Methodological aspects of determining nitrogen fixation of different forage legumes

Knowledge about the amount of fixed nitrogen of different legume crops is very important for calculation of farm N balances. According to literature the choice of determination method may have an impact on the estimated amount of N fixed by a legume sward. The aim of the study was to compare the three most important field methods for determination of nitrogen fixation under different sward management systems. In the present study the natural 15N abundance method gave lower fixation rates than the two alternative methods (total-N-difference method and 15N enrichment technique). The determination of N fixation based only on N in harvestable plant material underestimated the amount of fixed N on average by 70 kg ha-1 compared to techniques including also the amount of N in non harvestable plant part

Methodological aspects of determination of biological N-fixation of different forage legumes [Methodische Aspekte der Bestimmung der biologischen N-Fixierung verschiedener Futterleguminosen]

Knowledge about the amount of fixed nitrogen of different legume crops is very important for calculation of farm N balances. According to literature the choice of determination method may have an impact on the estimated amount of N fixed by a legume sward. The aim of the study was to compare the three most important field methods for determination of nitrogen fixation under different sward management systems. In the present study the natural 15N abundance method gave lower fixation rates than the two alternative methods (total-N-difference method and 15N enrichment technique). The determination of N fixation based only on N in harvestable plant material underestimated the amount of fixed N on average by 70 kg × ha-1 compared to techniques including also the amount of N in non harvestable plant parts

Rubber Tree (Hevea brasiliensis) Biomass, Nutrient Content, and Heating Values in Southern Thailand

Article 638201

Calculating Cost Savings Per Acre When Harvest Days are Stochastic

New cotton harvesters have been introduced that have higher performance rate as well as eliminate extra labor and accompanying equipment. The new machines build partial modules on board the harvester. Higher field efficiency (performance rate) lets a farmers harvest his cotton in a shorter period. Precipitation causes cotton losses in both quality and quantity of the cotton. This paper seeks to measure cost per acre when harvest days are stochastic by using historic precipitation data. Cost per acre will include the cost of losses from a loss function from precipitation. Cost per acre will be adjusted for conventional versus new technology by quantifying the losses that contribute to extra costs of extended harvesting.Cotton, harvester, fieldwork days, stochastic, cost per acre, Agribusiness, Farm Management,

State of Our Estuaries 2006

The 2006 State of the Estuaries Report includes twelve indicators intended to report on the health and environmental quality of New Hampshire’s estuaries. The New Hampshire Estuaries Project (NHEP) developed and now implements a Monitoring Plan to track environmental indicators, inform management decisions, and report on environmental progress and status. The Monitoring Plan describes the methods and data for 34 indicators used to determine if the environmental goals and objectives of the Management Plan are being met. For each indicator, the Monitoring Plan defines the monitoring objective, management goal, data quality objectives, data analysis and statistical methods, and data sources. Just as implementation of the Management Plan for New Hampshire’s estuaries involves the collaboration of many organizations and agencies, the NHEP Monitoring Plan relies on data compiled from organizations that are leaders in the management and protection of the state’s estuaries and coastal watershed resources

Environmental Indicator Report: Shellfish

During the fall and winter of 2001-2002, the New Hampshire Estuaries Project’s Technical Advisory Committee (TAC) developed a suite of environmental indicators to track progress toward the NHEP’s management goals and objectives. These indicators were fully described in terms of their performance criteria, statistical methods, and measurable goals in the NHEP’s Monitoring Plan published in March 2003 (NHEP, 2003). From September 2002 to April 2003, the NHEP Coastal Scientist prepared four “Indicator Reports” that summarized the available information and results of statistical tests for each of the indicators. The TAC reviewed and commented on these reports, and then recommended a subset of the most important or illustrative indicators to be presented to the Management Committee. Finally, after being presented to both the TAC and the Management Committee, 12 key indicators were incorporated in the 2003 State of the Estuaries report. The NHEP Coastal Scientist will update each indicator report at least every 3 years. A new State of the Estuaries report will be produced every three years. This report is an update to the first Shellfish Indicator Report, which was first published in September 2002

Yield, forage quality, residue nitrogen and nitrogen fixation of different forage legumes

Fixed nitrogen accumulated by legumes is the main nitrogen source for organic farming systems. Knowledge about the amount of fixed nitrogen, its pathways into forage yield, crop residues, soil-N and yield formation of the following crop is needed for designing crop rotations. In a field experiment conducted in Northern Germany differently managed (cut, mulched) legumes (red clover, alfalfa, white clover) in pure stands and in mixture with a companion grass (Lolium perenne) have been grown to determine Yield, forage-quality, N2-fixation and residue nitrogen. Cropped grass/legume reached higher N2-fixation than mulched. While green manure grass/legume left up to 296 kg ha-1 of N in mulch, stubble and roots on the field, most cropped grass/legume mixtures left less than 120 kg N ha-1 in crop residues. Cropped swards showed higher N2-fixation than the mulched mixtures. Swards with red clover or alfalfa reached higher legume contents and harvestable biomass than swards with white clover. Conclusions The results show that biomass production, forage yields, residue nitrogen and N fixation of grass/legume mixtures can be influenced by various combinations of legume species and management. The factors listed have to be considered carefully when planning crop rotations

Fast-Convergent Learning-aided Control in Energy Harvesting Networks

In this paper, we present a novel learning-aided energy management scheme ($\mathtt{LEM}$) for multihop energy harvesting networks. Different from prior works on this problem, our algorithm explicitly incorporates information learning into system control via a step called \emph{perturbed dual learning}. $\mathtt{LEM}$ does not require any statistical information of the system dynamics for implementation, and efficiently resolves the challenging energy outage problem. We show that $\mathtt{LEM}$ achieves the near-optimal $[O(\epsilon), O(\log(1/\epsilon)^2)]$ utility-delay tradeoff with an $O(1/\epsilon^{1-c/2})$ energy buffers ($c\in(0,1)$). More interestingly, $\mathtt{LEM}$ possesses a \emph{convergence time} of $O(1/\epsilon^{1-c/2} +1/\epsilon^c)$, which is much faster than the $\Theta(1/\epsilon)$ time of pure queue-based techniques or the $\Theta(1/\epsilon^2)$ time of approaches that rely purely on learning the system statistics. This fast convergence property makes $\mathtt{LEM}$ more adaptive and efficient in resource allocation in dynamic environments. The design and analysis of $\mathtt{LEM}$ demonstrate how system control algorithms can be augmented by learning and what the benefits are. The methodology and algorithm can also be applied to similar problems, e.g., processing networks, where nodes require nonzero amount of contents to support their actions