Analysis of the Status of Irrigation Management in North Carolina

Abstract

Farmers in North Carolina are turning to irrigation to reduce the impacts of droughts and rainfall variability on agricultural production. Droughts, rainfall variability, and the increasing demand for food, feed, fiber, and fuel necessitate the urgent need to provide North Carolina farmers with tools to improve irrigation management and maximize water productivity. This is only possible by understanding the current status of irrigated agriculture in the state and investigating its potential weaknesses and opportunities. Thus, the objective of this study was to perform a comprehensive analysis of the current state of irrigation management in North Carolina based on 15-year data from the Irrigation and Water Management Survey by the United States Department of Agriculture–National Agricultural Statistics Service (USDA-NASS). The results indicated a reduction in irrigation acres in the state. Also, most farms in the state have shifted to efficient sprinkler irrigation systems from gravity-fed surface irrigation systems. However, many farms in North Carolina still rely on traditional irrigation scheduling methods, such as examining crop conditions and the feel of soil in deciding when to irrigate. Hence, there are opportunities for enhancing the adoption of advanced technologies like soil moisture sensors and weather data to optimize irrigation schedules for improving water efficiency and crop production. Precision techniques and data-based solutions empower farmers to make informed, real-time decisions, optimizing water use and resource allocation to match the changing environmental conditions. The insights from this study provide valuable information for policymakers, extension services, and farmers to make informed decisions to optimize agricultural productivity and conserve water resources.

1. Introduction

As with most states in the southeastern region of the United States (U.S.), North Carolina’s climate has changed in recent decades, with evidence of increased annual average temperature, frequent occurrence of severe droughts, and significant rainfall variability [1,2]. This climatic variability poses significant challenges and threats to the sustainability and productivity of agriculture, an industry that is critical to the state’s economy [3]. The agricultural industry in North Carolina contributes billions of dollars to its economy through a wide range of products, including corn, soybeans, tobacco, cotton, and various fruits and vegetables [4]. For instance, the drought of 2007–2008 resulted in over USD 300 million in agricultural losses [5].

Despite the large annual rainfall amounts in North Carolina, it has been characterized by varying patterns over the years, mostly does not occur during the critical stages of plant growth, and can be absent for extended periods exceeding 30 to 60 days [6]. Rainfall variability has a substantial impact on the availability of water, soil moisture levels, and the overall health and yield of crops [7,8]. Additionally, droughts can cause significant crop losses due to insufficient water, negatively affecting farmers’ economic stability and overall food supply chain [9]. During severe droughts experienced in the 2007–2008 growing seasons in North Carolina, corn and soybean yields declined by up to 50% due to water stress [10]. Other researchers have also reported the negative impacts of droughts on agricultural production in other regions [11]. To alleviate these adverse impacts, farmers must adopt efficient irrigation management strategies to manage water resources effectively and sustainably [12]. Adopting these measures is crucial for maintaining a dependable water supply during periods of drought and for improving the ability of crops to withstand and produce under challenging conditions [13,14,15].

Generally, irrigation management is less complex in areas with little or no rainfall because water is usually applied to replace crop evapotranspiration (ET), which several methods can estimate [16]. In more humid regions like North Carolina, where significant rainfall occurs, soil water replenishment and storage by rainfall must be considered, along with an estimate of evapotranspiration supplied [17]. Because rainfall is frequent and contributes substantially to plant water needs, such areas may benefit from precision technologies and data-driven approaches like computer models to develop irrigation schedules [18]. Innovative precision irrigation technologies, such as soil moisture and plant sensors, have shown great potential in optimizing water use and improving crop yields [19,20]. These technologies precisely monitor soil and plant conditions, allowing for more efficient and targeted irrigation [21]. Soil moisture sensors offer real-time data on soil water content, aiding farmers in making informed decisions about irrigation timing and amounts [22]. However, despite the benefits of these technologies to increase water use efficiency and improve agricultural yields, the research focused on their application and effectiveness under North Carolina’s specific climatic and soil conditions is limited.

Region-specific studies on irrigation are critical for benchmarking, exploring challenges and opportunities, and assessing farmers’ uptake of the different technologies and strategies [15,23]. Specific to North Carolina, there is a lack of information in the literature about the status of irrigation management in North Carolina. Thus, this study aims to investigate the current status of irrigation management in North Carolina using the USDA-National Agricultural Statistics Service (NASS) survey data from 2003 to 2018. The findings of this study will provide a comprehensive overview of the current state of irrigation and highlight opportunities for adopting advanced irrigation practices. This study will provide information to local farmers and agricultural stakeholders and contribute to a broader understanding of sustainable irrigation practices in the southeastern United States. This study will also contribute to the global efforts to optimize water use in agriculture, particularly in regions with similar climatic conditions, agricultural practices, and resource limitations.

