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Saving energy in greenhouses is an important issue for growers. Here, we present a method to minimize the total energy that is required to heat and cool a greenhouse. Using this method, the grower can define bounds for temperature, humidity, CO2 concentration, and the maximum amount of CO2 available. Given these settings, optimal control techniques can be used to minimize energy input. To do this, an existing greenhouse climate model for temperature and humidity was expanded to include a CO2 balance. Heating, cooling, the amount of natural ventilation, and the injection of industrial CO2 were used as control variables.Standard optimization settings were defined in order to compare the grower's strategy with the optimal solution. This optimization resulted in a theoretical 47% reduction in heating, 15% reduction in cooling, and 10% reduction in CO2 injection for the year 2012. The optimal control does not need to maintain a minimum pipe temperature, in contrast to current practice. When the minimum pipe temperature strategy of the grower was implemented, heating and CO2 were reduced by 28% and 10% respectively.We also analyzed the effect of different bounds on optimal energy input. We found that as more freedom is given to the climate variables, the higher the potential energy savings. However, in practice the grower is in charge of defining the bounds. Thus, the potential energy savings critically depend on the choice of these bounds. This effect was analyzed by varying the bounds. However, because the effect can be demonstrated to the grower, the outcome has value to the grower with respect to decision making, an option that is not currently available in practice today.

Escalating energy costs are an increasing concern for South Asian farmers growing rice and wheat in rotation. Millions of people in the IGP (Indo-Gangetic Plains) depend on this cropping system for food and income security. CT (conservation tillage) practices, including mechanical BP (bed planting), PTOS (power-tiller operated seeding), and ST (strip tillage), are advocated by donors and development organizations as profitable, high yielding, and energy-efficient alternatives to TT (traditional tillage). However, most studies on the EUE (energy input use efficiency) of CT originate from researcher-controlled and on-station experiments. Comparatively little information is available on the EUE of CT practices as farmers apply them in their own fields, and under their own management decisions. This research responds to this gap, and analyzes EUE of each of these three CT options, compared to TT, by surveying 328 rice-wheat farmers in north-western Bangladesh. Concentrating on wheat production, we employed a non-parametric benchmarking technique involving slack-based measures of technical efficiency, along with a fractional regression model to identify and compute the wasteful use of energy. PTOS achieved the highest EUE score (0.92), followed closely by BP and ST (both 0.91), whereas TT (0.68) was significantly (p <0.001) different and lower than the CT practices.

In order to achieve the Paris Agreement goals of keeping the temperature rise well below 2 °C or even 1.5 °C, all countries would need to make fair and ambitious contributions to reducing emissions. A vast majority of countries have adopted reduction targets by 2030 in their Nationally Determined Contributions (NDCs). There are many alternative ways to analyze the fairness of national mitigation contributions. This article uses a model framework based on six equity principles of effort-sharing, to allocate countries’ reduction targets under global emissions scenarios consistent with meeting the Paris climate goals. It further compares these allocations with the NDCs. The analysis shows that most countries need to adopt more ambitious reduction targets by 2030 to meet 2 °C, and even more for 1.5 °C. In the context of 2 °C, the NDCs of the United States of America and the European Union lack ambition with respect to the approaches that emphasize responsibility; China's NDC projection falls short of satisfying any approach in 2030. In the context of 1.5 °C, only India, by implementing its most ambitious efforts by 2030, could be in line with most equity principles. For most countries, the NDCs would use most of their allowed emissions space for the entire 21 st century by 2030, posing a major challenge to transform to a pathway consistent with their fair contributions in the long-term.

In this study, we compare the relative importance of climate change to technological, management, price and policy changes on European arable farming systems. This required linking four models: the SIMPLACE crop growth modelling framework to calculate future yields under climate change for arable crops; the CAPRI model to estimate impacts on global agricultural markets, specifically product prices; the bio-economic farm model FSSIM to calculate the future changes in cropping patterns and farm net income at the farm and regional level; and the environmental model INTEGRATOR to calculate nitrogen (N) uptake and losses to air and water. First, the four linked models were applied to analyse the effect of climate change only or a most likely baseline (i.e. B1) scenario for 2050 as well as for two alternative scenarios with, respectively, strong (i.e. A1-b1) and weak economic growth (B2) for five regions/countries across Europe (i.e. Denmark, Flevoland, Midi Pyrenées, Zachodniopomorski and Andalucia). These analyses were repeated but assuming in addition to climate change impacts, also the effects of changes in technology and management on crop yields, the effects of changes in prices and policies in 2050, and the effects of all factors together. The outcomes show that the effects of climate change to 2050 result in higher farm net incomes in the Northern and Northern-Central EU regions, in practically unchanged farm net incomes in the Central and Central-Southern EU regions, and in much lower farm net incomes in Southern EU regions compared to those in the base year. Climate change in combination with improved technology and farm management and/or with price changes towards 2050 results in a higher to much higher farm net incomes. Increases in farm net income for the B1 and A1-b1 scenarios are moderately stronger than those for the B2 scenario, due to the smaller increases in product prices and/or yields for the B2 scenario. Farm labour demand slightly to moderately increases towards 2050 as related to changes in cropping patterns. Changes in N2O emissions and N leaching compared to the base year are mainly caused by changes in total N inputs from the applied fertilizers and animal manure, which in turn are influenced by changes in crop yields and cropping patterns, whereas NH3 emissions are mainly determined by assumed improvements in manure application techniques. N emissions and N leaching strongly increase in Denmark and Zachodniopomorski, slightly decrease to moderately increase in Flevoland and Midi-Pyrenées, and strongly decrease in Andalucia, except for NH3 emissions which zero to moderately decrease in Flevoland and Denmark.

