• Authors:
    • Graham, J.
    • Phelan, A.
    • Kelly, K. B.
    • Officer, S. J.
  • Source: Climate Change and Resources
  • Year: 2009
  • Authors:
    • Djurovic, D.
    • Dugalic, G.
    • Stevovic, V.
    • Paunovic, A.
    • Bokan, N.
  • Source: Agroznanje - Agro-knowledge Journal
  • Volume: 10
  • Issue: 3
  • Year: 2009
  • Summary: Average grain yields of maize, undoubtedly the most common field crop grown in the Balkans, are still significantly lower than its genetic and practical potential. All known cultural practices have not yet been applied sufficiently. Hence the constant need to conduct trials to confirm the necessity to employ known technological practices in the cultivation of old and novel maize hybrids. The generally low average yields of maize grown under dryland conditions can be increased by available cultural practices including the selection of drought-tolerant hybrids, adequate crop rotation, the use of the most suitable tillage system and basic fertilization, optimal plant density, interrow cultivation and fertilization. The trial was set up as a randomized block design on leached alluvial soil. The following hybrids were studied: NS 50402, NS 540, ZP 570, ZP 580 and ZP 599, being fertilized under three treatments: basic treatment (30 t/ha manure and 400 t/ha of composite 15:15:15 fertilizer prior to sowing), N1 (250 kg/ha CAN) and N2 (500 kg/ha CAN). The average yield of dry maize grain was 9.65 t/ha. Averagely for the hybrids, the low and high nitrogen application rates induced 0.32 t/ha and 0.55 t/ha yield increases, respectively. The plot fertilized every second year with manure and composite mineral fertilizer gave a satisfactory yield of 9.36 t/ha. The highest average yield of 10.61 t/ha under all treatments was produced by ZP580 hybrid. The above-average yield, achieved under non-irrigated conditions, was largely induced by combined organic and mineral fertilization, since the plants were able to better tolerate the drought conditions due to a sufficient amount of readily available nutrients.
  • Authors:
    • Davis, R. A.
    • Huggins, D. R.
    • Cook, R. J.
    • Paulitz, T. C.
  • Source: Canadian Journal of Plant Pathology
  • Volume: 31
  • Issue: 4
  • Year: 2009
  • Summary: Fusarium crown rot of wheat (Triticum aestivum), caused by Fusarium pseudograminearum and Fusarium culmorum, is a yield-limiting disease in the dryland wheat-production area of the intermountain Pacific Northwest and is exacerbated in water-stressed plants induced by overfertilizing with nitrogen (N). Plants with excess N deplete water from the soil profile more rapidly and become drought stressed prematurely. Traditionally a problem on winter wheat in summer fallow, this disease has become more important for spring wheat in continuous cropping areas managed for high grain protein levels. During 3 years with direct seeding (no till) near Pullman, Washington, we investigated whether a split application of N, with some applied the previous fall and some with planting, could limit the disease compared with all N applied in the spring and with no N as the check. We also investigated the influence of the previous (rotation) crop (winter and spring canola, Brassica rapa; barley, Hordeum vulgare; or peas, Pisum sativum) on disease, grain yield, grain protein concentration, and populations of Fusarium in the soil. Overall, the DNA concentration of F. culmorum was significantly greater than F. pseudograminearum, and F. culmorum was highest following spring barley. Disease severity and yield were consistently lower in the no-N treatments compared with the other N treatments. The split application reduced disease in only 1 of 3 years. The all-spring application resulted in higher grain protein in 2 of 3 years compared with the split application, but yield was not affected. The previous crop had small but significant effects on disease, but they were not consistent from year to year and often interacted with the N treatment. Grain protein was higher in wheat after pea in 2 of 3 years. In conclusion, splitting of N had little effect on fusarium crown rot, probably because the N level in both treatments was conducive for disease development. Even if not a host species, the previous crop had little effect on subsequent disease, probably because Fusarium persists for more than one season as chlamydospores and in crop residue in this dry summer climate.
  • Authors:
    • Shankar, M. A.
    • Murukannappa
    • Gajanan, G. N.