2. Materials and Methods

2.1. Study Area

North Carolina is located between 34°–36°21′ N latitude and 75°30′–84°15′ W longitude in the southeastern region of the U.S. (Figure 1). The state covers approximately 52,664 mi² (136,399 km²). It is characterized by a humid subtropical climate with hot, humid summers, mild winters, and susceptibility to extreme weather events such as hurricanes, heavy rainfall, and prolonged periods of drought [2]. North Carolina’s climate is variable across the state due to changes in topography, ranging from 46 m in the eastern coastal areas to 1829 m in the western mountain areas [24].

2.2. Data

Published survey data from the Irrigation and Water Management Survey (formerly called the Farm and Ranch Irrigation Survey) for the state of North Carolina collected by the United States Department of Agriculture–National Agricultural Statistics Service (USDA-NASS) were utilized for this study. The survey was conducted over five-year intervals, and this study used data from 2003 to 2018. Specifically, the analysis was performed for 2003, 2008, 2013, and 2018. This study analyzed data for the number of farms that practice irrigation, sources of irrigation information for farmers, methods used to make irrigation scheduling decisions, and the irrigation methods used. The analysis of the data was performed in Microsoft Excel.

3. Results and Discussion

3.1. Irrigated Farms and Acres

There has been a consistent decrease in the number of irrigated acres in North Carolina since 2003, as shown in Figure 2.

The results show a 54% reduction in irrigated farms between 2003 and 2018. In 2003, irrigated farms in North Carolina constituted about 13% of all the farms in the state. This gradually decreased to 11%, 9%, and 8% in 2008, 2013, and 2018, respectively. Several reasons were identified from the survey analysis explaining why irrigated farms decreased in the state. For instance, about 37% of the irrigated farms in the state discontinued irrigation due to sufficient soil moisture in 2003 (Figure 3). “Sufficient moisture” was identified as the main reason farmers discontinued irrigation on their farms in the state. This is logical, considering the significant total annual rainfall received in North Carolina. The total annual rainfall in North Carolina for the surveyed years ranged from 800 mm to 1600 mm [25].

These results suggest that the survey period, particularly for 2003, had abundant rainfall to meet crop water needs. However, there is evidence that the state experiences recurring droughts and erratic summer weather patterns, and rain does not always fall during the critical crop growth stages. Furthermore, the decline in irrigated farms may be attributed to the conversion of farmlands to other non-agricultural land uses [26]. According to the American Farmland Trust (AFT) [27], North Carolina is ranked second, after Texas, in terms of the susceptibility of agricultural land to conversion for reasons other than agriculture. The complex relationship between urban expansion and agriculture in North Carolina has significant impacts on agricultural production. Urbanization generally results in reduced farmland, particularly the number of irrigated farms. Irrigated farms only constituted an average of 10% of the total farms in North Carolina in the surveyed years. Thus, these existing farms in North Carolina require effective irrigation management to improve agricultural production, which is crucial to the state’s economy.

3.2. Irrigated Farm Acres by the Size of Farms

Figure 4 shows the number of irrigated farms by farm size in North Carolina. The analysis of farm sizes showed that about 88% of the irrigated farms were less than 1000 acres.

These results suggest that most irrigated lands in the state are small or medium-sized farms that cultivate high-value commodities, including vegetables, fruits, and field crops. These results concur with the findings of Hoppe [28], who reported that small farms account for more than 90% of the total number of farms in the U.S. According to the USDA, small farms are 179 acres or less in size or earn USD 50,000 or less in gross income per year [4]. Most specialty crops grown in North Carolina are produced by small farms, highlighting their significant contribution to the state’s agricultural industry [29]. Understanding farm size dynamics is essential for developing effective irrigation management strategies, as different farm sizes may have distinct water use patterns, technological needs, and economic constraints [30]. Further research is warranted to investigate these dynamics and their implications for water conservation efforts, agricultural productivity, and the long-term sustainability of irrigated agriculture in the region.

3.3. Irrigated Acres by Irrigation Methods

Figure 5 shows that there was about a 62% increase in the land irrigated by sprinkler irrigation systems between 2003 and 2008. The increased adoption of sprinkler systems during this period was likely motivated by the need to improve irrigation efficiency [31]. The results showed slight reductions in the use of sprinkler systems by about 9% and 5% in 2013 and 2018, respectively. Possible causes for this decline could encompass farmers moving to drip or trickle irrigation systems, economic influences, or a shift in the cultivation of crops that necessitate alternative irrigation systems. The use of drip, trickle, or low-flow micro irrigation systems in North Carolina increased by 80% between 2003 and 2013, followed by a slight drop of approximately 3% in 2018.

