Socio-economic characterisation of date palm (Phoenix dactylifera L.) growers and date value chains in Pakistan

Increasing food production to feed its rapidly growing population is a major policy goal of Pakistan. The production of traditional staples such as rice (Oryza sativa L.) and bread wheat (Triticum aestivum L.) has been intensified in many regions, but not in remote, drought-ridden areas. In these arid, marginal environments dates and their by-products are an option to complement staples given their high nutritive value and storability. To fill knowledge gaps about the role of date palm in the household (HH) income of rural communities and the structure of date value chains, this project studied date palm production across six districts in four provinces of Pakistan. During 2012–2013 a total of 170 HHs were interviewed with a structured questionnaire using a snowball sampling approach. The results showed that most of the HH were headed by males (99 %) who were married (74 %) and often illiterate (40 %). Agriculture was the main occupation of date palm growers (56 %), while a few coupled agricultural activities with business (17 %) or extra-farm employment opportunities (government 9 %; private sector 8 %). Date sales contributed >50 % to the total income of 39 % of HH and 90–100 % to 24 % of HH. Overall farmers grew a total of 39 date palm cultivars and cultivated an average of 409 ± 559 mature date palms. The majority of the respondents sold dates to commission agents (35 %), contractors (22 %) and wholesalers (21 %), while 28 % of HH cultivated date palms only for self-consumption. Date palm growers had only limited knowledge about high quality date cultivars, optimized farm management and about effective post-harvest conservation. Changes in extension and marketing efforts are needed to allow farmers to better exploit value chains in date thereby reaping higher benefits from improved market access to secure their often marginal income.

Nitrogen use efficiency and optimization of nitrogen fertilizer application for stable yields and high quality of cereals grown in conservation agriculture

In most agroecosystems, nitrogen (N) is the most important nutrient limiting plant growth. One management strategy that affects N cycling and N use efficiency (NUE) is conservation agriculture (CA), an agricultural system based on a combination of minimum tillage, crop residue retention and crop rotation. Available results on the optimization of NUE in CA are inconsistent and studies that cover all three components of CA are scarce. Presently, CA is promoted in the Yaqui Valley in Northern Mexico, the country´s major wheat-producing area in which from 1968 to 1995, fertilizer application rates for the cultivation of irrigated durum wheat (Triticum durum L.) at 6 t ha-1 increased from 80 to 250 kg ha-1, demonstrating the high intensification potential in this region. Given major knowledge gaps on N availability in CA this thesis summarizes the current knowledge of N management in CA and provides insights in the effects of tillage practice, residue management and crop rotation on wheat grain quality and N cycling. Major aims of the study were to identify N fertilizer application strategies that improve N use efficiency and reduce N immobilization in CA with the ultimate goal to stabilize cereal yields, maintain grain quality, minimize N losses into the environment and reduce farmers’ input costs. Soil physical and chemical properties in CA were measured and compared with those in conventional systems and permanent beds with residue burning focusing on their relationship to plant N uptake and N cycling in the soil and how they are affected by tillage and N fertilizer timing, method and doses. For N fertilizer management, we analyzed how placement, time and amount of N fertilizer influenced yield and quality parameters of durum and bread wheat in CA systems. Overall, grain quality parameters, in particular grain protein concentration decreased with zero-tillage and increasing amount of residues left on the field compared with conventional systems. The second part of the dissertation provides an overview of applied methodologies to measure NUE and its components. We evaluated the methodology of ion exchange resin cartridges under irrigated, intensive agricultural cropping systems on Vertisols to measure nitrate leaching losses which through drainage channels ultimately end up in the Sea of Cortez where they lead to algae blooming. A throughout analysis of N inputs and outputs was conducted to calculate N balances in three different tillage-straw systems. As fertilizer inputs are high, N balances were positive in all treatments indicating the risk of N leaching or volatilization during or in subsequent cropping seasons and during heavy rain fall in summer. Contrary to common belief, we did not find negative effects of residue burning on soil nutrient status, yield or N uptake. A labeled fertilizer experiment with urea 15N was implemented in micro-plots to measure N fertilizer recovery and the effects of residual fertilizer N in the soil from summer maize on the following winter crop wheat. Obtained N fertilizer recovery rates for maize grain were with an average of 11% very low for all treatments.

Low-altitude aerial photography for optimum N fertilization of winter wheat on the North China Plain

Previous research has shown that site-specific nitrogen (N) fertilizer recommendations based on an assessment of a soil’s N supply (mineral N testing) and the crop’s N status (sap nitrate analysis) can help to decrease excessive N inputs for winter wheat on the North China Plain. However, the costs to derive such recommendations based on multiple sampling of a single field hamper the use of this approach at the on-farm level. In this study low-altitude aerial true-color photographs were used to examine the relationship between image-derived reflectance values and soil–plant data in an on-station experiment. Treatments comprised a conventional N treatment (typical farmers’ practice), an optimum N treatment (N application based on soil–plant testing) and six treatments without N (one to six cropping seasons without any N fertilizer input). Normalized intensities of the red, green and blue color bands on the photographs were highly correlated with total N concentrations, SPAD readings and stem sap nitrate of winter wheat. The results indicate the potential of aerial photography to determine in combination with on site soil–plant testing the optimum N fertilizer rate for larger fields and to thereby decrease the costs for N need assessments.

