• Authors:
    • Begue, A.
    • Dubreuil, V.
    • Meirelles, M.
    • Arvor, D.
    • Shimabukuro, Y. E.
  • Source: Applied Geography
  • Volume: 32
  • Issue: 2
  • Year: 2012
  • Summary: The Amazonian state of Mato Grosso is the main production area for soybeans in Brazil and contains 31.3% of the national production as of 2009. The rapid evolution of the agricultural systems in this area shows that the region is experiencing a rapid agricultural transition. In this paper, we broke down this transition process into three steps: crop expansion, agricultural intensification and ecological intensification. We used remote sensing products to develop and compute satellite-derived indices describing the main agricultural dynamics during the cropping years from 2000-2001 to 2006-2007. Our results indicated that Mato Grosso is continuing to expand its agricultural sector, with a 43% increase in the net cropped area during the study period. Although this expansion mainly occurred in the cerrado ecoregion until the early 2000s, the forest ecoregion is experiencing expansion at this time. We observed that 65% of the crop expansion in Mato Grosso from 2000 to 2006 occurred in this ecoregion. However, we did not identify this crop expansion as the major driver of deforestation in Mato Grosso because only 12.6% of the cleared areas were directly converted into croplands. Agricultural intensification also evolved rapidly, as the proportion of the net cropped area cultivated with double cropping systems harvesting two successive commercial crops (i.e., soybean and corn or soybean and cotton) increased from 6% to 30% during the study period. Finally, we found that ecological intensification occurred because the region's farmers planted a non-commercial crop (i.e., millet or sorghum) after the soybean harvest to prevent soil erosion, improve soil quality, break pest cycles, maintain soil moisture and set the conditions for high-quality no-tillage operations. In 2006-2007, 62% of the net cropped area was permanently covered by crops during the entire rainy season. This practice allowed the farmers to diversify their production, as shown by the positive evolution of the Area Diversity Index. Future scholars can use the method proposed in this paper to improve their understanding of the forces driving the agricultural dynamics in Mato Grosso.
  • Authors:
    • Dercon, G.
    • Kumar S.
    • Garg, A. K.
    • Manchanda, J. S.
    • Aulakh, M. S.
    • Nguyen, M. L.
  • Source: Soil & Tillage Research
  • Volume: 120
  • Year: 2012
  • Summary: Continuing cereal-based crop rotations such as rice-wheat, intensive cultivation and complete removal of postharvest crop residue (CR) for animal consumption and fuel, or its burning have reduced the organic matter content and productivity of irrigated semi-arid subtropical soils of South Asia. Identification of effective strategies for the management of tillage and CR could foster sustainable and environmentally sound agricultural systems. To this effect, a 4-year field experiment was established with annual soybean-wheat rotation under subtropical climate conditions in the Indo-Gangetic Plains of Northwestern India to evaluate the integrated effects of tillage, CR retainment, mineral fertilizers and farmyard manure (FYM) on crop production, nutrients uptake, soil moisture storage and temperature dynamics. The experimental soil was loamy sand, poor in organic C and low in available P. Sixteen treatment combinations involved recommended and 25% higher NP rates without or with 10 t FYM ha -1 and CR incorporated in conventional tillage (CT) and retained on the soil surface in conservation agriculture (CA) system. The results clearly revealed that (a) soybean yield was 2-6% higher in CA than CT in different treatments with and without CR, (b) significantly higher uptake of N and P by soybean from CR-amended treatments of both CT and CA, which reflected its effect in improving the soybean yield, (c) the current fertilizer NP recommendation of 20 kg N and 26 kg P ha -1 for soybean is not adequate and either application of 25% higher NP rate (25 kg N and 33 kg P ha -1) or additional 10 t FYM ha -1 is required for optimum crop production of ~2500 kg ha -1, (d) CA conserved more water in soil profile than CT, however, the differences in soil moisture storage in CT vis-a-vis CA were not reflected in soybean yield presumably due to frequent wetting of soil by heavy monsoonal rains, (e) the wheat yield was highest in both CT and CA systems when grown with the application of 150 kg N and 33 kg P ha -1 without CR and was 7% higher in CA (4140 kg ha -1) than CT (4048 kg ha -1), and (f) retention of CR on soil surface in winter-grown wheat under CA reduced wheat yield by 8-24% and N uptake by 3-5% as a consequence of mulching effects creating cooler environment in surface soil layer during initial 3 weeks after seeding, which led to the delayed germination and relatively poor crop growth during initial period.
