eChapters

Introduction

Drought is one of the primary factors responsible for depressing rice yield in chronic areas and in destabilising rice production in drought-prone areas. It is a production constraint common to all rainfed rice cultures: wetland, upland, and deepwater (O’Toole and Chang 1979). Breeding for drought resistance, a major component of the International Rice Research Institute’s (IRRI) Genetic Evaluation and Utilization (GEU) Program since the early 1970s, aims at countering the adverse effects of drought in unfavoured rice production areas.

Rice germplasm has such remarkably rich diversity that a continuous spectrum of genotypes differing in the various physiological mechanisms can be found and is available for genetic manipulation (Chang et al. 1982a). However, effective evaluation methods are essential for unravelling the specific mechanism(s) involved and for devising eficient selection criteria in a breeding program. Moreover, the broad spread in growth duration among rice cultivars makes it impractical to obtain uniform evaluation of a large number of cultivars when they differ in physiological responses that are specific to certain growth stages. Methods that can accommodate large numbers are essential to breeding program.

Introduction

Man’s intervention in the evolution of plants, to adapt them to suit his needs, constitutes the practice of plant breeding. Historically regarded as an art and still too empirical to be accepted universally as a science, it has recently been described as a technology (Riley 1978). Whether art, science or technology, it certainly draws on a wide range of disciplines and embodies all those principles of organisation and management that determine success in any production-oriented programme.

Perhaps the biggest contribution that the plant breeder has made to increased production during the past 50 years has been in helping to alleviate the effects of natural hazards such as lodging, pests and diseases on crop production. While most of this progress has been through the manipulation of biotic stresses, much is still to be achieved under non-biotic stresses such as drought, salinity, temperature, etc. This argument is strengthened by the fact that in spite of the spectacular achievements made possible by the ‘Green Revolution’, the productivity level of most crop plants, including wheat and rice, has remained both low and static under stress conditions. Concerted efforts are needed through an approach of interdisciplinary research, since not much has been done to define criteria for stress assessment and evolving breeding approaches for incorporating stress tolerance in crop plants.

Introduction

Drought is the most common adverse environmental factor which limits crop production in different parts of the world. Often drought is accompanied by relatively high temperatures, which promote evapotranspiration, and hence could accentuate the effects of drought and thereby further reduce crop yields. Since these events occur more frequently in tropical and semitropical regions where most of the developing countries are situated, droughts are often associated with food shortages and an overall setback to developmental activities. Therefore, raising of drought-resistant crops is common sense to achieve stability in production and to enhance the possibility of self-suficiency in food. Consequently, breeding for drought resistance is a major objective of many research programmes in the international and national institutions. This has been so for the past several decades. But, it is disappointing that, there has not been any measurable success in these programmes compared with the success achieved in breeding for yield; or breeding for disease resistance or breeding for quality attributes. In fact, this was amply expressed by Arnon (1980) when he stated “Breeding for drought resistance has been a consistent theme for as long as I remember and probably the greatest source of wasted breeding efforts in the whole field of plant breeding.” However, the fact remains that we do hear of drought resistant varieties in many crops. For example, C-306 in wheat, Lalnakanda in rice and M 35-1 in Sorghum are some of the better known examples in India. It is also claimed that a large number of cultures among the Assam Rice Collection exhibit a considerably high degree of drought tolerance. Many land races and wild relatives of several crop species are said to contain drought resistant traits, which could be profitably utilised in breeding programmes. This situation is not unique to India alone but is a common experience in different parts of the world. However, to afirm a conviction a short questionnaire to assess the current state-of-art on breeding for drought resistance was distributed to 75 distinguished plant breeders and plant physiologists all over the world. The questionnaire and a summary based on the responses is as follows:

