**1. Introduction**

Climate change has become an important area of concern for India to ensure food and nutritional security for the growing population. Climate change has been one of the most talked about subjects by both scientists and common people today. The major concern has been the question of food security soon under the changed climatic situation. Climate is changing and this change is now for real. It has come as a daunting challenge to agriculture and agriculturists. The impacts of climate change are global, but countries like India are more vulnerable because of the high population depending on agriculture. The Government of India has accorded high priority to research and development to cope with climate change in the agriculture sector. The Prime Minister's National Action Plan on climate change has identified agriculture as one of the eight national missions. Therefore, the time has come to shift our focus from assessing the impact on agriculture to the management-based solution to cope with food production sustainability. Many researchers are underway to evolve climate-friendly, climate-smart, and climate-neutral agricultural technology for the benefit of society.

The impact of climate change has been increasingly visible in terms of change in temperature, precipitation, retreating ice caps and glaciers, sea level rise, atmospheric circulation pattern, and ecosystems. Climate change is not simply the increasing temperature but is indeed responsible for the increasing frequency of extreme weather events, such as heat waves, cold waves, droughts, and floods. In India, the increased frequency of pronounced heat waves, cold waves, droughts, and floods has already been realized in the last few decades. Analysis of long-term rainfall data confirmed the significant decreasing trend of annual as well as monsoonal rainfall in both the Brahmaputra and Barak basins of Assam, India [1]. Variability of rainfall has been increasing in terms of the increased frequency of high-intensity rains and the reduced number of rainy days, leading to localized flash floods and the occurrence of multiple dry spells [2]. The chapter will deal with strategies to adapt to climate variability from farmers' perspectives based on the experiences of the All-India Network Project on

*Adaptation Strategies for Climate Variability in the High Rainfall Zone of India, Assam DOI: http://dx.doi.org/10.5772/intechopen.107045*


**Table 1.**

*Number of land holdings according to size classes of Assam [3].*

National Innovations on Climate Resilient Agriculture (NICRA) being implemented in the North Bank Plains Zone of Assam (NBPZ), India since 2011.

#### **1.1 Physiography of Assam**

Assam is one of the states of northeast India situated between 24°and 28°16΄N latitude and 89°4΄and 96°E longitude. It is surrounded by Bhutan and Arunachal Pradesh in the north, Arunachal, Nagaland, and Manipur in the east, Mizoram, Tripura, and Meghalaya in the south, and Bangladesh, Meghalaya, and West Bengal in the west. Assam has a geographical area of 78,523 square km comprising fertile land and water resources. Despite these resources, Assam is lagging in the agriculture sector. The farming community mostly belongs to small (20.9%) and marginal (62.2%), with large farmers being very low (0.19%). The average farm size is decreasing over the years (1.11 ha) (**Table 1**) [3].

The physiography of the state can be divided into three distinct units: the plain, the plateau, and the hills. Two primary units for agricultural development in Assam are the Brahmaputra and the Barak valley, accounting for 80.8% of the total geographical area. The state of Assam has been divided into six agro-climatic zones based on physiographic variation, climate, soil, farming systems, crops and cropping systems, and hydrology under the National Agricultural Research Project (NARP) (**Table 2**).

#### **1.2 Soil and climate of Assam**

The major portion of the soils of Assam belongs to Inceptisols (49.3%) followed by Entisols (32.3%), Alfisols (12.3%), and Ultisols (6.1%). The texture of the soils varies from sandy loam to clay loam depending on the agroclimatic conditions and physiographic units. The soil of Assam is acidic having a pH range from 4.2 to 5.8. The average status of available nitrogen, phosphorus, and potassium status in the soil is low to medium, with a slight variation in the content [5, 6]. The soil of the state as a whole is deficient in boron and marginal in the case of zinc, iron, and aluminum toxicity are also observed sporadically.

