• Authors:
    • Tessier, D.
    • Curmi, P.
    • Guimaraes, M.
    • Tavares Filho, J.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 36
  • Issue: 1
  • Year: 2012
  • Summary: It is known that any kind of soil management causes changes in the soil physical characteristics and can affect agricultural yield. The purpose of this study was to evaluate soil properties of an Alfisol and soybean yield under different management systems for no-tillage annual crops, no-tillage with chiseling and no-tillage crop rotation. The 11-year experiment was initiated in the 1998/99 growing season, on 100*30 m plots (11% slope). Soil samples (5 per management system) were systematically collected (0-25 cm layer) in the summer growing season, to quantify soil organic matter, bulk density, macroporosity and flocculation, as well as soybean yield. The highest values for soil bulk density and organic matter content and the lowest for macroporosity were observed in the no-till system alone, whereas in the no-till system with quarterly chiseling the values for organic matter content were lowest, and no-tillage crop rotation resulted in the highest values for organic matter and macroporosity, and the lowest for soil bulk density. The average soybean yield was highest under no-till and trimestrial chiseling or crop rotation, and lowest for no-tillage annual crops no-tillage annual crops alone.
  • Authors:
    • Hoogmoed, W. B.
    • Oenema, O.
    • Cai D.
    • Jin, K.
    • Wu, X.
    • Zhao, Q.
    • Feng, Z.
    • Zhang, D.
    • Dai, K.
    • Wu, H.
    • Wang, X.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: Dryland farming in the dry semi-humid regions of northern China is dominated by mono-cropping systems with mainly maize ( Zea mays L.) or wheat ( Triticum aestivum), constrained by low and variable rainfall, and by improper management practices. Addressing these problems, field studies on tillage and residue management for winter wheat and spring maize were conducted at 4 sites in Linfen, Tunliu and Shouyang (Shanxi province) and Luoyang (Henan province). These studies (a.o.) explored the impacts of different tillage and residue application methods on soil physical conditions, water storage, water use, water use efficiency (WUE) and crop yields of wheat and maize. An analysis of the results of these studies is presented. Conservation tillage, comprising no-till as well as reduced tillage practices (subsoiling, deep ploughing) showed benefits which were more prominent in combination with residue application. Benefits compared to conventional tillage were found in the form of improved soil physical conditions, such as higher topsoil bulk densities but lower subsoil bulk densities. This resulted in a better water storage during the summer fallow or rainy season in winter wheat fields, and a better water conservation and soil protection in spring maize fields. Compared to conventional methods, reduced tillage gave yields around 13-16% higher in spring maize and round 9-37% higher in winter wheat. Yields under no-till were very close to those from conventional methods. Surface application of crop residue for maize was found to increase the risk for delayed seedling emergence, because of low temperatures, leading to a recommendation for incorporation of residue in combination with reduced tillage. For winter wheat, subsoiling in combination with straw mulching after harvest in summer every other two or three year, and no-till seeding is a promising practice for sandier soils and low rainfall conditions. For heavier clay loam soils, deep ploughing with straw mulching after wheat harvest in summer every other two or three year, and no-till seeding practice is recommended. For spring maize, deep ploughing with straw and fertilizers incorporation after harvest in fall, and no-till seeding practices are recommended. Subsoiling or no-till with residue mulching after harvest in fall, and no-till seeding practices in spring are also promising practices, the latter only in situations where low spring temperatures are not a problem. Continuous no-till is not recommended.
  • Authors:
    • Djigal, D.
    • Saj, S.
    • Rabary, B.
    • Blanchart, E.
    • Villenave, C.
