**2. Irrigation type for crop type**

All type of irrigation does not suit all crops, the diversity of crops responds differently to applied irrigation and all crops have varied requirements of water which also

varies with the soil types and weather. Cereals generally have fewer requirements for water, but it does not fit with Rice and maize which require a higher amount of water. The delta of water of the same stature crop may also vary as in the case of millet, sorghum, and maize which are comparable in terms of the duration of crop, but their delta of water is quite different. Moreover, the varieties of the crop also have varying levels of gene expression for drought and flooding tolerance in the two extreme conditions.

The pulses group mainly including the beans require comparatively less water and are mainly short duration in semi-arid regions with plenty of sunshine justified adaptation to drought is clear and the water productivity of beans is higher compared to other crops of similar duration, especially if compared with vegetables which require much more water compared to beans. Rice and sugarcane are highly hydrophilic and are major consumers of water among all field crops. Thus, the need arises to link the irrigation type with crop type and then through the study of crop type can fine-tune the water requirements for phonological crop stages which could be critical to be influenced severely by moderate drought even.

Irrigation types vary and are mostly dependent on technological development and resource availability and influenced by topography as well. High-efficiency irrigation systems are more technical and water-saving solutions that have been finding their way into modern agriculture and transforming the irrigation system of the world. Only the places with higher rainfall do not require such technical intervention a in case of south China s province here rainfall throughout the year I sufficient to manage the whole year's crop of sugarcane and double cropping of rice as well. Desertification on the other hand is putting pressure on arable land for low and marginal productivity of crops. Modern water-saving technologies like drip irrigation, sprinkler, and center pivot systems are proving essential for drylands around the world and bringing barren land into cultivation thus bringing a contributive role in the planet's food security [11].

#### **3. Water scarcity, climate change, and crop yield uncertainties**

Several uncertainties exist for sustainable crop yields in changing climate and in water-scarce regimes. In this study, the climate change impact on Pakistan's irrigation resources and food shortage are examined. According to the report, Pakistan's economy (21%) is built primarily on agriculture; nevertheless, the nation is struggling with crop food shortages, high inflation, and a lack of irrigation water. According to the study, even though Pakistan ranks 135th in the world in terms of per capita GHG emissions with 309 M tons of CO2 equivalent emissions, which is only 0.8 percent of global emissions, the country is severely hit by changing climate compared to other nations because of trans-border emissions of greenhouse gases. As a result, there has been a continuous rise in temperature of 0.76°C in the nation as a whole and 1.5°C in Pakistan's mountainous regions, which are home to over 5000 glaciers in the KHH mountains. According to the study, Pakistan had a progressive decline in surface water availability per person from 5260 m3 annually in 1951 to just 1000–1066 m<sup>3</sup> in 2008. Because the country, with its huge infrastructure and network of the largest integrated irrigation system globally, lacks adequate water reservoirs to hold extra water, the glaciers are melting and causing extreme events like floods as a result of rising temperatures, particularly in glacier-covered regions, and associated variations in precipitation pattern, Therefore, because glaciers tend to retreat quickly, a large

#### *Sustainable Irrigation Management for Higher Yield DOI: http://dx.doi.org/10.5772/intechopen.107153*

amount of water is wasted into the ocean along with harm to crops, food reserves, billions of dollars worth of cattle, infrastructure, and land resources. In Pakistan, 84 out of 137 districts (primarily in Khyber Pakhtunkhwa, FATA, and Baluchistan) are said to be undersupplied with both crop- and animal-based food, or around 61 percent of the total. The main cause of the current food deficit is the low crop output brought on by the temperature increase and the lack of irrigation water. According to the study, farmers are switching from cultivating water-loving crops including rice, wheat, cotton, and sugarcane to low-water-requirement crops and vegetables. Moreover, the crops' production is lower because of heavy evaporation and the harsh summertime heat. According to the report, Pakistan's output of key basic foods like wheat, rice, and sugarcane has decreased over the first 10 years of the twenty-first century [12].

#### **4. Soil water management**

To actively take part in keeping soil water content at an ideal level for all specified goals, including environmental requirements, is to practice soil water management. An ideal state often involves striking a balance between conflicting demands and the need to take the soil water system's long-term viability into consideration.

To effectively manage irrigation systems, a full understanding of soil water is needed. Irregular water evaporation increased demand and crop water stress can occur from under-watering, which can reduce the amount of accessible water below essential levels. Two factors: 1) the Texture of the soil, which influences due to its water-holding capacity and vary soil moisture content, water potential, and infiltration; and 2) root depth, which finds the amount of water that is accessible for plants. Utilizing irrigation water resources more effectively may result in being able to control the soil water balance. For managing irrigation systems, the two most significant indicators of soil water are (1) Soil moisture content, which refers to the total quantity of water in the soil, and 2) Soil water potential, a measurement standing for ready availability of water to plants.

#### **4.1 Soil structure constitution and composition**

Soil includes the particles, air, and water the three major components (see **Figure 1**). Water and air are trapped in the soil particles in pore spaces a measure of which is the porosity of the soil.

#### **4.2 Soil water potential**

Irrigation management is not only about how much water is in the soil but also depends on the ability of plants to pump up or access water. The dynamic condition of soil water with moisture as a standard reference is known as its potential, which is often stated as energy per unit of volume (bars or centi bar unit). Gravitational potential, matric potential, and solute potential are the three main factors that make up total soil water potential. The gravitational potential results from gravity's force dragging the water in the soil downward. Matric potential also referred to as soil water tension, is the term used to describe the force that the soil matrix exerts on the water

**Figure 1.** *Ref. [13].*

through capillarity and adhesion. Salts that have dissolved cause the solute potential in the soil water.
