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Context Sustainable management of the soil is one of the pillars of conservation agriculture (CA). Aims The objective of this study was to evaluate the long-term effects of soil management systems (SMS) on liming efficiency, soil chemical properties and wheat yield. Methods This study was part of a long-term experiment established in 1986 in Passo Fundo, Rio Grande do Sul, Brazil, but using data from 2008 to 2015 to explore the effects of agricultural lime applied in 2008. The experiment was laid out in a split-plot design where the main plot (SMS) were arranged in randomised blocks and the cropping systems (sub-plot treatments) were randomised within the main plots. This study assessed the effects of the SMS; i.e. two CA systems [no-tillage (NT) and reduced tillage] and two conventional tillage (CT) systems (disk ploughing + disk harrowing annually, and mouldboard ploughing + disk harrowing annually). Key results The NT system was the most sustainable due to improvements in soil organic carbon concentration. After liming, CT systems were more effective than CA systems in decreasing Al3+ toxicity and increasing soil pH and Ca2+ and Mg2+ concentrations at deeper soil layers. The NT system had a considerable advantage over other SMS, due to a greater average wheat yield (18%). Conclusions The SMS evaluated in this study modified chemical properties when compared with the native forest area. The NT system was the least detrimental to soil organic carbon, an important indicator of soil quality. Implications The NT system provided greater average wheat yield (18%), and thus was the most viable SMS for subtropical spring wheat production.

Made available in DSpace on 2022-05-01T07:59:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-09-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Stimulant fertilization isthe supplementary application of low doses of foliar fertilizers to otherwise well-fertilized crops, and literature suggests that it may increase grain yield. However, the physiological mechanisms behind this potential yield increase are not well understood. This study investigated the effect of supplementary foliar nitrogen (N) in soybean [Glycine max (L.) Merr.] and maize (Zea mays) nutrition, photosynthetic parameters, antioxidant metabolism, agronomic parameters, and grain yield. We tested the presence or absence of low rates of late season (R3 and V10 of soybean and maize, respectively) foliar N fertilization in a main season soybean followed by an off-season maize. While there were no effects of N application on leaf nutrient concentration, the net photosynthetic rate, stomatal conductance, water use efficiency, and carboxylation efficiency increased due to foliar N fertilization in both crops. The improvement in photosynthesis occurred due to a concomitant increase in Rubisco activity and in the concentration of sugar in the leaves prior to grain filling. Foliar N fertilization also improved antioxidant metabolism, suggesting that fertilized plants were less affected by environmental stresses during their cycle. The improvement in the metabolic activity due to foliar N did not affect grains per plant but increased a hundred grain mass and grain yield of both soybean and maize. Our results suggest that foliar N applied as stimulant fertilizer is a promising strategy to increase yield of maize and soybean crops. Dep. of Crop Science College of Agricultural Sciences São Paulo State Univ. (UNESP) Dep. of Agronomy Kansas State Univ., 2004 Throckmorton Plant Sciences Center, 1712 Claflin Road Dep. of Crop Science College of Agricultural Sciences São Paulo State Univ. (UNESP) CNPq: 134588/2018-5 CNPq: 303119/2016-0

BACKGROUND Integrated wheat management strategies can affect grain yield and flour end-use properties. However, the effect of integrated management and its interaction with environmental factors on the phenolic acid profiles of wheat has not been reported. The phenolic acid profile has become another parameter for the evaluation of wheat quality due to its potential health benefits. RESULTS Year × location × management and year × management × genotype interactions were significant for the total phenolic content (TPC) of wheat samples. The year × location × management × genotype interaction was significant for the concentration of trans-ferulic acid and several other phenolic acids. Field management practices with no fungicide application (e.g., farmer's practice, enhanced fertility) may lead to increased accumulation of phenolic compounds, especially for WB4458, which is more susceptible to fungi infection. However, this effect was also related to growing year and location. Higher soil nitrogen content at sowing also seems to affect the TPC and phenolic acid concentration positively. CONCLUSION Wheat phenolic acid profiles are affected by genotype, field management, environment, and their interactions. Intensified field management, in particular, may lead to decreased concentration of wheat phytochemicals. The level of naturally occurring nitrogen in the soil may also affect the accumulation of wheat phytochemicals. © 2021 Society of Chemical Industry.

