High N fertilizer application to irrigated wheat in Northern Mexico for conventionally tilled and permanent raised beds: Effects on N balance and short term N dynamics

Nitrogen (N) surpluses from fertilizer application can cause major environmental harm including pollution of surface water, groundwater, and air. To assess such negative externalities, N balances are a complex but useful tool to predict surpluses and to measure effects of nutrient optimization strategies in agriculture. The Yaqui Valley in north‐western Mexico is representative for thousands of square kilometres of intensive, irrigated wheat production under arid conditions worldwide and has been targeted for conservation agriculture in recent years. For these cropping systems, detailed N balances are scarce and often incomplete. To help fill this knowledge gap, data from a long‐term experiment were collected in 2013/14 on a Vertisol to examine the impact of three tillage‐straw management practices (CTB: conventionally tilled beds; PB‐straw: permanent raised beds with residue retention; PB‐burn: permanent raised beds with residue burning) on N dynamics. Tillage had significant effects on soil NO₃‐N, NH₄‐N, and total N contents across the cropping period. Soil total N content was at all sampling depths lowest in CTB. Soil NO₃‐N in the 0–90 cm profile was highest in PB‐burn over the cropping period and ranged from 77 kg ha^?1 in the bed before pre‐planting fertilizer application up to 269 kg ha^?1 in the furrow after the second fertilizer application. Annual simple N balances were +59 kg N ha^?1 in CTB, +39 kg N ha^–1 in PB‐straw, and +46 kg N ha^?1 in PB‐burn. Residual mineral soil N was significantly affected by tillage‐straw management and lowest for PB‐straw (+205 kg N ha^?1) and highest for CTB, and for PB‐burn (+283 kg N ha^?1 each) in the 0–90 cm soil profile. Soil NO₃‐N moved out of the effective wheat root zone, as indicated by the high residual NO₃‐N content at 30–90 cm depth, which is an important pathway of N leaching. Quantifiable N losses through leaching and volatilization averaged 100 kg N ha^?1. Our findings suggest that there is potential for substantial reductions in N inputs in all tillage‐straw systems to decrease N losses and to reduce mineral residual soil N, but care should be taken to avoid reducing grain protein content, which in PB straw was already below the quality standard. A knowledge transfer of the European “N_min” concept is advisable in this region to regulate N fertilizer over‐application.     

The impact of redox agents on sugar-snap cookie making

The impact of the oxidants potassium bromate and potassium iodate and the reducing agents L-cysteine, glutathione and sodium metabisulfite on sugar-snap cookie making was investigated. Spread behavior of cookie dough during baking (spread rate, set time and collapse) was monitored and texture properties of the baked cookies were determined. Low levels of redox agents impacted neither dough nor cookie properties. High levels of reducing agents (10,000 ppm on a flour base) significantly decreased set time, and, hence, cookie diameter. They also decreased the degree of collapse, which then, evidently, also increased cookie height. Earlier setting and higher resistance to structural collapse, but also the higher intrinsic break strength of the cookie material when adding high levels of reducing agents could be explained on a molecular level as resulting from earlier and more pronounced gliadin–glutenin cross-linking. In contrast, when high levels of oxidizing agents were added, a postponed setting, a more pronounced collapse and decreased intrinsic cookie break strength were observed. The present work demonstrates the importance of heat-induced gluten polymerization during cookie baking and confirms that free sulfhydryl groups are necessary for the polymerization reactions. A model illustrating the role of gluten cross-linking during cookie making is put forward.     

The effect of tillage,crop rotation and residue management on maize and wheat growth and development evaluated with an optical sensor

