Accurate crop growth and radiation use efficiency (RUE) measurements under optimal growth conditions are required to predict grain yield near the genetic growth potential and estimate climate change ...effects on crop production. Research was conducted to quantify RUE of maize during the whole growth period, vegetative period (VP, phenological development stage DVS < 1.0), and reproductive period (RP, DVS ≥ 1.0) under the optimal growth condition in Northeast China. Maize was grown in three population density treatments (9.0, 7.5, and 6.0 plants m−2, referred to HD, MD, and LD respectively) over three growing seasons (2017–2019). The maximum Leaf Area Index (LAI) was observed after the anthesis period (DVS = 1.2), ranged from to 4.9 to 6.9, and then gradually decreases. Photosynthetically active radiation (PAR) intercepted by the canopy of maize was approximate 10% during the early stage of the vegetative period (DVS < 0.3). Then greatest differences occurred during the late vegetative period (DVS = 0.3 to 0.8). When DVS > 1.0, there is no significant difference between the three population density conditions. Estimates of RUE were obtained based on the intercepted PAR (IPAR) and absorbed PAR (APAR). RUE value was 3.97 g MJ−1 APAR or 3.73 g MJ−1 IPAR in the whole growth period, and did not vary among density treatments. Moreover, maximum RUE occurred during VP (4.11 g MJ−1 APAR) and declined during RP (3.95 g MJ−1 APAR). Therefore, we recommend that maize models that rely on RUE for aboveground biomass accumulation should be using a value of 3.97 g MJ−1 APAR for predicting optimum maize grain yield in Northeast China, especially for the potential yield.
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•RUE was 3.97 g MJ−1 APAR or 3.73 g MJ−1 IPAR during the whole growth period.•Maximum RUE occurred in vegetative period and declined in reproductive period.•RUE value, 3.97 g MJ−1, should be used in the maize simulation model for predicting potential yield.
Abstract
Crop multi-model ensembles (MME) have proven to be effective in increasing the accuracy of simulations in modelling experiments. However, the ability of MME to capture crop responses to ...changes in sowing dates and densities has not yet been investigated. These management interventions are some of the main levers for adapting cropping systems to climate change. Here, we explore the performance of a MME of 29 wheat crop models to predict the effect of changing sowing dates and rates on yield and yield components, on two sites located in a high-yielding environment in New Zealand. The experiment was conducted for 6 years and provided 50 combinations of sowing date, sowing density and growing season. We show that the MME simulates seasonal growth of wheat well under standard sowing conditions, but fails under early sowing and high sowing rates. The comparison between observed and simulated in-season fraction of intercepted photosynthetically active radiation (FIPAR) for early sown wheat shows that the MME does not capture the decrease of crop above ground biomass during winter months due to senescence. Models need to better account for tiller competition for light, nutrients, and water during vegetative growth, and early tiller senescence and tiller mortality, which are exacerbated by early sowing, high sowing densities, and warmer winter temperatures.
Intercropping, i.e., growing several species in the same field for a major part of their growing periods, often improves yield and weed control, but their performance greatly varies across ...situations. The aim of this study was to evaluate the effects of bi-species legume–cereal intercrops on weed dynamics and their impact on crop production, in the absence of nitrogen or water stress, via simulations with FlorSys. This individual-based 3D model simulates daily crop–weed seed and plant dynamics over the years, from cropping system and pedoclimate, focusing on competition for light. The study tested seven species proportions in two species mixtures (wheat–faba bean and barley–pea) and nine spatial sowing patterns in three species mixtures (triticale–faba bean, wheat–faba bean, wheat–pea), in both cases comparing the intercrops with the corresponding sole crops (controls). Intercrops and controls were inserted into rotations and simulated over 30 years and repeated with 10 climate scenarios from South-Western France, either with or without weeds. The simulations showed that: (1) the intercrops that best controlled weeds were barley–pea and triticale–faba bean, (2) the spatial pattern alternating one cereal row with one legume row as well as the 67 %-cereal–33 %-legume and 100 %-cereal–50 %-legume species proportions were those that maximised yields and minimised losses due to weeds, (3) the weed biomass in intercrop was greater than or equal to that of the sole cereal, and less than that of the sole legume, and (4) legumes benefitted more from intercropping than cereals because cereals are more competitive against weeds. Intercrop yield was best when combining species with contrasting shading responses (etiolated with stockier plants, leafy with stemmier plants) but early and good plant emergence was essential, particularly for weed suppression.
•4 legume–cereal intercrops were simulated with 7 proportions or 9 sowing patterns.•Intercrops suppressed weeds better than legumes, but not always as well as cereals.•Yields and weed control were best when alternating 1 cereal row with 1 legume row.•67 %-cereal–33 %-legume and 100 %-cereal–50 %-legume species proportions were best.•Combining stocky with etiolated plants and leafy with stemmy plants increased yield.