  • Source: Soil & Tillage Research
  • Volume: 118
  • Year: 2012
  • Summary: Conservation agriculture (CA) is rapidly developing in Madagascar but little is known about its effects on local soil functioning. To assess some of those effects, we investigated the effects of three CA systems and two levels of fertilization on soil functioning using nematofauna as indicator. The systems consisted in (i) soybean (Glycine max L.)-maize (Zea mays L) rotation with mulch of residues, CA-R; (ii) bean (Phaseolus vulgaris L.)-soybean rotation with living mulch of Pennisetum clandestinum, CA-K; (iii) continuous maize with living mulch of Desmodium uncinatum, CA-D and were compared with soybean-maize under conventional tillage (CT) and natural fallow (NF). The fertilization levels consisted in ( i) farmyard manure, FYM; and (ii) farmyard manure + mineral fertilizers, FYM + NPK. Located in the Highlands of Madagascar, the experiment was setup in 1991 and andic Dystrustept soil had been sampled in 2005-2007. We measured nematode abundances and ecological indices as well as the abundance and biomass of soil macrofauna, soil water and organic C and N contents and plant yields. We hypothesized that (1) CA including maize in monoculture would lead to higher abundance of plant-parasitic nematodes; (2) both dead-residue mulch and inorganic fertilization would lead to a more basal nematode community structure; and (3) that the combination of system effects on soil nematode community would be able to forecast differential crop yields for the CA systems. Our results show that CA systems tested were able to support better/comparable maize and soybean yields compared with CT, provided that crop rotation is correctly managed. Supporting our first hypothesis, abundance of plant parasitic nematodes was (40-150 times) higher under maize monoculture. Abundance of soil nematofauna and trophic groups (excepted carnivores and omnivores) was stable during the three years. Inorganic fertilization increases carnivorous and omnivorous nematodes to 122% and 140%, respectively. Ecological indices showed that soil functioning of CA systems was intermediate between that NF and CT. CA systems were characterized by a highly structured soil food-web compared with CT. Yet, soil processes intensity revealed to be lower in CA with dead mulch compared with CA with living mulch, contrasting with our second hypothesis. The characterization of nematofauna discriminated well the different systems and supports our third hypothesis. Nematode structure and enrichment indices were significantly correlated to soil organic C and N content as well as grain yields. They proved to be powerful bio-indicators of soil functioning in the CA systems studied.
  • Authors:
    • Voltas, J.
    • Molist, M.
    • Guerrero, E.
    • Buxo, R.
    • Arab, G.
    • Ferrio, J.
    • Araus, J.
  • Source: Journal of Arid Environments
  • Volume: 86
  • Year: 2012
  • Summary: Modern Syria, and in particular the Middle Euphrates valley, has been occupied and overexploited since the beginnings of agriculture. Thus, the study of the economic and environmental characteristics of ancient settlements may offer new perspectives on the long-term effects of continuous agriculture in a fragile agroecosystem. In this work, we present a methodological framework that uses archaeological information to understand long-term effects of the extensification of agriculture in present-time arid areas. Specifically, we have compared the main economic features of a Neolithic site of the middle Euphrates, Tell Halula (ca. 10th millennium BP), with present-day data from the surrounding region. Population, crop distribution, cereal yields and arable land requirements during the first millennia after the emergence of agriculture were estimated from archaeological data and compared with a compilation of present-time official statistics and data derived from a field survey. We observed a trend towards a cereal-based farming during the Neolithic, associated to a decrease in the diversity of wild florae. This was accompanied by a growth in population during the earliest phases of the settlement (8200-7000 cal BCE), followed by a decline in population in the late phases (7000-5400 cal BCE), probably as a consequence of exceeding the capacity of the agroecosystem. A comparable situation to that found in early phases of Tell Halula was observed in modern communities, showing similar growth rates and a strong focus on cereal crops.
  • Authors:
    • Bohm, H.
    • Gronle, A.