Expression of genetic potential for growth and yield of a crop variety is directly dependent upon the environment comprising both climate (weather) and soil components. As discussed in the preceding chapter, the term ‘salt-affected soils’ encompasses a broad group of adverse but distinct soil conditions, namely, saline, alkali (sodic) and acid soils with further variations such as coastal and inland locations as well as arid and water-logged situations (Swaminathan 1977; Bresler et al. 1982). Factors limiting growth and yield of crop plants in various categories of problem soils are different and specific. Likewise, adaptive strategies evolved by plants to cope with the prevailing edaphic stresses, such as salt stress, also vary a great deal as indicated in Table 1. It is not unexpected therefore, that even varieties within a crop often show notable differences regarding tolerance to adverse soil conditions (Epstein et al. 1980; Devine 1982; Shannon 1984; Sayed 1985). Hence, it is essential that the breeder must understand the inherent charaderistics of the problem soil with which he is concerned and should also simultaneously appreciate that basically it is the sensitivity of crop variety, rather than the soil parameters per se, that essentially determines the occurrence as well as the magnitude of actual soil problem (Rana 1977). Since the degree of tolerance (adaptation) of crop varieties to different kinds of salt affected soils is genetically controlled, it is axiomatic that it can be improved through genetic manipulations by adopting suitable breeding procedures.

Introduction

Accumulation of excess soluble salts in the root zone of soils resulting in partial or complete loss of soil productivity is a worldwide phenomenon. The problems of soil salinity are widespread in the arid and semi-arid areas but salt-affected soils also occur extensively in the sub-humid and humid climates particularly in the coastal regions where the ingress of sea water through estuaries and rivers and through ground water movement causes large scale soil and water salinisation. Soil salinity is also a serious problem in areas where ground waters of high salt content are the only source of water available for irrigation. By far the most serious problems of salinity are being faced in the irrigated, arid and semi-arid regions of the world. Our ability to manage salt-affected soils and waters both in the irrigated and in the unirrigated regions will constitute a major effort in meeting potential food requirements. The magnitude of the problem can be appreciated from the following.

Review of the state of art of Drought on impact assessment, monitoring and management with special reference to agricultural production has revealed that Drought is still a complex natural disaster and difficult to forewarn in spite of advancements in atmospheric sciences and computational procedures. It is realized only after it is set in and is not known when it is likely to withdraw. A long way one has to travel to predict its occurrence, spread and its continuation to the next season over a region. The existing net work of observational set up in developing countries in Africa, Asia and in South America need to be strengthened further for effective monitoring of significant weather events at regional and micro regional level. With the rapid expansion of communication system over the past two decades, establishment of Automatic Weather Stations (AWS) at as many locations as possible even in remote regions should be taken up on priority basis and funding may be provided by the respective governments or by the International Organizations where ever necessary. Nations with limited resources may also be convinced to strengthen their weather observational net work in view of the increased occurrences of climate extremes and changing climate. Drought vulnerability regions over the globe were delineated based on sparse historical weather data which do not match with real surface conditions. Now, with the availability of weather data from more number of stations both temporally and spatially, drought prone regions over the world may be re-delineated. This would help the planners to allocate funds rationally to the affected regions. Globally every year, some regions or others may be experiencing droughts and more so in drought prone regions.

Good Practices for Drought Management
    7.1    Drought Planning and Preparedness
    7.1.1    Drought Planning in India
    7.2    Global Experiences in Drought Planning
    7.2.1    USA
    7.2.2    South Africa
    7.2.3    African Nations
    7.2.4    Namibia
    7.2.5    Ethiopia
    7.2.6    Botswana
Drought management plans in Europe
    7.2.7    Spain
    7.2.8    England and Wales
    7.2.9    Portugal
    7.2.10    Australia
    7.2.11    China
    7.2.12    Palestine
    7.2.13    Global Initiatives
    7.3    Drought Preparedness Action Plans in India
    7.3.1    Drought Preparedness Checklist
    7.4    Drought Preparedness Action Plans in Different Countries
    7.4.1    Arizona State in USA
    7.4.2    Texas State in USA
    7.4.3    Italy
    7.4.4    Mediterranean Region
    7.4.5    Pakistan
    7.4.6    Darfur in Sudan
    7.4.7    Bangladesh
    7.5    Indigenous Knowledge for Drought Management
    7.5.1    Astro Meteorological Methods
    7.5.2    Traditional Knowledge in Weather Prediction
     7.5.3    Traditional wisdom in Drought Risk Region (DRR)
        Rajasthan and Bundelkhand region in Uttar Pradesh
    7.5.4    Indigenous technologies for moisture conservation 
        in dry lands of semi-arid regions of India
    7.6    Traditional Wisdom for Drought Management in a few selected countries
    7.7    Role of Weather-based Agro-advisories
    7.7.1    Strategies for dissemination of advisories
    7.7.2    Role of ICAR and AICRPAM on Agromet Services
    7.7.3    Agromet Advisory services through mobile phone
    7.7.4    Status of Agromet Advisory Services in other Countries
    7.8    Value Addition to Agromet Information
    7.8.1    AICRP on Agrometeorology
    7.8.2    Thumb rules for weather-pest/diseases
    7.9    Contingency Crop Planning for Minimizing Risks
    7.9.1    Contingency Crop Planning for Rainfed Regions of India
    7.10    Drought Proofing Mechanisms
    7.10.1    Watershed Development for Drought Management
    7.10.2    Watershed Development in India
    7.10.3    The Success Stories of Watershed as a Drought Proofing Mechanism
    7.10.4    Watershed Policies and Recommendations
    7.10.5    Farm Ponds for Drought Management
    7.10.6    Success Stories of Farm Ponds
    7.11    Rainfed Technologies for the Drought Management in different agro climatic region
    7.12    Farmer’s Awareness on Climate Management
    7.12.1    India
    7.12.2    In other Countries
    7.13    Role of ICT in Climate Risk Management through AAS
    7.13.1    India
    7.13.2    Application of ICT in Providing Advisories in other Countries
    7.14    Integrated Drought Management Strategies through Farming Systems Approach
    7.14.1    Drought Adaptation Strategies in Rajasthan and in Maharashtra
    7.14.2    Improvement and Rural Livelihood
    7.15    Drought Mitigation Measures
    7.15.1    Drought Mitigation Plans
    7.15.2    Soil water Conservation and Recharging of Ground water Methods
    7.15.3    Traditional Water Harvesting and Conservation 
        Techniques
        References