Crop growth and development as well as yield are the result of the efficiency of the chosen agricultural management system within the boundaries of the agro-ecological environment. End-of-season yield results do not permit the evaluation of within-season management interactions with the production environment and do not allow for full understanding of the management practice applied. Crop growth and development were measured during the 2004, 2006 and 2008 crop cycles with an optical handheld NDVI sensor for all plots of the different management treatments of a long-term (since 1991) sustainability trial in the highlands of Mexico. Cropping systems varying in (1) tillage (conventional vs. zero tillage); (2) residue management (retention vs. removal); (3) rotation (monocropping vs. a maize [Zea mays L.]/wheat [Triticum aestivum L.] rotation) were compared. The NDVI-handheld sensor was evaluated as a tool to monitor crop growth and development and was found to be an excellent tool for this purpose. There was a strong relation between NDVI and biomass accumulation of maize and wheat. The measurement with the handheld sensor was non-destructive and fast so that a representative plot area could be measured easily and time-efficiently. Zero tillage induced different crop growth dynamics over time compared to conventional tillage. Zero tillage with residue retention is characterized by a slower initial crop growth, compensated for by an increased growth in the later stages, positively influencing final grain yield. Also crop rotation influenced early crop growth, with lower NDVI values for crops sown after wheat than crops after maize. Zero tillage with residue removal had low NDVI values throughout the growing season. Zero tillage with retention of crop residues results in time efficient use of resources, as opposed to conventional tillage, regardless of residue management, and zero tillage with residue removal. The results indicated that different tillage, rotation and residue management practices influence crop growth and development. It is important to monitor and understand crop growth under different management systems to select the right varieties and adjust timing and practice of input supply (fertilizer, irrigation etc.) in a holistic way in each cropping system.     

Conservation agriculture as a sustainable option for the central Mexican highlands

Tropical highlands of the world are densely populated and intensively cropped. Agricultural sustainability problems resulting from soil erosion and fertility decline have arisen all over this agro-ecological zone. Based on selected soil quality indicators, i.e. time-to-pond, aggregate distribution and stability (expressed as the mean weight diameter (MWD) for dry and wet sieving, respectively) and soil moisture, from a representative long-term sustainability trial initiated in 1991 in Central Mexico (2240 masl; 19.31°N, 98.50°W; Cumulic Phaeozem), some insights into the feasibility of conservation agriculture (CA) as part of a sustainable production system in the tropical highlands are given. Zero tillage plots with crop residue removal showed low aggregate distribution (average MWD = 1.34 mm) and stability (average MWD = 0.99 mm) resulting in top layer slaking, increased erosion and low time-to-pond values. Retaining the residue in the field with zero tillage avoided the above-mentioned negative evolution for both aggregate distribution as stability (average MWD = 2.77 and 1.51 mm, respectively) and even improved the physical conditions of the soil as compared to conventional practice. Throughout the growing season the lowest soil moisture content was found in zero tillage without residue (average over the entire growing season = 20.5% volumetric moisture content), the highest in zero tillage with residue retention (average = 29.7%) while conventional tillage had intermediate soil moisture values (average = 27.4%). Zero tillage without residue retention had most days of soil moisture values under permanent wilting point, while zero tillage with residue retention had the least. Taking into account these results, zero tillage with residue retention can clearly be a part of an integrated watershed management scheme towards sustainable agriculture in the tropical highlands. It is clear that to develop new management practices to improve water use, reduce erosion and enhance human labor/animal power focus must be on the use of conservation agriculture both for rainfed as well as irrigated production systems and be fine tuned for each system.     

Factors determining the occurrence of the agroforestry system withAcacia mearnsii in Central Java

In 1922, the colonial government introducedAcacia mearnsii in the tobacco-growing region of Wonosobo. Soon this species was accepted by the local people who developed an agroforestry system based on a rotation ofA. mearnsii and agricultural crops. Now, the growing of the black wattle is becoming less popular. To study the prospects for this agroforestry system 143 farmers from 5 villages were interviewed. The functions of this agroforestry system are the production of fuelwood and bark (which contains tannin for the leather industry), soil conservation and soil improvement. The following factors affectA. mearnsii growing: population density (which affects farm size and demand for domestic fuelwood), tobacco-processing (which requires fuel), topography and commercialization. If current trends continue, the contribution of the functions of this agroforestry system to welfare will not be sufficient to compete successfully with subsistence and cash crops like potatoes and tobacco. Therefore,A. mearnsii cultivation is expected to decline further. This article was written within the framework of the cooperation between the two departments in the Forestry and Nature Conservation (FONC) project sponsored by the Netherlands University Foundation For International Cooperation (NUFFIC).     

