A growth scale for the phasic development of common buckwheat

Growth scales give a standardized definition of crop development and increase the understanding among researchers and growers. In this research we defined a growth scale for the phasic development of common buckwheat that was mainly based on a sequence of easily recognizable changes occurring on the first and the terminal clusters of inflorescences formed on the main stem. Observations were carried out on plants grown in two years throughout spring. In an attempt to uniform the duration of phasic development across sowing dates, the length of phases and sub-phases was calculated in days and in thermal time using nine combinations of cardinal temperatures. A sequence of stages and various patterns of coordinated development were maintained throughout all sowings and years. Specifically, (1) the first inflorescence became visible after three true leaves had fully expanded on the main stem; (2) flowering reached the terminal inflorescence cluster before full-sized green fruits became visible in the first inflorescence, and (3) fruit ripening in the whole plant ended within two weeks of the end of ripening in the oldest inflorescence. Plant size was increased with the delay of sowing, and the length of the growth cycle was by approximately 400°Cd longer when plants experienced a day length longer than 15 h. This changed the correspondence between flowering and ripening stages, so that full flowering was associated with the development of green fruits in the first inflorescence when the cycle was short, but with their development in the terminal cluster when it was long. Trends in grain yield did not correspond to those in plant size and phase length. We are confident that this growth scale will be a valuable tool for following the progress of buckwheat development and to predict growth patterns and harvest time in response to temperature and photoperiod

Forage and grain yield of common buckwheat in Mediterranean conditions: Response to sowing time and irrigation

With the view to extending the cultivation of common buckwheat to Mediterranean environments, we investigated the responses of two varieties to three sowing times, early spring, late spring and late summer, in rainfed and irrigated conditions. Plants were harvested at two ripening stages for forage production and at maturity for grain yield. The crop cycle lasted 82-88 days independent of sowing time, whereas the thermal time was ∼1000 degree-days in early spring and late summer sowings, and 1200 degree-days when sown in late spring. Forage yield increased up to 75% between ripening stages. Early spring was the best sowing time for forage (4tha-1 dry weight) and grain yield (2tha-1 dry weight) in rainfed conditions. Late spring sowings give the highest forage yield when irrigated (6tha-1 dry weight), but were not suitable for producing grain, for the adverse effect of high summer temperatures on seed set and seed filling. Late summer sowings produced acceptable grain yield (1.5tha-1 dry weight), whereas short days and low temperatures limited forage production. Thus, in Mediterranean environments, buckwheat could be profitably introduced as a minor summer crop, sown in early spring for grain production and in late spring for forage production

Dos bienales, dos hemisferios, dos tendencias : las bienales de Venecia como pretexto para una reflexión

La Bienal de Arquitectura de Venecia es uno de los eventos más importantes al mundo para la arquitectura y el debate disciplinario. Dos de las pasadas bienales: la que tuvo como curador el holandés Rem Koolhaas en 2014 y la curada por el chileno Alejandro Aravena en 2016; con sus marcadas diferencias y oposiciones, son utilizadas como pretexto para una reflexión crítica sobre dos tendencias que pudieran definirse “hemisféricas”. La bienal de Koolhaas presentó una valiosa investigación histórico-enciclopédica, que emanaba una latente inquietud. La bienal de 2016, la primera Bienal curada por un arquitecto del “hemisferio sur” del mundo, intentaba de contra mostrar en su amplitud un panorama de trabajos socialmente más comprometidos, pero a su vez sesgaba hacia un exceso de pragmatismo. Posiblemente valorar en una reflexión comparativa estos dos enfoques pueda restituir más nitidez al pensamiento y a la acción, gracias a la síntesis entre posiciones antitéticas que, por si mismas parecen no abrazar el amplio espectro de las posibilidades y de las necesidades disciplinarias contemporáneas

Grain legumes differ in nitrogen accumulation and remobilisation during seed filling.

n grain legumes, the N requirements of growing seeds are generally greater than biological nitrogen fixation (BNF) and soil N uptake during seed filling, so that the N previously accumulated in the vegetative tissues needs to be redistributed in order to provide N to the seeds. Chickpea, field bean, pea, and white lupin were harvested at flowering and maturity to compare the relative contribution of BNF, soil N uptake, and N remobilisation to seed N. From flowering to maturity, shoot dry weight increased in all crops by approximately 50%, root did not appreciably change, and nodule decreased by 18%. The amount of plant N increased in all crops, however in field bean (17 g m−2) it was about twice that in chickpea, pea, and lupin. The increase was entirely due to seeds, whose N content at maturity was 26 g m−2 in field bean and 16 g m−2 in chickpea, pea, and lupin. The seed N content at maturity was higher than total N accumulation during grain filling in all crops, and endogenous N previously accumulated in vegetative parts was remobilised to fulfil the N demand of filling seeds. Nitrogen remobilisation ranged from 7 g m−2 in chickpea to 9 g m−2 in field bean, and was crucial in providing N to the seeds of chickpea, pea, and lupin (half of seed N content) but it was less important in field bean (one-third). All the vegetative organs of the plants underwent N remobilisation: shoots contributed to the N supply of seeds from 58% to 85%, roots from 11% to 37%, and nodules less than 8%. Improving grain legume yield requires either reduced N remobilisation or enhanced N supply, thus, a useful strategy is to select cultivars with high post-anthesis N2 fixation or add mineral N at flowering

