Search

The editorial discusses the importance of cover crops and green manures in providing essential ecosystem services to agroecosystems. It highlights the impact of agriculturization on soil health and the benefits of sustainable management practices, such as integrating cover crops into crop rotations. The research topic compiled studies that focused on nutrient cycling, soil fertility, plant nutrition, and environmental benefits of cover crops and green manures. The findings emphasize the multifaceted role of these crops in enhancing agroecosystem services and the need for a holistic approach to evaluate their contributions effectively. [Extracted from the article]

The objectives were to i) assess the effect of enhanced-efficiency nitrogen (N) fertilizers (EENF) [maleic itaconic acid copolymer (NSN) or 3,4-dimethylpyrazole phosphate (DMPP)] and urea on potato (Solanum tuberosum L.) tuber yield, N agronomic efficiency (NAE), N recovery efficiency in tuber (NREtuber) and plant (NREplant), N physiological efficiency, residual inorganic N in soil at harvest (Nresidual) and N losses (Nlosses) and ii) determine the impact of the amount of drainage water on NAE and Nlosses. On-farm experiments were conducted in seven sites with two fertilizers (EENF and urea) and two N rates (0 and 100 kg N ha−1). A N mass balance was used to calculate Nlosses. At two sites (one with NSN and one with DMPP), tuber yield response to N was greater with EENF than urea (avg. 5.0 Mg ha−1). NAE, NREtuber and NREplant were 17%, 31% and 25% higher with EENF than urea, respectively. These efficiencies decreased as drainage water increased. The estimated Nlosses were 12% lower with EENF, being the reduction particularly relevant with increasing drainage water. Therefore, using EENF in combination with irrigation management that ensures low drainage water amounts is essential for maximizing the fertilizer use efficiency and minimizing Nlosses in potato production systems. [ABSTRACT FROM AUTHOR]

Monitoring the availability of phosphorus (P) in soil under continuous cropping facilitates finding deficiency in crops and contributes to improving crop growth and nutrient management models. Soil P availability for crops is usually estimated by soil test P (STP), such as Bray‐1. This is widely used in the Americas. The relationship between the decrease of STP Bray‐1 and cumulative removal of P was evaluated in non‐P‐fertilized areas in long‐term studies. This removal was the sum of annual P removal over the study period as P exported in grains/crop outside the soil. The objectives were to: (a) quantify changes in STP as a function of cumulative P removal, (b) assess the relationship between relative decrease rate of STP and soil variables as well as annual removal of P by crops, and (c) develop a model to predict decrease of STP Bray‐1. Exponential decay functions were used to describe annual cumulative removal of P and STP from soil over time for 12 long‐term studies where no addition of P fertilizer was carried out. Changes in the relative rate of decrease of STP, relative to the initial STP Bray‐1 value at the onset of the experiment, were predicted by the ratio of soil organic matter to clay and silt and the average annual P removal by exponential decay (R2adj = 0.64; RMSE = 3.2 mg kg−1). We propose this predictive model as suitable to provide estimates of the relative decrease rate of STP by Bray‐1 and thereby improve management of P for optimizing crop yield. Highlights: STP Bray‐1 decrease and cumulative P removal were related by exponential decay functions.Relative decrease rate of STP Bray‐1 was related to SOM/(clay+silt) ratio and annual P removal.A predictive model of the relative decrease rate of STP Bray‐1 was fitted and validate.Our model is a useful tool to help predict soil P availability and nutrient management. [ABSTRACT FROM AUTHOR]

A trade-off between seed protein concentration (SPC) and yield has been reported for soybean. Therefore, assessing management practices that can nullify this trade-off is relevant to avoid further declines in SPC in the future as yield continues to increase. While the positive effect of irrigation on yield is well documented, only a few studies have assessed the impact of irrigation on SPC, showing conflicting results. The objective was to determine if the trade-off between seed yield and SPC persists when irrigation is applied and how management, soil, and weather factors influence the trade-off. We hypothesized that yield increases induced by irrigation would likely decrease SPC. Our experimental approach involved the use of producer-reported data, in-situ seed collection, and crop modeling. Yield and management data were collected from 268 soybean fields in Nebraska (USA), along with data on SPC, seed oil concentration (SOC), and seed carbohydrate concentration (SCC) determined from samples collected in each field. Field-specific phenological data were derived from model simulations. The combined data were then used to assess the effect of irrigation on seed yield and constituents as influenced by management, soil, and weather factors. On average, both seed yield (+0.86 Mg ha−1) and SPC (+3.2 g kg−1) were higher, but SOC (–2.0 g kg−1) was lower, and SCC was unaffected in irrigated versus rainfed field pairs. Yield and SPC increased simultaneously in response to irrigation in two-thirds of the fields, especially when environmental conditions did not favor seed oil synthesis (e.g. , cooler temperature and less incident solar radiation). A trade-off of higher seed yield and lower SPC occurred with irrigation in the remaining fields wherein conditions were favorable for seed oil synthesis (e.g. , warmer temperatures and greater radiation). Despite higher seed yield generated in irrigated versus rainfed fields, no concurrent reduction occurred in SPC in the majority of irrigated fields – a surprising finding that was not consistent with the general expectation that higher soybean yields typically result in yield-SPC trade-off. This study showed that irrigation-induced higher soybean yields are possible without an attendant SPC penalty when temperatures and radiation are conducive for its mitigation. We are unaware of any other yield-increasing practices – except nitrogen (N) fertilization - that do not result in a concomitant decline in SPC. A hypothesized higher N supply via soil N mineralization and/or biological N fixation in irrigated fields in this study may explain the absence of yield-protein trade-off. • There have been conflicting results about the effect of irrigation on soybean seed protein concentration • The yield-protein trade-off was assessed with producer data, in-situ seed sampling, and crop modeling • Irrigation increased both seed yield (+0.86 Mg ha−1) and protein concentration (+3.2 g kg−1) • Lower temperature and radiation nullified the yield-protein trade-off in irrigated fields • The higher N supply in irrigated fields may explain the absence of a yield-protein trade-off [ABSTRACT FROM AUTHOR]

