Biosolids affect the growth, nitrogen accumulation and nitrogen leaching of barley

Biosolids are organic fertilisers derived from treated and stabilised sewage sludge that increase soil fertility and supply nitrogen to crops over a long period, but can also increase the risk of nitrogen (N) leaching. In this work, spring barley was grown in lysimeters filled with soil amended with biosolids, and with and without mineral N fertilisation. Biomass and the N concentration and content of shoots and roots were determined at flowering and maturity, and the N remobilization was calculated during grain filling. Drainage water was collected and analysed for N leaching. Biosolids increased soil porosity and soil nitrate, and positively affected the growth and N uptake of barley. Compared to mineral fertilisers, biosolids produced 18% higher vegetative biomass and 40% higher grain yield. During grain filling, both N uptake and N remobilization were higher with biosolids, which increased the grain N content by 32%. Nitrogen loss in leachates was 1.2% of plant uptake with mineral fertilisers and 1.7% with biosolids. Thus, soil fertilisation with biosolids greatly benefits spring barley, only slightly increasing N leaching

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

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

Effect of preceding crop on the agronomic and economic performance of durum wheat in the transition from conventional to reduced tillage

Preceding crop greatly affects the agronomic and economic performance of durum wheat, but its interaction with tillage intensity was scarcely investigated at the early transition from conventional to reduced tillage. This work was aimed at studying how preceding crop determines the performance of durum wheat during the early transition from conventional to reduced tillage. To this end, the effect of four preceding crops (sunflower, durum wheat, alfalfa and maize) in interaction with two tillage systems without inversion (RT1 – chisel ploughing, disking twice, and harrowing and RT2 – disking twice and harrowing) and a conventional tillage (CT – mouldboard ploughing, disking twice, and harrowing) was studied on durum wheat in two years of cultivation. The effect of preceding crop on grain yield and yield components of durum wheat was different depending on tillage intensity, and this effect varied depending on the year of cultivation. Grain yield increased by 1.1–4.2 t ha−1 with the increase of the intensity of tillage in both years and all preceding crops, with the only exception of wheat crop following sunflower in 2009–2010 and following maize in 2010–2011. RT2 decreased wheat grain yield when compared with RT1 only with alfalfa as preceding crop. Differences in grain yield among tillage systems and crops preceding wheat in both years were mainly due to variations of mean kernel weight and number of spikes per unit area. The profitability of durum wheat varied according to the year of cultivation, the preceding crop and the tillage system. Overall, in both years profitability was lowest and negative following wheat under reduced tillage system, while it was highest and positive following alfalfa under CT. Reduced growth of durum wheat with reduced tillage systems was mainly consequence of weeds and volunteers plants development and nitrogen availability in soil resulting from nutrient immobilization. It can be concluded that potential yield penalties in durum wheat in the transition from conventional to reduced tillage can be alleviated by an appropriate selection of preceding crops

Hepatitis C Virus Infection: Evidence for an Association With Type 2 Diabetes

An increased prevalence of type 2 diabetes and impaired glucose tolerance has been consistently found in liver cirrhosis from any cause (1–3). Less clear is whether hepatitis C virus (HCV) infection is associated with type 2 diabetes in the absence of cirrhosis. Several reports have claimed a specific association between HCV infection and type 2 diabetes, but in most instances, patients were a mixture of cases with cirrhosis and hepatitis (4–6). Two clinic-based studies found an excess of type 2 diabetes in noncirrhotic HCV+ (NC-HCV+) patients compared with patients with chronic hepatitis of other origin (7–9), but another large study could not detect it (10). Furthermore, one clinic-based small study found a specific association with type 2 diabetes in NC-HCV+ patients (11) compared with a general population sample. The aim of this study was to establish the prevalence and clinical phenotype of type 2 diabetes in a large series of NC-HCV+ patients. A sample of the general population or patients with hepatitis B virus (HBV)-related noncirrhotic chronic hepatitis (NC-HBV+) was used as control subjects. From January 1995 to December 2001, 564 NC-HCV+ patients were consecutively examined at our center (none had been previously treated with interferon). Diagnosis of HCV infection was based on abnormal serum aminotransferases levels of >6 months' duration and positive testing for serum anti-HCV markers and

Remobilization of Dry Matter, Nitrogen and Phosphorus in Durum Wheat as Affected by Genotype and Environment

Field studies were carried out to determine dry matter (DM), nitrogen (N) and phosphorus (P) assimilation until anthesis and DM, N and P remobilization during grain filling in wheat. Twentyfive durum wheat (Triticum durum L.) varieties were grown in Tuscany at Grosseto and at Arezzo. At Grosseto 76% of DM was assimilated during pre-anthesis while at Arezzo the amount was 81%. At Grosseto 44% and at Arezzo 35% of N was accumulated until anthesis, while 33% of P was stored until anthesis in both localities. Cultivar differences in DM and N remobilization were positively related to pre-anthesis dry matter and N content at anthesis (r > 0.74). Environmental contraints on carbon, N and P availability in the plant are crucial factors in determining grain yield and N and P content in grain, affecting both accumulation and remobilization. In the low rainfall site of Grosseto, most of the grain yield originated from dry matter accumulation, while in the wetter environment of Arezzo remobilization and accumulation contributed equally to grain yield. Conversely, at Grosseto grain N content relied most on remobilization and at Arezzo remobilization and accumulation contributed equally. Finally, at Grosseto and at Arezzo accumulation of P was the main source of grain P content

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

La riduzione degli input nella omosuccessione di mais. Risultati di una prova sperimentale nella pianura di Pisa.

La sostenibilità di questtro sistemi colturali per il mais in omosuccessione è stata analizzata per cinque anni. I risultati ottenuti consentono di affermare che la riduzione degli input chimici e meccanici è possibile, senza pregiudicare la convenienza economica del sistema colturale, attraverso la coltivazione in banda, che si caratterizza per il minor impatto ambientale sia per quanto riguarda le perdite di nutrienti che di diserbanti