31. Applying hydraulic lift in an agroecosystem: forage plants with shoots removed supply water to neighboring vegetable crops.

• Authors:
  • Yano, K.
  • Araki, H.
  • Sekiya, N.
• Source: Plant and Soil
• Volume: 341
• Issue: 1/2
• Year: 2011
• Summary: When a plant encounters spatially heterogeneous soil moisture within its root system, usually drier surface and moister subsurface soils, water can move between these layers through the root system, a plant process known as hydraulic lift or redistribution. The water thus transferred is available not only for the plant itself but also for its neighbors. We examined application of this process as a possible biological irrigation tool. As 'donors', we used perennial forage plants with their shoots removed to minimize the effect of light-interception by them on the 'receiver' plants growing alongside them. In a horizontally split-root experiment, where an upper container was filled with sand and a lower one with water, superior donor species could maintain the upper sand in a fully hydrated condition for several weeks, increasing stomatal conductance in the receivers. The effects were also confirmed in a water-limited agricultural field, as significant differences were found in canopy temperature and yield in neighboring crop plants in the presence or absence of donor root systems. These results suggest that deep-rooting associate plants with their shoots removed function as an irrigation tool and improve crop production in water-scarce environments.

32. A new tool for determining fruit hardness for use in monitoring plant water deficits in mulched satsuma mandarin orchards.

• Authors:
  • Ichinokiyama, H.
  • Suzaki, N.
  • Okuda, H.
• Source: Agricultural Information Research
• Volume: 20
• Issue: 3
• Year: 2011
• Summary: In commercial orchards of satsuma mandarin in Japan, mulching cultivation has been developed to produce high quality fruit. It is, however, difficult to manage irrigation to produce consistent characteristics such as high fruit quality, fruit productivity, and tree vigor. The principal reason for this is that no simple, easy, and reliable indicator has been developed to evaluate tree water deficits. In this study, we demonstrated that the morning maximum leaf water potential could be estimated using the fruit hardness in the evening of the previous day. To assist farmers in estimating fruit hardness, we developed a set of three silicone rubber balls with different degrees of hardness as a reference tool, and verified their effectiveness. The experiment was performed in 2008 and 2009, and revealed that irrigation management during July and August using the silicone rubber reference balls gave good results, with high fruit quality and high fruit productivity. Fruit hardness estimated using the silicone rubber balls therefore appears to be a good indicator of irrigation management during July and August for mulched citrus orchards.

33. Agro-environmental monitoring using a wireless sensor network to support production of high quality mandarin oranges.

• Authors:
  • Hashimoto, A.
  • Ito, R.
  • Togami, T.
  • Kameoka, T.
• Source: Agricultural Information Research
• Volume: 20
• Issue: 3
• Year: 2011
• Summary: In Nanki, Mie Prefecture, Japan, the mulching and drip irrigation system produces high-quality fruit despite large variations in the weather. For this cultivation system, we developed a small, stationary agricultural robot, "Field Server", which measures environmental and growing conditions in real time in the orchard. Our goals were to solve the problem of loss of the skills developed by experienced farmers due to a lack of new agricultural workers and aging of farmers, and to cultivate mandarin oranges with the required quality under occasionally severe and highly variable climate conditions. In this research, we demonstrated the ability of Field Server to monitor the agro-environmental conditions that affect plant physiology and the farmer's attitude towards their work and demonstrated the eKo wireless sensor network that was designed for agricultural use. To accomplish our goals, we installed a sensor network to support long-term, stable operation, including optimal placement of sensor nodes, optimal installation of the sensors and modification of network connections with Internet, and developed user-friendly Field Server and eKo data browsing software to help agricultural workers. Long-term data acquisition for a 1-ha agricultural site became possible due to improvements of the eKo system's hardware and software. In addition, the development of databases and related software permitted comparisons of the acquired data with data obtained from nearby AMeDAS stations. The comparison revealed the importance of agro-environmental monitoring (especially for rainfall) close to the production area and of soil moisture measurement to guide irrigation and produce high-quality mandarin oranges.