    • Ganapathi
  • Source: Environment and Ecology
  • Volume: 27
  • Issue: 2
  • Year: 2009
  • Summary: A long term field experiment was conducted on cereal-legume cropping sequence leaving summer fallow at Bangalore during 1993 to 2006 in light textured red sandy loam soil to study the effect of long term use of glyricidia, farm yard manure and NPK fertilizers on soil fertility, crop productivity and nutrients losses. Plots of 3,000 m 2 each and having 2.5% slopes were delineated for each treatment. Appropriate instrumentation was done to quantity the nutrients loss. Continuous use of glyricidia to supply recommended N+50% recommended NPK recorded 16.8 and 142.6% higher yield followed by FYM and NPK in equal proportion (3.22 and 88.6%) in fingermillet and maize respectively as compared to recommended NPK (2,572 kg/ha and 1,150 kg/ha). FYM and 50% NPK recorded 35.8% higher soybean yield followed by FYM with 25.6% as compared to recommended NPK (453 kg/ha). Highest loss of OM, N, P and K were recorded under control and lowest losses were recorded in FYM and NPK in equal proportion, but least P loss (0.39 kg/ha) was recorded with 50% N with through glyricidia+50% NPK. In soybean, highest loss of OM, N, P and K were recorded in control and least loss of OM, P and K in FYM to supply 50% N+50% NPK. But least loss of N was in glyricidia to supply 50%+50% recommended NPK. In maize, highest loss of OM, N, P and K were recorded in control followed by recommended NPK. Irrespective of the crops the mean of seven years indicated that highest loss of OM, N, P and K were under control treatment Least loss of OM and N occurred under glyricidia to supply 50%+50% recommended NPK. But least losses P and K were recorded in NPK. Analysis of surface soil samples (0-15 cm) indicated that continuous addition of FYM or glyricidia to supply recommended N alone or along with NPK over a period of 13 years increased OC, biomass carbon and mean weight diameter as compared to NPK alone. Reduction in soil pH in recommended NPK from 5.6 to 4.5 and improvement in organics, increased available N, available K, sulfur, Zn, Cu Mn and Fe in organics alone or along with NPK as compared to recommended NPK.
  • Authors:
    • Moreno, F.
    • Murillo, J. M.
    • López-Garrido, R.
    • Melero, S.
  • Source: Soil & Tillage Research
  • Volume: 104
  • Issue: 2
  • Year: 2009
  • Summary: Short- and long-term field experiments are necessary to provide important information about how soil carbon sequestration is affected by soil tillage system; such systems can also be useful for developing sustainable crop production systems. In this study, we evaluated the short- and long-term effects of conservation tillage (CT) on soil organic carbon fractions and biological properties in a sandy clay loam soil. Both trials consisted of rainfed crop rotation systems (cereal-sunflower-legumes) located in semi-arid SW Spain. In both trials, results were compared to those obtained using traditional tillage (TT). Soil samples were taken in flowering and after harvesting of a pea crop and collected at three depths (0-5, 5-10 and 10-20 cm). The soil organic carbon fractions were measured by the determination of total organic carbon (TOC), active carbon (AC) and water soluble carbon (WSC). Biological status was evaluated by the measurement of soil microbial biomass carbon (MBC) and enzymatic activities [dehydrogenase activity (DHA), o-diphenol oxidase activity (DphOx), and beta-glucosidase activity (beta-glu)]. The contents of AC and MBC in the long-term trial and contents of AC in the short-term trial were higher for CT than TT at 0-5 cm depth for both sampling periods. Furthermore, DHA and beta-glucosidase values in the July sampling were higher in the topsoil under conservation management in both trials (short- and long-term). The parameters studied tended to decrease as depth increased for both tillage system (TT and CT) and in both trials with the exception of the DphOx values, which tended to be higher at deeper layers. Values of DHA and beta-glu presented high correlation coefficients (r from 0.338 to 0.751, p <= 0.01) with AC, WSC and TOC values in the long-term trial. However, there was no correlation between either TOC or MBC and the other parameters in the short-term trial. In general, only stratification ratios of AC were higher in CT than in TT in both trials. The results of this study showed that AC content was the most sensitive and reliable indicator for assessing the impact of different soil management on soil quality in the two experiments (short- and long-term). Conservation management in dryland farming systems improved the quality of soil under our conditions, especially at the surface layers, by enhancing its storage of organic matter and its biological properties, mainly to long-term. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Siri-Prieto, G.
