Precision Techniques can make Horticulture Sustainable

• Precision horticulture can increase yields with fewer inputs. 
• These techniques optimize growing conditions by improving decision-making based on analyzed data to maximize fresh produce quality and yield. 
• Monitoring quality in all stages is crucial for horticulture crops. 
• Precision horticulture techniques are suitable for outdoor and indoor farms. 

Precision horticulture is becoming attractive as it reduces input use. While this approach has obvious advantages for the farmers, this form of cultivation is also important because it is more sustainable than conventional intensive farming methods. In addition, precision techniques are suitable for high-value horticultural crops, as they can increase economic returns. 

High-Value Crops 

Horticultural crops include vegetables, fruits, medicinal, ornamental, beverages, and aromatic plants. They are crucial for human nutrition as they provide proteins, vitamins, minerals, and nutraceuticals. Horticultural crops are used as table food or for processing.   

Indoor and outdoor ornamental crops also improve life’s quality and aesthetic value. In addition, many horticultural crops are grown on marginal land where grains cannot be raised and are instrumental in land restoration.  

Horticultural plants are high-value crops that are intensively cultivated. Many horticultural crops provide raw materials for producing perfumes, cosmetics, oils, paints, alcoholic and non-alcoholic beverages, confectionery, chemicals, and pharmaceuticals. 

Need for Sustainable Horticulture 

Fruits and vegetables, which are horticultural crops, are often consumed fresh and have unique challenges regarding marketing and transportation. In addition, these crops are perishable and have a high water content, making them more prone to post-harvest losses than grain crops. As a result, a significant portion of fresh produce is wasted, with estimates ranging from 40-50% for fruits, vegetables, and root crops, compared to 30% for cereals and 20% for oilseeds.

This loss represents a waste of food and resources like land, water, and inputs used to grow. On the other hand, the UN estimates that the population of people is expected to reach 9.7 billion by 2050. When that time comes, a 50% increase in food production will be necessary. To deliver more fresh food, we have to prevent farm losses. Therefore, avoiding hunger and providing proper nutrition is essential, and horticulture is a crucial tool. 

Like agriculture, the negative impacts of horticulture also arise from the management of soil fertility, irrigation, control of weeds, insects, diseases, water use, and greenhouse gas emissions. 

Optimizing horticulture to produce better quality food and avoid rejection can reduce food loss and waste of natural resources and improve ROI for growers.  

Moreover, horticulture often still involves a high degree of expensive manual labor, even in areas with mechanized farming. Any technique that improves the yield and quality of crops can increase farm returns. 

Sustainable horticulture aims at reducing input use and its environmental impact. It can also improve resource use efficiency, water quality, and soil biodiversity. Sustainable horticulture should also improve yield to increase economic and social benefits for the grower. 

Precision Horticulture  

Several methods of making horticulture sustainable, of which precision techniques are getting much attention.  

There are several ways to make horticulture, or the cultivation of plants for food, medicine, or other purposes, more sustainable. One approach that is gaining much attention is the use of precision techniques. 

Growers can produce more by optimizing the amounts and timing of their inputs. Since horticulture consumes many resources, using only necessary inputs for a single tree or farm patch can reduce investments to benefit farmers. In addition, when inputs are added in the required quantity, there is less wastage and pollution in the air, soil, and water.

By producing more with less, precision horticulture promises to provide food and valuable nutrition to a growing population with limited and shrinking land resources.  

There are two management principles that precision horticulture uses: 

• Variable-rate application of fertilizers, irrigation, and treatments for weeds, pests, and diseases, to provide optimal growing conditions for the plants in the orchards. 
• Quality control of fresh produce at all stages in the supply chain because of its perishable nature. 

Precision Technology 

Precision horticulture uses technology for data collection, analytics, and data management. Using the information, growers make decisions that guide the use of more technology to manage orchards. 

Data collection 

Site-specific data is collected through remote sensing equipment and field networks of sensors. Sensors and handheld portable devices collect plant-specific data. Geographic Information Systems (GIS) are used to create spatial maps of the data, see Figure 1. These maps aid decision-making and management in the orchard and connect them to stakeholder responses throughout the supply chain.  

Figure 1. “Yield, fruit quality (BRIX and flesh width) are mapped in precision horticulture,” Fountas, 2013. ( Image credits: http://www.ecpa2013.udl.cat/docs/9ECPA-Keynote-Fountas.pdf) 

Site-specific data 

Remote sensing through satellites or drones provides imagery of the field and crop health. The data collected by remote sensing is usually analyzed as a second step by specialized analytic providers who use various combinations of AI, machine learning, and computer vision to provide reports. 

Precision techniques in horticulture involve collecting data on various aspects of the production process, such as soil fertility, plant density, biomass, weeds, pests, and diseases. Famers can analyze this data to identify patterns and create maps that show areas of high fertility, productivity, or stress. Growers can then use this information to make informed decisions about managing their orchards and optimizing their production practices. For example, they may use the data to determine where to allocate resources such as water, fertilizers, and pest control measures or to identify areas that may require additional attention or intervention.