  • Authors:
    • Tchoundjeu, Z.
    • Kalinganire, A.
    • Coe, R.
    • Sileshi, G. W.
    • Bayala, J.
    • Sinclair, F.
    • Garrity, D.
  • Source: Journal of Arid Environments
  • Volume: 78
  • Year: 2012
  • Summary: To address the decline in crop productivity in the drylands of West Africa, many initiatives have focused on combating soil degradation. Various practices including (1) parkland trees associated with crops, (2) coppicing trees, (3) green manure, (4) mulching. (5) crop rotation and intercropping, and (6) traditional soil/water conservation have been tested. The present study attempts to provide a comprehensive, quantitative synthesis of existing reports on the effect of conservation agriculture (CA) practices on crop yield response in Burkina Faso, Mali, Niger and Senegal. Out of a total of 155 reports found, 63 fulfilled all the appropriate criteria to be included in the meta-analysis of the effect of various conservation agriculture practices on the yield response of maize, millet and sorghum. The study revealed significant variability in cereal yield response (and hence risk) with all the practices examined. Despite the variability, the mean effects of the six CA practices on crop yield were more positive than negative except with parkland trees. However, for this last practice, species like Faidherbia albida exerts more positive impact on crop yield. Yield increases relative to the control were higher with green manure and mulching than with coppicing trees and parklands. Increases in yield in the six CA practices were higher on low to medium productivity sites for maize, millet and sorghum. Coppicing trees and rotations improved yields when the rainfall is >800 mm whereas the opposite happens with parkland and soil-water conservation measures. Mulching performed better when the rainfall is
  • Authors:
    • Breland, T. A.
    • Bleken, M. A.
    • Bakken, L. R.
    • Lunde, H. W.
    • Borgen, S. K.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 92
  • Issue: 3
  • Year: 2012
  • Summary: We applied a mechanistic ecosystem model to investigate the production and environmental performances of (1) current agricultural practice on two fields of a stockless organic cereal farm in southeast Norway and (2) alternative cereal-ley rotations and plowing time scenarios. Scenarios were simulated using historic weather data and a climate change scenario. Measured and simulated soil mineral N concentrations were generally low (1-4 g N m(-2)) and in good agreement. Simulated nitrate leaching was similar for the two fields, except when an extended period of black fallow weeding was practiced on one of them. Scenario simulations indicated that continuous cereal cropping undersown with a clover-grass winter cover crop performed best when evaluated by whole-rotation grain yield, the N yield/input-, and N loss/yield-ratios, and greenhouse gas emissions. However, the rotation had the largest soil organic matter losses. The N use and loss efficiency indicators were especially poor when ley years occurred consecutively and under fall plowing. Total greenhouse gas emissions were, however, smaller for the fall-plowed scenarios. In conclusion, our results indicated a modest potential for improving stockless systems by management changes in plowing time or crop rotation, which was hardly different in the climate change scenarios, although nitrate leaching increased substantially in the winter. Alternative strategies seem necessary to substantially improve the N-use efficiency in stockless organic grain production systems, e.g., biogas production from green manure and subsequent recycling of the digestate. Abandoning the stockless system and reintegrating livestock should also be considered.
  • Authors:
    • Zekaite, V.
    • Deveikyte, I.
    • Kadziuliene, Z.
    • Sarunaite, L.
    • Maiksteniene, S.
    • Arlauskiene, A.
    • Cesnuleviciene, R.