New approach of testing the effect of heat stress on eggshell quality: mechanical and material properties of eggshell and membrane

1. The effect of high temperature on eggshell quality was investigated by measuring the mechanical and material properties of shell and membranes. 2. Heat exposure resulted in a decrease in zootechnical performance and eggshell thickness, increase in egg breakage, and unchanged egg shape index. 3. The static stiffness (Kstat), dynamic stiffness (Kdyn) and modulus of elasticity of the eggshell were not significantly affected by high temperature. Membrane prolongation increased significantly while membrane attachment strength and breakage strength tended to decrease and increase, respectively. The relationships between these variables were changed by high temperature. 4. Neither Kstat nor Kdyn could give a reasonable explanation for the changed eggshell quality induced by heat stress. The decreased eggshell thickness and changed properties of shell membrane may be responsible, at least partially, for the decreased shell quality of eggs from heat-stressed hens.     

Wheat (Triticum aestivum L.) puroindoline functionality in bread making and its impact on bread quality

Wheat puroindolines (PINs) spontaneously adsorb at air/water interfaces and show excellent foaming properties. They can positively impact bread quality, in which the formation of stable foam is important for product quality. The impact of endogenous PINs on bread quality was studied by preparing gluten–starch blends from isolated gluten and starch fractions with different PIN levels, which allowed largely retaining the interaction between PINs and flour components. Our results indicate that blends with high PIN levels yielded more homogeneous crumb structures with fine gas cells than bread made with blends containing medium or low PIN levels. However, the mechanism by which PINs exert this crumb improving effect is not clear. Varying PIN levels impacted neither dough extensibility nor did it result in different PIN levels in dough liquor. Lipid removal yielded bread with a less homogeneous crumb gas cell distribution, indicating that lipids also are required to obtain good crumb structure.     

Metabolism of the food-associated carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine by human intestinal microbiota

2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine is a putative human carcinogenic heterocyclic aromatic amine formed from meat and fish during cooking. Although the formation of hazardous PhIP metabolites by mammalian enzymes is well-documented, nothing is known about the PhIP transformation potency of human intestinal bacteria. In this study, the in vitro metabolism of PhIP by human fecal samples was investigated. Following anaerobic incubation of PhIP with stools freshly collected from six healthy volunteers, we found that PhIP was extensively transformed by the human intestinal bacteria. HPLC analysis showed that the six human fecal microbiota transformed PhIP with efficiencies from 47 to 95% after 72 h incubation, resulting in one major derivative. ESI-MS/MS, HRMS, 1D (1H, 13C, DEPT) and 2D (gCOSY, gTOCSY, gHMBC, gHSQC) NMR, and IC analysis elucidated the complete chemical identity of the microbial PhIP metabolite as 7-hydroxy-5-methyl-3-phenyl-6,7,8,9-tetrahydropyrido[3',2':4,5]imidazo[1,2-a]pyrimidin-5-ium chloride. At present, no information is available about the biological activity of this newly discovered bacterial PhIP metabolite. Our findings however suggest that bacteria derived from the human intestine play a key role in the activation or detoxification of PhIP, a digestive fate ignored so far in risk assessments. Moreover, the variation in transformation efficiency between the human microbiota indicates interindividual differences in the ability to convert PhIP. This may predict individual susceptibility to carcinogenic risk from this suspected dietary carcinogen.     

DNA markers for eating quality of indica rice in Indonesia

Rice eating quality is considered to be one of the top priorities in determining the agronomical value of rice; thus, the rapid evaluation of eating quality at early breeding generations in breeding programmes for better eating quality is of great importance. In an attempt to develop DNA markers associated with eating quality of indica rice, we used multiple regression analysis to test 54 markers, which were preselected for their possible association with eating quality, using 24 indica varieties with different palatability scores. Of these markers, eighteen markers were found to be significantly associated with palatability according to sensory evaluation. Accordingly, a marker set in the model regression equation with a high R² (0.997) was formulated to estimate indica rice palatability. Validation suggests that markers and the statistical parameters formulated by the equation could be a potential tool to predict the palatability of cooked Indonesian indica rice and could be reliable in developing country‐dependent model equations for eating quality.     