Use of digital camera to assess nitrogen status of winter wheat in the Northern China Plain

The most widely used methods to assess the nitrogen (N) status of winter wheat (Triticum aestivum L.) are the determination of plant total N by combustion, the testing of nitrate in the leaf tissue and the use of SPAD readings. However, due to their labor requirements or high costs these methods can hardly be applied to the huge wheat growing areas of the Northern China Plain. This study therefore examined an alternative method to measure the N status of wheat by using a digital camera to record the visible green light reflected from the plant canopy. The experiment was conducted near Beijing in a multi-factorial field trial with three levels of N. The intensity of green light reflected from the wheat canopy was compared to the total N concentration, to the nitrate concentration of the basal stem, and to the SPAD readings of leaves. The results show significant inverse relationships between greenness intensity, canopy total N, and SPAD readings at booting and flowering. At booting, sap nitrate <2000mgL^-1 was inversely related to greenness intensity and to sap nitrate concentration in the basal stem. At sap nitrate ~2000mgL^-1, the greenness intensity reached a plateau. At booting and flowering, significant inverse relationships between greenness intensity and shoot biomass were found. The results show the potential of the new method to assess the N status of winter wheat.

A survey of wheat landraces in Oman

Little is known about the diversity of wheat (Triticum spp.) in Oman. Therefore, a survey was conducted in northern Oman to collect landraces of Triticum durum, T. aestivum and T. dicoccon for subsequent morphological characterization and investigations on stress adaptation. The results show that the cultivation of these landraces (the genetic composition of which remains to be studied in more detail) is done primarily by traditional farmers who preserve the inherited germplasm on often tiny plots in remote mountain oases. This type of traditional cultivation is under heavy economic pressure. An appendix of landraces of other crops collected in the Batinah region and in the mountain oases can be found online.

Discrimination between organically and conventionally grown winter wheat by means of holistic and selected analytical methods

Die Verordnung des Europäischen Rates (EC) 834/2007 erkennt das Recht des Konsumenten auf eine Entscheidung basierend auf vollständiger Information bezüglich der enthaltenen Zutaten im Produkt und deren Herkunft (Qualität der Verarbeitung). Die primäre Kennzeichnungsverordnung betont „organische“ Produktionsstandards ebenso wie die Notwendigkeit zur Kontrolle und Aufsicht. Jedoch ist zurzeit keine validierte Methode zur analytischen Diskriminierung zwischen „organischer“ und „konventioneller“ Herkunft von angebotenen Lebensmitteln verfügbar. Das Ziel der Dissertationsarbeit war die Überprüfung der Möglichkeit mit ausgewählten analytischen und holistischen Methoden zwischen organisch und konventionell angebautem Weizen objektiv zu unterscheiden. Dies beinhaltete die Bestimmung des Gesamtstickstoff (Protein) nach Dumas, zweidimensionale Fluoreszenzdifferenz Gelelektrophorese (2D DIGE) und die Kupferchloridkristallisation. Zusätzlich wurde die Anzahl der Körner pro Ähre (Kornzahl) bestimmt. Alle Bestimmungen wurden an rückverfolgbaren in den Jahren 2005 – 2007 in Belgien gesammelten Proben des Winterweizen (Triticum aestivum L. cv. Cubus) durchgeführt. Statistisch signifikante (p < 0.05) Unterschiede wurden innerhalb der untersuchten Probengruppen sowohl in der Kornzahl, dem Gesamtsticksoff (Eiweißgehalt), als auch in der Gesamtausbeute gefunden, wobei in den meisten Fällen die konventionellen Proben höhere Kornzahlen und Gesamtsticksoff (Eiweißgehalte) aufwiesen. Eine mit der 2D DIGE kompatible Probenvorbereitungsmethode für Winterweizen wurde entwickelt und auf einen internen Winterweizenstandard sowie die entsprechenden Proben angewendet. Die organischen Proben waren im Vergleich mit den konventionellen Gegenstücken in allen Fällen durch eine kleinere Anzahl von signifikant (p < 0.05) stärker exprimierten Proteinspots gekennzeichnet. Gewisse Tendenzen in Richtung der Bevorzugung bestimmter Regionen von stärker ausgeprägten Proteinspots auf aufeinanderfolgenden 2D Abbildungen in Abhängigkeit von der landwirtschaftlichen Methode konnten zwar beobachtet werden, jedoch konnte kein universelles Markerprotein zur Unterscheidung von konventionell und biologisch angebautem Winterweizen identifiziert werden. Die rechnergestützte Verarbeitung der digitalisierten Kristallisierungsbilder mittels multivariater statistischer Analyse und der Regression partieller kleinster Quadrate ermöglichte eine 100%ig korrekte Vorhersage der landwirtschaftlichen Methode unbekannter Proben sowie der Beschreibung der Kristallisierungsbilder. Diese Vorhersage bezieht sich nur auf den hier verwendeten Datensatz (Proben einer Sorte von drei Standorten über zwei Jahre) und kann nicht ohne weiteres übertragen (generalisiert) werden. Die Ergebnisse deuten an, dass die Quantifizierung der beschriebenen Parameter ein hohes Potential zur Lösung der gestellten Aufgabe besitzt.