6.1    Hydrological Cycle
    
6.2    Global Surface Waters
    
6.3    Surface Water over India
    
6.4    Ground Water Potentials in India
    
6.5    Influence of Drought on Water Resources, its Fauna and Flora
    6.5.1    Effects on Fauna and Flora
    
6.6    Influence of Changing Climate on Droughts and Water Resources
    6.6.1    Global warming and droughts at global scale
    6.6.2    Global warming on water resources at global scale
    6.6.3    Global warming and droughts at national scale in India
    6.6.4    Global warming impacts on water resources at National scale
        
References

5.1    Global Food Production
    5.1.1    Area Under Cultivation
    5.1.2    World Food Production
    
5.2    Variability in Global and Indian Food Grain Production
    
5.3    Impact of Phenomenal Drought During 2009 on Food Grain Production in Different Countries
    
5.4    Impacts on Livestock and Fisheries
    5.4.1    Livestock
    5.4.2       Milk Production
    5.4.3    Fisheries
    
5.5    Estimation of Food Grain Production in India using Rainfall indices
    5.5.1    Trend in the annual food grain production
    5.5.2    De-trended production index
    5.5.3    Construction of rainfall indices (RI)
    5.5.4    Development of model for estimation of production index
    5.5.5    Verification of model performance
    5.5.6    Estimation of Kharif Price Production
    
5.6    Forecasting of Agricultural Output Using Space, Agrometeorology and Land based Observation (FASAL)
        
References

4.1    Approaches for Drought Monitoring
    
4.2    Weather Network System in Different Countries
    
4.3    Drought Monitoring using Climatological, Hydrological and Combination Approaches in Different Countries
    
4.4    International Cooperation in Drought Monitoring
    
4.5    Drought Monitoring Mechanism in India
    
4.6    Early Warning and Decision Support System
    4.6.1    Software for Drought Detection, Monitoring and Early Warning
    4.6.2    Decision Support System for Droughts Developed Outside India
    
4.7    GIS and Drought Monitoring
        
References

3.1    Factors Contributing to Climate Change
    3.1.1    Natural Causes to Climate Change
    3.1.2    Human Causes to Climate Change
    
3.2    Climatic Trends
    3.2.1    Global level
    3.2.2    National level
    
3.3    Climate Projections
    3.3.1    Global level Projections on Future Changes in Climate
    3.3.2    Climate Projections at the National level
    3.3.3    Climate Projections at the Regional level
    3.3.4    Projections of Extremes in Rainfall and Temperature
    
3.4    Consequences of Climate Change on Droughts and Agriculture
    3.4.1    Impact of Climate Change on Agriculture in some States of India
    
References

2.1    Definition of Droughts
    
2.2    Types of Droughts
    2.2.1    Meteorological Droughts
    2.2.2    Agricultural Droughts
    2.2.3    Hydrological Droughts
    2.2.4    Socio-economic Droughts
    
