• Authors:
    • Sainju, U. M.
    • Jabro, J. D.
    • Caesar-TonThat, T.
  • Source: Journal of Environmental Quality
  • Volume: 39
  • Issue: 3
  • Year: 2010
  • Summary: Management practices are needed to reduce dryland sod CO(2) emissions and to increase C sequestration We evaluated the effects of tillage and cropping sequence combinations and N fertilization on dryland crop biomass (stems + leaves) and sod surface CO(2) flux and C content (0- to 120-cm depth) in a Williams loam from May to October, 2006 to 2008, in eastern Montana. Treatments were no-tilled continuous malt barley (Hordeum vulgaris L) (NTCB), no-tilled malt bailey pea (Pivot; sativum L) (NTB-P), no-tilled malt barley fallow (NTB-F), and conventional-tilled malt barley fallow (CTB-F), each with 0 and 80 kg N ha(-1) Measurements were made both in Phase I (malt barley in NTCB, pea in NTB-P, and fallow in NTB-F and CTB-F) and Phase II (malt barley in all sequences) of each cropping sequence in every year Crop biomass varied among years. was greater in the barley than in the pea phase of the NTB-P treatment, and greater in NTCB and NTB-P than in NTB-F and CTB-F in 2 out of 3 yr Similarly biomass was greater with 80 than with 0 kg N ha(-1) in 1 out of 3 yr. Soil CO(2) flux increased from 8 mg C m(-2) h(-1) in early May to 239 mg C m(-2) h(-1) in mid-June as temperature increased and then declined to 3 mg C m(-2) h(-1) in September. October Fluxes peaked immediately following substantial precipitation (>10 mm). especially in NTCB and NTB-P Cumulative CO(2) flux from May to October was greater in 2006 and 2007 than in 2008, greater in cropping than in fallow phases, and greater in NTCB than in NTB-F. Tillage did not influence crop biomass and CO(2) flux but N fertilization had a variable effect on the flux in 2008. Similarly, soil total C content was not influenced by treatments Annual cropping increased CO(2) flux compared with crop fallow probably by increasing crop residue returns to sods and root and rhizosphere respiration Inclusion of peas in the rotation wills malt barley in the no-till system, which have been known to reduce N fertilization rates and sustain malt barley yields, resulted in a CO(2) flux similar to that in the CTB-F sequence
  • Authors:
    • Sandor, M.
    • Domuta, C.
    • Vuscan, A.
    • Domuta, C.
    • Samuel, A.
  • Source: Research Journal of Agricultural Science
  • Volume: 42
  • Issue: 3
  • Year: 2010
  • Summary: The importance of phosphatase for plant nutrition has repeatedly been pointed out. In most soils, the organically bound P-fraction is higher than the inorganic. Phosphorus uptake by plants requires mineralization of the organic P-component by phosphatases to orthophosphate. Phosphatases are inducible enzymes that are produced predominantly under conditions of low phosphorus availability. Phosphatases are excreted by plant roots and by microorganisms. Microbial phosphatases dominate in soils. The phosphomonoesterases, so-called phosphatases differ in their substrate specificity and their pH optimum. One can thus differentiate between acid and alkaline phosphatases in the soil. Phosphatase activities were determined in the 0-20-, 20-40- and 40-60-cm layers of a preluvosoil submitted to a complex tillage (no-till and conventional tillage), crop rotation (2- and 3-crop rotations) and fertilisation [mineral(NP) fertilisation and farmyard-manuring] experiment. It was found that the activities decreased in the order: acid phosphatase activity > alkaline phosphatase activity. Each activity decreased with increasing sampling depth. No-till-in comparison with conventional tillage - resulted in significantly higher soil phosphatase activities in the 0-20-cm layer and in significantly lower activities in the deeper layers. The soil under maize or wheat was more phosphatase-active in the 3- than in the 2-crop rotation. In the 2-crop rotation higher soil phosphatase activities were recorded under wheat than under maize. Farmyard-manuring of maize - in comparison with its mineral fertilisation - led to a significant increase in each activity.
  • Authors:
    • Saseendran, S. A.
    • Nielsen, D. C.
    • Ma, L. W.
    • Ahuja, L. R.
    • Vigil, M. F.
