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"Sowing"
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Climate-driven simulation of global crop sowing dates
Aim: To simulate the sowing dates of 11 major annual crops at the global scale at high spatial resolution, based on climatic conditions and crop-specific temperature requirements. Location: Global. Methods: Sowing dates under rainfed conditions are simulated deterministically based on a set of rules depending on crop-and climate-specific characteristics. We assume that farmers base their timing of sowing on experiences with past precipitation and temperature conditions, with the intra-annual variability being especially important. The start of the growing period is assumed to be dependent either on the onset of the wet season or on the exceeding of a crop-specific temperature threshold for emergence. To validate our methodology, a global data set of observed monthly growing periods (MIRCA2000) is used. Results: We show simulated sowing dates for 11 major field crops world-wide and give rules for determining their sowing dates in a specific climatic region. For all simulated crops, except for rapeseed and cassava, in at least 50% of the grid cells and on at least 60% of the cultivated area, the difference between simulated and observed sowing dates is less than 1 month. Deviations of more than 5 months occur in regions characterized by multiple-cropping systems, in tropical regions which, despite seasonality, have favourable conditions throughout the year, and in countries with large climatic gradients. Main conclusions: Sowing dates under rainfed conditions for various annual crops can be satisfactorily estimated from climatic conditions for large parts of the earth. Our methodology is globally applicable, and therefore suitable for simulating sowing dates as input for crop growth models applied at the global scale and taking climate change into account.
Journal Article
Large-scale characterization of drought pattern: a continent-wide modelling approach applied to the Australian wheatbelt – spatial and temporal trends
* Plant response to drought is complex, so that traits adapted to a specific drought type can confer disadvantage in another drought type. Understanding which type(s) of drought to target is of prime importance for crop improvement. * Modelling was used to quantify seasonal drought patterns for a check variety across the Australian wheatbelt, using 123 yr of weather data for representative locations and managements. Two other genotypes were used to simulate the impact of maturity on drought pattern. * Four major environment types summarized the variability in drought pattern over time and space. Severe stress beginning before flowering was common (44% of occurrences), with (24%) or without (20%) relief during grain filling. High variability occurred from year to year, differing with geographical region. With few exceptions, all four environment types occurred in most seasons, for each location, management system and genotype. * Applications of such environment characterization are proposed to assist breeding and research to focus on germplasm, traits and genes of interest for target environments. The method was applied at a continental scale to highly variable environments and could be extended to other crops, to other drought-prone regions around the world, and to quantify potential changes in drought patterns under future climates.
Journal Article
Colonization resistance and establishment success along gradients of functional and phylogenetic diversity in experimental plant communities
1. Functional and phylogenetic diversity (FD and PD respectively) of the resident community are expected to exert a key role in community resistance to colonization by surrounding species, and their establishment success. However, few studies have explored this topic experimentally or evaluated the interactive effects of these diversity measures. 2. We implemented a diversity experiment to disentangle the role of FD and PD by sowing mixtures of 6 species, drawn from a pool of 19 species naturally coexisting in central European mesic meadows. The mixtures were designed to cover four independent combinations of high and low FD and PD. Species covers were estimated in spring and late summer over two growing seasons. We then assessed the establishment success of colonizers as a function of their mean traits and phylogenetic distance to the resident (i.e. sown) communities, as well as the resistance of the resident communities to natural colonizers as a function of their functional and phylogenetic structure. 3. Results generally indicated a temporal shift regarding which trait values made a colonizer successful, from an acquisitive strategy in early stages to a more conservative trait syndrome in later stages. 4. FD decreased community resistance to natural colonization. However, PD tempered this effect: with high PD, FD was not significant, suggesting complementary information between these two components of biodiversity. On average, colonizing species were more functionally distant from the resident species in sown communities with high functional diversity, i.e. those that were more colonized. 5. Synthesis. Our results confirm an interplay between FD and PD during community assembly processes, namely resistance to colonizers, suggesting that these two descriptors of biodiversity only partially overlap in their contribution to the overall ecological structure of a community. The hypothesis that higher FD increases resistance through a more complete use of resources was challenged. Results rather suggested that greater FD could provide an unsaturated functional trait space allowing functionally unique species to occupy it.
