Fall-planted cover crops are becoming popular among growers in the Midwest for various reasons, including weed suppression. Cereal rye is the most planted cover crop in Nebraska. Glyphosate availability was limited in 2022, so growers sought information about glyphosate alternatives for terminating cover crops, such as cereal rye. The objectives of this study were to evaluate alternative acetyl coA carboxylase (ACCase)-inhibiting herbicides for terminating cereal rye 15 days before soybean planting (DBSP), at soybean planting day (SPD), and 15 days after soybean planting (DASP) and their effect on weed control, density, biomass, soybean plant stand, and grain yield. Field experiments were conducted from 2018 to 2020 in southcentral Nebraska. Cereal rye biomass collected 15 days after termination was 394, 1,697, and 3,700 kg ha−1 in 2019 and 330, 1,304, and 4,550 kg ha−1 in 2020, respectively, for 15 DBSP at SPD and 15 DASP termination timings. Clethodim provided 77% control of cereal rye 15 DBSP compared with greater than 94% control with fluazifop-P-butyl, fluazifop-P-butyl/fenoxaprop-P-ethyl, quizalofop-P-ethyl, and glyphosate. Similarly, at SPD and 15 DASP termination timings, clethodim resulted in 66% and 31% control of cereal rye, respectively, compared to greater than 92% control with other ACCase-inhibitors and glyphosate. Palmer amaranth control at R5 soybean growth stage was 70%, 88%, and 96%, respectively, at 15 DBSP, SPD, and 15 DASP termination timing. Soybean yield was reduced to 2,184 kg ha−1 when cereal rye was terminated at 15 DASP compared to 4,566 kg ha−1 when terminated at SPD and 4,460 kg ha−1 with 15 DBSP.

As mid-southern U.S. rice producers continue to adopt furrow-irrigated rice (FIR) production practices, supplementary management efforts will be vital in combating Palmer amaranth due to the extended germination period provided by the lack of a continual flood. Previous research has revealed the ability of cover crops to suppress Palmer amaranth emergence in corn, cotton, and soybean production systems; however, research on cover crop weed control efficacy in rice production is scarce. Therefore, trials were initiated in Arkansas in 2022 and 2023 to evaluate the effect of cover crops across five site years on rice emergence, groundcover, grain yield, and total Palmer amaranth emergence. The cover crops evaluated were cereal rye, winter wheat, Austrian winterpea, and hairy vetch. Cover crop biomass accumulation varied by site year, ranging from 430 to 3,440 kg ha-1, with cereal rye generally being the most consistent producer of high-quantity biomass across site years. Rice growth and development were generally unaffected by cover crop establishment; however, all cover crops reduced rice emergence by up to 30% in one site year. Rice groundcover was reduced by 13% from cereal rye in one site year two weeks before heading but cover crops did not impact rough rice grain yield in any of the site years. Palmer amaranth emergence was reduced by 19 and 35% with cereal rye relative to the absence of a cover crop when rice was planted in April in Marianna and May in Fayetteville, respectively. In most trials, Palmer amaranth emergence was not reduced by a cereal cover crop. In most instances, legume cover crops resulted in less Palmer amaranth emergence than without a cover crop. Based on these results, legume cover crops appear to provide some suppression of Palmer amaranth emergence in FIR while having a minimal effect on rice establishment and yield.

The semiarid northeast coast of Brazil harbours just less than 44,300 ha of mangroves, 4% of Brazilian total. Notwithstanding this relatively small area, these forests have high ecological and economic importance, sustaining traditional fisheries and protecting biodiversity, including many threatened species. They present unique biogeochemical characteristics resulting in distinct ecosystem functioning compared to mangroves located in humid areas. Semiarid mangroves present lower aboveground biomass compared to humid region mangroves but show similar belowground biomass. Whereas mangrove soils in humid areas are strongly influenced by sulphate reduction, iron geochemistry is a primary driver of soil characteristics in semiarid mangrove soils, suggesting different responses to climate change drivers between them. Although legally protected, they have incurred continuous degradation due to regional drivers, mostly aquaculture and river damming, which differs from those in humid coast mangroves. Semiarid mangroves are also particularly sensitive to drivers associated with global climate change (high temperatures, reduced rainfall and sea level rise). These conditions occur at a global scale; however, the impacts are worsened by the natural conditions of semiarid coastlines, which already provide biologically stressful conditions for mangroves. This article compares the impacts of such drivers in semiarid mangroves with those of humid mangroves, focusing on their biogeochemical response and eventual rehabilitation.

