Monitoring crop growth and performance
The monitoring of crop growth and performance during developmental stages is an important aspect of agricultural management. It enables the farmer to implement timely interventions that ensure optimal yields at the end of the season.
Stress factors often prevent crops from developing at the rate they are capable of. Examples include:
- Poor water availability (e.g., due to in-season drought)
- Extreme temperatures (heat)
- Competition among plants for sunlight, nutrients, water or space
- Nutrient deficiency (e.g., artificial fertilizer or manure)
- Uncontrolled use of chemicals (toxicity)
- Fungal, bacterial or viral infection
- Attack from insects or other organisms, above or below the ground
- Some of the above arise from shortcomings in labor investment on the plot
Figure 4.2: (A) Drought impact on rice plants; (B) Stunted maize plants in areas with high soil salinity in the delta region of Bangladesh; (C) Lack of weeding; (D) Poorly performing maize plants due to lack of fertilizer during sowing period; (E) Maize leaf infected with maize rust; (F) Leaf damage from grasshoppers (Source: STARS AgriSense team / Tanzania Agricultural Extension Service)
RS images, by virtue of their wide area coverage and repetitive acquisition, provide valuable information that can assist smallholder farmers to monitor their lands throughout the cropping season (Atzberger, 2013; Boschetti et al., 2009; Roy et al., 2014; Shang et al., 2015). To some extent, analysis of RS data can improve the identification of the above-mentioned stress factors in time and allow appropriate interventions. Despite its potential, there are a number of factors that limit the use of RS data for agricultural management (Zurita-Milla et al., 2015). This section of the portal demonstrates the potentials and limitations of RS in supporting smallholder farmers and agricultural managers to efficiently manage their fields for optimal results. It also informs policy-makers of the types of intervention that can be planned: e.g., large-scale application of fertilizers deserves a different action than large-scale water shortages.