Egyptian wheat

Wheat as the major cereal crop in Egypt is the core of the government's food security policy. But there are rapid losses of the genetic resources of the country as a result of ongoing modernization and development. Thus we compiled the largest possible number of Egyptian accessions preserved in the world gene banks. In the present study we collected nearly 1000 Egyptian wheat accessions. A part from the Triticum species of the Egyptian flora four species have been found, which were recorded for the first time T. turanicum, T. compactum, T. polonicum and T. aethiopicum. To classify the Egyptian wheat species using morphological studies, 108 accessions were selected. Thereafter, these accessions were cultivated and evaluated morphologically to confirm the validity of the classified species. During the morphological evaluation study, a new case was noticed for the number of glumes in one of the Egyptian wheat accessions. Three glumes per spikelet were observed in a branched spike. This led us to assess the phenomenon in all varieties with branching spikes within the genus Triticum. All varieties which have branching spikes at least in some spikletes have three glumes. We considered the case of the third glume as indicator for the domestication syndrome. Also, a new case of other forms of branching in the genus Triticum was investigated, which was a compromise between true and false-branching. We called it true-false branching. Comparative anatomical studies were carried out between Egyptian Triticum species to investigate the possibility of using anatomical features to classify the Egyptian wheat species. It was concluded that it is difficult to use anatomical features alone to differentiate between two Triticum species, especially when they belong to the same ploidy level. A key for the identification of Egyptian Triticum taxa was established.

Pathogens occuring in the winter pea-maize-winter wheat rotation, their host specificity and the potential of compost in suppressing foot and root disease of peas

The overall aim of the work presented was to evaluate soil health management with a specific focus on soil borne diseases of peas. For that purpose field experiments were carried out from 2009 until 2013 to assess crop performance and pathogen occurrence in the rotation winter pea-maize-winter wheat and if the application of composts can improve system performance. The winter peas were left untreated or inoculated with Phoma medicaginis, in the presence or absence of yard waste compost at rate of 5 t dry matter ha-1. A second application of compost was made to the winter wheat. Fusarium ssp. were isolated and identified from the roots of all three crops and the Ascochyta complex pathogens on peas. Bioassays were conducted under controlled conditions to assess susceptibility of two peas to Fusarium avenaceum, F. solani, P. medicaginis and Didymella pinodes and of nine plant species to F. avenaceum. Also, effects of compost applications and temperature on pea diseases were assessed. Application of composts overall stabilized crop performance but it did not lead to significant yield increases nor did it affect pathogen composition and occurrence. Phoma medicaginis was dominating the pathogen complex on peas. F. graminearum, F. culmorum, F. proliferatum, Microdochium nivale, F. crookwellense, F. sambucinum, F. oxysporum, F. avenaceum and F. equiseti were frequently isolated species from maize and winter wheat with no obvious influence of the pre-crop on the Fusarium species composition. The spring pea Santana was considerably more susceptible to the pathogens tested than the winter pea EFB33 in both sterile sand and non-sterilized field soil. F. avenaceum was the most aggressive pathogen, followed by P. medicaginis, D. pinodes, and F. solani. Aggressiveness of all pathogens was greatly reduced in non-sterile field soil. F. avenaceum caused severe symptoms on roots of all nine plant species tested. Especially susceptible were Trifolium repens, T. subterraneum, Brassica juncea and Sinapis alba in addition to peas. Reduction of growing temperatures from 19/16°C day/night to 16/12°C and 13/10°C did not affect the efficacy of compost. It reduced plant growth and slightly increased disease on EFB33 whereas the highest disease severity on Santana was observed at the highest temperature, 19/16°C. Application of 20% v/v of compost reduced disease on peas due to all four pathogens depending on pea variety, pathogen and growing media used. Suppression was also achieved with lower application rate of 3.5% v/v. Tests with γ sterilized compost suggest that the suppression of disease caused by Fusarium spp. is biological in origin, whereas chemical and physical properties of compost are playing an additional role in the suppression of disease caused by D. pinodes and P. medicaginis.