  • Source: Agronomy Journal
  • Volume: 102
  • Issue: 5
  • Year: 2010
  • Summary: Long-term crop rotation effects on crop water use and yield have been investigated in the Central Great Plains since the 1990s. System models are needed to synthesize these long-term results for making management decisions and for transferring localized data to other conditions. The objectives of this study were to calibrate a cropping systems model (RZWQM2 with the DSSAT v4.0 crop modules) for dryland wheat ( Triticum aestivum L.), corn ( Zea mays L.), and proso millet ( Panicum miliaceum L.) production in the wheat-corn-millet (WCM) rotation from 1995 to 2008, and then to evaluate the model from 1992-2008 for two additional rotations, wheat-fallow (WF) and wheat-corn-fallow (WCF) on a Weld silt loam soil under no-till conditions. Measured biomass and grain yield for the above three rotations were simulated reasonably well with root mean squared errors (RMSEs) ranging between 1147 and 2547 kg ha -1 for biomass, and between 280 and 618 kg ha -1 for grain yield. Corresponding index of agreement (d) ranged between 0.70 and 0.95 for biomass, and between 0.87 and 0.97 for grain yield. The validated model was further used to evaluate two additional crop rotations: wheat-millet-fallow (WMF) and wheat-corn-millet-fallow (WCMF) (1993-2008) without prior knowledge of the two rotations. We found that the model simulated the mean and range of yield and biomass of the three crops well. These results demonstrated that RZWQM2 can be used to synthesize long-term crop rotation data and to predict crop rotation effects on crop production under the semiarid conditions of eastern Colorado.
  • Authors:
    • Kennedy, A. C.
    • Schillinger, W. F.
    • Young, D. L.
    • Paulitz, T. C.
  • Source: Field Crops Research
  • Volume: 115
  • Issue: 1
  • Year: 2010
  • Summary: Field burning of residue is a traditional management tool for irrigated wheat ( Triticum aestivum L.) production in the Inland Pacific Northwest of the United States (PNW) that can result in reduced air quality. A 6-year no-till field experiment to evaluate two complete cycles of a 3-year irrigated crop rotation of winter wheat-spring barley ( Hordeum vulgare L.)-winter canola ( Brassica napus L.) was sown (i) directly into standing residue of the previous crop, (ii) after mechanical removal of residue and, (iii) after burning of residue. The traditional practice of continuous annual winter wheat sown after burning residue and inverting the topsoil with a moldboard plow was included as a check treatment. Over-winter precipitation storage efficiency (PSE) was markedly improved when residue was not burned or burned and plowed after grain harvest. Grain yield of winter wheat trended higher in all no-till residue management treatments compared to the check treatment. Average grain yields of spring barley and canola were not significantly different among the no-till residue management treatments. Winter canola failed in 5 of 6 years due to a combination of a newly identified Rhizoctonia damping-off disease caused by Rhizoctonia solani AG-2-1 and cold temperatures that necessitated replanting to spring canola. Six-year average net returns over total costs were statistically equal over all four systems. All systems lost from $358 to $396 ha -1. Soil organic carbon (SOC) increased linearly each year with no-till at the 0-5 cm depth and accumulated at a slower rate at the 5-10 cm depth. Take-all of wheat caused by Gaeumannomyces graminis var. tritici was most severe in continuous annual winter wheat. The incidence and severity of Rhizoctonia on roots of wheat and inoculum of R. solani AG-8, was highest in the no-till treatments, but there was no grain yield loss due to this disease in any treatment. Residue management method had no consistent effect on Rhizoctonia root rot on barley. The annual winter grass downy brome ( Bromus tectorum L.) was problematic for winter wheat in the standing and mechanically removed residue treatments, but was controlled in the no-till residue burned and the burn and plow check. Another winter annual grass weed, rattail fescue ( Vulpia myuros L.), infested all no-till treatments. This was the first comprehensive and multidisciplinary no-till irrigated crop rotation study conducted in the Pacific Northwest.
  • Authors:
    • Silva, J. R. M. da
    • Silva, L. L.
    • Pisco, A. M. V.
    • Torres, C. J. V.
  • Source: International Conference on Agricultural Engineering
  • Year: 2010
  • Summary: Centre-pivot irrigation systems frequently cause surface runoff and erosion problems. This is more evident in complex topographies and low infiltrability soils. To overcome these problems farmers have tried different tillage systems, attaining different results, depending on soil type and irrigation management. Field tests, using small plots, were carried out in a Mediterranean soil with three different tillage systems: no-till, basin tillage and conventional tillage, as a control practice. Conventional tillage showed the highest runoff values (30% of collected water depth) with significant differences to no-till (15%) and basin tillage (2%). Maximum average values of sediment yields per irrigation event were lower for basin tillage (4.46 kg/ha) and no-till (9.59 kg/ha) compared to conventional tillage (23.45 kg/ha). The no-till system showed higher soil water content along all the irrigation season compared to the other two tillage systems. From a soil and water conservation point of view the basin tillage practice is the best option. But, from an economic point of view the no-till practice can be also a good option in these conditions.
