Download Arid Land Irrigation in Developing Countries. Environmental by Barton E. Worthington PDF

By Barton E. Worthington

Show description

Read Online or Download Arid Land Irrigation in Developing Countries. Environmental Problems and Effects PDF

Similar environmental books

Molecular Aspects of Oxidative Drug Metabolizing Enzymes: Their Significance in Environmental Toxicology, Chemical Carcinogenesis and Health

Provided listed here are fresh advances in biochemical, toxicological, and regulatory features of oxidative drug metabolizing enzymes. as a rule cytochrome P450-dependent and flavin-containing monooxygenases (FMO) are lined. furthermore, the ebook offers with genotoxicity stories and toxicological interactions of environmental chemical compounds and mechanisms of mutagenicity and tumor formation.

Local Environmental Change and Society in Africa

Social and typical scientists are at present passionate about globalization, yet this has no longer been matched by means of an equivalent curiosity within the societal results of neighborhood environmental switch. consciousness has hence been withdrawn from neighborhood and locality and transferred to international techniques, with an indifference to the truth of these on the receiving finish of the social, monetary and political difficulties that globalization create.

Biological and Environmental Effects of Arsenic

Subject matters in Environmental well-being, quantity 6: organic and Environmental results of Arsenic makes a speciality of the homes, features, and reactions of arsenic and its results at the setting. the choice first tackles the mobilization of arsenic via traditional and business methods and emissions, biking, and results of arsenic in soil ecosystems.

Extra resources for Arid Land Irrigation in Developing Countries. Environmental Problems and Effects

Example text

For some of the commoner pesticides, the concentrations which may be tolerated by man have been estimated and are in controversy. 056 mg/1. However, DDT accumu­ lates in high quantities in fish, and gets to man who uses fish as food. Evidence seems to suggest that contamination of water with pesticides is more the result of direct application to water than through agricultural runoff. Subsurface waters do not appear to provide direct routes into rivers and reservoirs. Generally, pesticides are believed to persist longer in water than in soils, and it is probable that most pesticides are readily absorbed onto soil particles.

However, this is seldom done and incor­ porated into an economic evaluation of a proposed irrigation scheme at the decisionmaking stage. Knowledge of the ecology of the plants could lead to modification of canal design which could prevent excessive growth of nuisance plants. Possible measures include manipulation of water level and flow and training canals to dryness for periods of time to prevent the build-up of excessive plant population. It is critically important to incorporate these and similar procedures to prevent or minimize problems at the planning stage by appropriate canal design, or design and loca­ tion of human dwellings.

Under favorable drainage conditions water with a mineral content varying from 2-7 g/1 can be utilized for irrigation. However, an increase of salt concentration in irrigation water will lead to a drastic increase of outflow from the irrigation system, in accordance 28 MODIFICATION OF SOIL AND WATER REGIMES with the water-salt balance equation. This, in turn, will elevate the required frequency of leachings, drainage rates and volumes of mineralized water to be drained from the system. Kovda's estimates of the general conditions of utilization of mineralized waters for irriga­ tion are shown on p.

Download PDF sample

Rated 4.31 of 5 – based on 33 votes