The quality of irrigation water has a significant impact on crop yield, degradation of soil, pollution of groundwater, and operation and life of irrigation systems. It also interacts with soil and its chemical and physical constituents. In irrigation engineering, water quality is evaluated by considering physical and chemical characteristics of water, but biological characteristics may also be important if wastewater is used for irrigation. This chapter discusses water quality from an agricultural irrigation viewpoint.

Sprinkler irrigation is becoming popular these days all over the world, especially because water is becoming scarce for meeting agricultural needs fully, and demands on water resources are growing from other competing sectors, such as industry, energy generation, waste disposal, domestic, and so on. The objective of this chapter is to discuss different aspects of sprinkler irrigation.

In Chapter 5, we learned about array syntax and how this enables us to use arrays not only to hold a collection of numbers but also to do calculations with those collections. In this chapter, we further explore how to analyze collections of data, such as arrays. Array syntax is powerful but there are many kinds of calculations that require the ability of examining and analyzing individual elements of an array.

Irrigation of crops and drainage of excess water have both positive and negative environmental consequences. Irrigation return flows degrade the quality of receiving streamflow as they transport pollutants. Although return flows cannot be entirely eliminated, they can be reduced by appropriate water management and improved conveyance and delivery systems. This chapter briefly discusses the importance of return flows and the pollutants transported by them.

Have you ever drunk more alcohol than you intended? Or smoked a cigarette after telling yourself that you were quitting smoking? Have you ever gotten a headache because you did not drink your morning coffee? By the time we are adults, nearly all of us have used substances such as alcohol, tobacco, or caffeine. Most of us can control our use of substances, but a sizeable minority develop one or more disorders due to substance use at some point in their lives. You probably know someone who has problems that are a result of substance use.

For irrigation management and maintenance, it is necessary to determine the volume of water that is applied to the field and the rate at which water is applied. Measurement devices are therefore included in irrigation systems. This chapter discusses different methods and devices that are commonly employed for determining flow rates and volume in agricultural irrigation.

In previous chapters, we looked at one-dimensional and two-dimensional arrays and used them in a variety of tasks, including data analysis, prognostic modeling, and the management of the output from multiple model runs. Arrays are, however, not limited to one or two dimensions. If we have a three-dimensional physical space – made up of length, width, and height – the measurements of some quantity every meter in length, width, and height in that space (at the same instant in time) would be nicely stored as elements in a three-dimensional array. If all such measurements are taken at regular intervals in time – say every hour – those values could be stored as elements in a four-dimensional array.

When we first learn to program, our programs are usually very short, limited in their functionality, and seldom more than a single file. For such short programs, written by a single person, we can keep track of the different versions of our program and describe to a new user how to install the program by writing out a description and instructions in a few files of documentation (perhaps a README.txt file or a short user’s manual written in Word).

In Section 10.2.4, we examined copying and deleting files and directories. The tools we used – copytree, rmtree, and move – automatically handled directory trees. For instance, a copy operation using copytree on a directory copies not just the topmost directory but all files and subdirectories underneath the topmost directory, and so on to every file and subdirectory. In the present chapter, we explore how a programming language implements the idea of “do-this-action-over-nested-levels” through the principle of recursion.

In Section 11.2, we discussed the importance of testing our programs in order for us to have confidence they are working the way they should. We discussed basic tests and the use of a debugger to help us step through our program slowly to find bugs. As our programs become larger, however, we need a more formalized framework and set of tools to help us in our testing. In this chapter, we introduce two such tools: linting or static checking, and formal unit testing frameworks. We conclude by describing the “test-driven development” mindset, which uses all these tools. That mindset can help us to write bulletproof programs.

The first six chapters of this book introduced you to behavior genetics as a field, refreshed your memory about Mendelian and molecular genetics, introduced the research methods of behavior genetics, and discussed how genetic variation can affect the brain structure and function. In the remaining chapters, we explore some of the most important areas of behavior genetic research, consider the future of behavior genetics, and examine ethical questions at the forefront of behavior genetics.

Drainage is the orderly removal of excess water from the soil surface as well as the soil profile or root zone. It directs the removal in a manner such that it does not erode the soil and damage crops. By so doing it provides a suitable environment for the maximization of plant growth, keeping in mind financial constraints. The objective of this chapter is to present rudiments of agricultural drainage.