The Impacts on Agriculture Production from Irrigating with Saline

Water and Ways to Efficiently Manage the Impacts

By: Kimberly McLeod

GEO 361

Objectives

• Understand salinity’s impact on agriculture lands• Understand the impacts of saline on crops• Determine how much saline is toxic to crops• Find solutions for farmers to deal with salinity

Introduction about the impactEarth’s water budget:

• Food production will need to increase by 38% by 2025• Stress to farmers to secure good irrigation water for their crops.

BUT some farmers have to use saline water because there are limited supplies of good quality of water or use shallow ground water that has high amounts of salt.

Reservoirs Earth's Percent Water Budget Residence Time Glaciers (F) 1.76 % 11,990 yrs Rivers (F) 0.00015 % 0.05 yrs Oceans 96.5% 2,652 yrs Groundwater (F) 1.7% 19,677 yrs Lakes (F) 0.013% 34.58 yrs Atmosphere 0.0009% 0.026 yrs

What is salinization?

A complex process: movement between salts (primarily NaCl) and water in the soil during seasonal cycles and its interactions with groundwater.

– Sources of the salt: rainfall, aeolian deposits, mineral weathering, and stored salts – According to the USGS- there are 3 categories for saline water

• Slightly saline: 1,000 to 3,000 ppm• Moderately saline: 3,000 ppm to 10,000 ppm• Highly saline: 10,000 to 35,000 ppm (ie Seawater = 35,000 ppm)

How saline water reaches the crops:

Results for irrigated lands:• Estimated that 20% of irrigated lands in the world are affects by salinity• Every year 0.2%-0.4% of total irrigated land is being retired because of high amount of salt. • Losing money: US spend $12 billon per year on impacts of salinity related to agriculture.

In general:• In 2003, it was reported that 15% of total land area of the world has been degraded by soil erosion, physical and chemical degradation (including soil salinization)

• More than 100 countries are affected by salinity

Impact of saline water on crops

Each plant needs to be addressed separately.

Two large groups: Halophytes (ie Date Palms) and Glycophytes (ie Faba beans, Tomatoes)

Generally, when a plant comes in contact with saline water there are physiological changes in the cell between the water and ionic status.

–High amounts of Na+ and Cl- causes an imbalance. Results in reduction of K+, Ca2+, Mn2+

–This mineral reduction impacts the plant’s growth from germination to harvest

Halophytes: Date Palms

Found in the Middle East and California because they can withstand long, dry summers and mild winters

Journal by Alhammadi et al:

• 8,000 ppm - 20,000 ppm of NaCl = no affects on growth

• 20,000 ppm + various salts = drastic decrease on growth

• Decrease in K+, Mg2+, Ca2+

• Conclusion: Don’t grow date palms with more than 20,000 ppm of NaCl

Glycophyte: Faba Beans

In the legume family that is native to North

Africa.

Experiment by El Fouly et al:

1. Control- No NaCl

3. 1,000 ppm NaCl -reduction in growth

Decrease in ability to take up water and injury to cells in leaves

Conclusion: With 1,000 ppm NaCl inhibits the growth of the crop. Do not use more than 1,000 ppm of NaCl.

So what can be done to increase the growth of the

crops when farmers have to use saline water?

Solution: Micronutrient Foliar Spray

Made of: Fe, Mn, Zn

1. Control

2. Control + Micro

3. 1,000 ppm NaCl

4. 1,000 ppm + Micro

Solution: Better Irrigation TechniquesBad: Furrow Good: Drip

To conclude:• Earth has a shortage of fresh water to meet everyone’s

needs• Farmers are under pressure to produce more food but

some are forced to use saline water• Salinity affects every climatic zone but primarily arid and

semi-arid climates because of high evapotranspiration rates

• Using saline water has detrimental effects on land such as retirement and the decrease in crop yields

• How much salt in the water determines if the plant survives or dies

• Two solutions include Micronutrient Foliar Spray and better irrigation techniques

Questions?