Industrial hemp is a multi-purpose plant which contains various biologically active compounds and has a broad application in numerous markets. The study aims to investigate industrial hemp variety ...Felina 32 growing potential in the Nordic-Baltic region, to assess the impact of fertilization by mineral, organic and combined fertilizers on plants secondary metabolites accumulation into their inflorescence. In addition, sowing density (15 and 35 kg/ha) influence on fatty acids methyl esters, cannabinoids, essential oil yield and composition were taken into the qualitative and quantitative evaluation. The results reveal that tested agronomical practice tested significantly affected fatty acids and essential oil yield. Increased sowing density 2.3 times from 15 kg/ha to 35 kg/ha slightly increased CBD content (+ ∼23 %) in hemp inflorescence. 73 volatile compounds were found in the essential oil composition of which the highest amount showed sesquiterpenes: (E)-β-caryophyllene, caryophyllene oxide and humulene epoxide II. The research performed strengthens the hypothesis that industrial hemp could be cultivated in the North-Baltic climate as a multi-use crop through complete utilization of the plant material using inflorescences to produce essential oils as a source of natural antioxidants, flavour and fragrance additives.
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•The industrial hemp cultivated in Nemoral climate grows up to 11 t ha−1 biomass.•Applied agrotechnological measures had a significant effect on FAMEs composition.•Analyzed samples were rich in cannabinoids and EO.•The most predominant compounds in EO composition were sesquiterpenes.
The present study was undertaken to determine the effect of sowing date and sowing density on stand architecture, yield components, seed yields, and seed quality in crambe (Crambe abyssinica Hochst. ...ex R.E. Fries) grown in north-eastern Poland in 2020–2022. The experiment had a split-plot design with four sowing dates (early: 30 March–1 April; and delayed by 7, 14, and 21 days) and five sowing densities (150, 200, 250, 300 and 350 live hulled seeds m–2). Crambe seed yields were determined by growing degree days (GDD) during the entire growing season (positive correlation), and by precipitation during flowering (positive correlation) and ripening (negative correlation). Higher values of GDD during the growing season and lower precipitation levels during ripening increased the crude fat (CF) content and decreased the total protein (TP) content of crambe seeds. Higher values of GDD during flowering contributed to the accumulation of crude fiber (CFR) in crambe seeds. Sowing date was a key factor influencing seed yields and crop quality because it affected GDD and precipitation distribution in each growth stage. The yield of hulled seeds was highest (2.17–2.23 Mg ha–1) when crambe was sown early at a density of 200–250 live hulled seeds m–2. When sowing was delayed by 21 days, the CF and CFR content of crambe seeds decreased by 6% and 17%, respectively, whereas their TP content increased by 7%. An increase in sowing density to 350 hulled seeds m–2 increased the CF and CFR content of seeds by 8% and 7%, respectively. Abyssinian oil contained 82–85% of MUFAs (including 63–65% of C22:1), 13–15% of PUFAs, and 2–3% of SFAs. The content of C20:1 increased and the content of C22:1 decreased when crambe was sown with a 21–day delay.
•Seed yields were correlated with GDD and rainfall during flowering and ripening.•Early-sown crambe was most productive.•The optimal sowing density was 200–250 live hulled seeds m–2.•Delayed sowing decreased the crude fat content of seeds and the C22:1 content of oil.•Delayed sowing increased the total protein and crude fiber content of seeds.
During this study, an indoor experiment was conducted to determine the effect of mixed seeding rates of legumes used as green manure on the substrate fertilizer, growth characteristics, and bioactive ...compounds of baby leaf vegetables. The mixed seeding treatment was designed for milkvetch ( Astragalus sinicus L.), tatsoi ( Barassica rapa L.), kale ( Brassica oleracea var. sabellica L.), and spinach ( Spinacia oleracea L.) using five rates for each. Accordingly, a total of 15 treatments (3 baby leaf species × 5 mixed seeding rates) were constructed using a randomized complete block design with three replications for each treatment. During the baby leaf vegetable harvest, we evaluated the macronutrient levels (nitrogen, phosphorus, and potassium) in the substrate as well as the growth parameters and carotenoid contents. The substrate in the treatment mixed with milkvetch showed significantly higher levels of nitrogen, phosphorus, and potassium compared with those of tatsoi and kale sown alone ( P ≤ 0.05). However, there were no significant differences in macronutrients observed in substrate-sown spinach with or without the milkvetch mixture. The growth and carotenoid levels of each baby leafy vegetable sown alone were significantly higher than those of each baby leafy vegetable sown with the mixed seeding treatment ( P ≤ 0.05). Sowing the milkvetch–vegetable mixtures did not result in a significant increase in the growth and carotenoid levels of the three baby vegetables. The results showed that planting milkvetch with tatsoi and kale had a significant impact on substrate fertilization. However, regarding short-term vertical indoor farming, the growth and carotenoid responses of the three greens may be different. Nonetheless, we still believe that the combined interactions of legumes can provide long-term benefits by enhancing the biological functionality of the growing medium for balanced indoor agriculture production.