Over the last decade Brazil has implemented a new and ambitious biofuel program: the National Program of Production and Use of Biodiesel (PNPB). When launching this program in 2004 the government stated that it wanted to avoid the same kind of geographical concentration, single crop focus, dominance of agribusiness, and exclusion of family farmers that have occurred with bioethanol production through the ProÁlcool policy since 1975. This paper compares the life histories of the bioethanol and the biodiesel policies of Brazil by analyzing their substantive policy content; the power and politics of actors that struggle for the design and implementation of the policies; and the polity in terms the organization and institutionalization of the policies. The paper concludes that both policies have become submerged by and dependent on the polity and politics of primarily the energy and agricultural sectors that operate as the two semi-autonomous governance fields. This submerging has shaped the substantive contents of biofuels policies, and explains why the 2004 biodiesel policy PNPB, in spite of its objectives for social inclusion and rural development, faces similar problems in implementation as its predecessor, the 1975 bioethanol policy ProÁlcool.

Natural supply of nitrogen is often limiting coffee production. From the viewpoints of growth and biomass production, adequate nitrogen supply is important. Growing coffee under full sunlight not only enhances potential yields but also increases demands for nitrogen fertilizer, the extent of which is ill quantified. This paper provides a comprehensive analysis of N uptake and distribution, biomass production, photosynthetic characteristics of 2.5 years old trees and first bean yields of 3.5 years old coffee trees in response to four radiation treatments (30%–100% of full sun), factorially combined with four rates of nitrogen supply (0–88 g tree−1 y−1). The experiment was arranged in a randomized split-split plot design and was conducted at Jimma University horticultural farm, Ethiopia, using three coffee varieties. With larger N application and higher level of radiation, more N was utilized and more biomass and yield were produced. The fertilizer-N recovery ranged from 7 to 17% and declined with larger N supply and increased with radiation level. Coffee trees provided with larger amount of N had higher amounts of N per unit leaf area, light-saturated rate of leaf photosynthesis and first bean yield compared to trees grown in low N supply and limited radiation. The relation between biomass and plant N content was conservative across coffee varieties and can be used to estimate N content from biomass or calculate required uptake to produce a given amount of biomass. Though testing of the relation for other climatic conditions is advisable, this relation can also be used in the development of process-based quantitative coffee tree growth models,. Achieving synchronies between N supply and coffee trees demand without excess or deficiency requires further investigation of options to improve the low nitrogen recovery.

Micropollutant removal in an algal treatment system fed with source separated wastewater streams was studied. Batch experiments with the microalgae Chlorella sorokiniana grown on urine, anaerobically treated black water and synthetic urine were performed to assess the removal of six spiked pharmaceuticals (diclofenac, ibuprofen, paracetamol, metoprolol, carbamazepine and trimethoprim). Additionally, incorporation of these pharmaceuticals and three estrogens (estrone, 17β-estradiol and ethinylestradiol) into algal biomass was studied. Biodegradation and photolysis led to 60-100% removal of diclofenac, ibuprofen, paracetamol and metoprolol. Removal of carbamazepine and trimethoprim was incomplete and did not exceed 30% and 60%, respectively. Sorption to algal biomass accounted for less than 20% of the micropollutant removal. Furthermore, the presence of micropollutants did not inhibit C. sorokiniana growth at applied concentrations. Algal treatment systems allow simultaneous removal of micropollutants and recovery of nutrients from source separated wastewater. Nutrient rich algal biomass can be harvested and applied as fertilizer in agriculture, as lower input of micropollutants to soil is achieved when algal biomass is applied as fertilizer instead of urine.