טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentBouwer Bernadette
SubjectSustainable Use of: Soil - Water - Nutrient Resource to
Secure Crop Production while Minimizing Nitrogen
Environmental Pollution
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Emeritus Abraham Shaviv
Full Thesis textFull thesis text - English Version


Abstract

Increasing food production is necessary in order to sustain the rapid population growth over the next decades. Extensification of agricultural land is restricted in most countries due to its damaging impact on natural ecosystems and yet sustainable increase from farmland intensification is feasible. To do so, water and nutrients efficient application are required. Recent studies have examined nitrogen fertilization misuse and its impact on atmospheric pollution along with soil and water resources contamination. The necessity of yield increase along with minimized agricultural environmental impact lead researches to explore approaches for a sustainable intensification. Despite its important role for plant growth, misuse of nitrogen fertilization has led to ~50% loss through volatilization, leaching and runoff. In the last 50 years, crop production has increased by a factor of 3 while N fertilizers application by a factor of 10, illustrating the massive overuse.

Global yield gap assessments conclude that 45%-70% crop production increase is possible with accurate fertilization and irrigation on underperforming farmlands. Low yields are prevalent especially in developing countries due to fertilization overuse or deficient application along with low water and nutrient use efficiency. The global yield gap atlas (GYGA) project provides an agronomic and local yield gap assessment tool, along with a public transparent dataset and protocol for policy makers and users. To sustainably enhance crop production, integrated nutrient management (INM) practice is recommended. INM combines traditional low cost methods along with innovative technologies to assist in soil nutrient balance. Innovative nutrient management practices and technologies can reduce nitrogen loss and increase plant N uptake. Among those practices are split fertilizers application, spatial dosing, nitrification/urease inhibitors and controlled/slow release fertilizers.

In view of food and water scarcity which is expected to worsen as population grows and climate change takes place, rigorous policy and operative yield benchmarks are necessary. The N-Print approach incorporates N calculators that calculate N footprint of a specific entity and proposes an alternative choice with low N consumption. This approach can assist policy makers as well as consumers in adopting low N footprint production and consumption patterns

To address the need for sustainable crop production increase, the innovative nitrogen use efficiency (NUE) indicator was examined. The NUE indicator was developed by the EU nitrogen expert panel to provide an operative tool for NUE assessment and N benchmarks for policy makers and farmers. By defining N input, output and surplus, the indicator tool provides the NUE of the system and recommends changes in nitrogen application, accordingly. The first constrain of the indicator is NUE desirable range: 50% <NUE<90%, which guarantees high resource use efficiency and avoids soil mining. To the NUE constrain, two more benchmarks are added: desirable minimum productivity along with maximum N surplus, both of 80 kg N per hectare annually. Those benchmarks address the increased food demand and the need to minimize N environmental impact, respectively. Being an informative and uniformed tool, the NUE can promote sustainable agricultural policies and substantially reduce nitrogen environmental pollution while increasing crop production.