Journal Article
Grassland management impacts on soil carbon stocks: a new synthesis
Grassland ecosystems cover a large portion of Earths' surface and contain substantial amounts of soil organic carbon. Previous work has established that these soil carbon stocks are sensitive to management and land use changes: grazing, species composition, and mineral nutrient availability can lead to losses or gains of soil carbon. Because of the large annual carbon fluxes into and out of grassland systems, there has been growing interest in how changes in management might shift the net balance of these flows, stemming losses from degrading grasslands or managing systems to increase soil carbon stocks (i.e., carbon sequestration). A synthesis published in 2001 assembled data from hundreds of studies to document soil carbon responses to changes in management. Here we present a new synthesis that has integrated data from the hundreds of studies published after our previous work. These new data largely confirm our earlier conclusions: improved grazing management, fertilization, sowing legumes and improved grass species, irrigation, and conversion from cultivation all tend to lead to increased soil C, at rates ranging from 0.105 to more than 1 Mg C·ha⁻¹yr⁻¹. The new data include assessment of three new management practices: fire, silvopastoralism, and reclamation, although these studies are limited in number. The main area in which the new data are contrary to our previous synthesis is in conversion from native vegetation to grassland, where we find that across the studies the average rate of soil carbon stock change is low and not significant. The data in this synthesis confirm that improving grassland management practices and conversion from cropland to grassland improve soil carbon stocks.
Journal Article
Production performance and stability of mixed forage grasslands improved by planting proportion and mode in Horqin sandy land, China
Sowing mixed artificial grassland can aid grassland husbandry and restoration. However, the optimal mix and sowing mode for forage grass and legume grass in Horqin Sandy Land, China, remains unidentified. In this study, grassland production performance and stability were investigated using three mixed-sowing modes (peer-mixed, cross-mixed, and intercropping) and five mixed sowing ratios (awnless brome: alfalfa at 1:0, 1:1, 3:2, 2:1, 5:2, 3:1, 0:1). The cross-mixed sowing mode with a 2:1 ratio had the highest yields and greatest total nitrogen accumulation. All treatments had a land equivalent ratio ≥ 1, and C3 (cross-mixed at a 2:1 ratio, 2021 and 2022) had the largest value. The C3 treatment had the highest LERN, which was not significantly different from those of C1 (cross-mixed at a 1:1 ratio), C2 (cross-mixed at a 3:2 ratio), I2 (intercropping at a 3:2 ratio), and I3 (intercropping at a 2:1 ratio) treatments in 2021 and 2022. The sustainable yield index of C3 was significantly higher than those of the other treatments, excluding C2 (
P
< 0.05). TOPSIS evaluation indicated that cross-mixing at a 2:1 ratio is ideal and represents a crucial intercropping technique for establishing efficient and sustainable grassland ecosystems, which could further facilitate animal husbandry development.
Journal Article
Growth and Yield Responses of Soybean to Row Spacing and Seeding Rate
Some growers in northern latitudes plant soybean [Glycine max (L.) Merr.] with a row crop planter in 0.38 m rows, but an economic analysis concluded that drilled soybean in rows <0.25 m was optimum in the North-Central United States. We planted two varieties in 0.19, 0.38, and 0.76 m rows at 321,000; 371,000; 420,000; and 469,000 seeds ha-1 in New York in 2008 and 2009 to evaluate how soybean compensates to wide rows or low seeding rates in the Northeast United States. Soybean had limited compensation in biomass, pods, and seeds plant-1 at wider rows so row spacing had linear responses for biomass accumulation (598, 554, and 497 g m-2 in 0.19, 0.38. and 0.76 m rows, respectively) and leaf area index (LAI, 3.64, 3.47, and 3.16) at seed initiation; pod (1012, 935, and 875 pods m-2) and seed density (2272, 2230, and 2072 seeds m-2, respectively) at harvest; and yield (3.37, 3.12, and 2.86 micrograms ha-1, respectively). Compensation in biomass, pods, and seeds plant-1 at lower seeding rates resulted in similar biomass accumulation (528-570 g m-2), LAI (3.38-3.46), pod (921-965 pods m-2), and seed densities (2123 to 2234 seeds m-2) across seeding rates. Nevertheless, yield showed a quadratic response to seeding rate (3.04, 3.25, and 3.12 Mg ha-1 at 321,000; 420,000; and 469,000 seeds ha-1, respectively) with no row spacing interaction. Soybean compensated more at lower seeding rates than at wider rows, but field-scale studies are being conducted to evaluate the economics of both practices.