  • Source: ZEMDIRBYSTE-AGRICULTURE
  • Volume: 98
  • Issue: 4
  • Year: 2011
  • Summary: Intercropping of cereals and grain legumes is a technology intended to enhance biodiversity in organic agroecosystems, increase and stabilize yields and make better use of plant growth resources. The experiments were designed to investigate the intercrops' yield advantage in different soil, climate and plant competition conditions in organic farming. Field trials were carried out during 2007-2010 at the Lithuanian Institute of Agriculture at three different soil sites: on a loamy Endocalcari-Epihypogleyic Cambisol ( CMg-p-w-can) (Dotnuva), on a clay loam Endocalcari-Endohypogleyic Cambisol ( CMg-n-w-can) (Joniskelis) and on a sandy loam Hapli-Albic Luvisol ( LVe-ha) (Perloja). Pea ( Pisum sativum L. (Partim)) and spring wheat ( Triticum aestivum L. emend. Fiori et Paol.), spring barley ( Hordeum vulgare L.), oat ( Avena sativa L.) and spring triticale (* Triticosecale Wittm.) were sown as intercrops (50:50 - a relative proportion of grain legume and spring cereal seeds) or as a sole crop. The result showed that weather and soil conditions during plant emerge determined the optimal productive density and created a basis for competition between the intercrop components. Spring cereals were dominant due to higher aggressivity index and competition rate compared with peas. Under various soils' conditions the aggressivity of cereals increased with increasing density of pea. In productive soils (Dotnuva, Joniskelis), the highest competitive and suppressive power in the intercrops was exhibited by oats, in low productivity soils (Perloja) - the dominant species varied. Under the conditions of various soils, the production of pea intercrop with oats or barley was directly affected by cereals, while pea intercropped with wheat or triticale by the two components of the intercrop. In terms of grain yield, intercrops ranked as follows: pea/oats > pea/wheat, pea/triticale > pea/barley. In loamy soil (Dotnuva), these regularities were less consistent, therefore the advantages of intercrops' yield over sole crops' yield were negligible when the relative yield total (RYT) was >1.0, except for the pea intercropped with barley. In Joniskelis and Perloja, the relative yield total showed greater and more stable yield advantages of intercrops, except pea intercropped with triticale. The efficiency of intercrops stood out even more vividly in the treatments managed under organic cropping system for a longer period of time.
  • Authors:
    • Shahid, A.
    • Saghir, A.
    • Jamil, M.
    • Zubair, M.
    • Farooq, M.
    • Awais, R.
  • Source: Pakistan Sugar Journal
  • Volume: 26
  • Issue: 2
  • Year: 2011
  • Summary: Sugarcane is a long duration crop and is suitable for intercropping with other short duration crops to maximize the farmer income from the unit area. Thus, this study was designed to find out the possibility of wheat, lentil and gram intercropping with autumn planted sugarcane crop. The study was carried out at National Agricultural Research Centre, Islamabad during 2004-05 cropping season. Sugarcane variety RB-72-454 was used as test crop and planted at 1.2 meter row distance in the first week of September, 2004. Two rows of each wheat, lentil and gram crop were seeded in the month of November in between cane rows. Sugarcane crop was harvested in the month of December, 2005. Lentil and gram were harvested in the month of April while, wheat in May. The results of the study indicted that sugarcane planted alone produced highest cane yield of 130.5 t ha -1, while sugarcane intercropped with wheat produced lowest cane yield of 105.5 t ha -1. The yields of wheat, lentil and gram were 1.18, 0.57 and 0.43 t ha -1, respectively. However, it was observed that intercropping of wheat, lentil and gram with sugarcane decreased cane yield by 19.2, 18.6 and 14.3%, respectively. The maximum economic return of Rs. 156641 ha -1 was noticed when sugarcane was planted without intercropping, whereas, intercropping of sugarcane with wheat resulted in minimum return of Rs. 138889 ha -1. Findings of the study revealed that autumn planting of sugarcane without any intercropping is more profitable than intercropping with cereal and leguminous crops.