Appropriate genotype selection and management can impact wheat (Triticum aestivum L.) yield in dryland environments, but their impact on yield components and their role in yield modulation are not well understood. Our objectives were to evaluate the yield response of commercial winter wheat genotypes to different management practices reflecting a stepwise increase in management intensity (including a reduction in crop density under high input), and to quantify how the different yield components modulate wheat yield. A factorial experiment evaluated six management (M) intensities [“farmer practice” (FP), “enhanced fertility” (EF), “ecological intensification” (EI), “increased foliar protection” (IFP), “water-limited yield” (Yw), and “increased plant productivity” (IPP)] and four winter wheat genotypes (G) in four Kansas environments (E). Average grain yield was 4.9 Mg ha–1 and ranged from 2.0 to 7.4 Mg ha–1, with significant two-way interactions (E × M and E × G). The EF usually maximized yields in dry environments, while EI, which consisted of EF plus one fungicide application, maximized yields in environments with greater water availability. Across all sources of variation, kernels m–2 and aboveground biomass were the strongest modulators of yield as compared to kernel weight and harvest index, while spikes m–2 and kernels spike–1 modulated yields at a similar magnitude. Foliar fungicides improved yield through increased green canopy cover duration and greater radiation intercepted during grain filling. When crop density was reduced from 2.7 to 1.1 million plants per hectare in an otherwise high-input system, plants produced more productive tillers (with genotype-specific response); however, reduced green canopy cover at anthesis and reduced cumulative solar radiation intercepted during grain filling limited wheat yield—although large differences in canopy cover or intercepted radiation were needed to cause modest changes in yield. Treatments more intensive than EI were not warranted as EF or EI maximized yields at all environments, and practices that promote biomass and kernels m–2 are to be targeted for future increases in wheat yield.

Nutrient management can reduce crop yield gaps, but available literature is mostly restricted to studies limited in time, geography, or in the number of nutrients evaluated. Our objective was to synthesize long-term experiments evaluating wheat (Triticum aestivum L.) yield and grain-N concentration (GNC) response to N, P, and K fertilizer rates and their interactions. We used data from three long-term (1966–2016) experiments conducted in Oklahoma (USA) comprising 155 site-years for yield (n = 8035) and 90 site-years for GNC (n = 4580). The last year of the experiments was the baseline to de-trend yield and GNC data. We first explored relationships between grain yield and GNC, grain N removal, apparent recovery of applied N in the grain (N recovery), and N-use efficiency (NUE) as affected by the presence and rate of N, P, and K across the entire dataset. Then, we subdivided the dataset into yield-environments based on the different data quartiles, and analyzed it using descriptive statistics, multi-level modeling, differences from the control, and conditional inference trees. Our main findings were: i) wheat yield was negatively related to GNC, but positively associated with N removal, N recovery, and NUE. ii) The co-application of P and, to a lesser extent, K, increased N removal and NUE but decreased GNC. iii) The proportion of variability in yield and GNC explained by fertilizer management increased with an increase in yield-environment. iv) Wheat yield response to N and to P were typically quadratic, although response to P was restricted to high yielding environments. v) Wheat GNC increased linearly with increases in N rate, but decreased with increases in P and K rate. vi) Conditional inference trees suggested that the co-application of P and K improved yields but decreased GNC. The co-application of P and K can increased wheat yield, N removal, and NUE, but the increases in yield were greater than those in N removal, thus decreasing GNC.

