151. Contribution of relay intercropping with legume cover crops on nitrogen dynamics in organic grain systems

• Authors:
  • Mary, B.
  • Jeuffroy, M. H.
  • Amosse, C.
  • David, C.
• Source: NUTRIENT CYCLING IN AGROECOSYSTEMS
• Volume: 98
• Issue: 1
• Year: 2014
• Summary: Nitrogen (N) management is a key issue in livestock-free organic grain systems. Relay intercropping with a legume cover crop can be a useful technique for improving N availability when two cash crops are grown successively. We evaluated the benefits of four relay intercropped legumes (Medicago lupulina, Medicago sativa, Trifolium pratense and Trifolium repens) on N dynamics and their contribution to the associated and subsequent cash crops in six fields of organic farms located in South-East France. None of the relay intercropped legumes affected the N uptake of the associated winter wheat but all significantly increased the N uptake of the succeeding spring crop, either maize or spring wheat. The improvement of the N nutrition of the subsequent maize crop induced a 30 % increase in grain yield. All relay intercropped legumes enriched the soil-plant system in N through symbiotic fixation. From 71 to 96 % of the N contained in the shoots of the legumes in late autumn was derived from the atmosphere (Ndfa) and varied between 38 and 67 kg Ndfa ha(-1). Even if the cover crop is expected to limit N leaching during wintertime, the presence of relay intercropped legumes had no significant effect on N leaching during winter compared to the control.

152. Nitrous oxide emissions from a clay soil receiving granular urea formulations and dairy manure.

• Authors:
  • Kebreab, E.
  • Gao, X. P.
  • Flaten, D. N.
  • Tenuta, M.
  • Asgedom, H.
• Source: Web Of Knowledge
• Volume: 106
• Issue: 2
• Year: 2014
• Summary: Soil N 2O emissions vary with N source. A study was undertaken on a clay soil in the Red River Valley, Manitoba, Canada, to determine the effect of granular N fertilizers and dairy manure on N 2O emissions from a field cropped to rapeseed ( Brassica napus L.) in 2009 and spring wheat ( Triticum aestivum L.) in 2010. Treatments included an unamended control, granular urea, controlled-release urea (ESN), stabilized urea (SuperU), and solid dairy manure added at rates to achieve a total of 140 kg available N ha -1 (product plus soil N test). The N fertilizers were broadcast and shallowly incorporated each spring before planting; the manure was broadcast incorporated the previous fall. Nitrous oxide emissions were monitored from planting to freeze in fall and during spring thaw in 2011 using static-vented chambers. In both years, N 2O emissions occurred within 4 to 5 wk of planting but not in fall after manure application. Area-scale cumulative N 2O emissions (SigmaN 2O, kg N ha -1) from planting to freeze were control < ESN=manure < urea=SuperU. Nitrous oxide emission factors were 0.017 kg N 2O-N kg -1 available N added for urea and SuperU and 0.007 kg N 2O-N kg -1 available N for ESN. Seventy-eight percent of the variation in SigmaN 2O could be explained by NO 3- intensity, an integration of soil NO 3- concentrations during the study periods. Greater SigmaN 2O were also associated with higher yields. These findings suggest that N release rates, as indicated by NO 3- intensity and yield, determined N 2O emissions. The results highlight the challenge of meeting crop demand yet reducing N 2O emissions by selection of an N source.

