What is the effect of plowing time and herbicide dose on the structure of potato weeds? Can it be combated with the help of technology and science? Does climate change have an impact on the growth of agricultural products?

Potatoes are of great importance in agriculture and nutrition of the world's people, and in order to pay more attention to this product and its role in feeding people, especially to exploit its high production potential and nutritional value, the Food and Agriculture Organization of the United Nations (FAO) named 2008 the Year of the Potato (Agricultural Statistics, 2007). Currently, potatoes are cultivated in more than 140 countries around the world, and in some countries they are the staple food of the people and one of the most important agricultural products (Jafari Zare, 1997; Agricultural Statistics, 2007; Martin et al., 1976). Among the various agricultural products in the world, potatoes are ranked fourth after wheat, rice, and corn in terms of production volume (Fabrio et al., 2001).

According to the latest statistics from the Ministry of Agriculture in 2007, potatoes are cultivated in 79% of the world's countries (Agricultural Statistics, 2007). In 2000, FAO announced global potato production of nearly 321 million tons of tubers from 19.6 million hectares of cultivated area. The average global potato production is about 16 tons per hectare (Kashyap and Panda, 2001).

In Iran, the area under potato cultivation has gradually increased from about 128,092.1 hectares in the 1960s to 154,852.3 hectares in the 1970s and then to about 163,844 hectares in the 1985 crop year. During this period, the country's total production increased from 2,061,991 tons in the 1960s to 3,220,994 tons in the 1970s and then to about 4,218,522 tons in the 2006 crop year. The area under potato cultivation in East Azerbaijan Province in 2006 was 9,513 hectares and its yield in the same year was reported to be 30.7 tons per hectare (Agricultural Statistics, 2007).

One of the problems of potato cultivation, like other crops, is the widespread invasion of weeds, which reduce its yield. According to studies by Baziramakenga and Leroux (1994), a density of 150 plants per square meter of the plant and its competition with potatoes throughout the entire growing season reduced potato yield by a maximum of 78 percent. In experiments by Beltrano and Kaldiz (1993), it was found that the weed grass reduces potato yield by 28 to 68% depending on the degree of contamination of the field. ¬¬There are many weeds in the potato field that reduce the quantity and quality of the crop. Weed control during potato growth is essential to obtain higher yields and increase its quality. Research has shown that weeds that grow along with crops can reduce crop yield by competing for nutrients, space, light and moisture.

Weed damage to agricultural crops in developed countries has been reported to be about 10% with the application of different control methods and depending on environmental conditions, crop type and weed flora (Zimdahl, 1980; Takot, 1993). During the evolution of agriculture, humans and cropping systems have greatly influenced the formation and spread of weeds, making them an integral part of cropping patterns. Currently, various methods are used to control and reduce the effects of weeds in cropping systems, including chemical (herbicides), physical (fire), mechanical (ploughing), biological (natural enemies), and agronomic (planting date, density, and rotation) strategies (Kandra, 1990).

Although in recent years, weed control has increasingly relied on the use of various herbicides, significant success has not been achieved (Qorineh et al., 2004). The cost of using herbicides in weed control is 10 to 20 percent of production costs (Labrada, 2003). This has led to changes in the diversity of weed species in fields, one of which is the evolution of herbicide-resistant weeds (Schaner, 1995). In addition, the increasing trend in herbicide use has also brought about side effects such as adverse effects on the environment, human health, disruption of critical habitats, interference with agricultural operations, and reduced income (Leibman et al., 2004; Bazdereev et al., 2004). Therefore, efforts to reduce reliance on herbicide use for weed control while maintaining consistent yields can have a significant impact on net profit of agricultural products. In recent years, due to the long-term effects of herbicides on the environment and high economic costs, many farmers and researchers have been searching for alternative systems that rely less on herbicide use.

The selection of each agricultural operation should be done with awareness of the potential problems that weeds can cause in the field. Plowing is one of the agricultural operations whose timing can have a significant impact on weed management.