Journal Article
Graphical analysis of multi-environmental trials for wheat grain yield based on GGE-biplot analysis under diverse sowing dates
Background
Information on the nature and extent of genetic and genotype × environment (GE) interaction is extremely rare in wheat varieties under different sowing dates. In the present study, the GGE biplot method was conducted to investigate genotype × environment interaction effects and evaluate the adaptability and yield stability of 13 wheat varieties across eight sowing dates, in order to facilitate comparison among varieties and sowing dates and identify suitable varieties for the future breeding studies.
Results
Considerable genotypic variation was observed among genotypes for all of the evaluated traits, demonstrating that selection for these traits would be successful. Low broad sense heritability obtained for grain yield showed that, both genetic and non-genetic gene actions played a role in the control of this trait, and suggested that indirect selection based on its components which had high heritability and high correlation with yield, would be more effective to improve grain yield in this germplasm. Hence, selection based on an index may be more useful for improvement of this trait in recurrent selection programs. The results of the stability analysis showed that the environmental effect was a major source of variation, which captured 72.21% of total variation, whereas G and GE explained 6.94% and 18.33%, respectively. The partitioning of GGE through GGE biplot analysis showed that, the first two PCs accounted for 54.64% and 35.15% of the GGE sum of squares respectively, capturing a total of 89.79% variation. According to the GGE biplot, among the studied varieties, the performance of Gascogen was the least stable, whereas Sirvan, Roshan, and Pishtaz had superior performance under all sowing dates, suggesting that they have a broad adaptation to the diverse sowing dates. These varieties may be recommended for genetic improvement of wheat with a high degree of adaptation.
Conclusion
The results obtained in this study demonstrated the efficiency of the GGE biplot technique for selecting high yielding and stable varieties across sowing dates.
Journal Article
Optimizing sowing window and cultivar choice can boost China's maize yield under 1.5 °C and 2 °C global warming
Climate change, with increased temperatures and varied rainfall, poses a great challenge to food security around the world. Appropriately assessing the impacts of climate change on crop productivity and understanding the adaptation potential of agriculture to climate change are urgently needed to help develop effective strategies for future agriculture and to maintain food security. In this study, we studied future maize yield changes under 1.5 °C (2018-2037) and 2 °C (2044-2063) warming scenarios and investigated the adaptation potential across China's Maize Belt by optimizing the sowing date and cultivar using the APSIM-Maize model. In comparison to the baseline scenario, under the 1.5 °C and 2 °C warming scenarios, we found that without adaptation, maize yields would increase in the relatively cool regions with a single-cropping system but decrease in other regions. However, in comparison with the baseline scenario, under the 1.5 °C and 2 °C warming scenarios with adaptation, maize yields would increase by 11.1%-53.9% across the study area. Across the maize belt, compared with the baseline scenario, under warming of 1.5 °C, the potential sowing window would increase by 2-17 d, and under warming of 2 °C, this sowing window would increase by 4-26 d. The optimal sowing window would also be significantly extended in the regions with single-cropping systems by an average of 10 d under the 1.5 °C warming scenario and 12 d under the 2 °C warming scenario. Late-maturing cultivar achieved higher yield than early-middle maturing cultivars in all regions except the north part of Northeast China. Adjusting the sowing date by increasing growth-period precipitation contributed more (44.5%-96.7%) to yield improvements than shifting cultivars (0%-50.8%) and climate change (−53.1% to 23.0%) across all maize planting regions except in the wet southwestern parts of the maize belt. The differences among the maize planting regions in terms of high adaptation potential provide invaluable information for policymakers and stakeholders of maize production to set out optimized agricultural strategies to safeguard the supply of maize.
Journal Article
Current Status and Future Directions for Combined Tillage and Sowing Technology and Equipment
As the focus of the development of mechanized tillage and sowing, combined tillage and sowing machines have a variety of functions, such as seedbed preparation, fertilizer sowing, and pressing. Compared with the traditional single-function planter, these machines effectively shorten the operation cycle, reduce production costs, and promote increased production and income. This paper categorizes the machines into these combined rotary tillage and sowing machine, the combined disk harrow and sowing machine, and the combined multi-link tillage and sowing machine according to the form of the tillage and operation. It also systematically elaborates on the technical characteristics, application scenarios, and operational requirements of different types of combined tillage and sowing machines. Additionally, this paper outlines key technologies, such as seedbed preparation and precision sowing. Considering the current state of scientific and technological advancements and the practical needs of agricultural production, it also suggests future research directions and trends, offering valuable insights for subsequent studies in this field.
Journal Article