  • Source: Julius-Kühn-Archiv
  • Volume: 1
  • Issue: 434
  • Year: 2012
  • Summary: The reduction of soil tillage depth is of special interest in organic farming. However, shallow ploughing often results in higher weed abundances in comparison to deep ploughing. Thus, the objective of this study was to evaluate whether the high weed suppressive ability of spring and winter pea-cereal intercrops can compensate for the higher weed growth in shallow ploughing compared to deep ploughing in organic farming. Peas and cereals were grown as sole crops and intercrops under shallow and deep ploughing in experiments on a sandy loam soil in Northern Germany in 2009, 2010 and 2011. Semi-leafless spring peas-oats, semi-leafless winter peas-triticale and regular-leaf type winter peas-triticale intercrops were examined. At harvest, weed shoot biomass in semi-leafless spring and winter pea sole crops under deep ploughing were slightly higher than those of the corresponding intercrops under shallow ploughing. Whereas weed shoot biomass in semi-leafless winter peas-triticale intercrops under deep ploughing was comparable to shallow ploughing, the cultivation of spring peas-oats intercrops under shallow ploughing led to a significantly higher weed growth than did deep ploughing. The regular-leaf type winter pea grown as a sole crop, or an intercrop with triticale, showed a higher weed suppressive ability than the semi-leafless peas. The tillage system had no significant influence on the weed infestation of sole and intercropped regular-leaf type winter peas. Semi-leafless spring peas-oats and winter peas-triticale intercrops could compensate for weed infestation differences under shallow ploughing compared to the corresponding pea sole crops under deep ploughing. Due to the high weed suppressive ability of regular-leaf type winter peas, shallow ploughing and deep ploughing, as well as sole cropping and intercropping, led to comparable weed infestation.
  • Authors:
    • Schlegel, A.
    • Halvorson, A.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 5
  • Year: 2012
  • Summary: Limited irrigation management practices are being used in the Central Great Plains to conserve water by optimizing crop water use efficiency. Limited irrigation may reduce total crop biomass production and amount of crop residue returned to the soil. Crop residue production within four no-till (NT) crop rotations [continuous corn ( Zea mays L.) (CC); corn-winter wheat ( Triticum aestivum L.) (CW); corn-winter wheat-grain sorghum ( Sorghum bicolor L. Moench) (CWS); corn-winter wheat-grain sorghum-soybean [ Glycine max (L.) Merr.] (CWSSb)] was measured and changes in soil organic carbon (SOC) and total soil nitrogen (TSN) stocks were monitored for 10 yr. Crop residue yields varied with crop being produced and with rotation, as did residue N and C returned to the soil. The C/N ratio of the residue varied with crop. The SOC and TSN pools increased with time in all rotations. The rate of gain in SOC and TSN mass for each rotation was 717, 477, 335, and 270 kg SOC ha -1 yr -1 and 114, 92, 87, and 84 kg TSN ha -1 yr -1 for the CC, CW, CWS, and CWSSb rotations, respectively, in the 0- to 30.5-cm soil depth. The rate of change in SOC and TSN mass was lowest with CWSSb (8.7 Mg residue ha -1 yr -1) and highest with CC (12.0 Mg residue ha -1 yr -1). Approximately 6.8 to 7.6 Mg residue ha -1 yr -1 would be needed to maintain SOC stocks under limited irrigation.
  • Authors:
    • Reicosky, D.
    • Porter, P.
    • Baker, J.
    • Ochsner, T.
    • Krueger, E.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 4
  • Year: 2012
  • Summary: Recent proliferation of large dairies has prompted concern regarding environmental impacts of associated corn silage production and high-rate manure application. Our objectives were to compare environmental impacts and forage production of monocrop corn ( Zea mays L.) silage and rye ( Secale cereal L.)-corn silage double-crop systems with multiple corn planting dates and high-rate manure application near Morris, MN. From 2007 to 2009, corn for silage was seeded into a silt loam as a monocrop in early and mid-May and as a double-crop after rye in mid-May and early June. Manure was fall applied annually at average total N and P rates of 393 and 109 kg ha -1, respectively. Double-cropping reduced total forage dry matter (DM) yield 2 of 3 yr and reduced corn DM yield 15 to 25%. Soil NO 3-N to 90 cm accumulated at an average rate of 71 kg N ha -1 yr -1 with monocropping, but accumulation was not observed with double-cropping. Soil organic C concentration from 0 to 5 cm increased in the monocrop (18%) and double-crop (26%) systems over 3 yr. Average soil solution NO 3-N concentration was high with monocropping (52 mg L -1) and double-cropping (37 mg L -1), but estimated leaching load averaged only 8 kg ha -1 yr -1. Fall and spring ground cover was often less than 10% with monocropping but was usually greater than 30% with double-cropping. The primary environmental concerns identified for monocrop corn silage were soil NO 3-N buildup and inadequate ground cover. Double-cropping addressed each concern but often decreased forage production.
