Remotely Sensing Crop Nutrients

At a latitude of 20°16′S and a longitude of 30°56′E lay the ruins of an ancient stone city. From above, it resembles a giant grey bracelet spanning about 80 hectares. At its peak, around 3 A.D., the city was home to over 10,000 people and thrived on agriculture and gold trade. It was at one point erroneously believed to have been the site of King Solomon’s mines. Around 15 A.D., however, there appears to have been a mass exodus. Some say due to dwindling resources. The Shona people called the place Dzimba Dza Mabwe meaning houses of stone. Words believed to be the origin of the name Zimbabwe. Where Dr. Charles Mutisi and his team are developing a technology that remotely determines the nutrient needs of crops in agricultural fields.

What is remote sensing?

Not to be confused with remote viewing which finds its home in parapsychology, remote sensing involves collecting data about an object without having any physical contact with the object being observed.

There are several types of remote sensing systems used in agriculture but the most common is a passive system that senses the electromagnetic energy reflected from plants. The sun is the most common source of energy for passive systems. Passive system sensors can be mounted on satellites, manned or unmanned aircraft, or directly on farm equipment.

Source: Extension

Dr. Mutisi, Dean of the Department of Agricultural Research, and his team are using a combination of satellite imagery and geographic information with an aim to assist farmers to not only determine the nutrient needs of any crop but also to predict its yields.

“The technology is able to assess land on which all crops including tobacco, soya beans and maize are grown”, says Dr. Mutisi.

The ability to predict yields with some precision is indeed one that could have a huge positive impact on Zimbabwe’s agricultural sector.

Zimbabwe, Africa’s Tobacco Giant

Zimbabwe is the largest producer of tobacco in Africa and the 5th largest producer of flue-cured tobacco in the world. It is a major foreign exchange earner for the country - estimated at USD 500m - and the mainstay of thousands of small to medium-scale communal farmers.

According to a paper titled Remote Sensing Applications in Tobacco Yield Estimation and the Recommended Research in Zimbabwe published in September 2013 it was noted “The current conventional tobacco yield forecasts rely on seed purchase records, land area, and visual assessment of the crop. Since farmers’ records may not be exhaustive, the current forecast may not be accurate.” and further stated “Remote sensing can complement or even improve the current conventional tobacco yield prediction methods used. This is because remote sensing provides useful information on real time crop condition as well as for yield forecasting.”

As though by some synchronicity, a year later, in September 2014, Dr. Mutisi and his team began developing the technology after receiving funds from Zimbabwe’s Ministry of Agriculture Mechanization and Irrigation Development.

According to the team, the technology could describe, assess and visually depict geographically referenced features, processes and activities on earth to inform strategic and operational decision-making.

Beyond Agriculture

The technology is currently undergoing testing at the University before it is rolled out in other African countries. Mutisi and his team foresee the technology being a major boost to farmers in Zimbabwe and Africa as a whole.

“We have developed this agricultural technology to use it at the university farm on a trial run starting in January 2016 before it is rolled out in other African countries.” stated Dr. Mutisi.

But the team sees potential use for the technology outside of agriculture.

“We are also working in the area of exploration and actual quantification of the minerals in the country using the same system. The ultimate goal is to have a Zimbabwe and Africa map of minerals which documents the exact quantities.”

The University is still in the process of securing patents for the technology at which point further details about how it works will be available to the public. What is encouraging, however, is that the technology is not only homegrown but also locally funded.

Based on an article found on

Image Source: The Progressive Nationalist