2.3    Criteria for Classification of Droughts
    Meteorological Droughts
    Agricultural Droughts
    Hydrological Droughts
    
2.4    Data requirements in Drought Analysis
    
2.5    Drought Indices
    2.5.1    Rainfall-based Indices
    2.5.2    Climate Derivate Based Indices
    2.5.3    Remote Sensing Based Indices
    2.5.4    Processes Based Indicators
    
2.6    Assessment of Drought Prone Regions in India
    
2.7    Indicators for Declaration of  Droughts in India
    2.7.1     Rainfall Deficiency
    2.7.2    Area Under Sowing
    2.7.3    Normalized Difference Vegetation Index
    
2.8    Drought Management Procedures in India
    
2.9    Drought Code adopted by Local Governments
    
2.10    Spatial Variability of Droughts and their Frequency of Occurrence in India
    
2.11    Drought Vulnerability Assessment
    
2.12    Vulnerability of Society to Drought
        
References

1.1    General Circulation of the Atmosphere
    
1.2    World Climates
    
1.3    World Climate Classification by Köppen’s method
    
1.4    Climatic Classification over India
    
1.5    Asian Summer Monsoon and Rainfall Distribution
    
1.6    The Indian Monsoon
    Features of monsoon
    Monsoon circulation
    Onset of monsoon
    Withdrawal of monsoon
    Southwest monsoon rainfall
    Active phase of monsoon
    Break monsoon conditions
    Winter monsoon

1.7    Causes for Failure of Monsoon
    
    Prediction of onset of monsoon rainfall

1.8    Spatial Distribution of Weather Parameters over India
    Rainfall
    Temperature
    Humidity
    Sunshine and Radiation
    Wind speed

1.9    Famines in India
    
1.10    Historical Evidences of Droughts
    
1.11    Distribution of Drought Prone Regions over the Globe
    1.11.1    Occurance of drought in different countries
    
1.12    Distribution of Drought Prone Regions in India
    
1.13    Weather Phenomena Associated with Droughts
    
1.14    Effect of Droughts on Natural Resources
    1.14.1    Surface water resources
    1.14.2    Groundwater sources
    
1.15    Impact of Latest Droughts on Crop Production in India
    
1.16    Economic Impacts of Droughts in India
    
1.17    Economic Impacts of Droughts in other Nations
        
References

Soil and nutrients are important factors for sustainable crop production in agriculture. Water erosion contributes more than 60% to the area under soil degradation in India. Soil erosion has been a serious threat to sustainable agriculture. However, soil and water conservation measures plays important role in improving the productivity of natural resources. India presently supports 17% of the global population with a geographical area of 329 Mha on merely 2.5% world’s land area and 4% fresh water resources. The net cultivable area in the country is about 140Mha is remaining constant or even squeezing from the pressures of urbanization, industrialization, infrastructure development and to house the ever increasing population. The loss of productive soil is another concern. The loss of fertile top soil by water erosion is estimated to be about 5334 Mt per year with it nearly 8.4 million tonnes (mt) of nutrients was estimated in eroded soil still holds true about in i.e. 2.5 mt nitrogen, 3.3 mt phosphorus and 2.6 mt potassium per hectare is lost due to ill soil and water management practices (Dhruvanarayana and Ram Babu, 1983).

Soil microorganisms are believed to play a major regulatory role in organic carbon dynamics, as key architects in nutrient transformation, and physical engineering of soil structure. The microbial populations of the soil alone encompass an enormous diversity of bacteria, algae, fungi, protozoa, and actinomycetes. Microbial diversity is being regulated by substrate and water availability, temperature, climatic regime and soil structure, which is considered as a transformation agent for soil organic matter and a labile pool of organic and inorganic nutrients. Extensive cultivation with repeated tillage operation often disrupts soil aggregates stability and destroys aggregates carbon and therefore, soil lose their physical properties and nutrient supplying capacity in a long-run.

Introduction 

Conservation tillage has been defined based on percent cover of the soil surface with crop residue (CTIC, 2000). Quantifying crop residue cover on the soil surface is important for improving estimates of surface energy balance, net primary productivity, nutrient cycling, and carbon sequestration. Quantifying crop residue cover is also an important factor in controlling soil erosion and evaluating the effectiveness of conservation tillage practices (Barnes et al., 2003). Collecting this information by conventional method of survey and line transact are time-consuming, labor intensive, costly and can involve destructive sampling (Morrison et al., 1993). Moreover, field data are limited because they provide point, rather than area information. Remote sensing technique revealed as promising tool in providing such spatial data over a large area in a time and cost-effective manner.