Changes in biological properties and antioxidant capacity of an agricultural soil amended with sewage sludge

The effects of applying sewage sludge (SS) to agricultural soil (at low rate of 22.5, LRS, and at high rate of 45 t ha−1 dry basis, HRS) were monitored over a 120-d experimental period. Total organic carbon (TOC), water- soluble organic carbon (WSOC), alkali-soluble phenols, basal respiration, 10 specific enzyme activity, dehydrogenase activity (DH-ase), metabolic potential (MP) and FDA-hydrolytic activity (FDA) were strongly increased by both rates of SS applications. In the SS amended soil, about 70% of the organic C added with the material remained at the end of the experiment. Basal respiration increased with increasing SS doses. The 15 specific enzyme activity and the MP indicate an increase in the enzyme activity in soil. AQ10 The addition of SS led to higher values than the control of all the tested parameters up to the end of the experimental period. The anti- oxidant capacity (trolox equivalent antioxidant capacity, TEAC) was influ- 20 enced by SS addition only when applied at HRS. After 120 days only HRS value of TEAC (5.13 mM g−1) was higher than control (4.09 mM g−1). The pattern of TEAC did not enable any link to be established between antioxidant capacity and both alkali-soluble phenols and basal respira- tion in soil

Forage potential of winter cereal/legume intercrops in organic farming

This research was performed to assess the potential of cereal/legume intercropping to enhance forage yield and quality when compared with cereal sole crops under the constrains imposed by UE organic farming regulations. Sole crops (SC) and intercrops (IC) of two winter cereals, barley (Hordeum vulgare L.) and durum wheat (Triticum durum Desf.), and two legumes, white lupin (Lupinus albus L.) and common vetch (Vicia sativa L.), were evaluated at two harvest times for dry matter yield (DMY), crude protein concentration (CPC), and nitrogen yield (NY). Yield values and dry matter concentration (DMC) were generally higher when cereals were at the hard dough compared to the late milk stage. On average, intercropping increased forage yield by 72%, NY by 190%, and CPC by 40 g kg-1, compared to cereal sole crops, but the choice of legume species affected the yield advantage and the composition of forage. Land equivalent ratio (LER) of intercrops was always higher than 1, ranging from 1.39 to 1.61. Intercropping also enhanced weed suppression, compared to sole crop

Submergence sensitivity of durum wheat, bread wheat and barley at the germination stage

Soil waterlogging at initial growth stages can cause heavy yield losses of winter cereals. Therefore, the screening for submergence tolerance traits in seeds of commercial varieties is of high concern worldwide. Ten Italian varieties of durum wheat (Triticum durum Desf.), bread wheat (T. aestivum L.) and barley (Hordeum vulgare L.) were investigated for their ability to germinate in submerged conditions and to recover after submergence periods of three to 15 days. Submergence prevented germination and decreased germinability, at rates that increased with duration of submergence. Sensitivity ranked in the order: barley >durum wheat >bread wheat. We related the higher sensitivity of barley to its slower germination and slightly higher leakage of electrolytes, whereas the percentage of abnormal seedlings was lower than in other species. It was less than 4%, compared to less than 15 and 8% in durum wheat and bread wheat, respectively. Wide varietal differences were found in all species. According to variety, after 6-day submergence, germinability ranged from 2 to 42% in barley, from 5 to 80% in durum wheat, and from 30 to 77% in bread wheat. Varieties with more than 40% seed survival were three, six and seven per species, in the same order. The differential submergence sensitivity of varieties indicates a potential to select for waterlogging tolerance within Italian genotypes of winter cereal crops

Cadmium uptake and translocation in durum wheat varieties differing in grain-Cd accumulation

Wheat grain products are the primary source of dietary Cd-intake for humans. Since varieties differ markedly in grain-Cd accumulation, efforts are needed to find traits associated with low, or high, accumulation. Two durum wheat varieties, selected in a field screening as low (Creso) and high (Svevo) grain-Cd accumulating, were grown on soil spiked with 1.5, 3 and 4.5 mg Cd/kg. Growth patterns, Cd uptake and translocation were investigated at heading and maturity. Cadmium did not affect plant growth and grain yield, but grain-Cd concentration always exceeded the permissible limit of 0.2 mg Cd/kg, and was approximately double in Svevo than in Creso. At maturity, total Cd-uptake increased linearly with supply in Creso, from 13 to 23 μg/plant, and was approximately 18 μg/plant, irrespective of Cd level, in Svevo. Partitioning to shoot was higher in Svevo than in Creso, both at heading and maturity. We suggest that reduced plant height, high root to shoot biomass ratio during vegetative growth and elevated post-heading dry matter accumulation promoted Cd accumulation into grain. Since these traits are common to modern wheat varieties, risks of grain Cd-contamination can increase in the future