• Authors:
    • Martiniello, P.
  • Source: European Journal of Agronomy
  • Volume: 35
  • Issue: 4
  • Year: 2011
  • Summary: Rotations experiment have been investigated from 1991 to 2008 under irrigated and rainfed condition in Mediterranean environment. The crops studied were: annual winter binary mixture (BM), perennial meadow (ME) and durum wheat (W) continuously rotated for 3 years and W rotated on itself for all period of experiment (CW). The forage rotations emphasized on the impact made on biochemical characteristics of topsoil and productivity of the crops. The 3 years continuous wheat rotation over forage crops assess the advantage of forage crops left in the soil on seed yield and on quality of kernel. The continuous wheat rotation (CW) reduced the soil biochemical parameters, seed yield and quality of kernel. The value of organic carbon, C/N and total nitrogen, under rainfed in comparison to the values present in the topsoil at the beginning of experiment were 6.4% and 2.48 higher and 11.2% lower in ME and lower 5.2% in organic carbon and 2.8% total nitrogen and 0.21 higher in C/N in BM. The agronomic advantages allowed by forage rotations expire their effect after 3 years of continuous wheat. Yearly yield W gain under rainfed was 11.3 kg (ha yr) -1 in BM and 62 kg (ha yr) -1 in ME. The qualitative traits of wheat kernel rotated on forage were higher than those of continuous wheat CW. Results of biochemical characteristics obtained at the end of experiment evidenced that W after BM and ME rotations sustained, under irrigated and rainfed condition, the content of organic carbon and total nitrogen and C/N in the topsoil of the cropping system while continuously CW allowed strong impact of the parameter values present at beginning of experiment (organic carbon, total nitrogen and C/N was reduced under rainfed by 23.5%, 18.2 and 0.32 and 30.3%, 15.4% and 1.72 under irrigated, respectively).
  • Authors:
    • Loon, G.
    • Hugar, L.
    • Patil, S.
    • Sarkar, A.
  • Source: Ecohealth
  • Volume: 8
  • Issue: 4
  • Year: 2011
  • Summary: In order to support agribusiness and to attain food security for ever-increasing populations, most countries in the world have embraced modern agricultural technologies. Ecological consequences of the technocentric approaches, and their sustainability and impacts on human health have, however, not received adequate attention particularly in developing countries. India is one country that has undergone a rapid transformation in the field of agriculture by adopting strategies of the Green Revolution. This article provides a comparative analysis of the effects of older and newer paradigms of agricultural practices on ecosystem and human health within the larger context of sustainability. The study was conducted in three closely situated areas where different agricultural practices were followed: (a) the head-end of a modern canal-irrigated area, (b) an adjacent dryland, and (c) an area (the ancient area) that has been provided with irrigation for some 800 years. Data were collected by in-depth interviews of individual farmers, focus-group discussions, participatory observations, and from secondary sources. The dryland, receiving limited rainfall, continues to practice diverse cropping centered to a large extent on traditional coarse cereals and uses only small amounts of chemical inputs. On the other hand, modern agriculture in the head-end emphasizes continuous cropping of rice supported by extensive and indiscriminate use of agrochemicals. Market forces have, to a significant degree, influenced the ancient area to abandon much of its early practices of organic farming and to take up aspects of modern agricultural practice. Rice cultivation in the irrigated parts has changed the local landscape and vegetation and has augmented the mosquito population, which is a potential vector for malaria, Japanese encephalitis and other diseases. Nevertheless, despite these problems, perceptions of adverse environmental effects are lowest in the heavily irrigated area.
  • Authors:
    • Vanotti, M. B.
    • Matheny, T. A.
    • Stone, K. C.
    • Hunt, P. G.
    • Szogi, A. A.