    • Ernst, O.
  • Source: Soil & Tillage Research
  • Volume: 105
  • Issue: 2
  • Year: 2009
  • Summary: Soil degradation associated with tillage is a major problem in Uruguayan agriculture. Either rotation of crops with pastures (ROT) or no-till (NT) cropping have been proposed as alternatives to minimize the impact of agriculture on soil quality. The combined impact on soil properties of ROT and NT has not been evaluated. In this study, we report results of the first 12 years of a long-term experiment established on a clay loam soil in western Uruguay. The objective was to determine the influence of conventional tillage (CT) and NT on systems under continuous cropping (CC, two crops per year) or ROT (3.5-year annual crops/2.5-year pastures). Soil samples taken at the beginning of the experiment in 1994 and in 2004 were analyzed for organic carbon (SOC), total organic carbon (TSOC) and total nitrogen content (STN), and for water-stable aggregation (WAS). Soil loss and erodibility indicators were studied using microrain simulator. With 12 years, the cumulative carbon (C) inputs of aboveground biomass were similar between tillage, but C input in CC was 50% higher than ROT. This difference was explained because 84% of the pastures dry matter was consumed by animals. Nevertheless we estimated a higher below ground biomass in ROT compared to CC systems (24.9 Mg ha-1 vs. 10.9 Mg ha-1). NT presented 7% higher SOC than CT (0-18 cm) with no differences between rotation systems. While all treatments declined in STN during 12 years, ROT had 11% and 58% higher STN and WAS than CC systems, with a large impact of the pasture under CT. Runoff and erosion were minimized under NT in both rotations systems. Thus, including pastures in the rotation, or switching from CT to NT improved soil quality properties. The expected benefit of combining NT and ROT will likely require more years for the cumulative effect to be detectable in both C input and soil properties.
  • Authors:
    • Vyn, T.
    • McIntyre, L.
    • Brewer, J.
    • West, T.
    • Santini, J.
    • Boomsma, C.
  • Source: Soil & Tillage Research
  • Volume: 106
  • Issue: 2
  • Year: 2009
  • Summary: Research emphasizing slower plant growth and delayed maturity in continuous maize ( Zea mays L.), no-till (MM-NT) systems has often led to the conclusion that lower grain yields in this environment are associated with reduced plant heights. Yet prior research has shown that early-season and mature plants are not always shorter in MM-NT systems, suggesting that overall plant height may not be an accurate morphometric indicator of decreased yield in MM-NT environments. Given that plant-to-plant morpho-physiological uniformity is strongly associated with higher yield in maize, we hypothesized that greater plant height variability would provide a better agronomic explanation for yield loss in MM-NT environments than overall plant height reductions. This 14-year study primarily examined the effects of crop rotation {maize-soybean [ Glycine max (L.) Merr.] and continuous maize} and tillage system (no-till and moldboard plow) on the yield, 4-week plant population, and 4- and 8-week plant height and plant height variability of a single maize cultivar. Due to sizeable year-to-year variation, actual crop response means for the MM-NT; maize-soybean, no-till (MB-NT); and continuous maize, moldboard plow (MM-PL) treatment combinations were expressed relative to the accompanying means for the maize-soybean, moldboard plow (MB-PL) treatment. In numerous years, the MM-NT system exhibited reduced actual and relative yields and lower 4- and 8-week plant heights compared to the other treatment combinations. Both actual and relative 4- and 8-week plant height variability were rarely greatest for the MM-NT treatment, and in only a few years were actual and/or relative plant density lowest for this system. However, single-factor regression analyses between relative yield and the aforementioned relative agronomic measures revealed that a decline in relative MM-NT yield was most strongly associated with an increase in relative 4-week plant height variability. Multi-factor regression analyses between relative yield, relative 4-week plant height variability, and various weather parameters suggested that this strong inverse relationship was potentially a manifestation of (i) non-uniform germination, emergence, and early seedling growth and (ii) later-season intra-specific competition. Regression analyses between relative 4-week plant height variability and various weather parameters suggested that phenomenon (i) was potentially promoted by cool and moist or warm and dry pre-plant weather conditions while phenomenon (ii) was possibly encouraged by low precipitation and/or high temperatures during rapid stem elongation. While MM-NT systems should be managed to limit plant density reductions and minimize growth and developmental delays, increased focus should be placed on minimizing the occurrence of plant-to-plant variability in these environments.