  • Authors:
    • Orr, W.
    • Cooper, J.
    • Chataway, R.
    • Cowan, R.
  • Source: Animal Production Science
  • Volume: 51
  • Issue: 10
  • Year: 2011
  • Summary: Dairy farms located in the subtropical cereal belt of Australia rely on winter and summer cereal crops, rather than pastures, for their forage base. Crops are mostly established in tilled seedbeds and the system is vulnerable to fertility decline and water erosion, particularly over summer fallows. Field studies were conducted over 5 years on contrasting soil types, a Vertosol and Sodosol, in the 650-mm annual-rainfall zone to evaluate the benefits of a modified cropping program on forage productivity and the soil-resource base. Growing forage sorghum as a double-crop with oats increased total mean annual production over that of winter sole-crop systems by 40% and 100% on the Vertosol and Sodosol sites respectively. However, mean annual winter crop yield was halved and overall forage quality was lower. Ninety per cent of the variation in winter crop yield was attributable to fallow and in-crop rainfall. Replacing forage sorghum with the annual legume lablab reduced fertiliser nitrogen (N) requirements and increased forage N concentration, but reduced overall annual yield. Compared with sole-cropped oats, double-cropping reduced the risk of erosion by extending the duration of soil water deficits and increasing the time ground was under plant cover. When grown as a sole-crop, well fertilised forage sorghum achieved a mean annual cumulative yield of 9.64 and 6.05 t DM/ha on the Vertosol and Sodosol, respectively, being about twice that of sole-cropped oats. Forage sorghum established using zero-tillage practices and fertilised at 175 kg N/ha.crop achieved a significantly higher yield and forage N concentration than did the industry-standard forage sorghum (conventional tillage and 55 kg N/ha.crop) on the Vertosol but not on the Sodosol. On the Vertosol, mean annual yield increased from 5.65 to 9.64 t DM/ha (33 kg DM/kg N fertiliser applied above the base rate); the difference in the response between the two sites was attributed to soil type and fertiliser history. Changing both tillage practices and N-fertiliser rate had no affect on fallow water-storage efficiency but did improve fallow ground cover. When forage sorghum, grown as a sole crop, was replaced with lablab in 3 of the 5 years, overall forage N concentration increased significantly, and on the Vertosol, yield and soil nitrate-N reserves also increased significantly relative to industry-standard sorghum. All forage systems maintained or increased the concentration of soil nitrate-N (0-1.2-m soil layer) over the course of the study. Relative to sole-crop oats, alternative forage systems were generally beneficial to the concentration of surface-soil (0-0.1 m) organic carbon and systems that included sorghum showed most promise for increasing soil organic carbon concentration. We conclude that an emphasis on double- or summer sole-cropping rather than winter sole-cropping will advantage both farm productivity and the soil-resource base.
  • Authors:
    • Jimenez-Munoz, J.
    • Sobrino, J.
    • Julien, Y.
  • Source: International Journal of Applied Earth Observation and Geoinformation
  • Volume: 13
  • Issue: 5
  • Year: 2011
  • Summary: Several previous studies have shown that the inclusion of the LST (Land Surface Temperature) parameter to a NDVI (Normalized Difference Vegetation Index) based classification procedure is beneficial to classification accuracy. In this work, the Yearly Land Cover Dynamics (YLCD) approach, which is based on annual behavior of LST and NDVI, has been used to classify an agricultural area into crop types. To this end, a time series of Landsat-5 images for year 2009 of the Barrax (Spain) area has been processed: georeferenciation, destriping and atmospheric correction have been carried out to estimate NDVI and LST time series for year 2009, from which YLCD parameters were estimated. Then, a maximum likelihood classification was carried out on these parameters based on a training dataset obtained from a crop census. This classification has an accuracy of 87% (kappa=0.85) when crops are subdivided in irrigated and non-irrigated fields, and when cereal crops are aggregated in a single crop, and performs better than a similar classification from Landsat bands only. These results show that a good crop differentiation can be obtained although detailed crop separation may be difficult between similar crops (barley, wheat and oat) due to similar annual NDVI and LST behavior. Therefore, the YLCD approach is suited for vegetation classification at local scale. As regards the assessment of the YLCD approach for classification at regional and global scale, it will be carried out in a further study.