153. Application of flue gas desulfurization gypsum and its impact on wheat grain and soil chemistry.

• Authors:
  • Cihacek, L. J.
  • DeSutter, T. M.
  • Rahman, S.
• Source: Journal of Environmental Quality
• Volume: 43
• Issue: 1
• Year: 2014
• Summary: The 11 major electricity-generating coal combustion stations in the northern Great Plains have the potential to produce almost 1 million Mg of flue gas desulfurization gypsum (FGDG) annually, which is a very attractive fertilizer (Ca and S) and amendment for sodic and acid soils. The potential environmental impacts of applying FGDG to soils in this region have not been fully investigated. The objectives of this research were to determine the influence of FGDG on soil chemical characteristics and to determine the impact that FGDG has on hard red spring wheat ( Triticum aestivum L.) yields and element analysis of the grain. Flue gas desulfurization gypsum and commercial gypsum were applied at rates of 0, 2.24, 11.2, and 22.4 Mg ha -1 to two soils in southwestern North Dakota in the spring of 2007. Soil and grain chemistries were monitored for two growing seasons. Wheat grain yields and elemental analysis of the grain were generally not affected by the gypsum treatments, indicating that the gypsum products did not negatively affect plant productivity. In addition, soil elemental analysis was similar across the treatments at both sites in both years. The results from this study indicate that its application to soil at rates used for sodic soil remediation (Mg ha -1) did not negatively affect the chemistries of either the soils or the wheat evaluated in this study compared with a commercial gypsum product or control soils.

154. Assessing the potential of an algorithm based on mean climatic data to predict wheat yield

• Authors:
  • Destain, J. P.
  • Destain, M. F.
  • Bodson, B.
  • Ferrandis, S.
  • Leemans, V.
  • Dumont, B.
• Source: Precision Agriculture
• Volume: 15
• Issue: 3
• Year: 2014
• Summary: The real-time non-invasive determination of crop biomass and yield prediction is one of the major challenges in agriculture. An interesting approach lies in using process-based crop yield models in combination with real-time monitoring of the input climatic data of these models, but unknown future weather remains the main obstacle to reliable yield prediction. Since accurate weather forecasts can be made only a short time in advance, much information can be derived from analyzing past weather data. This paper presents a methodology that addresses the problem of unknown future weather by using a daily mean climatic database, based exclusively on available past measurements. It involves building climate matrix ensembles, combining different time ranges of projected mean climate data and real measured weather data originating from the historical database or from real-time measurements performed in the field. Used as an input for the STICS crop model, the datasets thus computed were used to perform statistical within-season biomass and yield prediction. This work demonstrated that a reliable predictive delay of 3-4 weeks could be obtained. In combination with a local micrometeorological station that monitors climate data in real-time, the approach also enabled us to (i) predict potential yield at the local level, (ii) detect stress occurrence and (iii) quantify yield loss (or gain) drawing on real monitored climatic conditions of the previous few days.

155. Long-term tillage and crop rotation effects on soil quality, organic carbon, and total nitrogen.

• Authors:
  • Verhallen, A.
  • Hayes, A.
  • Congreves, K. A.
  • Eerd, L. L. van
  • Hooker, D. C.
• Source: Canadian Journal of Soil Science
• Volume: 94
• Issue: 3
• Year: 2014
• Summary: Long-term studies allow for quantification of the effects of crop production practices, such as tillage and crop rotation, on soil quality and soil C and N stores. In two experiments at Ridgetown, ON, we evaluated the long-term (11 and 15 yr) effect of tillage system and crop rotation on soil quality via the Cornell Soil Health Assessment (CSHA) at 0-15 cm and soil organic C (SOC) and total N at 5-, 10-, and 20-cm increments to 120 cm depth. The CSHA soil quality score and SOC and total N were higher with no-till (NT) than fall moldboard plough with spring cultivation (conventional tillage, CT) and rotations with winter wheat [soybean-winter wheat (S-W) and soybean-winter wheat-corn (S-W-C)] compared with rotations without winter wheat. In both long-term trials, NT had ca. 21 Mg ha -1 more or 14% higher SOC than CT in the 0- to 100-cm soil profile, a trend which contrasts previous research in eastern Canada. Thus, the two long-term trial results at Ridgetown suggest that to improve soil quality and storage of C and N, growers on clay loam soil in southwestern Ontario should consider adopting NT production practices and including winter wheat in the rotation.