  • Authors:
    • Singh, V. K.
    • Sah, A. K.
    • Prakash, O.
    • Singh, R. K.
    • Singh, S. N.
  • Source: Outlook on Agriculture
  • Volume: 39
  • Issue: 3
  • Year: 2010
  • Summary: Rice-wheat is the most commonly employed cropping system on around 14 million hectares of land extending across the Indo-Gangetic Plain (IGP). The IGP region covers the South Asian countries of Pakistan (2.2 million ha), India (10.5 million ha), Nepal (0.5 million ha) and Bangladesh (0.8 million ha). The major challenge facing the IGP's rice-wheat cropping system is to sustain long- term productivity. This system has a pivotal role in the food security and livelihoods of millions of farmers and workers of populous countries such as India, particularly in central Uttar Pradesh. The system's productivity and economic gains have been consistently decreasing, mainly because of the delayed sowing of wheat after the rice harvest and the fatigued soil condition. The region's farmers lose valuable time for pre-sowing irrigation and field preparation due to the gap of two to three weeks between the harvesting of rice and the planting of wheat. If wheat sowing is delayed beyond the optimal time (by late November), yields plummet at the rate of 30 kg per ha per day. The adoption of resource conservation technologies, such as zero tilled wheat sowing, is considered essential to maintain the productivity of the rice-wheat cropping system. Economic analysis of data for two years from six on- farm demonstrations shows that the zero tillage method of wheat cultivation is the most economical and attractive option for the farming community of central Uttar Pradesh. A high grain yield and reduced cost of cultivation per hectare, reduction in the density of weeds, especially Phalaris minor, and greater water saving were noted in zero tilled wheat sowings compared with conventional practices. As a result of field demonstrations and farmer training programmes, the introduction of zero till drill wheat sowing has expanded rapidly and has made significant contributions to the tillage revolution in the study area.
  • Authors:
    • Millen, J.
    • Evans, D.
    • Sadler, E.
    • Camp, C.
    • Stone, K.
  • Source: Applied Engineering in Agriculture
  • Volume: 26
  • Issue: 3
  • Year: 2010
  • Summary: Availability of spatially-indexed data and crop yield maps has caused increased interest in site-specific management of crop inputs, especially water and fertilizer As commercial equipment to implement site-specific applications of water and nutrients becomes available, crop response to variable inputs and decision support systems will be required to ensure profitable crop production while conserving natural resources and protecting the environment. The objective of this research was to determine corn yield response to a range of nitrogen fertilizer and irrigation amounts on a relatively uniform southeastern Coastal Plain soil under conservation tillage. Corn was grown in a field experiment using a center pivot irrigation system that had been modified to make site-specific applications of water and fertilizer during the period 1999-2001 on a site near Florence, South Carolina. Treatments included three antecedent crop rotations (prior four years), three irrigation regimes (0, 75%, and 150% of a base rate, IBR), and four nitrogen fertilizer amounts (50%, 75%, 100%, and 125% of a base rate, NBR), and with Put. replications. As expected, corn grain yields increased with irrigation and N fertilizer Mean corn grain yields for the three-year study ranged from 6.3 to 8.9 Mg/ha for the 0% IBR avail-twin, 9.4 to 10.5 Mg/ha for the 75% IBR treatment, and 10.0 to 10.6 Mg/ha for the 150% IBR treatment. The mean corn grain yields in response to N applications ranged from 6.4 to 8.0 Mg/ha for the 50% IBR treatment, 8.6 to 9.4 Mg/ha for the 75% NBR treatment, 9.1 to 10.9 Mg/ha for the 100% NBR treatment, and 8.8 to 11.7 for the 125% NBR treatment. However, the nature of the response varied among the three years, mainly because of differences in rainfall and rainfall distribution during the growing season. Also, during the first,year there was less response to N fertilizer (7.9 to 9.1 Mg/ha) possibly because of residual soil N from antecedent soybean crop. A regression analysis indicated that the slopes of the corn yield response to increased N fertilizer application were low for both irrigated and rainfed treatments in 1999. In both 2000 and 2001, the slopes were greater for the corn yield response to increased N fertilizer In 2000, the irrigated treatments had a greater slope of the yield response for additional N fertilizer than did the minted treatments. Using an orthogonal contrast analysis, the overall yield response for the combined irrigation treatments to N fertilizer was quadratic in 1999 and 2000, and linear in 2001. These quadratic yield response's indicated that, for these conditions, a potential upper limit on production for the applied N-fertilizer and water (rainfall and irrigation) was approached. For the minted treatment, yield response to N fertilizer was linear in all three years. These results provide useful information that should be helpful in developing management strategies and decision support systems for profitable management of both water and N fertilizer on spatially-variable soils in the southeastern Coastal Plain while conserving natural resources and protecting the environment.
