A Review of the Available Land Cover and Cropland Maps for South Asia

A lack of accuracy, uniqueness and the absence of systematic classification of cropland categories, together with long-pending updates of cropland mapping, are the primary challenges that need to be addressed in developing high-resolution cropland maps for south Asia. In this review, we analyzed the details of the available land cover and cropland maps of south Asia on national and regional scales in south Asia and on a global scale. Here, we highlighted the methodology adopted for classification, datasets used, classification system used for classifying different land covers and croplands and the resolution of datasets available. This listed review of different available datasets can help the reader to know which datasets to be used in their study and to understand which methodology to be chosen to further developing the accurate high-resolution land cover and cropland maps for advanced studies and for better understanding of ground reality in a timely updated version. We tried to identify the major concerns, particularly the inadequacy of knowledge regarding the spatial distribution of major crop types within south Asia, which hinder policy and strategic investment and delay the efforts to improve food security for a rapidly growing human population at a time of constant market instability and changing global climate. The overall focus of this paper is on reviewing the need for timely updated high-resolution cropland maps of south Asia

Multi-criteria analysis and ex-ante assessment to prioritize and scale up climate smart agriculture in semi–arid tropics, India

The strategies that integrate food security, adaptation and mitigation options in agriculture are of high importance to manage the increasing risk of climate change in vulnerable semi-arid regions for the livelihood security of poor agriculture-dependent people. To address the growing problems of food security and climate change, multiple institutions and programs have demonstrated evidences for developing Climate-Smart Villages (CSVs) across regions which can act as a sustainable model for adapting to changing climate and improve farmers’ welfare. However, it remain a major challenge to upscale CSV approach. This paper presents a framework and evidence based designing of a strategy for scaling up Climate Smart Agriculture (CSA) in Telangana State of India. Climate risk and vulnerability mapping at disaggregate level; Inventory of CSA practices and respective technical coefficients; multicriteria analysis for participatory prioritization of location specific CSA practices and identification of barriers and incentives; ex-ante impact analysis of potential adoption and investment and infrastructure needs to implement CSA practices at local level and strategy for CSA integration into district level plans have been the key steps of this CSV approach. Local level vulnerability assessments and participatory prioritization based on index calculated for climate smartness and ease of adoption for each proposed practice, formed the basis of prioritizing CSA interventions suitable for particular location. Further the ex-ante impact analysis of selected climate smart interventions in different regions of Telangana was the next step. We also generated relevant geospatial maps for irrigated as well as rainfed major crops under vertisols and light soils. These maps helped in identifying context specificity of CSA interventions. Based on participatory prioritization, five CSA practices such as Ridges and Furrows, Broad bed and furrow for soil and moisture conservation and drainage, Farm pond for critical/supplemental irrigation, Crop residue management (cotton) and drip irrigation system were considered for ex-ante assessment considering district wise actual area and yields of major crops and rainfall level for 5 years from 2010-11 to 2014-15. The proposed framework and different tools help to understand the district wise potential for promotion of CSA practices/technologies, public and private investment needs, economic impacts of the interventions to enable informed decision making for climate smart agriculture. Stakeholders’ consultations during different stages of this process was very important for integrating their perspective and creating ownership. Piloting of evidence based scientific framework guides investments and policy making decisions on scaling up CSA in Telangana state