156. Long-term effect of pulse crops inclusion on soil-plant nutrient dynamics in puddled rice (Oryza sativa L.)-wheat (Triticum aestivum L.) cropping system on an Inceptisol of Indo-Gangetic plain zone of India

• Authors:
  • Ganeshamurthy, A. N.
  • Ghosh, P. K.
  • Venkatesh, M. S.
  • Hazra, K. K.
  • Kumar, N.
  • Nadarajan, N.
  • Singh, A. B.
• Source: Nutrient Cycling in Agroecosystems
• Volume: 100
• Issue: 1
• Year: 2014
• Summary: Given inherent qualities like N-fixation, P-solublization and nutrient recycling pulses remain the most preferred option for diversification of cereal-based rotations. A long-term experiment was used to assess the effect of including pulses in rice-wheat rotation on soil-plant nutrient dynamics under inorganic and organic nutrient management. Results revealed that pulses were equally responsive to organic and inorganic nutrient management while, growth of cereals especially wheat was restricted severely under organic production system due to low nutrient input. The annual input (kg ha(-1)) of N (103.6-160.8) and P (25.9-34.7) under organic treatment was almost A1/2 of the recommended inorganic rate, while organics supplied higher K and S. Under organic management, the apparent balance of all the nutrients was negative whereas, inorganic fertilization resulted in positive balance of N, P and Zn. Long-term inclusion of pulses in rice-wheat rotation significantly increased soil organic C and available nutrients thus, increased the nutrient uptake by cereals. Mungbean inclusion in rice-wheat rotation significantly (P a parts per thousand currency sign 0.05) increased uptake of N (23.0 %), P (32.9 %) and K (21.1 %) by rice crop. Continuous inorganic fertilization enriched soil available N, P, Zn and B. While organic management maintained higher SOC, available K and S over inorganic treatment. Thus, the study suggested that under organic management N and P nutrition is limiting factor for cereals and needs inorganic supplementation. The study also indicates the need for including pulses in conventional rice-wheat system for optimum nutrient acquisition and long-term soil health management.

157. Diverse responses of winter wheat yield and water use to climate change and variability on the semiarid Loess Plateau in China.

• Authors:
  • Liu, W. Z.
  • Li, J.
  • Yang, X. Y.
  • Chen, C.
  • Cleverly, J.
  • He, L.
  • Yu, Q.
• Source: Agronomy Journal
• Volume: 106
• Issue: 4
• Year: 2014
• Summary: Crop production and water use in rainfed cropland are vulnerable to climate change. This study was to quantify diverse responses of winter wheat ( Triticum aestivum L.) yield and water use to climate change on the Loess Plateau (LP) under different combinations of climatic variables. The crop model APSIM was validated against field experimental data and applied to calculate yield and water use at 18 sites on the LP during 1961 to 2010. The coefficient of variation of yield ranged from 12 to 66%, in which the vulnerability of yield increased from the southeast (12%) to the northwest (66%). This change was attributed to the gradual increase in precipitation variation from the southeast to the northwest. An obvious warming trend during 1961 to 2010 resulted in a significant decrease in the growth duration by 1 to 5 d decade -1. The yield at 12 sites was significantly reduced by 120 to 720 kg ha -1 decade -1. Evapotranspiration was significantly decreased by 1 to 26 mm decade -1; however, water use efficiency at most sites showed no significant trend. Eighteen sites were classified into three climatic zones by cluster analysis: high temperature-high precipitation-low radiation (HHL), medium temperature-medium precipitation-medium radiation (MMM), and low temperature-low precipitation-high radiation (LLH). The trend of decreasing yield was smallest in the HHL cluster because of a minimal reduction in precipitation, while decreasing trends in yield and evapotranspiration were larger in the LLH and MMM because of larger reductions in precipitation. The results imply that among strategies such as breeding for long duration or drought tolerance, modification of the planting date will be necessary to avoid high temperatures associated with climate change.