34. Towards an agronomic assessment of N2O emissions: a case study for arable crops

• Authors:
  • van Groenigen, K. J.
  • van Kessel, C.
  • Oenema, O.
  • Velthof, G. L.
  • van Groenigen, J. W.
• Source: European Journal of Soil Science
• Volume: 61
• Issue: 6
• Year: 2010
• Summary: Agricultural soils are the main anthropogenic source of nitrous oxide (N2O), largely because of nitrogen (N) fertilizer use. Commonly, N2O emissions are expressed as a function of N application rate. This suggests that smaller fertilizer applications always lead to smaller N2O emissions. Here we argue that, because of global demand for agricultural products, agronomic conditions should be included when assessing N2O emissions. Expressing N2O emissions in relation to crop productivity (expressed as above-ground N uptake: "yield-scaled N2O emissions") can express the N2O efficiency of a cropping system. We show how conventional relationships between N application rate, N uptake and N2O emissions can result in minimal yield-scaled N2O emissions at intermediate fertilizer-N rates. Key findings of a meta-analysis on yield-scaled N2O emissions by non-leguminous annual crops (19 independent studies and 147 data points) revealed that yield-scaled N2O emissions were smallest (8.4 g N2O-N kg-1N uptake) at application rates of approximately 180-190 kg Nha-1 and increased sharply after that (26.8 g N2O-N kg-1 N uptake at 301 kg N ha-1). If the above-ground N surplus was equal to or smaller than zero, yield-scaled N2O emissions remained stable and relatively small. At an N surplus of 90 kg N ha-1 yield-scaled emissions increased threefold. Furthermore, a negative relation between N use efficiency and yield-scaled N2O emissions was found. Therefore, we argue that agricultural management practices to reduce N2O emissions should focus on optimizing fertilizer-N use efficiency under median rates of N input, rather than on minimizing N application rates.

35. Annual emissions of dissolved CO2, CH4, and N2O in the subsurface drainage from three cropping systems

• Authors:
  • Yagi, K.
  • Nakajima, Y.
  • Sawamoto, T.
  • Nishimura, S.
  • Minamikawa, K.
• Source: Global Change Biology
• Volume: 16
• Issue: 2
• Year: 2010
• Summary: Abstract: Indirect emission of nitrous oxide (N2O), associated with nitrogen (N) leaching and runoff from agricultural lands is a major source of atmospheric N2O. Recent studies have shown that carbon dioxide (CO2) and methane (CH4) are also emitted via these pathways. We measured the concentrations of three dissolved greenhouse gases (GHGs) in the subsurface drainage from field lysimeter that had a shallow groundwater table. Above-ground fluxes of CH4 and N2O were monitored using an automated closed-chamber system. The annual total emissions of dissolved and aboveground GHGs were compared among three cropping systems; paddy rice, soybean and wheat, and upland rice. The annual drainage in the paddy rice, the soybean and wheat, and the upland rice plots was 1435, 782, and 1010mmyr -1, respectively. Dissolved CO2 emissions were highest in the paddy rice plots, and were equivalent to 1.05-1.16% of the carbon storage in the topsoil. Dissolved CH4 emissions were also higher in the paddy rice plots, but were only 0.03-0.05% of the aboveground emissions. Dissolved N2O emissions were highest in the upland rice plots, where leached N was greatest due to small crop biomass. In the soybean and wheat plots, large crop biomass, due to double cropping, decreased the drainage volume, and thus decreased dissolved GHG emissions. Dissolved N2O emissions from both the soybean and wheat plots and the upland rice plots were equivalent to 50.3-67.3% of the aboveground emissions. The results indicate that crop type and rotation are important factors in determining dissolved GHG emissions in the drainage from a crop field.