    • Busscher, W. J.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 22
  • Year: 2011
  • Summary: The wastewater from swine production facilities has been typically managed by treatment in anaerobic lagoons followed by land application. However, there have been considerable advances in superior treatment technologies. Wastewater from one of these technologies was effective for subsurface drip irrigation of bermudagrass. The objectives of this experiment were to assess accumulation of soil nitrogen and carbon along with grain yield, dry-matter accumulation, and plant nitrogen accumulation of soybean [ Glycine max (L) Merr., cv.] and wheat [ Triticum aestivum (L), cv.] when supplementally irrigated with treated swine effluent via subsurface drip irrigation (SDI). The soil series was Autryville loamy sand (loamy, siliceous, subactive, thermic Arenic Paleudults). Its low unsaturated hydraulic conductivity of 0.00170.0023 mm h -1 caused problems with water movement to either the soil surface or laterally to adjoining soybean and wheat roots. This condition contributed to complete crop failure in soybean in 2 years and generally poor yields of wheat. In a good rainfall year, the soybean yield was somewhat satisfactory and benefited from the supplemental irrigation. In that year, nonirrigated and irrigated soybean mean yields were 1.55 versus 1.98 Mg ha -1, respectively. The mean yield of wheat was only 1.06 Mg ha -1, and it was not affected by irrigation. The means for soil nitrogen and carbon in the 0- to 15-cm depth were 414 and 5,679 mg kg -1, respectively, and they were not affected by the water treatments. Thus, neither soil conditions nor soybean/wheat production were greatly enhanced by the SDI system.
  • Authors:
    • Walter-Shea, E. A.
    • Singh, R. K.
    • Irmak, A.
    • Verma, S. B.
    • Suyker, A. E.
  • Source: Transactions of the American Society of Agricultural and Biological Engineers and Papers in Natural Resources. Paper 334.
  • Volume: 54
  • Issue: 1
  • Year: 2011
  • Summary: We evaluated the performance of four models for estimating soil heat flux density (G) in maize (Zea mays L.) and soybean (Glycine max L.) fields under different irrigation methods (center-pivot irrigated fields at Mead, Nebraska, and subsurface drip irrigated field at Clay Center, Nebraska) and rainfed conditions at Mead. The model estimates were compared against measurements made during growing seasons of 2003, 2004, and 2005 at Mead and during 2005, 2006, and 2007 at Clay Center. We observed a strong relationship between the G and net radiation (R n) ratio (G/R n) and the normalized difference vegetation index (NDVI). When a significant portion of the ground was bare soil, G/R n ranged from 0.15 to 0.30 and decreased with increasing NDVI. In contrast to the NDVI progression, the G/R n ratio decreased with crop growth and development. The G/R n ratio for subsurface drip irrigated crops was smaller than for the center-pivot irrigated crops. The seasonal average G was 13.1%, 15.2%, 10.9%, and 12.8% of R n for irrigated maize, rainfed maize, irrigated soybean, and rainfed soybean, respectively. Statistical analyses of the performance of the four models showed a wide range of variation in G estimation. The root mean square error (RMSE) of predictions ranged from 15 to 81.3 W m -2. Based on the wide range of RMSE, it is recommended that local calibration of the models should be carried out for remote estimation of soil heat flux.
  • Authors:
    • Verma, S. B.
    • Vanegas, D. X.
    • Xiao, X. M.
    • Kalfas, J. L.
    • Suyker, A. E.
  • Source: Agricultural and Forest Meteorology
  • Volume: 151
  • Issue: 12
  • Year: 2011
  • Summary: Information on gross primary production (GPP) of maize croplands is needed for assessing and monitoring maize crop conditions and the carbon cycle. A number of studies have used the eddy covariance technique to measure net ecosystem exchange (NEE) of CO 2 between maize cropland fields and the atmosphere and partitioned NEE data to estimate seasonal dynamics and interannual variation of GPP in maize fields having various crop rotation systems and different water management practices. How to scale up in situ observations from flux tower sites to regional and global scales is a challenging task. In this study, the Vegetation Photosynthesis Model (VPM) and satellite images from the Moderate Resolution Imaging Spectroradiometer (MODIS) are used to estimate seasonal dynamics and interannual variation of GPP during 2001-2005 at five maize cropland sites located in Nebraska and Minnesota of the U.S.A. These sites have different crop rotation systems (continuously maize vs. maize and soybean rotated annually) and different water management practices (irrigation vs. rain-fed). The VPM is based on the concept of light absorption by chlorophyll and is driven by the Enhanced Vegetation Index (EVI) and the Land Surface Water Index (LSWI), photosynthetically active radiation (PAR), and air temperature. The seasonal dynamics of GPP predicted by the VPM agreed well with GPP estimates from eddy covariance flux tower data over the period of 2001-2005. These simulation results clearly demonstrate the potential of the VPM to scale-up GPP estimation of maize cropland, which is relevant to food, biofuel, and feedstock production, as well as food and energy security.