Introduction to the Cereals & Europe Focus Issue

In May 2013, the Laboratory of Food Chemistry and Biochemistry, KU Leuven, organized the 4th Cereals & Europe Spring Meeting in the university's hometown Leuven, Belgium. The C&E Spring Meeting was endorsed by AACC International and its European Section, Cereals & Europe, and partially sponsored by key companies such as platinum‐level sponsor Puratos, gold‐level sponsors Chopin Technologies, CSM, DSM, DuPont, Kellogg, and Perten Instruments, and silver‐level sponsors Bühler, Cargill, Megazyme, Nestlé, and Novozymes. It was attended by more than 200 cereal scientists and technologists from 24 countries representing both academia and industry. The C&E Spring Meeting's theme was “Unlocking the Full Potential of Cereals: Challenges for Science Based Innovation.” The program, hence, focused on different aspects of cereals related to corporate challenges and new technologies, which were explored during 55 oral presentations and 56 poster presentations and reflected in six major session topics: cereal biotechnology; cereal constituents and ingredients; cereal‐based food production and processing; structure–function relationships; analytical aspects; and nutritional aspects of cereal‐based foods, food processing, and ingredients. There is obviously great potential in exploiting cereals as a tool to address the challenges of science‐based innovation. One of these challenges is reflected in the interest of today's consumers in the relationship between food and health. Here, genetic and molecular approaches can be used to improve both the content and composition of health‐promoting constituents in cereals. Other challenges the industry faces include increased incidence and/or diagnosis of celiac disease, wheat allergies, and gluten sensitivity. Not surprisingly, the quest for alternative cereals, ingredients, and products that meet the needs of consumers facing these intolerances, allergies, or sensitivities is ongoing and becomes more and more important. Alternatively, thoroughly understanding the changes in cereal constituents and ingredients during food production and processing as well as their structure–function relationships will allow cereal scientists to alter their properties. This, in turn, will provide a means of meeting new nutritional, structural, and textural criteria. Examples include the challenges associated with increasing the amount of dietary fiber in a formulation, replacing gluten with other proteins, and improving the eating characteristics of both fresh and stored (as a result of improved shelf life) products. Understanding the structural and textural properties and relating them to (often biopolymer) constituent and ingredient properties present some interesting challenges. However, there is more to the story than this. Modern cereal research ends neither at the moment at which food products are produced nor at the moment at which their properties have been analyzed. It also digs further into and focuses increasingly on what happens to foods and their constituents within the gastrointestinal tract. By doing so, cereal research increasingly aims at catching sight of the direct relationship between food, food digestion, and human health. Despite advances in each of the aforementioned topics, significant challenges in cereal research still need to be addressed. In doing so, cereal researchers in both academia and industry should keep in mind that consumer demands are constantly changing. We here have selected six peer‐reviewed papers from the 2013 C&E Spring Meeting: Effects of Genotype and Environment on Phenolic Acids Content and Total Antioxidant Capacity in Durum Wheat. D. Martini, F. Taddei, I. Nicoletti, R. Ciccoritti, D. Corradini, and M. G. D'Egidio Effect of High‐Pressure Processing on the Features of Wheat Milling By‐products. A. Marti, A. Barbiroli, F. Bonomi, A. Brutti, S. Iametti, M. Marengo, M. Miriani, and M. A. Pagani Effect of Wheat Grain Steaming and Washing on Lipase Activity in Whole Grain Flour. J. L. De Almeida, B. Pareyt, L. R. Gerits, and J. A. Delcour Ultrasonic Characterization of Unyeasted Bread Dough of Different Sodium Chloride Concentrations. F. Koksel, A. Strybulevych, J. H. Page, and M. G. Scanlon Correlation of Quality Parameters with the Baking Performance of Wheat Flours. S. M. Thanhaeuser, H. Wieser, and P. Koehler Study of the Chemical Changes and Evolution of Microbiota During Sourdoughlike Fermentation of Wheat Bran. F. Manini, M. Brasca, C. Plumed‐Ferrer, S. Morandi, D. Erba, and M. C. Casiraghi The papers included in this focus issue demonstrate that the 2013 C&E Spring Meeting brought together multidisciplinary perspectives. We hope that they can serve as a basis for further discussions between cereal researchers from both academia and industry and help them to fully unlock the potential of cereals to address the present corporate challenges to science‐based innovation. We thank all of the speakers, attendees, session chairs, sponsors, participants, and team members of the Laboratory of Food Chemistry and Biochemistry. Click on Current Issues on left and then July/August 2014 to view the six articles noted above. (From the Mobile site, go to the July/August 2014 issue.)