36. Forest Carbon Partnership Facility - Introduction and Early Lessons -- Briefing to Guyana Civil Society

• Authors:
  • Andrasko, K.
  • Bosquet, B.
• Year: 2010

37. Cover crop use in tomato production in plastic high tunnel.

• Authors:
  • Hirata, T.
  • Hoshino, Y.
  • Hane, S.
  • Hajime, A.
• Source: Horticulture Environment and Biotechnology
• Volume: 50
• Issue: 4
• Year: 2009
• Summary: More than 70% of fresh tomato is produced in plastic high tunnel or greenhouse and much fertilizer and agricultural chemicals have been applied for tomato production. Cover crop is one of the important tools for sustainable agro-production because of improving soil properties. Effect of cover cropping on soil properties and tomato production in plastic high tunnel was examined in Sapporo, Japan, snow cover region. Plastic high tunnel was set before snow-melting, late in March, 2007. Two cover crops, legume (hairy vetch; Vicia villosa R.) and non legume (wild oat; Avena sterigosa L.), were planted each alone or mix-planted in the plot (0.8 m in width and 3.5 m in length) early in April. Seeding density in mono-culture was 5 kg/10a in hairy vetch and 10 kg/10a in wild oat. For bi-culture, density was 3.5 kg/10a in hairy vetch and 5 kg/10a in wild oat. Above ground biomass (dry weight) was shown 445 kg/10a in hairy vetch and 982 kg/10a in wild oat late in May. However, in mix-culture, it was 190 kg/10a in hairy vetch and 602 kg/10a in wild oat. Cover crops were killed for residue mulch just before tomato planting. Seedlings of tomato 'Momotaro' were planted in the plots covered with cover crop residue and 12 kg/10a N fertilizer application (12 kg N/10a) and bare plot with 12 kg/10a or 24 kg/10a N fertilizer (24 kg N/10a) application. Nitrate concentration of the petiole sap in the leaf just below the first fruit cluster was higher in the tomatoes grown in bare plot with 24 kg N/10a and in hairy vetch mulch with 12 kg N/10a at 40 days after transplanting. Large yield was shown in bare plot with 24 kg N/10a (7.9 t/10a) and in hairy vetch plot with 12 kg N/10a (7.8 t/10a). The yield in bare plot with 12 kg N/10a and Mix plot with 12 kg N/10a was 6.9 t/10a. The yield in wild oat plot with 12 kg N/10a was the smallest (6.1 t/10a). Soil carbon in the plots with cover crop mulch became higher than that of bare plots after tomato production. It will be possible to obtain current yield and to increase soil carbon in cover cropping with reduction of N fertilizer. This technique will lead the organically grown system in plastic high tunnel production.

38. Effects of charcoal addition on N2O emissions from soil resulting from rewetting air-dried soil in short-term laboratory experiments

• Authors:
  • Okazaki, M.
  • Toyota, K.
  • Yanai, Y.
• Source: Soil Science and Plant Nutrition
• Volume: 53
• Issue: 2
• Year: 2007
• Summary: Laboratory experiments were conducted to examine the effect of charcoal addition on N2O emissions resulting from rewetting of air-dried soil. Rewetting the soil at 73% and 83% of the water-filled pore space (WFPS) caused a N2O emission peak 6 h after the rewetting, and the cumulative N2O emissions throughout the 120-h incubation period were 11 ± 1 and 13 ± 1 mg N m-2 , respectively. However, rewetting at 64% WFPS did not cause detectable N2O emissions (-0.016 ± 0.082 mg N m-2 ), suggesting a severe sensitivity to soil moisture. When the soils were rewetted at 73% and 78% WFPS, the addition of charcoal to soil at 10 wt% supressed the N2O emissions by 89% . In contrast, the addition of the ash from the charcoal did not suppress the N2O emissions from soil rewetted at 73% WFPS. The addition of charcoal also significantly stimulated the N2O emissions from soil rewetted at 83% WFPS compared with the soil without charcoal addition (P < 0.01). Moreover, the addition of KCl and K2SO4 did not show a clear difference in the N2O emission pattern, although Cl- and SO42-, which were the major anions in the charcoal, had different effects on N2O-reducing activity. These results indicate that the suppression of N2O emissions by the addition of charcoal may not result in stimulation of the N2O-reducing activity in the soil because of changes in soil chemical properties.