Sprinkler irrigation dominates the irrigation systems in North Carolina, as shown in Figure 5. The pattern follows the trend in the U.S., particularly in the West, to adopt efficient center-pivot irrigation systems [32]. This shows that more farmers in North Carolina are moving towards precision agriculture, which focuses on minimizing agricultural water consumption and enhancing the effectiveness of water distribution [33]. The slight decrease in 2018 could be attributed to costs or evolving agricultural practices. The total area irrigated by gravity flow systems was generally small in all the surveyed years compared to other irrigation types. By 2018, the land area under gravity irrigation had decreased by 18% compared to 2003. Gravity irrigation systems are known for their low irrigation efficiencies compared to other irrigation systems [34]. They rely on the characteristics of the land and are less efficient compared to pressurized systems [35,36]. The efficiency of gravity irrigation systems ranges from 40% to 70%, while that of pressurized systems ranges from 70% to 95% [37,38]. In contrast, pressurized systems are typically more efficient because they experience less water loss due to evaporation and deep percolation [39]. These trends in the irrigation types used in North Carolina appear to be influenced by various causes, such as the advancement of irrigation technology, increasing water expenses, improvement in awareness of the importance of water conservation due to sustainability concerns, and shifts in crop patterns necessitating alternative irrigating methods [40]. The results suggest that farmers need constant support in adopting water-conserving irrigation technology to enhance agricultural production [41].

The choice of irrigation systems by farmers is also influenced by other factors. The diversity in soil composition, from sandy soils in the coastal plains to clayey soils in the Piedmont regions of North Carolina, coupled with the variation in crop types and microclimates, indicates that the irrigation practices may need adjustment to suit specific regional conditions. For instance, areas with sandy soils may require more frequent irrigation schedules than regions with loamy or clay soils, which retain moisture for longer periods [42,43].

3.4. Irrigation Scheduling Methods

Figure 6 shows the number of farms categorized by the method for making irrigation scheduling decisions in North Carolina. The irrigation scheduling methods used by farmers in North Carolina include looking at the condition of the crop, the feel of soil, personal scheduling, evapotranspiration-based scheduling, soil moisture sensors, commercial and government services, and water supplier-based recommendations.

The results show that farmers in North Carolina mostly rely on crop conditions and the feeling of the soil to make irrigation scheduling decisions. The data for the year 2013 recorded the highest number of farms making irrigation scheduling decisions based on the condition of the crops, with 2408 farms. Relying only on crop appearance and the feeling of the soil may be subjective and inclined to potential inaccuracies. These traditional methods do not consider the conditions below the soil surface to determine the current soil moisture. As a result, such methods may not identify problems until plants show signs of water stress, which may be too late for effective intervention. Additionally, soil moisture assessment by feeling the soil is subjective and can differ based on individual experience. The approach lacks the quantitative data necessary for accurate irrigation management, which can result in the possibility of excessive or insufficient irrigation. Personal scheduling was the third highest-ranked method for irrigation scheduling in North Carolina during all the survey years. This type of irrigation scheduling may be based on routine or convenience rather than actual crop needs, leading to irrigation inefficiencies and loss of crop yields. It ignores real-time soil and weather conditions, which may result in applying water when it’s not needed or missing the best times for irrigation [44]. Using scientific data-driven irrigation scheduling methods such as soil moisture devices and daily evapotranspiration is relatively low in North Carolina. These results suggest that opportunities exist in North Carolina to improve irrigation management by adopting precision techniques to enhance water efficiency and crop yields and implementing innovative outreach programs.

Effective irrigation scheduling strategies are crucial in North Carolina to reduce the growing risks associated with frequent droughts and erratic summer precipitation, both of which threaten the stability and productivity of the state’s agriculture. Various commercially available soil water sensing systems have been designed to schedule irrigation effectively [45]. These devices include tensiometers, neutron probes, heat pulse sensors, fiber optic sensors, soil resistivity sensors (porous blocks), and electromagnetic (EM) sensors [46,47]. Soil water sensing technology has advanced over the years, allowing farmers to make well-informed irrigation timing and quantity decisions. North Carolina farmers can utilize these technologies to optimize their irrigation schedules according to the specific requirements of their crops, thereby lowering water consumption and waste. The soil moisture sensing devices can be incorporated into decision support systems that gather data from multiple sources, such as weather forecasts, crop models, and historical climate data [48]. These data help farmers decide when and how much to irrigate. The sensor technologies can also assist farmers in predicting water requirements before the emergence of stress indicators in the crops, enabling them to adopt proactive irrigation strategies instead of reactive ones.