There is an increasing emphasis worldwide on breeding wheat cultivars with higher biomass and grain yield, whilst reducing excessive input of N fertilizers. Modern plant breeding has narrowed the genetic base of bread wheat, so exploring new sources of genetic variation for leaf photosynthesis traits and biomass to underpin grain yield improvement has become necessary. Our objectives were to quantify the genetic variability in a range of landrace-derived lines and elite bread wheat genotypes in flag-leaf photosynthesis traits, biomass and N-use efficiency for potential application in pre-breeding. Sixteen bread wheat genotypes including elite spring wheat cultivar Paragon × landrace crosses were tested in two field experiments in the UK. Averaging across years, pre-anthesis flag-leaf photosynthesis rate ranged amongst genotypes from 26.0 to 31.5 μmol/m2/s (P < 0.001) and post-anthesis from 14.2 to 18.6 μmol/m2/s (P < 0.001). Two landrace-derived lines had greater post-anthesis flag-leaf photosynthesis rate (P < 0.001) than their elite parent Paragon. There was a trend for a positive correlation among genotypes between post-anthesis flag-leaf photosynthesis rate and biomass (r = 0.47, P = 0.06). Two landrace derivatives showed higher post-anthesis flag-leaf stomatal conductance than Paragon. Our results indicated that introgression of traits from wider germplasm into elite UK modern wheat germplasm offers scope to raise flag-leaf photosynthetic rate and biomass.

The scope of environmental impact assessments (EIAs) has traditionally been limited to on-site effects. This approach faces limitations when dealing with intricate value chains. Particularly for projects involving biomass-to-energy facilities, the primary environmental impacts often originate from off-site biomass production. This article considers the resulting limitations of EIAs by using two legal disputes in France as illustrative examples. In the Gardanne and the La Mède cases, French Administrative Courts sought to establish the necessity for project proponents to incorporate supply-related impacts into the EIA process. Strategies aimed at broadening the scope of EIAs, either by expanding the assessed project boundaries or by invoking the concept of cumulative impacts, were not deemed the most relevant approaches. Instead, the concept of ‘indirect impact’ emerged as a valuable tool for incorporating supply-related impacts. However, to prevent the indirect impact concept from being disregarded as too ambiguous or ineffective, it should be complemented by precise criteria to determine whether an impact may be considered indirect. We study these avenues within the broader evolving landscape of EIA laws, and by exploring ways to harmonize EIAs with other regulatory instruments governing value chains.

Phenological studies for Cuban bulrush [Oxycaryum cubense (Poepp. & Kunth) Lye] have been limited to the monocephalous form in Lake Columbus (Mississippi). Accordingly, there is little available information on potential phenological differences among O. cubense forms (monocephalous vs. polycephalous) and populations in other geographic locations in the United States. Therefore, seasonal patterns of biomass and starch allocation in O. cubense were quantified from two populations in Lake Columbus on the Tennessee-Tombigbee Waterway in Mississippi (monocephalous), two populations from Lake Martin in Louisiana (polycephalous), and two populations from Orange Lake in Florida (polycephalous). Monthly samples of O. cubense inflorescence, emergent, and submersed tissue were harvested from two plots per state from October 2021 to September 2022. During monthly data collection, air temperature and photoperiod were recorded. Starch allocation patterns were similar among all sites, with starch storage being less than 1.5% dry weight for all plant tissues. Biomass was greatest in Lake Columbus (monocephalous; 600.7 g dry weight [DW] m−2) followed by Lake Martin (polycephalous; 392.3 g DW m−2) and Orange Lake (polycephalous; 233.85 g DW m−2). Peak inflorescence biomass occurred in the winter for the Lake Martin and Orange Lake populations and in the summer for the Lake Columbus population. Inflorescence biomass in Lake Columbus had a positive relationship (r2 = 0.53) with warmer air temperatures. Emergent and submersed biomass generally had negative relationships with both photoperiod and temperature (r2 = 0.02 to 0.77) in all sites. Peak biomass was also negatively related to temperature and photoperiod. Results from this study indicate that there are differences in biomass allocation between the two growth forms of O. cubense and that growth can occur at temperatures below freezing. Low temperature tolerance may allow this species to expand its range farther north than previously suspected.