Legume cover crops are often considered a valuable alternative for supplying nitrogen (N) to cropping systems. However, certain pathways of N released from their residues to successor crops remain unclear. Aiming to assess N contribution and residual N from hairy vetch (Vicia villosa Roth.) cover crop in succeeding crops, we examined i) soil N availability and mineralizable-N, ii) crop yields, and iii) plant N sourcing within the soybean [ Glycine max (L.) Merrill]-wheat (Triticum aestivum L.) cropping sequence in the southeastern Argentine Pampas. Three field experiments were conducted over three seasons: E1 (2018/19), E2 (2019/20), and E3 (2020/2021) in the southeast of Buenos Aires province. The crop sequence studied was hairy vetch/soybean-wheat. Factors investigated were hairy vetch inclusion and bare fallow, and wheat N fertilizer (150 and 0 kg N ha−1). Hairy vetch aboveground dry matter and its N concentration were measured at hairy vetch termination and six times thereafter (residues) during the succeeding soybean, using the litter bag method. Soybean biomass, N concentration, and the relative abundance of ureides (RAU) as an indicator of N fraction derived from biological nitrogen fixation (BNF), were examined. Soil NO 3 --N and anaerobically incubated N (Nan) were sampled during the soybean season and at wheat sowing. At physiological maturity, soybean and wheat grain yields, along with grain N concentrations, were determined. Hairy vetch N released during soybean season ranged from 79 to 175 kg N ha−1. Soil NO 3 --N content at soybean sowing increased 5.5 kg ha−1 per Mg of hairy vetch dry matter, while Nan increased 3.6 mg kg−1 per Mg of hairy vetch dry matter. Soybean seed yields, seed N content, and N uptake showed no significant change with increased hairy vetch dry matter. Likewise, RAU at R5 decreased from 2.4 to 5.5 units (%) per Mg of hairy vetch dry matter. Concerning wheat, hairy vetch produced a slight increase in soil residual N at sowing. Only in one experiment (E1), hairy vetch dry matter led to improvements in wheat grain yield and N content. Our study outlined new insights into hairy vetch N contribution, primarily linked to increased soil N availability in the immediate soybean, the relatively higher soybean N uptake from soil compared to BNF, and the dilution of soil N contribution to wheat as second crop in the sequence. These findings support the recommendation of using hairy vetch as a predecessor for an immediate cereal or non-N fixing crops. • Nitrogen (N) dynamics were studied in a hairy vetch – soybean – wheat sequence. • Hairy vetch increased soil nitrate-N and mineralizable-N for the following soybean. • Increased hairy vetch N residues decreased soybean N fixation at the seed filling stage. • Hairy vetch neither affected subsequent soybean yields nor its total N uptake. • Hairy vetch marginally increased soil nitrate-N but did not affect mineralizable-N for wheat. [ABSTRACT FROM AUTHOR]

It is unclear if additional inoculation with Bradyrhizobia at varying soybean [Glycine max (L.) Merr.] growth stages can impact biological nitrogen fixation (BNF), increase yield and improve seed composition [protein, oil, and amino acid (AA) concentrations]. The objectives of this study were to evaluate the effect of different soybean inoculation strategies (seed coating and additional soil inoculation at V4 or R1) on: (i) seed yield, (ii) seed composition, and (iii) BNF traits [nodule number and relative abundance of ureides (RAU)]. Soybean field trials were conducted in 11 environments (four states of the US) to evaluate four treatments: (i) control without inoculation, (ii) seed inoculation, (iii) seed inoculation + soil inoculation at V4, and (iv) seed inoculation + soil inoculation at R1. Results demonstrated no effect of seed or additional soil inoculation at V4 or R1 on either soybean seed yield or composition. Also, inoculation strategies produced similar values to the non-inoculated control in terms of nodule number and RAU, a reflection of BNF. Therefore, we conclude that in soils with previous history of soybean and under non-severe stress conditions (e.g. high early-season temperature and/or saturated soils), there is no benefit to implementing additional inoculation on soybean yield and seed composition.