  • Authors:
    • Gramig, B.
    • Reeling, C.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 146
  • Issue: 1
  • Year: 2012
  • Summary: Agricultural ecosystems are a source of greenhouse gas (GHGs) emissions and losses of nutrients to waterways. Several studies have recognized this and have documented the potential to reduce GHG fluxes and nutrient loss to waterways by using carbon offsets to fund the implementation of land retirement and afforestation. However, the ability to use land for both agricultural production and environmental conservation is also important. This study develops a novel analytical framework that is used to examine the cross-media (water and air) environmental effects of implementing offset-funded conservation practices in a working-lands setting. The framework is applied to a case study which examines the extent to which carbon pricing can affect practice implementation costs and the optimal distribution of these practices throughout an agricultural watershed. Results indicate that carbon offsets can reduce conservation practice implementation costs and have the potential to reduce greater amounts of nonpoint source pollution for a given cost of implementation. This conclusion has significant implications for policymaking, particularly with regard to using markets for GHG emissions to achieve water quality improvements where water quality trading or government conservation programs have historically been unsuccessful. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Okeyo, J.
    • Vanlauwe, B.
    • Kimetu, J. M.
    • Waswa, B.
    • Bationo, A.
    • Kihara, J.
    • Mukalama, J.
    • Martius, C.
  • Source: Experimental Agriculture
  • Volume: 48
  • Issue: 2
  • Year: 2012
  • Summary: Reduced tillage is said to be one of the potential ways to reverse land degradation and ultimately increase the productivity of degrading soils of Africa. We hypothesised that crop yield following a modest application of 2 t ha(-1) of crop residue in a reduced tillage system is similar to the yield obtained from a conventional tillage system, and that incorporation of legumes in a cropping system leads to greater economic benefits as opposed to a cropping system involving continuous maize. Three cropping systems (continuous maize monocropping, legume/maize intercropping and rotation) under different tillage and residue management systems were tested in sub-humid western Kenya over 10 seasons. While soybean performed equally well in both tillage systems throughout, maize yield was lower in reduced than conventional tillage during the first five seasons but no significant differences were observed after season 6. Likewise, with crop residue application, yields in conventional and reduced tillage systems are comparable after season 6. Nitrogen and phosphorus increased yield by up to 100% compared with control. Gross margins were not significantly different among the cropping systems being only 6 to 39% more in the legume-cereal systems relative to similar treatments in continuous cereal monocropping system. After 10 seasons of reduced tillage production, the economic benefits for our cropping systems are still not attractive for a switch from the conventional to reduced tillage.
  • Authors:
    • Lawton-Rauh, A.
    • Agudelo, P.
    • Leach, M.
  • Source: Plant Disease
  • Volume: 96
  • Issue: 1
  • Year: 2012
  • Summary: Rotylenchulus reniformis is a highly variable nematode species and an economically important pest in many cotton fields across the southeastern United States. Rotation with resistant or poor host crops is a method for management of reniform nematode. We studied the effect of six planting schemes covering four 120-day planting cycles on the predominant genotype of R. reniformis. Rotations used were: (i) cotton to corn; (ii) susceptible soybean to corn; (iii) resistant soybean to cotton; (iv) corn to cotton; (v) continuous susceptible soybean; (vi) continuous cotton. After each 120-day cycle, amplified fragment length polymorphisms (AFLPs) produced from four primer pairs were used to determine the effect of crop rotation on the predominant genotype of reniform nematode. A total of 279 polymorphic bands were scored using four primer combinations. Distinct changes in genotype composition were observed following rotations with resistant soybean or corn. Rotations involving soybean (susceptible and resistant) had the greatest effect on population structure. The characterization of field population variability of reniform nematode and of population responses to host plants used in rotations can help extend the durability of resistant varieties and can help identify effective rotation schemes.