Symbiotic dinitrogen fixation in forage legumes amended with high rates of de-inking paper sludge

The paper de-inking process produces a waste by-product, de-inking paper sludge (DPS), which contains paper fibers, clay particles, and inks and has high C and Ca and low N and P concentrations. Use of high rates of DPS to increase the soil organic matter thus requires provision of high rates of N for adequate plant growth. Using dinitrogen (N2)-fixing forage legumes is an alternative to the N fertilization under such circumstances. In a 2-yr field study (1995 and 1996), the effect of different rates of DPS (0, 50, or 100 Mg dry matter ha−1), applied once in October 1994, were evaluated on symbiotic N2 fixation of forage legumes established on two soil types in Eastern Quebec, Canada. Symbiotic N2 fixation was measured in alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.), red clover (Trifolium pratense L.), and sweetclover (Melilotus officinalis L.); bromegrass (Bromus inermis L.) was used as the reference (non N2–fixing) crop. Dinitrogen fixation was estimated by the 15N natural abundance method. The percentages of N derived from the atmosphere increased significantly with DPS in the year of establishment (1995). In the first production year (1996), the effects of DPS on N2 fixation were mainly observed at the first cut. Our results show that DPS used as an organic amendment generally led to similar or greater forage legume productivity and greater N2 fixation compared with unamended controls in the first production year and is compatible with sustainable agricultural practices

The Effect of hormone priming and corm weight on the yield of flowers and characteristics of daughter corms of saffron in the first year

Saffron is one of the most important crops and medicinal plants in Iran and plays an important role in non-oil exports of the country. Although Iran has the largest area under cultivation of saffron, its yield is low compared with global production. The main objective of this study is to investigate the yield of flowers and quantitative characteristics of daughter corms under the effects of application of plant growth regulators priming and two different corm sizes. A factorial experiment arrangement in RCBD with four replications was conducted, under the terms of pot at the College of Aburaihan-University of Tehran, Iran during 2015. Small (3-5g) and large (8-10g) mother corm sizes were hormonal priming by gibberelic acid (GA3), cytokinin (BA), auxin (IBA) with 250 ppm concentration and before cultivation. The start of flowering, number and flowers yield, fresh weight of flower, fresh and dry weight of stigma, number and weight of daughter corms per mother corms were measured. The results showed that in all traits except the start of flowering large corms weighing of 8 to 10 g were cultivated in comparison with small corms and this was significant at the 1% level. Application of cytokinins hormone in comparison with control for all traits except the start of flowering and weight of daughter corms showed a significant difference at 1%. Application of gibberellic acid hormone treatment also accelerated flowering. In addition, it increased the weight of daughter corms by 56% in large mother corms compared to control and this had a significant difference from control at 1%. Auxin (IBA) in the number of flowers had no significant difference with control and also in other traits, although IBA was better than control, with both BA and GA3 treatments had a significant difference. The results indicated that the use of large mother corms with hormonal priming with BA and GA3 will improve flower and corm yield in the first year

Using models for estimation of leaf area index in Cucurbita pepo L.

In order to find plant growth characteristic relationships with leaf area index in Pumpkin (Cucurbita pepo L.), an experiment was conducted based on randomized complete block design with three replications. Three planting dates (Apr. 20, May 21 and Jun. 21) performed at the research field of Abooreihan Campus, the University of Tehran, Pakdasht, Tehran, Iran, in 2009–2010 cropping season. Sampling was performed during the whole growing season and leaf area (LA), leaf no. per plant, leaf dry weight (LDW), leaf fresh weight (LFW), node no. per main stem and plant height, were measured. The aim of this study was to collect and evaluate nonlinear regression models in the plant growth characteristic studies (exponential, Gaussian, linear, quadratic, symmetric, sigmoid). Root Mean Square Error (RMSE), the standard error of the estimate (SE) and coefficient of determination (R2) were used to find the appropriate model(s). The result showed that, the linear model predicted significant relationships between LAI and LA (R2 = 90), LAI and leaf no. per plant (R2 = 90), LAI and node no. per main stem (R2 = 90), LAI and LDW (R2 = 98) and LAI and LFW (R2 = 98). These result showed that the linear model can be used for estimation of LAI Pumpkin, especially where there is no LAI-meter available. Keywords: Pumpkin, Allometric relationships, Leaf area, Vegetative characteristics, Linear mode