Measures for reducing nitrate leaching in orchards: A review

Flashcards of key terms and concepts.

What is a major consequence of improper management of N fertilization in agriculture, particularly in fruit production systems?

A large amount of nitrate leaching.

What are some adverse effects of high levels of nitrate in drinking water?

Harm to the human body.

What are some approaches evaluated for reducing nitrate leaching in orchards?

Using grass cover, applying controlled-release N fertilizer, and adding nitrification inhibitors.

What roles do N fertilizers play in agriculture?

Crop growth and food security.

Groundwater nitrate pollution can pose challenges to what?

Human health and the ecological balance.

What is the average renewal period of groundwater?

1400 years.

What is the WHO's stipulated limit for nitrate content in drinking water?

Not exceed 50 mg L−1 (equivalent to 11.3 mg L−1 for NO−3 – N).

What root structures can capture nitrate to the greatest extent from the soil?

Herringbone and dichotomy root structures.

What are isotopes?

The same chemical element with the same atomic number (same proton number) but different masses (different neutron numbers).

What is 15N used for in the soil-plant system?

Mark different forms of N fertilizers to understand the process of N absorption and transportation in plants.

What is the main way to track nitrate pollutants in groundwater?

The d15N and d18O isotopes of nitrate.

What are some limitations of isotopic techniques in tracking nitrate pollution sources?

Large spatial difference in nitrate, very expensive and complicated measurement method.

What is the GWF?

Grey Water Footprint, a tool for measuring and generating a map of nitrate contamination in groundwater.

What instrument can be used to measure soil nitrate N solutions quickly and accurately?

Cardy meter.

What can using 15N as a tracer describe?

The absorption and distribution of N in soil by trees and microbial responses to inorganic N supply in orchard soil.

What is the HYDRUS-1D model used for?

To predict the future nitrate change.

What does the quantity of nitrate leaching depend on?

The amount of N fertilizer applied.

What does the leaching estimation and chemistry model (LEACHM) simulate?

The transport of water and solutes in unsaturated or partially saturated soils.

What is considered as the "4R" principle?

Right fertilizer type”, “right application rate”, “right application time” and “right application method”.

What is a major role of biochar?

Help to retain nitrate ions in the pores, which may affect the nitrification and denitrification progress and increase the use of N fertilizer.