To improve the adoption of soil moisture sensors in North Carolina, stakeholders such as agricultural professionals, government organizations, technology providers, and farmer cooperatives should cooperate to share knowledge and offer access to these technologies effectively [49]. Training programs and demonstration projects can enhance farmers’ proficiency and confidence in utilizing soil moisture sensing equipment [50]. Policymakers can promote the implementation of precision irrigation technologies by offering financial incentives, providing refunds for technology adoption, or implementing cost-sharing schemes [51]. These regulations can mitigate the upfront costs and enhance the affordability for farmers to adopt cutting-edge irrigation management practices. Implementing irrigation scheduling in North Carolina, enhanced by soil moisture sensing technologies and facilitated by a cooperative network of participants, is a fundamental component in addressing the persistent difficulties presented by climate change [6].

3.5. Irrigated Acres by Sprinkler Methods

The utilization of the center-pivot irrigation systems has shown substantial and steady growth, expanding from 10,696 acres in 2003 to 64,066 acres in 2018 (Figure 7).

The significant expansion of the system is likely attributable to its high efficiency and efficacy in distributing water over large areas on the farm. The utilization of the big gun irrigation system reached its highest point in 2003, covering an area of 33,583 acres. However, there was a decline in subsequent years, with the system only covering 11,415 acres by 2018. The drop may be attributed to a shift towards more efficient center-pivot systems, as big gun irrigation systems throw water droplets high in the air, promoting higher evaporation rates [52]. The results also showed an 80% reduction in the utilization of hand-move techniques in North Carolina, decreasing from 3055 acres in 2003 to 604 acres by 2018. The labor-intensive nature of this method is likely to have caused this significant drop, indicating that farmers are increasingly implementing automated methods to lower labor costs and enhance productivity. The utilization of linear move systems also declined from 2250 acres in 2003 to 604 acres in 2018. The decline in this system may be attributed to its limited applicability to certain field shapes and the higher investment required compared to alternative systems. Overall, the results demonstrate a shift towards utilizing the center-pivot irrigation systems, emphasizing their position as a leading technology in field irrigation in North Carolina. The general transition from labor-intensive techniques that require manual labor and are less efficient, like the big gun and hand-move irrigation systems, illustrates a broader pattern in agriculture towards mechanization and improved water management [13].

3.6. Sources of Irrigation Information Used by Farmers

In all the survey years, the analysis showed that most farms in North Carolina prefer obtaining irrigation information from university specialists (Figure 8), with about 28% in 2003 and 38% in 2018.

These results show that farmers in North Carolina increasingly rely on academic expertise and scientific research to inform their irrigation decisions, indicating a growing trust in research-based information. In 2003, more than 25% of farmers depended on neighboring farmers as their primary source of information. However, their impact has gradually decreased, reaching just below 12% by 2018. The decrease in reliance on traditional sources of information may be attributed to improved outreach approaches by cooperative extension agents and the increasing adoption of advanced technology in agriculture [53]. The dependence on equipment dealers is also significant in North Carolina, increasing from 15% in 2003 to 22% in 2018. This phenomenon may be attributed to the dynamic nature of irrigation technology and the essential role played by dealers in communicating up-to-date information regarding the most recent equipment and systems. The utilization of electronic information experienced a significant increase from 7% in 2003 to 12% in 2008, subsequently declining to 8% in 2018. The initial rise can be attributed to technological advancement, while the later decline may be related to the abundance of online information, which can occasionally be of inconsistent quality. The farmers’ reliance on private consultants for irrigation information ranged between 5% and 9% throughout the survey. Although still considered a valuable resource, farmers may be more drawn towards obtaining information directly from technology dealers and academic specialists. The percentage of farms relying on information from federal agents and media was not significantly different from 2003 to 2018, but these sources experienced a 1% decline. This implies that although government guidance and media may be valuable sources of agricultural information, farmers in North Carolina now prioritize obtaining more specialized information from universities and dealers rather than relying on general news. A small proportion of farms depended on their water supplier for irrigation information for all the survey years. It appears most farms in North Carolina have their primary water sources on site, such as streams and ponds, and therefore do not depend on suppliers for irrigation water.