Crop production of a significant portion of the Great Plains has greatly simplified the landscape, which can affect insect pest outbreaks. The Hessian fly is an important economic pest of wheat, a major crop grown in the region. However, outbreaks are often limited to localized events, which may be difficult to predict. Better understanding of where Hessian fly outbreaks are more likely to occur would help producers make informed management decisions. Therefore, the objective of our study was to describe the spatial distribution of Hessian fly infestation within commercial wheat fields, while examining how a simplified landscape may contribute to the distribution of Hessian fly infestations. Spatial distribution modeling was conducted in select fields (n = 6) infested with Hessian fly puparia. A geographic information system was used to create sampling grids for each field (n = 34–50 sample points/field), with one meter row of plants sampled at each sample point. The number of puparia and plants infested at each sample point were used to construct Hessian fly distribution maps for each field. Correlations between environmental factors and fly distribution were then examined. Results show that host plants (wheat and grasses) adjacent to the borders of study fields did not affect the distribution of puparia or plants infested within the field. Rather, the proportion of wheat within a 1 km radius of sampled fields affected the level of Hessian fly infestation, with a smaller proportion of wheat within the 1 km radius increasing the probability of Hessian fly infestation in sampled fields. The results of this study show previously unknown distribution of Hessian fly infestation within commercial wheat fields, resulting in new hypotheses about Hessian fly management in agroecosystems.

We combined field studies to regional soil databases with the objective of presenting a protocol to forecast regional gains in winter wheat (Triticum aestivum L.) forage and grain yield and revenue, from liming or selecting a variety tolerant to acidic soils. First, we developed forage and grain yield response curves to soil pH using a variety by soil pH study conducted during 3 yr (2013–2015) at two Oklahoma locations. Second, we used a database of soil pH samples representing 93% of the wheat growing region of the state (n = 11,905) coupled with 15-yr average county yield and harvested area to estimate potential gains for grain-only and dual-purpose scenarios. Relative grain yield maximized at soil pH of 5.8 for sensitive varieties and 4.8 for tolerant varieties. Forage yield maximized at soil pH of 6.0 for sensitive varieties and 5.5 for tolerant varieties. About 35% of the region had pH limiting to dual-purpose and 28% to grain-only production. Liming could improve grain-only statewide yield in 0.14 Mg ha–¹ and revenue in US$19 ha–¹, and adoption of tolerant varieties could increase yield in 0.11 Mg ha–¹ and revenue in $10 ha–¹. Liming could improve dual-purpose revenue in $37 ha–¹ and variety selection in $28 ha–¹ due to improved yield and forage. Potential additional statewide wheat production resulting from variety selection is 53,800 Mg and from liming 82,500 Mg. Our protocol can be used to aid development of agricultural policies and research prioritization at regional levels where acidic soils are prevalent.

Made available in DSpace on 2021-06-25T11:14:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (1) Background: The aim of this study was to explore whether supplementary magnesium (Mg) foliar fertilization to soybean and maize crops established in a soil without Mg limitation can improve the gas exchange and Rubisco activity, as well as improve antioxidant metabolism, converting higher plant metabolism into grain yield. (2) Methods: Here, we tested foliar Mg supplementation in soybean followed by maize. Nutritional status of plants, photosynthesis, PEPcase and Rubisco activity, sugar concentration on leaves, oxidative stress, antioxidant metabolism, and finally the crops grain yields were determined. (3) Results: Our results demonstrated that foliar Mg supplementation increased the net photosynthetic rate and stomatal conductance, and reduced the sub-stomatal CO2 concentration and leaf transpiration by measuring in light-saturated conditions. The improvement in photosynthesis (gas exchange and Rubisco activity) lead to an increase in the concentration of sugar in the leaves before grain filling. In addition, we also confirmed that foliar Mg fertilization can improve anti-oxidant metabolism, thereby reducing the environmental stress that plants face during their crop cycle in tropical field conditions. (4) Conclusions: Our research brings the new glimpse of foliar Mg fertilization as a strategy to increase the metabolism of crops, resulting in increased grain yields. This type of biological strategy could be encouraged for wide utilization in cropping systems. Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP) Throckmorton Plant Science Center Department of Agronomy Kansas State University (KSU), 1712 Claflin Road Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP) CNPq: 134588/2018-5 CNPq: 303119/2016-0