The climate of Assam is humid subtropical in nature with warm humid summer and cool dry winter. The rainfall in Assam is in general high, but its distribution over time and space is not uniform and even. The monsoon period is characterized by high-intensity rainfall, while the winter (December to February) is virtually dry. Flood is a regular feature affecting the *Kharif* rice (winter paddy) production in about 7.75 Lakh ha of agricultural land annually. The mean annual maximum temperature


#### **Table 2.**

*Agro-climatic zones of Assam [4].*

lies between 23.6°C and 31.7°C, while the mean minimum temperature varies from 10°C to 25.2°C. The interception of bright sunshine is only 36 to 38% of the astronomically possible sunshine hours from June to August due to continuous overcast sky. Though sunshine hours are the longest from November to February (70 to 74%) radiation is not up to the desired level due to foggy weather.

#### **1.3 Flood**

A flood is a natural calamity where the state is exposed to vagaries of climate to an extreme scale, endangering the life and property of the farmers. The state is home to a mega network of rivers comprising 48 major and 128 small rivers, which are responsible for the annual floods, resulting in an average annual loss of Rs.200 crores for the state. Horticulture crops occupy 7.57 and 15.25% of total land and total cropped area, respectively.

#### **1.4 Land use pattern**

Assam has a total geographical area of 78,523 square km, of which 24.91% is under forest. The net cropped area constitutes 35.1% of total land area and 70.66% of total cultivated area. About 58.5% area is mono-cropped, especially with winter rice, with the cropping intensity being 146% (RKVY-Assam, 2022). About 186 lakh hectares and 1.51 lakh hectares are remaining fallow and waste. The state has a population of 31.17 million and the population of the state is expected to swell to 35.6 million by 2025, putting tremendous pressure on land and water resources.

#### **1.5 Irrigation status in Assam**

Irrigation is very critical in terms of nullifying the ill effect of weather vagaries, getting a response to input and other management practices, and exploiting the genetic potential of modern varieties. Irrigation has gained much importance given weather extremities line flood and drought-like situations frequently occurring as a result of climate change. At present only 18.5% of the net cultivated area of the state is under irrigation.

#### **1.6 Present status of rainfall and temperature variability**

#### *1.6.1 Temperature*

According to the fourth assessment report of the Intergovernmental Panel on Climate Change (2021), the increase in global surface temperature from 1850 to 1900 is assessed to be 1.09 [0.95 to 1.20] °C [7]. In the northeast region of India, the annual mean temperature is reported to be rising at a rate of 0.04°C per decade [8]. Assam also exhibits warming trends throughout with minor spatial variations. Analysis of temperature data during 1961–2010 reveals a warming trend in both mean maximum and minimum temperature. The magnitude of minimum temperature was higher compared to those of maximum temperature. Similar trends were also observed by other researchers [9].

#### *1.6.2 Rainfall scenario of Assam*

Assam experiences an average annual rainfall of 1980 mm, while during premonsoon (March–May), monsoon (June–September), post-monsoon (October– November), and winter period (December–February) average rainfall received is 486.5 mm (24.57%), 1279 mm (64.64%), 150.3 mm (7.59%), and 63.3 mm (3.20%), respectively (**Table 3**).

Deka and Mahanta reported a declining tendency of annual rainfall at a rate of 7.9 mm per 100 years in the NE region of India [10]. The summer monsoon rainfall in the region is decreasing (−48.0 mm/100 years), while rainfall during the post-monsoon season exhibited an increasing trend (+36.3 mm/100 years). The contribution of June, August, and September rainfall to annual rainfall exhibits a decreasing trend, while the contribution of July and October rainfall marks a rising trend [11]. On an annual basis, a long-term decreasing trend of rainfall has been observed in both the Brahmaputra basin and the Barak basin of Assam. Decreasing tendency (39.1 mm/decade) in the Barak valley, while in the Brahmaputra basin the annual decreasing trend was 9.6 mm per decade also reported [11]. About 72 million hectares of net sown area in India is rainfed, which is practiced in diverse climates and agro-ecologies contributing to about 40% of


#### **Table 3.**

*Mean season-wise annual rainfall and rainy days in NBPZ of Assam [5].*

the country's food basket. The agricultural production, productivity, and stability in rainfed areas are more vulnerable to climate variability, particularly during the kharif season, due to high dependency on the southwest monsoon. Monsoon failures result in a drought that has serious implications for small and marginal farmers. The annual average rainfall and the seasonal monthly distribution of rainfall for two districts of Assam (the study area and the adjacent district of the domain area) situated in the NBPZ of Assam had been shown in **Figures 1**–**4**, respectively.