  • Authors:
    • Maul, J. E.
    • Buyer, J. S.
    • Austin, E. E.
    • Treonis, A. M.
    • Spicer, L.
    • Zasada, I. A.
  • Source: Applied Soil Ecology
  • Volume: 46
  • Issue: 1
  • Year: 2010
  • Summary: Soil microorganisms (bacteria, fungi) and microfauna (nematodes, protozoa) have been shown to be sensitive to organic amendments, but few experiments have investigated the responses of all these organisms simultaneously and across the soil profile. We investigated the impact of organic amendment and tillage on the soil food web at two depths in a field experiment. Over three growing seasons, field plots received seasonal organic amendment that was either incorporated into the soil (tilled) or not (no-till) as part of a tomato/soybean/corn cropping system. Un-amended, control plots that were either tilled or no-till were also included. We hypothesized that the addition of amendments would have a bottom-up effect on the soil food web, positively influencing the abundance of microorganisms, protozoa, and nematodes, primarily in the surface layers of the soil, but that this effect could be extended into deeper layers via tillage. Organic amendment had positive effects on most measured variables, including organic matter, respiration, protozoan and nematode density, and the abundance of PLFA biomarkers for bacteria and fungi. These effects were more pronounced in the 0-5 cm depth, but most variables increased with amendment in the deeper layer as well, especially with tillage. Denaturing Gradient Gel Electrophoresis (DGGE) of bacterial rDNA fragments indicated that distinct bacterial communities were selected for among tillage and amendment treatments and depths. Nematode faunal indices were not influenced by amendment, however. Increased nematode density in amended soils encompassed all trophic groups of free-living nematodes, with the greatest response among fungal-feeders, particularly with tillage. Increased biomass of microorganisms and decomposer microfauna in amended, tilled soils (0-5 cm depth) corresponded with a decline in the abundance of plant-parasitic nematodes. In control soils (0-5 cm depth), tillage reduced the relative abundance of fungal-feeding nematodes and increased the density of bacterial-feeding nematodes, in particular nematode species contributing to the Enrichment Index. When combined with organic amendment however, tillage was associated with increases in fungal-feeding nematodes and fungal biomarker PLFA. The results of this study suggest that when combined with amendment, tillage enhances the soil food web beyond the effect of amendment alone and is associated with declines in plant-parasitic nematodes.
  • Authors:
    • Mielniczuk, J.
    • Vezzani, F. M.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world
  • Year: 2010
  • Summary: Soil use for agricultural production may increase soil structure quality as long as conservation management practices are adopted. The aggregates and single particles distribution into diameter classes (9.51-4.76, 4.76-2.00, 2.00-0.25, 0.25-0.053, 0.25 mm) also were increased from 22.8% to 53.5% and the C stock reached 17.9 Mg/ha building a complex soil structure with the capacity to increase soil quality.
  • Authors:
    • Daniel, H.
    • King, K.
    • Williams, A.
    • Martin, B.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Symposium 3.1.2 Farm system and environment impacts
  • Year: 2010
  • Summary: No-till farming in Australia has revolutionised the way many farmers crop. Some of the moisture retention advantages of no-till farming have resulted in a reduced reliance of in-crop rain as well as increasing yields and profitability. Less clear is the effect on biological properties. Early results of a survey of the no-till cropping soils of the central west of NSW showed that most no-till cropping areas have lower soil carbon levels and lower microbial activity than nearby uncropped soils. This indicates that many no-till cropping soils may not be as sustainable as first thought. A long-fallow field trial was conducted on "Magomadine" near Coonamble NSW Australia using surface applied amendments (straw, compost, feedlot manure, biochar and zeolite) to investigate their effect on biological, chemical and physical soil properties. Early results are suggesting that the application of 10t/ha of straw can significantly ( P<0.05) increased soil moisture (24%), microbial respiration (50%), microbial biomass (21%), and mean weighted diameter of soil aggregates (75%). This research has highlighted the importance that high stubble residues have in improving these soil properties during a long-fallow.