Juan Manuel Herrera

Agroscope · Field Crops

Food security and economic stability of many developing countries rely on the resilience of major crops to climatic variability and climatic anomalies. Since climate change forecasts predict an increasing frequency and intensity of climatic disturbances, the need to increase our knowledge about the influence of climate variability on crop productiv...

Potato sprouting during storage occurs after a break in dormancy, leading to a decrease in quality and consequently economic losses. We used 3379 records from multi-year and multi-environment trials of 537 potato varieties to identify the main factors driving potato dormancy and to develop predictive models for an efficient sprouting forecast. The...

A changing regulatory environment and growing awareness are driving the need for crop improvement in organic agriculture. Contrary to conventional breeding, evidence on the economic effects of research and development in organic breeding is lacking. This study assesses adoption, economic impact, and rates of return to organic crop improvement resea...

The challenges of securing future food security will require deployment of innovative technologies to accelerate crop production. Plant phenotyping methods have advanced significantly, spanning low-cost hand-held devices to large-scale satellite imaging. Field-based phenotyping aims to capture plant response to the environment, generating data that...

Winter oilseed rape (OSR) can be grown intercropped with frost-sensitive service plant mixtures. This practice may reduce weed pressure and contribute to providing N for OSR after service plant freezing. However, there is little knowledge of how plants interact together and with the soil in diverse annual crop mixtures. To assess these interactions...

Climatic change effects on crop yields are expected to be crop‐ and site‐specific. Here, DSSAT models were used to evaluate climatic change effects and mitigation strategies on maize and soybean yields in soils of the subtropical and semi‐arid region of Chaco. Simulations were performed for the DK747 and A8000 genotypes, calibrated for CERES‐Maize...

Limited information exists on how tillage and nitrogen (N) fertilization affects small-scale variation in nitrogen use efficiency (NUE) and crop performance. In a two-year field study under temperate conditions, we investigated how tillage (NT, no-tillage; CT, conventional tillage) and N fertilization affected the small-scale variation in NUE and w...

An increased nitrogen (N) supply was proposed to avoid grain yield (GY) reductions and successfully implement conservation agriculture (CA). We investigated interactions effects of tillage system and N supply on winter wheat (Triticum aestivum L.) at two sites in the Swiss midlands with no (0 kg N ha−1) and high (150–160 kg N ha−1) N supply using 1...

Changes in soil structure can be monitored in undisturbed soil samples through the micromorphometric analysis of thin sections. In this methodology, it is common that individual images (three to ten repetitions) are used and that they cannot be related in different scales between soil components; in addition, although a minimum study area is establ...

Identifying opportunities and limitations for closing yield gaps is essential for setting right the efforts dedicated to improve germplasm and agronomic practices. This study analyses genotypes × environments interaction (G × E), genetic progress, and grain yield stability under contrasting production systems. For this, we analyzed datasets obtaine...

Thanks to positive interactions between species, growing mixtures of cover crops allows improving the ecosystem services provided by cover crop cultivation. In this study, the influence of species diversity but also of species identity and mixture composition on cover crop biomass production and its stability in diverse growing conditions was studi...

Most studies in Mexico on the decomposition of crop roots are carried out on small surfaces and under controlled conditions; this fact limits the regional information. In contrast, local soil knowledge provides information that allows to know the distribution and agronomic management of soil in larger areas. The objective was to determine the rate...

Europe accounts for around 20% of the global cereal production and is a net exporter of ca. 15% of that production. Increasing global demand for cereals justifies questions as to where and by how much Europe’s production can be increased to meet future global market demands, and how much additional nitrogen (N) crops would require. The latter is im...

Although the semiarid and subhumid Chaco regions in northern Argentina have been traditionally considered marginal and unsuitable for cultivating grain maize for human and livestock nutrition, this crop is increasingly being adopted by local farmers. The low maize yields observed in the area suggest that climatic constraints limit productivity, whi...

Large scale prediction of the performance of genotypes is fundamental for understanding genotype by environmental interactions (G × E), predicting accurately genotypic performance in specific environments, and increasing our knowledge to develop future crop varieties. We derived environmental limiting factors from daily weather data for critical cr...

La producción y descomposición de las raíces en agrosistemas modula los cambios en la estructura del suelo. Sin embargo, la cuantificación de este fenómeno está limitada por el uso de técnicas destructivas. Dos métodos se proponen para resolver este problema: los núcleos de crecimiento interno y el análisis micromorfológico. El primero permite moni...