Introduction

In general economic model, technological change in agriculture is expected to cause the commodity supply curve to shift down and out against a stationary demand curve, giving rise to an increase in quantity produced and consumed, and at a relatively lower price. Agricultural economists have used supply and demand models of commodity markets to represent agricultural research impacts, beginning with Schultz (1953) and Griliches (1958), with important subsequent contributions by Duncan and Tisdell (1971), Akino and Hayami (1975), among others. Such a model is explicitly used in many studies. However, low crop productivity, food insecurity, hunger and malnutrition; inadequate farming knowledge and skills, implements and inputs are characteristic of smallholder agriculture in developing countries including India. Many researchers argue that conservation agriculture can guarantee higher crop productivity, food security, improved net income of the farmers and environmental protection, better than the traditional systems of cultivation practices.

Introduction

Modern agriculture has been of great help in alleviating hunger from the world, because the world population more than doubled itself during the last half of the 20th century; it increased from 2.5 billion in AD 1950 to 7.1 billion in 2012 (USCB, 2013). It is predicted that the world population will again double itself by the end of the 21st century and will touch the 12 billion mark. Most of this increase in population has been, and will be, in the developing countries in Asia, Africa and South America. India occupies 2.4 percent of the total land area of the world, but supports 16.7 per cent of the world population. Like many other developing countries in the world, population in India is increased from 345 million in 1947 to 1210 million as per the 2011 census with a growth rate of 1.76 during last decade. Therefore, pressure on land has been mounting up at an alarming rate. Population growth coupled with live stock population expansion, urbanization and industrialization are major contributory factors to it. The unscientific and unplanned exploitation of this limited resource takes its toll in terms of degrading the land. A large proportion of the land area shows clear evidence of advanced and continuing degradation seriously affecting the country’s productive resource base (Abrol and Sehgal, 1994). Jammu & Kashmir and  Nagaland  have maximum share of their land (94%) under degradation. This is primarily due to large areas under mountains, cold deserts and other such degraded lands. In the agriculturally prominent states like Uttar Pradesh (63%), Madhya Pradesh (50%) and Karnataka (46%) (Shalander Kumar, 2011) the extent of land degradation is of great concern and posing a big threat to the natural resources, resulting in almost 5 billion tonnes soil and 6 million tones of nutrient loss every year (Singh, 2009).

Introduction

With the advent of agricultural intensification, soil quality has been the important concern for the scientists, environmentalists and the planners at the global level. Research efforts have been made at the experimental fields, research laboratories and few specific locations, in order to establish the yardsticks, standards and critical values of soil parameters to ascertain the quality of the soil. The primary aim is the management of soil resources as per the need and their rejuvenation through best practices in hand. The idea, as it was aimed at, has now percolated down to the minds of end users-the farmers. The state and Central governments have been sensitized and are attaching great priority to the soil health. In states like Tamil Nadu, Gujarat, Goa, Uttar Pradesh crores of farmers are given “Soil Health Cards”. Central Govt. has the plan to issue these cards to all farmers in the country, detailing the deficiencies in soil and the amount of fertilizer needed.

Introduction

The organic matter added to soil externally as FYM, crop residues, leaf fall, root deposition etc. has been a part and parcel of Indian agriculture. The total carbon added to soil is subject to microbial decay and slowly the major portion of it finds way back to the atmosphere. There is every possibility that atmospheric CO₂ concentration will increase in near future; that will further lead to increased attention of scientific community to make soil a possible sink for atmospheric CO2. when the carbon sequestration is thought with the perspective of reducing carbon dioxide emission for healthy atmosphere at one hand and improving soil health on the other, there is utmost need to opt for technologies that can fulfill both these objectives. There is growing interest in the use of charcoal or ‘biochar’ to sequester carbon in soil and improve soil fertility (Lehmann and Joseph, 2009). There are many types of soil additives and fertilizers used to improve the structure and functions of soil. Biochar has re-emerged as an issue in the last ten years as everyone is looking for sustainable ways to improve soils and decrease use of chemical fertilizers.