Sensors and the Internet of Things (IoT) are the mainstay of smart farming to find the water status of soil or even individual trees to identify irrigation needs. Analytics combines data from sensors and weather stations on farms to provide information for water management.  

Plant-specific data 

Plant data gives information for managing production and harvest. Plant sensors collect data about biotic and abiotic stress, canopy size, density, yield, and crop quality.   

Stress, canopy size, and density are used for making variable-rate applications. By appropriate thinning, it is possible to improve yield, reduce input use, and increase the sustainability of orchards. 

Plant-specific data is advantageous since many fruits are perennial trees with broader spacing than annual crops. These can be obtained from sensors or portable devices.   

Monitoring Fruit Quality on the Farm 

Figure 2: “Fruit quality and orchard operation information structure,” Bollen et al. ( Image credits: http://www.regional.org.au/au/gia/07/197praat.htm) 

Measuring fruit quality begins at the orchards even before they are ripe. Therefore, fruit quality depends on genetics and management practices like thinning, fruit load, nutrition, pest, and disease control, see Figure 2.    

Nowadays, sensors also monitor fruits; they track the fruit status to inform water management or fruit development to identify maturity to decide harvest time.  

Many handheld devices can collect data on the quality parameters of fruits in situ to decide harvest time. The standard parameters measured are dry matter content, soluble solid contents, internal color, and acidity. These devices also have chemometrics to provide predictive analytics immediately to show the relevant information.  

Some industry standards that can be used for a wide range of fruits are near-infrared spectroscopy-based quality meters that make non-destructive measurements, such as: 

• F-750 Produce Quality Meter
• F-751 Avocado Quality Meter
• F-751 Mango Quality Meter
• F-751 Kiwifruit Quality Meter

With portable instruments, it is possible to note differences between individual plants and different sides of a plant. For example, orchard owners know that fruits ripen faster on the sunny side and outer canopy than on the side in the shade or within canopies. Remote imagery cannot capture these nuances as it can’t reach lower and inner canopies. Sampling different parts of a tree gives a more accurate picture of fruits’ maturity development, helping in more precise decision-making. 

Post-Harvest Quality Control  

After harvest, these tools are also used for sorting fruits based on maturity for packaging and choosing produce for processing. In addition, quality control through the devices is necessary during transportation and storage to maintain quality, cull spoilt ware, choose fruits for retailing, and fix prices. 

The atmospheric conditions are also controlled during storage by monitoring the levels of the three critical gases, ethylene, oxygen, and carbon dioxide, using gas analyzers. Felix Instruments Applied Food Sciences tools can monitor ethylene mitigation systems, ripening, degreening, and storage to optimize fruit quality and reduce spoilage. 

There are also instruments to measure the quality of fresh produce in packaging by headspace and MAP analysis. 

Informed Decision-making Increases Sustainability 

Figure 3: Precision horticulture in greenhouses can reduce water consumption, van der Hoeven, 2017. (Image credits: https://www.biobasedpress.eu/2017/03/precision-horticulture-consumer-wants/) 

Data-driven precision horticulture can help growers in decision-making to improve several aspects of farming that will also make food production more sustainable: 

• Finetune harvest time using maturity indices based on the dry matter or BRIX will improve acceptance by retailers and consumers to reduce food waste. Moreover, early harvest can extend transport and storage time.   
• By improving growing conditions and farm operations, growers can boost dry matter content closely associated with consumer preference. 
• Monitoring fruit quality in post-harvest stages will further reduce fresh produce waste, increase yield sold, and reduce waste. 
• Help in food sorting and processing fruits and vegetables makes better use of harvest based on their quality. 

Precision techniques can optimize growth not only in open orchards but also in indoor farming and greenhouses. These closed environments allow growers to monitor and control growing conditions better than open fields. In addition, these cultivation methods increase food production by extending growing seasons, expanding the area in vertical farms, reducing water use through hydroponics, etc, see Figure 3. 

Challenges Ahead 

However, there are more challenges in applying precision techniques to perennials than annual crops. Many horticultural crops are perennial, and the temporal stability of the orchards is essential. Field and yield data have been necessary for many years to change tree management practices.  

Also, while data collection and analyzing technology is relatively well developed for small and big farms, technology for farm management is available only for big farms, like mechanical harvesters or smart irrigation systems. Most horticultural farms are small-scale, but there needs to be more precision technologies and practices for these small orchards, which must be developed. So growers have to conduct operations like spraying and harvesting by hand. These issues must also be addressed to ensure social sustainability in horticulture. 

Sources 

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Fountas, S. 2013. Precision Horticulture. Retrieved from http://www.ecpa2013.udl.cat/docs/9ECPA-Keynote-Fountas.pdf 

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Introduction to Horticulture – NCERT. (n.d.) Retrieved from https://ncert.nic.in/textbook/pdf/ievs101.pdf 

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