Four spring wheat genotypes (Triticum aestivum L.) were grown without (N0 = 0 kg N ha⁻¹) and under ample (N1 = 250 kg ha⁻¹) nitrogen (N) fertilizer in field experiments in two seasons. The aim was to assess genotypic variation in N use efficiency (NUE) components and N-related indices during grain filling thus to identify superior wheat genotypes....

This work studies the factors responsible for amaranth (Amaranthus retroflexus) growth suppression by different cover crops (CC). In field trials with two shading levels amaranth biomass was similar, demonstrating that light interception by CC was not the primary mechanism responsible for amaranth growth suppression. We could show that below a thre...

Congregated information on maize and wheat root morphology and their distribution as influenced by tillage and soil physical conditions is meager. Root growth under no-tillage (NT) or conventional tillage (CT) is variable: Under NT, higher bulk density slows root elongation and provides shorter roots but simulate root branching; results may be oppo...

Soil nitrogen (N) dynamics can be modified by cover crops in rotations with cereals. Although, roots are a major source of N, little is known about the dynamics of root decomposition of cash and cover crops. The objective of this study was to assess the effects that cover crop species have on i) the decomposition of spring wheat roots during the gr...

Root decomposition is a fundamental process for the development of cultivated plants, has a direct effect on the soil nutrient cycles, regulates carbon transferences in the agrosystem, and represents a significant CO2 flow into the atmosphere. On its quantification and analysis are employed destructive techniques that limit the interpretation of th...

A ‘protein potential’ concept has been developed by analogy with the ‘grain yield’ concept, with the aim of better understanding the factors influencing wheat protein content and identifying the most stable varieties as well as the amount of protein that remains to be reached. The protein potential of 18 varieties of winter wheat covering all quali...

Nitrogen (N) losses negatively impact groundwater quality. Spring wheat genotypes varying in N-fertilizer recovery were studied (by using lysimeters) for their potential to minimize NO3-N leaching during spring and summer, over a three-year period. Additionally, we examined to what extent root growth and NO3-N leaching explain the well-known differ...

Nitrogen (N) fertilizers are one of the most expensive inputs in agricultural settings. Additionally, the loss of N increases costs, contributes to soil acidification, and causes off-site pollution of the air, groundwater and waterways. This study reviews current knowledge about technologies for N fertilization with potential to increase N use effi...

Organic cropping systems have been promoted as a sustainable alternative to minimize the environmental impacts of conventional practices. Relatively little is known about the potential to reduce NO 3-N leaching through the large-scale adoption of organic practices. Moreover, the potential to mitigate NO 3-N leaching and thus the N pollution under f...

Wheat (Triticum aestivum L.) grains are widely used as a feed. Contrasting to the demand of a high viscosity for bread making, a low viscosity is required for monogastric livestock. The impact of genotype and climate on this trait is largely unknown. Therefore, seven wheat varieties grown at five sites in Switzerland from 2007 to 2009 were analyzed...

Soils are the basis of human existence by being the substrate for food and crop production. Soils hovever, are increasingly threatened by degradation, pollution, erosion, loss of organic matter, salinization and other processes that render them unuseable for crop and food production. Soil degradation is not only a national problem, its effects str...

Two strategies for seeding irrigation are used for irrigated wheat. Wet sowing utilizes pre-sowing irrigation to germinate weed seeds and thus control weeds, followed by sowing. Dry sowing plants into dry soil that is irrigated soon afterward, resulting in higher soil moisture during germination and emergence than wet sowing. Field observations hav...

Efficient use of nitrogen (N) by wheat crop and hence prevention of possible contamination of ground and surface waters by nitrates has aroused environmental concerns. The present study was conducted in drainage lysimeters for three years (1998–2000) to identify whether spring wheat genotypes (Triticum Aestivum L.) that differ in N-related traits d...

Cereal residues represent a major resource for livestock feeding during the dry season in southern Africa. When kept on the soil surface instead of feeding them to livestock, crop residues can contribute to increasing soil fertility and maintaining crop productivity in the short- and the long-term. We explored these trade-offs for smallholder cotto...

No tillage or zero tillage (NT) is the extreme form of reduced tillage; NT with residue retention is a main component of conservation agriculture. Using a literature survey and meta-analysis, this study aimed to (i) summarize the results of studies comparing the grain yield of wheat [Triticum aestivum L. and Triticum turgidum L. subsp. durum (Desf....

The nitrogen (N) fertilization of wheat (Triticum aestivum L.) is important for stable and high grain yield. However, the effect of N on root growth and survivorship is poorly understood. The objec-tives of this study were (1) to determine the effect of varying N availability on the growth and sur-vivorship of roots and (2) to determine whether gen...