  • Authors:
    • Fahed, S.
    • Rana, G.
    • Katerji, N.
  • Source: Hydrological Processes
  • Volume: 25
  • Issue: 1
  • Year: 2011
  • Summary: In this paper two models are presented for calculating the hourly evapotranspiration lambda E (W m -2) using the Penman-Monteith equation. These models were tested on four irrigated crops (grass, soya bean, sweet sorghum and vineyard), with heights between 0.1 and 2.2 m at the adult growth stage. In the first model (Katerji N, Perrier A. 1983. Modelisation de l'evapotranspiration reelle ETR d'une parcelle de luzerne: role d'un coefficient cultural. Agronomie 3(6): 513-521, KP model), the canopy resistance rc is parameterized by a semi-empirical approach. In the second model (Todorovic M. 1999. Single-layer evapotranspiration model with variable canopy resistance. Journal of Irrigation and Drainage Engineering-ASCE 125: 235-245, TD model), the resistance rc is parameterized by a mechanistic model. These two approaches are critically analysed with respect to the underlying hypotheses and the limitations of their practical application. In the case of the KP model, the mean slope between measured and calculated values of lambda E was 1.010.6 and the relative correlation coefficients r2 ranged between 0.8 and 0.93. The observed differences in slopes, between 0.96 and 1.07, were not associated with the crop height. This model seemed to be applicable to all the crops examined. In the case of the TD model, the observed slope between measured and calculated values of lambda E for the grass canopy was 0.79. For the other crops, it varied between 1.24 and 1.34. In all the situations examined, the values of r2 ranged between 0.73 and 0.92. The TD model underestimated lambda E in the case of grass and overestimated it in the cases of the other three crops. The under- or overestimation of lambda E in the TD model were due: (i) to some inaccuracies in the theory of this model, (ii) to not taking into account the effect of aerodynamic resistance ra in the canopy resistance modelling. Therefore, the values of rc were under- or overestimated in consequence of mismatching the crop height. The high value of air vapour pressure deficit also contributed to the overestimation of lambda E, mainly for the tallest crop. The results clarify aspects of the scientific controversy in the literature about the mechanistic and semi-empirical approaches for estimating lambda E. From the practical point of view the results also present ways for identifying the most appropriate approach for the experimental situations encountered.
  • Authors:
    • Halloran, J. M.
    • Olanya, O. M.
    • Griffin, T. S.
    • Honeycutt, C. W.
    • Larkin, R. P.
    • He, Z.
  • Source: Phytopathology
  • Volume: 101
  • Issue: 1
  • Year: 2011
  • Summary: Four different potato cropping systems, designed to address specific management goals of soil conservation, soil improvement, disease suppression, and a status quo standard rotation control, were evaluated for their effects on soilborne diseases of potato and soil microbial community characteristics. The status quo system (SQ) consisted of barley under-seeded with red clover followed by potato (2-year). The soil-conserving system (SC) featured an additional year of forage grass and reduced tillage (3-year, barley/timothy-timothy-potato). The soil-improving system (SI) added yearly compost amendments to the SC rotation, and the disease-suppressive system (DS) featured diverse crops with known disease-suppressive capability (3-year, mustard/rapeseed-sudangrass/rye-potato). Each system was also compared with a continuous potato control (PP) and evaluated under both irrigated and nonirrigated conditions. Data collected over three potato seasons following full rotation cycles demonstrated that all rotations reduced stem canker (10 to 50%) relative to PP. The SQ, SC, and DS systems reduced black scurf (18 to 58%) relative to PP; ST reduced scurf under nonirri2ated but not irrigated conditions; and scurf was lower in DS than all other systems. The SQ. SC, and DS systems also reduced common scab (15 to 45%), and scab was lower in DS than all other systems. Irrigation increased black scurf and common scab but also resulted in higher yields for most rotations. SI produced the highest yields under nonirrigated conditions, and DS produced high yields and low disease under both irrigation regimes. Each cropping system resulted in distinctive changes in soil microbial community characteristics as represented by microbial populations, substrate utilization, and fatty acid methyl-ester (FAME) profiles. SI tended to increase soil moisture, microbial populations, and activity, as well result in higher proportions of monounsaturated FAMEs and the FAME biomarker for mycorrhizae (16:1 omega 6c) relative to most other rotations. DS resulted in moderate microbial populations and activity but higher substrate richness and diversity in substrate utilization profiles. DS also resulted in relatively higher proportions of FAME biomarkers for fungi (18:2 omega 6c), actinomycetes, and gram-positive bacteria than most other systems, whereas PP resulted in the lowest microbial populations and activity; substrate richness and diversity; proportions of monounsaturated and polyunsaturated FAME classes; and fungal, mycorrhizae, and actinomycete FAME biomarkers of all cropping systems. Overall, soil water, soil quality, and soilborne diseases were all important factors affecting productivity, and cropping systems addressing these constraints improved production. Cropping system approaches will need to balance these factors to achieve sustainable production and disease management.