Plant invasion science is a relatively new research field dealing with the causes and consequences of organisms introduced into and invading areas outside their native range, and in the case of plants, mostly on species that conquer semi-natural and natural ecosystems. It is mainly driven by fundamental scientific questions and ecological theories, also by the practice of conservation, with a focus on community, ecosystem, and biogeography (Kueffer et al., 2013). In contrast, weed science has a long tradition supported by agronomy with good links to the private sector, and is mainly driven by practical management and control questions, and innovations in agricultural engineering (Hall et al., 2000; Fernandez-Quintanilla et al., 2008; Jordan et al., 2016). Its main focus is on cultivated land (i.e., the land used for producing major food and animal feed, including perennial crops and managed grassland) and the reduction of biomass at a site. This distinct history, focus,and approach between the two disciplines have recently been further elaborated by Müller-Schärer et al. (2018). Here we hypothesize that these differences between the two disciplines might also be evident on how consequences of future climate change for harmful plants and their management are being addressed. We acknowledge that both invasion and weed science also deal with harmful plants at historical places, in cities, and along linear transport structures, such as roads, railway tracts, and rivers, although not being their main focus. To account for and repeal this overlap, we excluded these habitat types in our literature survey. Anthropogenic climate changes driven by greenhouse gas emissions include increases in temperature and CO2 emissions, changing patterns of precipitation and the severity, and frequency of extreme climatic events (i.e., drought, flood, fires, intense storms, and heat waves). These changes are predicted to select on means and plasticities of plant traits and vital rates to better cope with these changing environmental conditions, with consequences for competitive interactions, local abundances, spread and impact on plant communities and ecosystems, and ultimately on ecosystem services and people’s livelihoods (Vilà et al., 2007). Climate change, especially effects of increased CO2 and temperature have been postulated to affect weed germination, emergence pattern, their competitive ability, and thus, also crop yield, but yet few studies experimentally addressed climate change effects on weed growth, water limitations, or herbicide efficiency (Ziska, 2016). Decreasing efficiency of herbicides under climate change may lead to an increased risk for the evolution of herbicide-resistant weeds (Matzrafi et al., 2016). Thus, for both invasive alien plants (IAP in the following) and weeds, these changes will also create a need for adapted control strategies as part of mitigation planning (Chauhan, 2020). This offers a wide range of climate features to elaborate upon, a variety of study questions and methods, and a multitude of impacts and outcomes to study, ranging from changes in functional traits, population dynamics, and distribution of the harmful plants up to their consequences for crop yield and ecosystem services. Here, we first conduct a literature survey to explore if and how studies on IAP differ from crop and grassland weeds when considering effects of climate change. These findings allow us then to identify the strengths and gaps, as well as the commonalities and differences when studying climate change effects in these disciplines, and to derive what can be learnt from each other for understanding, predicting, and mitigating outcomes of climate change. The fact that climate change studies are predominantly headed by researchers from Europe, followed by America and Asia, and least in Africa, as based on continent of the first author (Figure 1A), may reflect that the re-orientation in weed science toward including, among others, climate change issues, is still less advanced in Asia and Africa (Ward et al., 2014). Our finding that monocots are relatively more often studied in weed science than in invasion science is not surprising given the high number of monocot weeds in crop and grassland habitats as compared alien monocot species in non-crop habitats (Daehler, 1998). Main plant traits and responses driving population dynamics range from seed fate in the seed bank (Walck et al., 2011), physiological seed dormancy (Ooi et al., 2012), and accordingly seedling emergence pattern (Classen et al., 2010), relative growth rate (Bütof et al., 2012), morphological characteristics (Guerin et al., 2012) up to canopy structure (Pangga et al., 2013), seed production (Nguyen et al., 2017), environment maternal effects (Dwyer and Erickson, 2016), and shifts in the weed flora (Peters et al., 2014), all being sensitive to climate change effects. Climate change is expected to also highly influence herbicide effects via changing herbicide uptake, translocation, and metabolism (Varanasi et al., 2016). This may also break herbicide selectivity and cause crop damage (Jursík et al., 2020). Furthermore, resistant populations are expected to arise via changes in herbicide effects under climate change conditions (Refatti et al., 2019). However, climate change features on weed biology often have been studied in isolation, focusing on increase in temperature or CO2 only, and although such basic knowledge is getting more readily available, so far only few studies are addressing practical implementations to mitigate climate change effects. Invasion scientists so far only rarely investigated processes at a local range, such as plant traits and the population dynamics of IAP. On the other hand, modeling studies, often based on latitudinal or altitudinal climate gradients, have been used more often in plant invasion science, but could also be explored more often by weed scientists to address expected outcomes of climate change at a larger spatial scale. Studies on the impact of the target plants and on their management must be an important component of weed studies under climate change, as weed science, fundamentally, has been founded on the basis of weed management. Any study on biology, evolution, ecology, physiology, and population genetics is eventually looking for an approach to managing weeds (Zimdahl, 2018). In line with this, the main conclusions in weed science publications are expected to end up with a recommendation to manage undesirable vegetation (https:// www.cambridge.org/core/journals/weed-science/information/ instructions-for-authors). On the other hand, impact and management studies remain greatly neglected in plant invasion science (Figure 2G). Invasion science has recently made significant progress in classifying and conceptualizing invasion processes (Wilson et al., 2020) and in documenting the increasing number of invasions worldwide coupled with ever increasing costs for the society, but these achievements are of little help to practitioners confronted with alien invasive plants (Plank et al., 2016; Nkambule et al., 2017; Zhang et al., 2020). Thus, an increased focus on specific ecosystem and society impacts of the target plant and on its management is greatly in need when exploring outcomes of climate change for IAP, especially to mitigate climate change effects for areas of high conservation value presently under great risk from IAP (Slodowicz et al., 2018).