Background There is a large body of literature on competitive interactions among plants, but many studies have only focused on above-ground interactions and little is known about root-root dynamics between interacting plants. The perspective on possible mechanisms that explain the outcome of root-root interactions has recently been extended to incl...

Competition between crops and weeds may be stronger at the root than at the shoot level, but belowground competition remains poorly understood, due to the lack of suitable methods for root discrimination. Using a transgenic maize line expressing green fluorescent protein (GFP), we nondestructively discriminated maize roots from weed roots. Interact...

Soil is a multifunctional component of terrestrial systems. One of the factors that influence these functions is its structure and the indicator most commonly used for its study is aggregate stability. There is a close relationship between soil structure and plant growth. The way roots interact with soil properties, especially their structure, requ...

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Nitrogen (N) availability is the primary nutrient limitation for both total food supply and protein content in food. Nitrogen fertilizers are expensive inputs in cereal cropping systems and loss of N increases cropping costs, reduces crop yields, contributes to soil acidification, and causes off-site pollution of groundwater and waterways. The effe...

The productivity of white yam (Dioscorea rotundata Poir) must increase to sustainably meet the demand of the increasing populations in the developing world where this is a staple crop. Although this could be achieved through the use of mineral fertilizers, reports indicate limited effects of these inputs on tuber yield. We hypothesized (i) that D....

The use of living mulch (LM) systems for maize (Zea mays L.) cultivation may reduce soil erosion and nitrate leaching. However, the yield of maize cultivated in LM is lower than in conventional farming systems. This decrease has often been attributed to belowground competition, but the lack of a suitable method to demonstrate such competition has p...

The objective of this study was to investigate the root growth and nitrogen (N) accumulation of spring wheat during grain filling under split N management. Two spring wheat genotypes were grown in a field with sandy loam soils at three levels of N fertilization (18, 21, and 24 g N m−2). Variations in N availability across soil depth were performed...

In a two-year (1999–2000) field experiment four Swiss spring wheat (Triticum aestivum L.) genotypes (cvs. ‘Albis’, ‘Toronit’ and ‘Pizol’ and an experimental line ‘L94491’) were compared for genotypic differences in the root parameters that determine uptake potential and nitrogen use efficiency (NUE):root surface area (RSA) and its components, root...

The limited flexibility available in the configuration of commercial minirhizotron imaging systems makes it difficult to adapt these systems to new applications. It is also too expensive to introduce modifications, which are often very temporary to these systems at the end of the development process.In order to identify the roots of a single specie...

Growing nitrogen (N) catch crops can reduce NO(3)-N leaching after cultivating cereals. The objective of this study was to relate NO(3)-N leaching to variation in the uptake of N and the size and distribution of the root systems of different catch crops species. In a 3-yr lysimeter experiment, phacelia (Phacelia tanacetifolia Benth.), sunflower (He...

Roots are essential for growth, survival and fitness of plants. Most often roots of different plants share a certain soil volume, for example when weeds establish within a crop canopy. The study of the co-location of roots in such plant mixtures is, however, not trivial, because it is not easy to assign single roots to the respective plants. To ove...

Roots take up most of the resources required by a plant, but a lack of efficient research tools hinders our understanding of the function and relevance of the root system. This is especially evident when the research focus is not on a single plant, but on multiple plants that share the same soil resources. None of the available methods allow for si...

An experiment covering a 2-yr spring wheat (Triticum aestivum L.) catch crop succession was conducted in lysimeters to account for the losses of N due to leaching. We sought to relate these losses to the N uptake of the main crop and to integrate the estimated N loss and uptake into a balance. The non-winter hardy catch crops [yellow mustard (Sinap...

Little is known about the spatial and temporal characteristics of the root growth of spring wheat and its modification by nitrogen (N) supply. For 4 years the cultivar Toronit was fertilized with 20 (LN) or 270 kg N ha−1 (HN) in lysimeters. The shoot traits were measured at harvest, while root growth was screened regularly at 10 soil depths in mini...

Three spring wheat genotypes (cv. Albis and Toronit and the experimental line L94491) identified to vary in nitrogen use efficiency characteristics, were studied in lysimeters under two levels of N supply (0 and 250 Kg N ha-1) in 1999 and 2000. No. of roots cm-2 were obtained from regular minirhizotron observations at soil depths of 0.10, 0.25, 0....

Our aim was to develop a model for the dynamic simulation of root morphology and architecture. The model intended to support the identification of root traits maximizing the capture of resources from soil. The effects of mechanical constraints in the soil were implemented as well as the distribution, availability, uptake characteristics and dynamic...