The diversity of irrigation information sources reflects a more extensive ecosystem where many stakeholders work with farmers. The rise in specific sources indicates a preference for accuracy, durability, and the implementation of data-driven methods in agriculture. The decline in other domains highlights the necessity for farmers to have access to reliable and applicable information that they can directly implement in their operations. The methods of sharing information are evolving into a more integrated network where various stakeholders exchange information and actively collaborate with farmers to ensure that knowledge is effectively utilized. This transformation includes continuous assistance, the creation of technological interfaces that are easy for users to navigate, and the promotion of knowledge exchanges within the community so farmers may trade experiences and solutions.

3.7. Potential Innovative Irrigation Management and Outreach Programs

Several studies have highlighted the critical role that agricultural extension services play in technology adoption decisions, specifically irrigation technologies [54,55,56]. Effective outreach campaigns specifically designed to address North Carolina’s distinct climatic challenges are essential for promoting modern irrigation management techniques, given the economic significance of agriculture in the state [57]. Extension programs associated with universities have served as a long-standing relationship between academic research and the farming community [58]. These programs offer farmers the opportunity to acquire knowledge about cutting-edge technology in soil moisture sensing and gain expertise in interpreting and utilizing the data generated by these technologies. Establishing demonstration sites on local farms can effectively demonstrate the practical advantages of climate-smart irrigation scheduling techniques. The demonstration sites can serve as primary hubs for farmers to directly observe the effects of these technologies on water preservation and agricultural productivity. Regular and organized educational workshops and seminars are crucial in ensuring that farmers know the most effective methods and techniques. Furthermore, these events can serve as a platform for farmers to exchange their knowledge and perspectives with colleagues, promoting a community dedicated to acquiring knowledge and generating new ideas [59].

The development and promotion of mobile apps and Internet of Things (IoT) devices that offer convenient access to irrigation scheduling tools have the potential to transform water management [60]. These applications can potentially provide farmers with up-to-date information, notifications, and suggestions directly on their smartphones, hence enhancing the accessibility and user-friendliness of the technology [61]. Partnerships among the government, corporate entities, and research organizations can expedite advancing and implementing irrigation technology for precision agriculture [62]. These collaborations can also offer financial support and incentives for farmers who are eager to embrace these advancements. By including the younger generation in schools and community initiatives, the long-term viability of agricultural advancements can be guaranteed. Young people can learn about water conservation early on through agricultural youth programs emphasizing irrigation technologies. Establishing drought response teams comprising skilled farmers, extension agents, and scientists can also offer vital assistance during water scarcity. These teams can provide quick guidance and support, helping to reduce the adverse effects of droughts on crop yield. Providing subsidies or tax incentives for farmers to buy soil moisture sensors and other irrigation management systems might help reduce the initial financial strain. Also, cost-sharing initiatives can enhance the feasibility of farmers’ investments in this technology, such as the agricultural cost-sharing program by the Chesapeake Bay Foundation [62]. Creating customized irrigation management plans can assist farmers in implementing the fundamental principles of irrigation scheduling that fit the specific needs of their farms. Extension specialists or private consultants can help farmers in developing individualized programs. North Carolina can guarantee that its farmers are adequately prepared to confront the difficulties of contemporary agriculture in a shifting climate by executing these inventive outreach initiatives and providing them with the essential knowledge, resources, and technology. These initiatives help preserve precious water supplies and enhance the overall resilience and sustainability of North Carolina’s agricultural industry.

4. Conclusions

This study analyzed the state of irrigation in North Carolina based on the published data in the Irrigation and Water Management Survey (previously known as the Farm and Ranch Irrigation Survey) conducted over five-year intervals from 2003 to 2018 by the USDA–National Agricultural Statistics Service (USDA NASS). The results showed a decrease in the number of irrigated farms in North Carolina between 2003 and 2018. Also, most farms in the state have shifted to efficient sprinkler irrigation systems from gravity-fed surface irrigation systems. However, most farms in North Carolina still rely on traditional irrigation scheduling methods, such as examining crop conditions and the feel of soil in deciding when to irrigate. Overall, opportunities exist in North Carolina to improve irrigation management by adopting precision techniques to enhance water efficiency and crop yields and implementing innovative outreach programs. Further research should investigate the performance of precision irrigation technologies and the impediments to their adoption for North Carolina conditions. There is also a need to investigate the combined effects of multiple environmental factors, including temperature, humidity, and unexpected weather events, on irrigation management. By developing models that integrate these variables, researchers can create more robust and adaptable irrigation strategies that better reflect the complexities of real-world agricultural conditions.