Mapping drought-induced changes in rice area in India

Rice is a staple food crop of India and is grown on 44 Mha (2011–12), 58.6% of which are irrigated. An inevitable phenomenon which looms over all aspects of human life and affects rice production in India is drought. Assessing drought damage using geospatial datasets available in the public domain, such as the Normalized Difference Vegetation Index (NDVI) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS), can provide specific and local ecoregion information for developing drought-resistant rice varieties. Based on multi-temporal NDVI data and field observations in 2009, we developed a methodology to identify and map drought-affected areas in India. A long-term (10-year) average of NDVI during the rainy (kharif) season (June–October) was compared with NDVI from a known drought year (2002–03) to identify changes in rice area. Rainfall data from the Tropical Rainfall Monitoring Mission (TRMM) was used to support the drought analysis. Spectral matching techniques were used to categorise the drought-affected rice areas into three classes – severe, moderate, and mild based on the intensity of damage assessed through field sampling. Based on these ground survey samples, spectral signatures were generated. It was found that the rice area was about 16% less in the drought year (2002–03) than in a normal year (2000–01). A comparison of the MODIS-derived rice area affected by drought in 2002 for each state and district against the difference in the kharif season harvested rice area between 2000 and 2002 (from official statistics) revealed a substantial difference in harvested area in 2002 that was largely attributable to drought. An 84.7% correlation was found between the MODIS-derived drought-affected area in 2002 and the reduction in harvested area from 2000–01 to 2002–03. Good spatial correlation was found between the drought-affected rice areas and reduction of rice harvested areas in different rice ecologies, indicating the usefulness of such geospatial datasets in assessing abiotic stress such as drought and its consequences

Dynamics and drivers of land use and land cover changes in Bangladesh

Bangladesh has undergone dramatic land use and land cover changes (LULCC) in recent years, but no quantitative analysis of LULCC drivers at the national scale exists so far. Here, we quantified the drivers of major LULCC in combination with biophysical and socioeconomic observations at the sub-district level. We used Landsat satellite data to interpret LULCC from 2000 to 2010 and employed a Global SurfaceWater Dataset to account for the influences of water seasonality. The results suggest that major LULCC in Bangladesh occur between agricultural land and waterbodies and between forest and shrubland. Exclusion of seasonal waterbodies can improve the accuracy of our LULCC results and driver analysis. Although the gross gain and loss of agricultural land are large on the local scale, the net change (gross gain minus gross loss) at a country scale is almost negligible. Climate dynamics and extreme events and changes in urban and rural households were driving the changes from forest to shrubland in the southeast region. The conversion from agricultural land to standing waterbodies in the southwest region was mainly driven by urban household dynamics, population growth, distance to cities and major roads, and precipitation dynamics. This study, which is the first effort accounting for water seasonality and quantifying biophysical and socioeconomic drivers of LULCC at the national scale, provides a perspective on overall LULCC and underlying drivers over a decadal time scale and national spatial scale and can serve as a scientific basis for developing land policies in Bangladesh

Crop type identification and spatial mapping using Sentinel-2 satellite data with focus on field-level information

Accurate monitoring of croplands helps in making decisions (for insurance claims, crop management and contingency plans) at the macro-level, especially in drylands where variability in cropping is very high owing to erratic weather conditions. Dryland cereals and grain legumes are key to ensuring the food and nutritional security of a large number of vulnerable populations living in the drylands. Reliable information on area cultivated to such crops forms part of the national accounting of food production and supply in many Asian countries, many of which are employing remote sensing tools to improve the accuracy of assessments of cultivated areas. This paper assesses the capabilities and limitations of mapping cultivated areas in the Rabi (winter) season and corresponding cropping patterns in three districts characterized by small-plot agriculture. The study used Sentinel-2 Normalized Difference Vegetation Index (NDVI) 15-day time-series at 10m resolution by employing a Spectral Matching Technique (SMT) approach. The use of SMT is based on the well-studied relationship between temporal NDVI signatures and crop phenology. The rabi season in India, dominated by non-rainy days, is best suited for the application of this method, as persistent cloud cover will hamper the availability of images necessary to generate clearly differentiating temporal signatures. Our study showed that the temporal signatures of wheat, chickpea and mustard are easily distinguishable, enabling an overall accuracy of 84%, with wheat and mustard achieving 86% and 94% accuracies, respectively. The most significant misclassifications were in irrigated areas for mustard and wheat, in small-plot mustard fields covered by trees and in fragmented chickpea areas. A comparison of district-wise national crop statistics and those obtained from this study revealed a correlation of 96%