Review and analysis of perennial cereal crops at different maturity stages

The article presents an overview of perennial grain crops, gives a comparative characteristic of annual winter wheat and perennial grain crops such as Trititrigia (Trititrigia cziczinii Tsvelev), Thinopyrum intermedium, perennial rye (Secale cereale L) and perennial sorghum (Sorghum x derzhavinii Tzvel.). The study aims to consider the main perennial crops grown in Russia and in the world, to compare their quality indicators, sowing agrotechnical requirements, cultivation conditions, yields, and to justify the choice of perennial crops that meet the needs and climatic conditions of the Rostov region. Presented is the generalized information on the grain quality changes during maturation, ripeness phases of grain crops are considered. Based on the review, the optimal ripeness phases, at which it is advisable to harvest are presented. Literature review showed that in the phase of lactic (мoлoчнaя cпeлocть) and wax maturity (вocкoвaя cпeлocть) wheat grain contains the greatest amount of basic nutrients. It was found that perennial crops have a positive effect on the state of the soil: prevent its erosion and depletion; there is an accumulation of carbon, soil methane CH 4. Comparative characterization of perennial crops with annual crops shows increased protein content - on average 2-3% higher. Also considered are the green mass quality indicators of perennial crops as a source of nutrients in the feed-production technology.

Review and analysis of technologies for harvesting perennial grain crops

In agriculture, according to the data of the statistical collection, the production of grain crops occupies a large part. At the moment, much attention is paid to the study of perennial crops such as Thinopyrum intermedium and Trititrigia cziczinii Tsvelev. These crops help to: slow down soil erosion, protect water resources, and minimize the leaching of nutrients [1,2]. The non-cereal part of the crop is a significant reserve for strengthening the fodder base of animal husbandry, expanding the range of sources of raw materials for the microbiological industry in the production of fodder proteins. The article provides an overview of technologies and equipment for harvesting grain crops, on the basis of which one of the optimal harvesting method for perennial crops is distinguished - stripping. Based on the results of the literature review, the main technologies used for harvesting grain crops were identified: direct and indirect singlephase and two-phase combine harvesting technologies; one-, two- or three-phase non-combine harvesting technologies including the “neveika” method; standing stripping technology. The purpose of this article is to review existing harvesting technologies and equipment, selection of the optimal harvesting technology for perennial crops such as Trititrigia cziczinii Tsvelev and Thinopyrum intermedium.

Economic Evaluation of the Production of Perennial Crops for Energy Purposes—A Review

Biomass is widely used for the production of renewable energy, which calls for an economic evaluation of its generation. The aim of the present work was to review the literature concerning the economic evaluation of the production of perennial crop biomass for energy use. Statistical analysis of the bibliographic data was carried out, as well as an assessment of methods and values of economic indicators of the production of perennial crops for bioenergy. Most of the papers selected for the review were published in the years 2015–2019, which was probably stimulated by the growing interest in sustainable development, particularly after 2015, when the United Nations declared 17 sustainable development goals. The earliest articles concerned the economic analysis of plantations of short rotation coppice; the subsequent ones included the analysis of feedstock production in terms of the net present value and policy. The latest references also investigated transport and sustainability issues. The crops most commonly selected for production cost analysis were willow, poplar, and Miscanthus. The cost of production of willow and poplar were similar, 503 EUR ha−1 year−1 and 557 EUR ha−1 year−1, respectively, while the cost of Miscanthus production was significantly higher, 909 EUR ha−1 year−1 on average. By analogy, the distribution of revenue was similar for willow and poplar, at 236 EUR ha−1 year−1 and 181 EUR ha−1 year−1; Miscanthus production reached the value of 404 EUR ha−1 year−1. The economic conditions of perennial crop production differed in terms of geography; four areas were identified: Canada, the USA, southern Europe, and central and northern Europe.

Comparing the Deep Root Growth and Water Uptake of Intermediate Wheatgrass (Kernza®) to Alfalfa.

AimsWater is the most important yield-limiting factor worldwide and drought is predicted to increase in the future. Perennial crops with more extensive and deep root systems could access deep stored water and build resilience to water shortage. In the context of human nutrition, perennial grain crops are very interesting. However, it is still questionable whether they are effective in using subsoil water. We compared intermediate wheatgrass (Kernza®) Thinopyrum intermedium, a perennial grain crop, to alfalfa Medicago sativa, a perennial forage, for subsoil root growth and water uptake.MethodsUsing TDR sensors, deuterium tracer labelling, minirhizotrons and the Hydrus-1D model we characterised the root distribution and water uptake patterns of these two perennial crops during two cropping seasons under field conditions down to 2.5 m soil depth.ResultsBoth crops grew roots down to 2.0 m depth that were active in water uptake but alfalfa was deeper rooted than intermediate wheatgrass. All experimental methods concluded that alfalfa used more water from below 1.0 m depth than intermediate wheatgrass. However, simulations predicted that intermediate wheatgrass used more than 20 mm of water after anthesis from below 1 m soil depth. Simulations confirmed the advantage of deep roots in accessing deep soil water under drought.ConclusionsIn regions with high groundwater recharge, growing deep-rooted perennial crops have great potential to exploit deep soil water that is often left unused. However, the road to a profitable perennial grain crop is still long and breeding intermediate wheatgrass (Kernza®) cultivars for increased root growth at depth seems to be a worthy investment for the development of more drought tolerant cultivars.

Perennial Crop Dynamics May Affect Long-Run Groundwater Levels

During California’s severe drought from 2011 to 2017, a significant shift in irrigated area from annual to perennial crops occurred. Due to the time requirements associated with bringing perennial crops to maturity, more perennial acreage likely increases the opportunity costs of fallowing, a common drought mitigation strategy. Increases in the costs of fallowing may put additional pressure on another common “go-to” drought mitigation strategy—groundwater pumping. Yet, overdrafted groundwater systems worldwide are increasingly becoming the norm. In response to depleting aquifers, as evidenced in California, sustainable groundwater management policies are being implemented. There has been little modeling of the potential effect of increased perennial crop production on groundwater use and the implications for public policy. A dynamic, integrated deterministic model of agricultural production in Kern County, CA, is developed here with both groundwater and perennial area by vintage treated as stock variables. Model scenarios investigate the impacts of surface water reductions and perennial prices on land and groundwater use. The results generally indicate that perennial production may lead to slower aquifer draw-down compared with deterministic models lacking perennial crop dynamics, highlighting the importance of accounting for the dynamic nature of perennial crops in understanding the co-evolution of agricultural and groundwater systems under climate change.