysis and a multilayer-perceptron artificial neural network analysis. The best prediction of ripeness and oil content models were obtained using the latter method, while the best free fatty acid prediction model was developed by the first method. The models were then employed in the machine-vision inspection systems of the machine. The system best prediction accuracy of ripeness, oil content and free fatty acid models was 93.5, 96.41, and 89.32%, with standard error of prediction being 0.065, 0.044 and 0.068, respectively. The system was tested through a series of field tests, and successfully examined more than 12 t of fruits bunch per hour, without causing damage.

Changes in Climate Extremes over North Thailand, 1960–2099

This study analyzes 24 climate extreme indices over North Thailand using observed data for daily maximum and minimum temperatures and total daily rainfall for the 1960–2010 period, and HadCM3 Global Climate Model (GCM) and PRECIS Regional Climate Model simulated data for the 1960–2100 period. A statistical downscaling tool is employed to downscale GCM outputs. Variations in and trends of historical and future climates are identified using the nonparametric Mann-Kendall trend test and Sen’s slope. Temperature extreme indices showed a significant rising trend during the observed period and are expected to increase significantly with an increase in summer days and tropical nights in the future. A notable decline in the number of cool days and nights is also expected in the study area while the number of warm days and nights is expected to increase. There was an insignificant decrease in total annual rainfall, number of days with rainfall more than 10 and 20 mm. However, the annual rainfall is projected to increase by 9.65% in the future 2011–2099 period compared to the observed 1960–2010 period.

Temporal climate trend of Ping Basin of Thailand and implications for Mekong Region

The Ping Basin is the major basin in Northern Thailand with drainage area of 35,000 km 2 . Climate trend of Ping Basin for current period (1961-2010) and projected trend (2011-2059) are discussed for maximum and minimum temperature and precipitation. Current trend was analyzed from actual representative three stations data and averaging at basin level. Measures of the variability analysis included temporal variability, trend, anomaly, coefficient of variation (C.V) and index. The basin showed high temporal climate variability throughout the study period (1961-2059). The current period showed significant positive trend of minimum temperature and negative trend of maximum temperature while no significant trend in precipitation with high variability, fluctuation and inconsistency. Minimum temperature of Ping increased at a faster rate than that of Thailand. In the first two decades (1961-80), maximum temperature increased by 1.5 ° C and decreased by1 ° C in the later decades (1981-2010) while minimum temperature dropped by 2.3 ° C in the period of 1961-80 and increased by 1.53°C in the years 1981-2010 as compared to the long term 50 years normal temperature of 1961-2010. Intercomparison of 5 GCMs at 50 km spatial scale in projecting future trends indicated that all the five models show similar prediction of future mean temperature while ECHAM5 had the most robust prediction power of rainfall. Projected trend (2011-2059) from ECHAM4 PRECIS RCM debiased, calibrated and validated at finer 20 km spatial scale shows precipitation will increase as compared to current intensity and minimum temperature will significantly increase at a higher rate (R 2=0.76 at the rate of 0.042°C\annum) than maximum temperature (R2=0.5 at the rate of 0.038 ° C\annum). Our findings are consistent with projections for Mekong Basin.

Oil palm pest infestation monitoring and evaluation by helicopter-mounted, low altitude remote sensing platform.

Timely detection of pest or disease infections is extremely important for controlling the spread of disease and preventing crop productivity losses. A specifically designed radio-controlled helicopter mounted low altitude remote sensing (LARS) platform can offer near-real-time results upon user demand. The acquired LARS images were processed to estimate vegetative-indices and thereby detecting upper stem rot (Phellinus Noxius) disease in both young and mature oil palm plants. The indices helped discriminate healthy and infested plants by visualization, analysis and presentation of digital imagery software, which were validated with ground truth data. Good correlations and clear data clusters were obtained in characteristic plots of normalized difference vegetation index (NDVI)LARS and green normalized difference vegetation indexLARS against NDVISpectro and chlorophyll content, by which infested plants were discriminated from healthy plants in both young and mature crops. The chlorophyll content values (μmol m−2) showed notable differences among clusters for healthy young (972 to 1100), for infested young (253 to 400), for healthy mature (1210 to 1500), and for infested mature (440 to 550) oil palm. The correlation coefficients (R2) were in a reasonably acceptable range (0.62 to 0.88). The vegetation indices based on LARS images, provided satisfactory results when compared to other approaches. The developed technology showed promising scope for medium and large plantations.

