In Chapter 9, we were introduced to objects and object-oriented programming (OOP). In the objects we considered, however, the classes those objects were instances of were all written by others. We just made use of the templates or common patterns that describe the array, list, string, and other objects discussed in that chapter to make arrays, lists, strings, etc.

Trickle irrigation is becoming popular throughout the world largely because of the shortage of water available for agriculture. In contrast with surface and sprinkler irrigation methods, in trickle irrigation water can be applied to the root zone of individual plants. For crops, water may be applied under low pressure and water use efficiency can be as high as 90% or more and the ground slope is no longer a serious limitation. Trickle irrigation systems can be designed either analytically or numerically under the assumption of constant or varying discharge. This chapter presents basic concepts of trickle irrigation and different design approaches, and illustrates them with examples.

Surface irrigation is commonly practiced around the world, more so in developing countries. There are different methods of surface irrigation and selection of a particular method depends on a number of factors, including climate, soil, crop, water availability, landscape, availability of labor, energy, cost and benefit, and traditions. This chapter discusses the preliminaries of the entire irrigation system.

Different types of crops require different types of climate and soil. Further, different crops and their optimum production have different irrigation requirements with respect to the frequency of irrigation, timing of irrigation, and amount of irrigation water per irrigation. The objective of this chapter is to briefly discuss the types of crops and their water requirements.

Pencil and paper are two of the greatest tools ever invented for studying science and engineering problems. But, there comes a point when the amount of data and complexity of the calculations require us to use more powerful approaches. The calculator is a scientist or engineer’s basic workhorse for making those calculations. While Python has a wide range of applications, from graphing to modeling to data analysis, the simplest (and sometimes most useful) way is to use Python as a calculator.

Have you interacted with anyone today? For nearly everyone, the answer to that question is “yes.” We tend to live with or around other people, and our lives are greatly impacted by their behaviors. Our behaviors impact their lives too. Broadly speaking, animals act in ways that enhance their survival and reproduction. When those behaviors involve others of the same species, we define them as social behaviors. Social psychology is the subdiscipline of psychology that studies how people impact the thoughts, feelings, and behaviors of others. Of course, humans are not the only animals affected by the behaviors of others. Social behavior can be studied in many species and is sometimes even studied between species such as humans and dogs.

In Section 22.4.2, we mentioned just-in-time compilation tools such as cython and numba that enable us to write parts of our Python code in another language or convert our Python code into an optimized non-Python version. The goal with using cython and numba is to enable our Python code to run faster. There are times, however, when we have a collection of legacy Fortran or C++ routines – battle-tested and reliable – that we want to use “as-is” from inside Python. The code files already exist external to Python, so we want to compile and wrap them up and expose them to Python to use.

So far, we have seen how to use Python to access and/or store information in two different kinds of file formats: text files (Chapter 9) and image files (Chapter 13). The former hold numbers, letters, punctuation characters, and some special characters. The latter hold the image information and are encoded in formats such as the Portable Network Graphics (PNG) and Joint Photographic Experts Group (JPEG) formats.

In cropland, water evaporates from soil and is transpired by plants, that is, water is transported to the atmosphere by evaporation plus transpiration which together constitute evapotranspiration (ET). Determination of ET is fundamental to determining crop water requirements. Evapotranspiration is an energy-driven process. The energy balance constitutes the basis of quasi-theoretical methods that have been developed for determining ET. Empirical methods are also based on data that reflect some components of the energy balance. This chapter discusses the process of evaporation and some of the methods that are used in irrigation engineering for computing evaporation.