Abstract: Objective of this study was to evaluate the effect of different controlled release fertilizer technologies on nutrient leaching and plant growth parameters of two palm species, Chinese Fan (Livistona chinensis) and Queen (Syagrus romanzoffiana). We compared Nutri-Pak (12-4-12 controlled release packet) and Harrell’s (12-4-12 controlled release polymer coated urea) against Atlantic (8-4-12 controlled release polymer coated urea, coated sulfate of potash), the most commonly used palm fertilizer in South Florida. Plants were grown in 25 cm (11 L) pots under 70% shade, watered weekly, with pest and weed control done as required. Plant growth parameters: number of leaves, leaf length and width, and basal diameter, were measured every two months. Leachate was collected weekly after irrigation and a two-month composite sample was analyzed for nutrient concentrations. There was no difference in the growth parameters among the three fertilizers for Chinese Fan plants. However for Queen, Atlantic and Harrell’s had significantly thicker basal diameter than Nutri-Pak. Significant difference in the concentration of nutrients in the leachate was observed among the fertilizer types. Throughout the study period, Nutri-Pak had a lower concentration of nutrients in the leachate than Atlantic and Harrell’s. Our research indicates that Nutri-Pak control release fertilizer is comparable to other commercial fertilizers in Chinese Fan growth, but the larger Queen palms likely require an additional packet. Nutri-Pak fertilizer resulted in less nutrient leaching and could be a better environmental choice.
Abstract: Plant growth correlates with net carbon gain on a whole plant basis. Over the last several decades, the driving factors shaping plant morphology and performance have become increasingly clear. This review seeks to explore the importance of these factors for grass performance. Briefly, these fall into factors influencing photosynthetic rates directly, competition between plants in a canopy, and nutrient status and availability.
Abstract: The growing need for food, energy and materials demands a resource efficient approach as the world’s population keeps increasing. Biochar is a valuable product that can be produced in combination with bio-energy in a cascading approach to make best use of available resources. In addition, there are resources that have not been used up to now, such as, e.g., many agro-residues that can become available. Most agro-residues are not suitable for high temperature energy conversion processes due to high alkali-content, which results in slagging and fouling in conventional energy generation systems. Using agro-residues in thermal processes, therefore, logically moves to lower temperatures in order to avoid operational problems. This provides an ideal situation for the combined energy and biochar production. In this work a slow pyrolysis process (an auger reactor) at 400 °C and 600 °C is used as well as two fluidized bed systems for low-temperature (600 °C–750 °C) gasification for the combined energy and biochar generation. Comparison of the two different processes focuses here on the biochar quality parameters (physical, chemical and surface properties), although energy generation and biochar quality are not independent parameters. A large number of feedstock were investigated on general char characteristics and in more detail the paper focuses on two main input streams (woody residues, greenhouse waste) in order to deduct relationships between char parameters for the same feedstock. It is clear that the process technology influences the main biochar properties such as elemental- and ash composition, specific surface area, pH, in addition to mass yield quality of the gas produced. Slow pyrolysis biochars have smaller specific surface areas (SA) and higher PAH than the gasification samples (although below international norms) but higher yields. Higher process temperatures and different gaseous conditions in gasification resulted in lower biochar yields but larger TSA, higher pH and ash contents and very low tar content (16-PAH). From the feedstock data looked at in more detail, a few trends could be deducted in the attempt to learn how to steer the biochar characteristics for specific uses.
Abstract: The amendment of soil with biochar has been demonstrated to have an effect not only on the soil physicochemical properties, but also on soil microbial community composition and activity. Previous reports have demonstrated significant impacts on soil microbial community structure. These impacts are modulated not only by the biochar composition, but also on the soil’s physicochemical characteristics. This indicates that soil characteristics must be considered prior to biochar amendment. A significant portion of the soils of the southeastern coastal plain are severely degraded and, therefore, candidates for biochar amendment to strengthen soil fertility. In this study we focused on two common soil series in the southeastern coastal plain, utilizing feedstocks endemic to the area. We chose feedstocks in four ratios (100% pine chip; 80:20 mixture of pine chip to poultry litter; 50:50 mixture of pine chip to poultry litter; 100% poultry litter) prior to pyrolysis and soil amendment as a biochar product. Soil was analyzed for bioavailable nutrients via Mehlich-1 extractions, as well as microbial community composition using phospholipid fatty acid analysis (PLFA). Our results demonstrated significant shifts in microbial community composition in response to biochar amendment, the effects of which were greatest with 100% poultry litter biochar. Strong relationships between PLFAs and several Mehlich-1 extractable nutrients (Al, Cu, Fe, and P) were observed.
Abstract: This study investigated the response of corn silage to different combinations of zinc (Zn) and phosphorus (P) soil supply when grown in sandy soil. The soil was naturally poor in extractable Zn and rich in plant-available P. The experiment was conducted in outdoor containers. The treatments consisted of soil supply combinations of 3 levels of Zn (0, 5 and 10 mg Zn kg−1 of dry soil) and 4 levels of P (0, 12, 36 and 72 mg P2O5 kg−1 of dry soil). The results showed the absence of a significant effect (at p ≤ 0.05) of Zn-P interaction on plant growth, plant mineral content or total aerial dry weight at harvest. P application depressed Zn shoot content, and conversely, Zn supply slightly reduced P shoot content. The total aerial dry weight at harvest was not enhanced by P application. However, it was significantly increased by Zn supply of 5 mg·kg−1 only for the highest P (72 mg·kg−1) application (at p ≤ 0.05). This increase was around 15% compared to no Zn soil supply. It was especially linked to kernel dry weight and particularly to pollination rate. For the highest level of P supply, Zn applications significantly enhanced (at p ≤ 0.05) the kernel dry weight and the pollination rate by 22.1% and 38.4% respectively, compared to no Zn supply.
Abstract: Post-harvest losses represent a significant threat to food security and farmer incomes worldwide. It is an inefficiency in the global food production system that is avoidable. In deducing principles of designing and implementing agricultural extension programs to reduce post-harvest losses, valuable lessons can be gleaned from the handful of previous extension projects and programs addressing post-harvest loss. Abstracting principles from previous experiences and using this to inform future post-harvest loss prevention programs is an evidence-based approach to arrive at solutions to this problem. This paper reviews extension programs for post-harvest loss prevention, before presenting key principles abstracted from the review that should be taken into consideration for future post-harvest loss prevention programs. This paper aims to contribute to knowledge on the role of agricultural extension in the design of post-harvest loss reduction efforts in developing countries.