Made available in DSpace on 2020-12-10T20:07:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-15 Kansas Wheat Alliance Kansas Agricultural Experiment Station (KAES) The complex and interactive effects of genotype (G), environment (E), and management (M) can be a barrier to the development of sound agronomic recommendations. We hypothesize that long-term variety performance trials (VPT) can be used to understand these effects and improve regional recommendations. Our objective was to explore long-term VPT data to improve management and variety-selection recommendations using winter wheat (Triticum aestivum L.) in the U.S. central Great Plains as a case-study. Data of grain yield, variety, and trial management were collected from 748 wheat VPT conducted in the states of Colorado, Kansas, and Oklahoma over nineteen harvest years (2000-2018) and 92 locations, resulting in 97,996 yield observations. Using 30-yr cumulative annual precipitation and growing degrees days, we partitioned the study region into 11 contiguous sub-regions, which we refer to as growing adaptation regions (GAR). We used variance component analysis, gradient boosted trees, and conditional inference trees to explore the management and variety trait effects within each GAR. For the variety trait analysis, the VPT dataset was reduced to account for varieties for which 17 agronomic traits and 11 disease/insect reaction ratings were available (65,264 yield observations). GAR accounted for 46 % of the total variation in grain yield, M for 32 %, residuals (including interactions) for 13 %, year for 7 %, and G for 2 %. Conditional inference trees identified interactions among management practices and their effects on yield within each GAR. For instance, water regime was the most important practice influencing wheat yield in the semi-arid western portion of the study region, followed by sowing date and fungicide. In dryland trials, there was typically an interaction between fungicide, sowing date, and tillage system, depending on GAR. Other management practices (e.g. dual-purpose management, crop rotation, and tillage practice) also significantly affected yield, depending on GAR. The main variety trait associated with increased yields depended on region and management combination. For instance, drought tolerance was the most important trait in dryland trials while stripe rust tolerance was more relevant in irrigated trials in the semi-arid region. In this research, we demonstrated an approach that uses widely available long-term VPT data to improve management and variety selection recommendations and can be used in other regions and crops for which long-term VPT data are available. Kansas State Univ, Dept Agron, Manhattan, KS 66506 USA Kansas State Univ, Dept Stat, Manhattan, KS 66506 USA Kansas State Univ, Dept Plant Pathol, Throckmorton Hall, Manhattan, KS 66506 USA Colorado State Univ, Dept Soil & Crop Sci, Ft Collins, CO 80523 USA Oklahoma State Univ, Dept Plant & Soil Sci, Stillwater, OK 74078 USA Sao Paulo State Univ, Dept Crop Prod, Jaboticabal, SP, Brazil Sao Paulo State Univ, Dept Crop Prod, Jaboticabal, SP, Brazil Kansas Wheat Alliance: GAGR004805BG5828

Wheat (Triticum aestivum L.) grain yield response to plant density is inconsistent, and the mechanisms driving this response are unclear. A better understanding of the factors governing this relationship could improve plant density recommendations according to specific environmental and genetics characteristics. Therefore, the aims of this paper were to: i) execute a synthesis-analysis of existing literature related to yield-plant density relationship to provide an indication of the need for different agronomic optimum plant density (AOPD) in different yield environments (YEs), and ii) explore a data set of field research studies conducted in Kansas (USA) on yield response to plant density to determine the AOPD at different YEs, evaluate the effect of tillering potential (TP) on the AOPD, and explain changes in AOPD via variations in wheat yield components. Major findings of this study are: i) the synthesis-analysis portrayed new insights of differences in AOPD at varying YEs, reducing the AOPD as the attainable yield increases (with AOPD moving from 397 pl m-2 for the low YE to 191 pl m-2 for the high YE); ii) the field dataset confirmed the trend observed in the synthesis-analysis but expanded on the physiological mechanisms underpinning the yield response to plant density for wheat, mainly highlighting the following points: a) high TP reduces the AOPD mainly in high and low YEs, b) at canopy-scale, both final number of heads and kernels per square meter were the main factors improving yield response to plant density under high TP, c) under varying YEs, at per-plant-scale, a compensation between heads per plant and kernels per head was the main factor contributing to yield with different TP.