Napier grass (
Pennisetum purpureum
Schumach) comprises up to 80% of the cattle diet in many tropical and subtropical regions and is used primarily by smallholder farmers. Despite the grass’s high ...yield, resulting animal productivity from this grass is low. One of the key reasons for the low animal productivity of Napier grass is its low nutritive value under current management. Taken together, previous work has shown the current yield, crude protein (CP), and metabolisable energy (ME) of Napier grass to be 26 t dry matter (DM)/ha/year, 96 g/kg DM, and 8.7 MJ/kg DM, respectively, ranging from 2 to 86 t DM/ha/year, 9 to 257 g CP/kg DM, and 5.9 to 10.8 MJ ME/kg DM, respectively, suggesting an opportunity for significant improvement on both yield and nutritive value of this grass. The DM yield and nutritive value of this grass are inversely related, indicating a trade-off between yield and quality; however, this trade-off could be minimised by increasing sowing density and harvesting frequency. Available literature shows that this simple management strategy of increasing sowing density (50 cm × 40 cm) and harvesting frequency (11–12 harvests/year) provides 71 t DM/ha with 135 g/kg DM CP and 10.8 MJ ME/kg DM. This quality of Napier grass has the potential to increase both milk and meat production substantially in the tropics and subtropics, and the farmers will likely find this simple management acceptable due to the high yield obtained through this management. However, there is a paucity of work in this field. Therefore, management strategies to improve the nutritive value of Napier grass are required to increase milk and meat production in the tropics and subtropics and in doing so improve the food security of more than half of the global population living in these regions.
Oat (
L.) and common vetch (
L.) intercropping in the northern regions of China has resulted in substantial production capabilities. However, there is currently a dearth of comprehensive research on ...whether this intercropping system can enhance productivity through increased sowing densities and underlying interspecies interaction mechanisms.
A two-year field experiment was conducted in 2022 and 2023 to investigate the yield, biological efficiency, economic efficiency, and competition indicators of oats and common vetch in a high-density intercropping system. Two cropping patterns (monocropping and intercropping) and five sowing densities (D1: 4.5×10
plants ha
; D2:5.4×10
plants ha
; D3:6.3×10
plants ha
; D4: 7.2×10
plants ha
; and D5: 8.1×10
plants ha
) were arranged in a randomized block design.
At the same sowing density, the intercropped oats exhibited greater grain yield than the monocultures. Increasing the oat sowing density significantly enhanced oat yield, with the D3 level in intercropping showing the highest yield increase, ranging from 30.98% to 31.85%, compared with the monoculture. The common vetch intercropping grain yield was maximized in the D2 treatment. The land equivalent ratio was maximized at the D2 level in both years and was significantly higher than D1, with the land equivalent coefficient, system productivity index, and percentage yield difference suggesting that increasing oat sowing densities improved the productivity of the intercropping system, with the best performance observed at the D2 level. For both years, the proportionate actual yield loss of oat was the highest at the D3 level; significantly surpassing D1, proportionate actual yield loss of common vetch and actual yield loss were the highest at level D2, both significantly surpassing D1. These indicates that appropriate densification contributes to the realization of the advantages of intercropping. With an increased oat sowing density, the economic benefits of the intercropping system were maximized at the D2 and D3 levels. Regarding intercropping competition, oat was the dominant crop under different sowing densities (Aggressivity for oat (A
)>0, relative crowding coefficient for oat (K
)>1, competition ratio for oat (CR
)>1), whereas common vetch was the inferior crop. Compared with the D1 level, the D2 level harmonized the aggressivity, competitive ratio, and relative crowding coefficients of oat and common vetch, significantly increasing crowding coefficient for common vetch (K
) and competition ratio for common vetch by 19.76% to 21.94% and 4.80% to 7.51%, respectively, while reducing K
and CR
.
This result suggests that in the intercropping of common vetch and oat in alpine regions, rational densification can harmonize interspecific competition and thus improve the biological efficiency and economic benefits of intercropping systems.
Sowing native seeds is a common approach to reintroduce native plants to degraded systems. However, this method is often overlooked in wetland restoration despite the immense global loss of diverse ...native wetland vegetation. Developing guiding principles for seed‐based wetland restoration is critical to maximize native plant recovery, particularly in previously invaded wetlands. Doing so requires a comprehensive understanding of how restoration manipulations, and their interactions, influence wetland plant community assembly. With a focus on the invader Phragmites australis, we established a series of mesocosm experiments to assess how native sowing density, invader propagule pressure, abiotic filters (water and nutrients), and native sowing timing (i.e., priority effects) interact to influence plant community cover and biomass in wetland habitats. Increasing the density of native seeds yielded higher native cover and biomass, but P. australis suppression with increasing sowing densities was minimal. Rather, community outcomes were largely driven by invader propagule pressure: P. australis densities of ≤500 seeds/m2 maintained high native cover and biomass. Low‐water conditions increased the susceptibility of P. australis to dominance by native competitors. Early sowing of native seeds showed a large and significant benefit to native cover and biomass, regardless of native sowing density, suggesting that priority effects can be an effective restoration manipulation to enhance native plant establishment. Given the urgent wetland restoration need combined with the limited studies on seed‐based wetland restoration, these findings provide guidance on restoration manipulations that are grounded in ecological theory to improve seed‐based wetland restoration outcomes.