Waterhemp has evolved resistance to Group 2, 5, 9, 14, and 27 herbicides in Ontario, Canada, making control of this challenging weed even more difficult. Acetochlor is a Group 15, chloroacetanilide herbicide that has activity on many small-seeded annual grasses and some small-seeded annual broadleaf weeds, including waterhemp. The objective of this study was to ascertain if acetochlor mixtures with broadleaf herbicides (dicamba, metribuzin, diflufenican, sulfentrazone, or flumioxazin), applied preemergence (PRE), increase multiple-herbicide-resistant (MHR) waterhemp control in soybean. Five trials were conducted over 2 yr (2021 and 2022). The acetochlor mixtures caused ≤7% soybean injury, except acetochlor + flumioxazin, which caused 19% soybean injury. Acetochlor applied PRE controlled MHR waterhemp 89% at 4 wk after application (WAA). Dicamba, metribuzin, diflufenican, sulfentrazone, or flumioxazin controlled MHR waterhemp 59%, 67%, 58%, 64%, and 86%, respectively, at 4 WAA. Acetochlor applied in a mixture with dicamba, metribuzin, diflufenican, sulfentrazone, or flumioxazin provided good to excellent control of MHR waterhemp; control ranged from 91% to 98% but was similar to acetochlor applied alone. Acetochlor alone reduced MHR waterhemp density and biomass 98% and 93%; acetochlor + flumioxazin reduced waterhemp density and biomass by an additional 2% and 7%, respectively. This research concludes that acetochlor applied in a mixture with flumioxazin was the most efficacious mixture evaluated for MHR waterhemp control.

Facing increasing nonrenewable and environmental concerns with fossil power generation, renewable energy is being supported by government mechanisms. With the power generation cost of renewables generally higher than fossil fuels, determining the optimal level of these mechanisms requires an understanding of households’ prosocial behavior toward renewables. The issue is determining the magnitude households are willing to pay (WTP) for alternative renewables. Our hypothesis is this behavior varies by the type of renewable energy. As a test of this hypothesis, we apply a discrete choice experiment to measure households’ WTP. Results support our hypothesis with a positive WTP for solar energy, leading to a 62% reduction in solar subsidy, and a negative WTP for biomass and wind sources.

One of the largest remnants of tropical dry forest is the South American Gran Chaco. A quarter of this biome is in Paraguay, but there have been few studies in the Paraguayan Chaco. The Gran Chaco flora is diverse in structure, function, composition and phenology. Fundamental ecological questions remain in this biome, such as what bioclimatic factors shape the Chaco’s composition, structure and phenology. In this study, we integrated forest inventories from permanent plots with monthly high-resolution NDVI from PlanetScope and historical climate data from WorldClim to identify bioclimatic predictors of forest structure, composition and phenology. We found that bioclimatic variables related to precipitation were correlated with stem density and Pielou evenness index, while temperature-related variables correlated with basal area. The best predictor of forest phenology (NDVI variation) was precipitation lagged by 1 month followed by temperature lagged by 2 months. In the period with most water stress, the phenological response correlates with diversity, height and basal area, showing links with dominance and tree size. Our results indicate that even if the ecology and function of Dry Chaco Forest is characterised by water limitation, temperature has a moderating effect by limiting growth and influencing leaf flush and deciduousness.