  • Authors:
    • Zhang, F. S.
    • Sun, J. H.
    • Li, L.
  • Source: Soil Science and Plant Nutrition
  • Volume: 57
  • Issue: 1
  • Year: 2011
  • Summary: Intercropping two species at different growth stages is common in temperate and tropical areas. An apparent recovery of growth is observed in late-maturing species after early-maturing species have been harvested, but the mechanism remained unclear. This study tested the hypothesis that the roots of late-maturing species occupy greater below-ground space at later growth stages. The monolith method was employed to investigate the spatial and temporal distribution of maize grown alone (no interspecific interactions), maize intercropped with wheat (asymmetric interspecific facilitation before wheat harvesting), and maize intercropped with faba bean (symmetric interspecific facilitation) on August 8, September 2 and September 30, after harvesting of wheat (July 15) or faba bean (August 2). The results show that maize intercropped with wheat occupied more below-ground space at late growth stages than at early growth stages when the two crops grew at the same time, thus supporting our hypothesis. Furthermore, we also found that interspecific interactions during the co-growth stage of the two species led to a longer root life span in both maize intercropped with wheat and faba bean compared to the maize grown alone. The findings may partly explain the recovery of late-maturing species found in intercropping systems between two crop species with different growth stages and the complementary effect on the relationship between plant biodiversity and productivity.
  • Authors:
    • Mengel, D. B.
    • Olson, B. L.
    • Martin, K. L.
    • Diaz, D. A. R.
    • Liesch, A. M.
    • Roozeboom, K. L.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 6
  • Year: 2011
  • Summary: Soybean [ Glycine max (L.) Merr.] production has increased by more than 55,000 ha in the last 25 yr in the western third of Kansas, a region with soils that can be prone to Fe chlorosis. The objective of this study was to evaluate the relative effectiveness of varietal selection, seed-applied Fe fertilizer, and foliar Fe application to reduce the incidence of Fe chlorosis under irrigated soybean production. Seven locations with a history of Fe deficiency in soybeans were selected. The study consisted of a factorial design with three foliar treatments (two chelated Fe fertilizer forms and no foliar), two seed-applied Fe fertilizer treatments (with and without chelated Fe fertilizer), and two different varieties (a nontolerant and tolerant commercial variety). Plant population, chlorophyll meter (CM) readings (V3 and V6 growth stage), plant height at maturity, and grain yield were measured. Foliar Fe application did not affect any plant parameter except for CM reading and grain yield at one location. However, the use of seed-applied chelated Fe fertilizer significantly increased CM readings at the V3 and V6 growth stages, plant height at maturity, and grain yield across all locations. Given soil conditions conducive to the development of severe iron chlorosis, seed-applied chelated Fe fertilizer increased yields by approximately 55% for both varieties. Chlorosis quantified as CM readings at V3 to V6 growth stage may not be correlated to the yield potential of a variety in all environments. This suggests that producers should choose the best varieties primarily based on yield potential if supplemental seed-applied Fe fertilizer will be used.
  • Authors:
    • Tamas, D.
    • Hoble, A.
    • Dîrja, M.
    • Luca, L. C.
  • Source: Agricultura, stiinta si practica (Agricultural Practice and Science Journal)
  • Volume: 20
  • Issue: 3/4
  • Year: 2011
  • Summary: This paper provides a comprehensive analysis of the climatic conditions during 2009, 2010 and 2011 of the agricultural area of Transylvanian Plain, in the general context of the progressive warming of the atmosphere and significantly reduced rainfall. Testing of some soyabean cultivars is initiated in 2009 in Vitisoara, Turda, under irrigated conditions and other technological factors.