  • Authors:
    • Florio, G.
    • Brigi, A.
    • Sandrini, S.
    • Bona, S.
    • Coletto, L.
    • Sambo, P.
  • Source: Proceedings of the Conference on integrated assessment of agriculture and sustainable development: Setting the Agenda for Science and Policy (AgSAP 2009), Hotel Zuiderduin, Egmond aan Zee, The Netherlands, 10-12 March 2009
  • Year: 2009
  • Authors:
    • Gentry, T.
    • Aitkenhead-Peterson, J.
    • Gonzalez-Chavez, M.
    • Zuberer, D.
    • Hons, F.
    • Loeppert, R.
  • Source: Soil & Tillage Research
  • Volume: 106
  • Issue: 2
  • Year: 2009
  • Summary: Tillage and crop rotation/intensity can influence soil biological properties and relevant soil processes including C sequestration. This study determined the effects of long-term (25 years) no till (NT) and conventional tillage (CT) management and cropping sequence [continuous wheat (CW; Triticum aestivum L.) and a rotation of sorghum ( Sorghum bicolor L. Moench), wheat and soybean (RW; Glycine max L. Merr)] on soil microbial community structure and labile and recalcitrant microbial bio-products in central Texas. Fatty acid methyl ester (FAME) profiles, microbial biomass (MB-C, -N and -P), hot water extractable soil carbohydrates (HWE-SC) and easily extracted- (EE-) and total-glomalin-related soil proteins (T-GRSP) were analyzed. Principal component analysis of the FAME data indicated that crop management modified and selected microbial populations. In general, NT-RW resulted in the greatest richness and biodiversity of the total microbial community, soil organic C, MB-P, HWE-SC, EE- and T-GRSP. No tillage increased labile and more recalcitrant bio-products, soil organic C and total N compared to CT. The soil microbial biomass C:N:P ratio, an indicator of ecosystem nutrient limitation, suggested that the CT-RW treatment may have a soil P limitation, which was not observed in the other treatments. The treatments preferentially selected for different microbial communities, which generated microbial products that significantly influenced soil C and N retention. Our results suggested that NT in conjunction with crop rotation (RW) can be recommended for increased soil C sequestration.
  • Authors:
    • Cadisch, G.
    • Giller, K.
    • Kamiri, H.
    • Gathumbi, S.
    • Ndufa, J.
  • Source: Agronomy Journal
  • Volume: 101
  • Issue: 6
  • Year: 2009
  • Summary: The deliberate planting of fast-growing N 2-fixing legume monoculture species in rotation with cereal crops can be an important source of N for soil fertility replenishment. We hypothesized that mixed-species fallows have a higher potential of giving long-term residual benefits in terms of biomass, nutrients, and quality of residuals leading to long-term nutrient supply to postfallow maize ( Zea mays L.) crops. To test these hypotheses, two experiments were established in farmers' fields on very fine Kandiudalfic Eutrudox soils with monoculture and mixed-species fallows. Treatments included: sesbania [ Sesbania sesban (L.) Merr.], crotalaria ( Crotalaria grahamiana Wight and Arn.), pigeonpea [ Cajanus cajan (L.) Millsp.], siratro [ Macroptilium atropurpureum (DC.) Urb.], and calliandra ( Calliandra calothyrsus Meissn.) as monoculture-species fallow and mixture fallows of sesbania+crotalaria, sesbania+pigeonpea, sesbania+siratro, or sesbania+calliandra compared with continuous maize cropping with or without N fertilizer, and natural weed fallow. Total aboveground biomass ranged from 4.1 to 20.5 Mg ha -1 for monoculture and 7.8 to 23.3 Mg ha -1 for mixed-species fallows. Recyclable fallow biomass N ranged from 70 to 313 kg ha -1 and there was a positive interaction in some mixtures leading to increased N accumulation. Postfallow maize yields for fallows over five cropping seasons were 161-272% or 61-103% higher when compared with continuous maize without or with N fertilizer, respectively. Long-term postfallow effects on maize yield were linearly related to the amount of recycled fallow N yield. Thus, choice of fallow species to mix should be primarily driven by a better risk management strategy and an increased basket of multiple products and services.