Influence of Dimensions of UHMW-PE Protuberances on Sliding Resistance and Normal Adhesion of Bangkok Clay Soil to Biomimetic Plates

A number of investigations into application of polymers for macro-morphological modification of tool surface have been carried out. These researches, with extensive stress on convex or domed protuberations as one of the widely used construction units, have tried to harness benefits from using polymers in agriculture. Ultra high molecular weight polyethylene (UHMW-PE) has proved an emerging polymer in its application to reduce soil adhesion. This research was conducted to study the effect of shape (flat, semi-spherical, semi-oblate, semi short-prolate and semi long-prolate) and dimensions (base diameter and dome height) on sliding resistance and normal adhesion of biomimetic plates. To incorporate both shape and size, a dimensionless ratio of height to diameter (HDR) was introduced to characterize the effect of construction unit’s physique. Experiments were conducted in Bangkok clay soil with dry (19.8% d.b.), sticky (36.9% d.b.) and flooded (60.1% d.b.) soil conditions respectively. Soil at sticky limit exhibited the highest sliding resistance (77.8 N) and normal adhesion (3 kPa to 7 kPa), whereas these values were 61.7 N and <0.2 kPa in dry, and 53.7 N and 0.5 kPa to 1.5 kPa in flooded soil conditions. Protuberances with HDR ≤ 0.5 lowered sliding resistance by 10%–30% and the same reduced normal adhesion by 10%–60%. The amount of reduction in both sliding resistance and normal adhesion was higher in flooded soil. Lighter normal loads obviously produced lesser resistance and adhesion.

Performance analysis of different rice-based cropping systems in tropical region of Nepal

Energy inputs, environmental impacts and economic outputs are the main concerns in todays agricultural production systems. The current study investigated the energy, environmental and financial performances of different rice-based cropping systems (CSs). The CSs studied were: Rice-Wheat-Fallow (R-W-F), Rice-Wheat-Maize (R-W-M), Rice-Wheat-Mungbean (R-W-Mu), Rice-Lentil-Maize (R-L-M), Rice-Lentil-Mungbean (R-L-Mu), Rice-Garlic (R-G) and Rice-Onion (R-O). Primary data were collected from 210 randomly selected farms by using structured questionnaire. In this study, Data Envelopment Analysis (DEA) was used to analyze the technical efficiencies of the farms in order to estimate their energy inputs saving potential, under different CSs. Among the studied systems, R-W-M, R-L-M and R-W-Mu were found energy efficient, R-L-Mu, R-W-F and R-W-Mu were efficient considering their greenhouse gas emissions, and R-G, R-O and R-L-M were more profitable systems. Based on the combined energy, environmental and economic criteria, we conclude that R-L-M, R-L-Mu and R-W-M are the most energy, environmentally and economically efficient CSs as compared to other systems in the study. The mean technical efficiency scores of farms indicated a considerable potential of reducing energy inputs (18-34%), without compromising the economic return of the majority farms under different CSs. The results of this study support eco-efficient CSs with modern production technologies.

Enhanced broadband greenness in assessing Chlorophyll a and b, Carotenoid, and Nitrogen in Robusta coffee plantations using a digital camera

Direct-leaves measurement of spectral indices using a digital camera with a portable small chamber and custom illumination is used to take images of 600 leaves from 40 coffee plants. In this research, several vegetation indices (VIs) are developed and evaluated. Through a series of experiments, Chlorophyll a and b, Carotenoids, and Nitrogen critical level of Robusta coffee plants are analyzed and evaluated using selected VIs obtained from spectra of different tools like Spectrometer, digital camera, and SPAD-502 Chlorophyll meter. The actual Nitrogen critical level was determined using Kjeldahl laboratory test. Beside Hue, the newly proposed VIs could significantly improve the correlation in estimating photosynthetic pigments (Chlorophyll a and b, Carotenoids) and Nitrogen critical level of Robusta coffee plant. Finally, consumer-grade digital camera with custom chamber is shown to be used for rapid and accurate in situ estimation of Chlorophyll a and b, Carotenoids, and Nitrogen critical level of Robusta coffee plant from direct-leaves measurement.

Factors influencing rubber marketing by smallholder farmers in Thailand

ABSTRACT This article assesses the factors determining the type of rubber product that farmers are willing to sell and the factors influencing their marketing channel choice in Thailand. Primary data were collected through questionnaire administration from 280 rubber farmers in two southern provinces. The results of the logit regression model revealed that membership of farmers’ organisation, access to knowledge and information, and total area of immature rubber positively influenced the sale of fresh latex. Membership of farmer organisations and accessibility to market infrastructure also significantly positively influenced the sale of fresh latex to farmer groups. The implications for rubber marketing are presented.

Are peatland farming systems sustainable? Case study on assessing existing farming systems in the peatland of Central Kalimantan, Indonesia

Abstract Economically, peatland plays an important role since they can be reclaimed for agriculture. Shallow peat (<100 cm) can be used to grow food crops including vegetables. Peatland has also become attractive for development of large-scale oil palm and rubber plantations. However, peatland has a number of constraints in terms of greenhouse gas (GHG) emission, especially CO2 emissions in the degraded peatland. These arise from decomposition of peat. Common sense suggests three alternatives to manage GHG emissions from degraded peatland: conservation and restoration, natural recovery, and agricultural use. In this context, the challenge is to utilize degraded tropical peatland for agriculture while avoiding the negative impacts, and ensuring its environmental sustainability. This research attempts to contribute toward developing better management plans. Results of this study show that rice farming has highest sustainable score in degraded peatland. Rice farming secured a 52.14% sustainability score, while oil palm and rubber farming exhibited 47.55 and 47.67% sustainable scores, respectively. Therefore, rice farming can be considered as the first alternative for development of degraded peatland. Improved oil palm and rubber farming systems may also be subsequently considered if their sustainability can be improved.