In highlands, the increase in altitude results in a drastic decrease in temperature (T) that delays phenological development of maize, decreasing light interception during the cycle. This could be partially overcome by increasing plant density, but information is scarce for designing specific management options. The objective of this work was to describe changes in canopy development, photosynthetic performance, biomass and yield of maize grown at contrasting plant densities (5.7 plants m−2, locally used, and 8.7 plants m−2, 50% higher). Three experiments were carried out in two high-altitude environments within the Argentinean Andean region, Hornillos (HOR, 2380 masl, 2019–20 and 2020–21) and El Rosal (ERO, 3350 masl, 2019–20), and complementary data were obtained from samplings in 8 farmer’s fields (from 2400 to 3400 masl, 2022–23). In the experiments, mean T during the first 150 days of the cycle was 33% lower at ERO, which implied 39 extra days but 25% shorter thermal time to achieve silking. The higher plant density significantly increased leaf area index and light interception at ERO, whereas at HOR, this was only evident during the second season. At the leaf level, plants grown at ERO had thicker leaves with higher chlorophyll (+36%) and nitrogen (40%) content. Photosynthetic electron transport rate at full irradiance was +20% higher at ERO but significantly varied throughout the day with lowest values in the morning, which was not observed at HOR and was not related to light intensity or stomatal conductance. At HOR, the increase in plant density did not improve light interception, nor yield in 2019–20 (with average yields of 6356 kg ha−1) but it did improve both in 2020–21 when generally lower yields were attained (4821 kg ha−1). Across farmer’s fields, increasing densities consistently reduced yield per plant (r2 = 0.57***) but improved yield per area basis, which was maximised at 10 pl m−2 as a result of a steady increase in kernel number m−2 (up to 15 pl m−2). Thus, in these high-altitude environments, increasing plant density beyond recommended (6 pl m−2) is a promising approach for improving yield, with major penalties of supra-optimum densities being related to kernel weight. Further work is needed to explore the effect of different factors limiting kernel growth, over plant density responses.

There have been no systematic experiments conducted in Nevada's water-limited environment that examined the simultaneous benefits of soil health and feed value derived from cool-season cover cropping systems. The objective of this study was to determine the influence of different annual cool-season cover crop systems on above and belowground biomass production, plant tissue carbon and nitrogen, forage nutritive value (crude protein, acid, and neutral detergent fiber), relative feed value (RFV), and short-term soil health indicators under irrigation in a semi-arid environment. Treatments (cover crop systems) were a fallow (no cover crop), five monocultures of rye (Secale cereale L.), winter lentil (Lens culinaris Medik.), arrowleaf clover (Trifolium vesiculosum Savi), white sweetclover (Melilotus alba), forage kale (Brassica oleracea L.), and two three-species mixtures in 50-25-25 seeding ratios (CCM 1: rye, winter lentil, arrowleaf clover; CCM 2: rye, white sweetclover, forage kale). Cover crop systems were arranged in an RCBD with three replications. Plots were fall seeded in Reno, NV early October of each year (2020 and 2021) and terminated at the end of July of 2021 and 2022, respectively. Averaged across years, aboveground biomass production was lowest for the monoculture of winter lentil (4104 kg DM ha−1; SE = 1551) compared to all other cover crop systems (average = 7593 kg DM ha−1; SE = 1551). Biomass carbon produced was lowest for winter lentil (1717 kg ha−1; SE = 675) relative to all other cover crop systems (average = 3227 kg ha−1; SE = 675). The CCM 1 system had a greater C/N ratio (36.3) than CCM 2 and the monocultures of winter lentil, arrowleaf clover, and white sweetclover (average = 24.9). Belowground biomass did not differ among cover crop systems (average = 3161 kg DM ha−1; SE = 962). Crude protein concentration was similar among cover crop systems but the RFV was greatest for forage kale (RFV = 165; SE = 4.0) among all cover crop systems. Soil total N and organic carbon concentration did not differ among cover crop systems but soil K concentration was greatest under fallow (428 mg kg−1 soil; SE = 26) relative to all other systems (average = 345.6 mg kg−1 soil; SE = 26). Soil microbial community biomass was not altered by cover crop system or its interaction with year. While the short-term impact of the cover crop systems on soil health indicators was minimal relative to the fallow system, the overall results suggested that there is potential to integrate cover crops in Nevada's semi-arid environment under irrigation.