ABSTRACT
Like Chapter 11, this one is comparably rich in details and facts. Focus is here concentrated on the roles of water and nutrients for farm production. Neither of these aspects is controversial, especially not from an environmental point of view. You will learn that plants are threatened by surpluses as well as shortages of water. Attention is given to drainage of excess water, which it is necessary to consider in both rainfed and irrigated fields. Irrigation is in part discussed in wider perspectives, such as water as a common pool resource, but also from practical points of view. The second half of this chapter deals with plant nutrients. We will examine nutrient needs in general and the so-called macronutrients and micronutrients that are necessary for managing crop farming in the long run. A variety of plant nutrient sources are highlighted, ranging from purchased inorganic fertilizers to crop residues and waste, which reminds us of market and subsistence oriented farmers' different farming opportunities.
After this chapter you are expected to:
Be able to account for the main water functions in plants
Be familiar with soil drainage and explain why drainage is important
Be familiar with different kinds of farmland irrigation
Be able to discuss the pros and cons of crop irrigation from different points of view
Be able to account for the main factors that impact the need for crop nutrients and understand why farming requires continuous care of the crop nutrient situation
Know the main categories of macro- and micronutrients
Know the main kinds of inorganic and organic fertilizers
Understand why market and subsistence oriented farmers often have different strategies for crop nutrient supply
Understand the importance of nutrient circulation, for practical farming and long-term sustainability in global agriculture
Key words
Water uptake, excess water, drainage, humidity, drought, irrigation, inorganic fertilizer, organic fertilizer, macronutrients, micronutrients, manure, crop residues, waste, nitrogen fixing plants, green fertilizer, liming, pH, recirculation.