39. Global potential bioethanol production from wasted crops and crop residues

• Authors:
  • Dale, B. E.
  • Kim, S.
• Source: Biomass and Bioenergy
• Volume: 26
• Issue: 4
• Year: 2004
• Summary: The global annual potential bioethanol production from the major crops, corn, barley, oat, rice, wheat, sorghum, and sugar cane, is estimated. To avoid conflicts between human food use and industrial use of crops, only the wasted crop, which is defined as crop lost in distribution, is considered as feedstock. Lignocellulosic biomass such as crop residues and sugar cane bagasse are included in feedstock for producing bioethanol as well. There are about 73:9 Tg of dry wasted crops in the world that could potentially produce 49:1 GL year-1 of bioethanol. About 1:5 Pg year-1 of dry lignocellulosic biomass from these seven crops is also available for conversion to bioethanol. Lignocellulosic biomass could produce up to 442 GL year-1 of bioethanol. Thus, the total potential bioethanol production from crop residues and wasted crops is 491 GL year-1, about 16 times higher than the current world ethanol production. The potential bioethanol production could replace 353 GL of gasoline (32% of the global gasoline consumption) when bioethanol is used in E85 fuel for a midsize passenger vehicle. Furthermore, lignin-rich fermentation residue, which is the coproduct of bioethanol made from crop residues and sugar cane bagasse, can potentially generate both 458 TWh of electricity (about 3.6% of world electricity production) and 2:6EJ of steam. Asia is the largest potential producer of bioethanol from crop residues and wasted crops, and could produce up to 291 GL year -1 of bioethanol. Rice straw, wheat straw, and corn stover are the most favorable bioethanol feedstocks in Asia. The next highest potential region is Europe (69:2 GL ofbioethanol), in which most bioethanol comes from wheat straw. Corn stover is the main feedstock in North America, from which about 38:4 GL year -1 of bioethanol can potentially be produced. Globally rice straw can produce 205 GL of bioethanol, which is the largest amount from single biomass feedstock. The next highest potential feedstock is wheat straw, which can produce 104 GL of bioethanol. This paper is intended to give some perspective on the size ofthe bioethanol feedstock resource, globally and by region, and to summarize relevant data that we believe others will 0nd useful, for example, those who are interested in producing biobased products such as lactic acid, rather than ethanol, from crops and wastes. The paper does not attempt to indicate how much, if any, of this waste material could actually be converted to bioethanol.

40. Nitrous oxide concentrations in an Andisol profile and emissions to the atmosphere as influenced by the application of nitrogen fertilizers and manure

• Authors:
  • Sakamoto, K.
  • Inubushi, K.
  • Li, X.
• Source: Biology and Fertility of Soils
• Volume: 35
• Issue: 2
• Year: 2002
• Summary: A field experiment was conducted to determine N2O concentrations in the soil profile and emissions as influenced by the application of N fertilizers and manure in a typical Japanese Andisol, which had been under a rotation of oat and carrot for the previous 3 years. The treatments include ammonium sulphate (AS). controlled-re lease fertilizer (CRF) and cattle manure (CM) in addition to a control; all the fertilizers were applied either at 150 kg N ha(-1) or 300 kg N ha(-1) at the time of sowing carrot. NO emissions from the soil surface were measured with closed-chamber techniques. while N2O concentrations in the soil profile were measured using stainless steel sampling probes inserted into the soil at depths of 10, 20. 40, 60, 80 and 100 cm. Moreover. soil water potential, soil temperature and rainfall data were also recorded. The results indicated that N2O concentrations in the soil profile were always greater than in the atmosphere, ranging from 0.36 mul N2O-N 1(-1) to 5.3 mul N2O-N l(-1). The relatively large accumulation of N2O in the lower profiles may be a significant source for N2O flux. Taking the changes of soil mineral N into consideration, most emissions of NO were probably produced from nitrification. The accumulation of NO in the soil profile and emissions to the atmosphere were differently influenced by the amendments of N fertilizers and manure. being consistently higher in CRF than in CM and AS treatments at the corresponding application rates, but no significant difference existed with respect to the various N sources.