158. Estimating net N mineralization under unfertilized winter wheat using simulations with NET N and a balance approach

• Authors:
  • Boettcher, J.
  • Kage, H.
  • Ratjen, A.
  • Heumann, S.
• Source: Nutrient Cycling in Agroecosystems
• Volume: 99
• Issue: 1-3
• Year: 2014
• Summary: Eliminating uncertainty in soil N supply could reduce fertilizer input, but the amount of N mineralized during plant growth is usually still unknown. We aimed to test the relatively simple two-pool net N mineralization model NET N that uses site-specific temperature and soil water functions as well as pedotransfer functions for deriving the pool sizes and was developed for NW Germany. The objectives were to (1) evaluate, if field net N mineralization under unfertilized winter wheat could be satisfactorily simulated, and to (2) examine the variation in time patterns of net N mineralization within years and sites and from two functional N pools: a rather small, fast mineralizable N pool (N-fast) and a much greater, slowly mineralizable N pool (N-slow). NET N simulations for 36 site-year-combinations and up to five dates within the growing season were evaluated with detailed N balance approaches (calculated from: soil mineral N contents, plant N uptake using estimates of green area index, simulated N leaching). Simulated net N mineralization was highly significantly correlated (r(2) = 0.58; root mean square error = 24.2 kg N ha(-1)) to estimations from the most detailed balance approach, with total simulated net N mineralization until mid August ranging from 62.1 to 196.5 kg N ha(-1). It also became evident that N mineralization from pool N-slow-in contrast to pool N-fast-was considerably higher for loess soils than for sandy or loamy soils. The results suggest that NET N was adequate for simulations in unfertilized winter wheat. However, further field studies are necessary for proving its applicability under fertilized conditions.

159. Impact of mineral N fertilizer application rates on N2O emissions from arable soils under winter wheat

• Authors:
  • Kuhlmann, H.
  • Lammel, J.
  • Senbayram, M.
  • Lebender, U.
• Source: Nutrient Cycling in Agroecosystems
• Volume: 100
• Issue: 1
• Year: 2014
• Summary: Nitrogen fertilizers are a major source of nitrous oxide (N2O) emissions from arable soils. The relationship between nitrogen application rates and N2O emissions was evaluated during the growth period of winter wheat (similar to 140 days) at six field sites in north-western Germany. Nitrogen was applied as calcium-ammonium-nitrate, with application rates ranging between 0 and 400 kg N ha(-1). One trial was conducted in 2010, three trials in 2011 and two trials in 2012. Additionally, post-harvest N2O emissions were evaluated at two field sites during autumn and winter (2012-2013). The emission factors (during the growth period) varied between 0.10 and 0.37 %. Annual N2O emissions ranged between 0.46 and 0.53 % and were consistently lower across all sites and years than to the IPCC Tier 1 default value (1.0 %). Across all sites and years, the relationship between N2O and N application rate was best described by linear regression even if nitrogen amounts applied were higher than the nitrogen uptake of the crop. Additionally, annual N2O emissions per unit of harvested wheat grain were calculated for two field sites to assess the environmental impact of wheat grain production. Yield-scaled N2O emissions followed a hyperbolic function with a minimum of 177 and 191 g N2O-N t grain yield(-1) at application rates of 127 and 150 kg N ha(-1), followed by an increase at higher N application rates. This relationship indicates that wheat crop fertilization does not necessarily harm the environment through N2O emissions compared to zero fertilization. Thus, improving nitrogen use efficiency may be the best management practice for mitigating yield-scaled N2O emissions.

160. The Area IV Soil Conservation Districts Cooperative Research Farm: Thirty years of collaborative research to improve cropping system sustainability in the Northern Plains

• Authors:
  • Olsen, D.
  • Harner, L.
  • Merrill, S.
  • Tanaka, D.
  • Sanderson, M.
  • Nichols, K.
  • Hendrickson, J.
  • Archer, D.
  • Liebig, M.
• Source: JOURNAL OF SOIL AND WATER CONSERVATION
• Volume: 69
• Issue: 4
• Year: 2014