  • Authors:
    • Dordas, C.
    • Vlachostergios, D.
    • Lithourgidis, A.
    • Damalas, C.
  • Source: European Journal of Agronomy
  • Volume: 34
  • Issue: 4
  • Year: 2011
  • Summary: Intercrops of pea ( Pisum arvense L.), a popular legume used in intercropping systems with winter cereals for forage and silage production, with wheat ( Triticum aestivum L.), rye ( Secale cereale L.), and triticale (* Triticosecale Wittmack) in two seeding ratios (60:40 and 80:20) were compared with monocrops of pea and cereals for two growing seasons. Growth rate, dry matter yield, and N uptake were determined in each intercropping system. Furthermore, several indices were used to evaluate the intercropping systems and analyze the competition and the interrelationships between mixture components. Growth rate of cereals was lower in the mixtures than in the monocrops. Dry matter yield was higher in triticale monocrop, followed by its two intercrops, and the pea-wheat 80:20 intercrop. Moreover, triticale monocrop, pea-triticale intercrops, and pea-wheat 80:20 intercrop showed the highest crude protein yield and N uptake. The land equivalent ratio (LER), relative crowding coefficient (K), actual yield loss (AYL), and system productivity index (SPI) values were greater for the pea-triticale mixtures and the pea-wheat and pea-rye mixtures (80:20), indicating an advantage of intercropping. In most intercrops, the values of partial K, AYL, aggressivity, and competitive ratio (CR) indicated that the cereal was more competitive than pea. The highest values of monetary advantage index (MAI) and intercropping advantage (IA) were recorded for the pea-triticale and the pea-wheat mixtures (80:20). Overall, pea-triticale and pea-wheat mixtures (80:20) were more productive and produced better forage quality than the other mixtures and thus could be adopted by the farmers as alternative options for forage production.
  • Authors:
    • Leap, J.
    • Klonsky, K. M.
    • Shennan, C.
    • Smith, R. F.
    • Muramoto, J.
    • Ruiz, M. S.
    • Gliessman, S. R.
  • Source: HortScience
  • Volume: 46
  • Issue: 8
  • Year: 2011
  • Summary: Legume/cereal mixed winter cover crops are commonly used by organic growers on the central coast of California, but they are unable to provide sufficient nitrogen (N) for a high N-demanding vegetable crop such as broccoli and supplemental fertilizer application may be necessary. The goals of this project were to evaluate the contribution of N from a mixed legume/cereal cover crop (CC) and feather meal and blood meal as organic fertilizers (OF) to an organic broccoli crop and to evaluate economic benefits of CC and OF to the subsequent organic broccoli crop. Trials were conducted at two sites (A and B) with different management histories. Cover crops were grown over the winter and incorporated into the soil in the spring and subsequently broccoli [ Brassica oleracea L. (Italica group)] was grown in 2006 at both sites and in 2007 at B only. Cover crop and no CC treatments were grown with supplemental organic fertilizers at four fertility levels (0, 84, 168, and 252 kg N/ha of OF) with four replicates. Generally broccoli head yields at A (14.9 to 26.3 Mg.ha -1) were higher than at B (0.7 to 17.4 Mg.ha -1 in 2006 and 5.5 to 17.9 Mg.ha -1 in 2007). Yield and aboveground biomass N were significantly increased by OF at rates up to 168 kg N/ha at A and to 252 kg N/ha at B and by CC in 2006 at both sites but not in 2007 at B. Although N content of the CC was similarly low at A (2006) and at B (2007), immobilization of soil mineral N occurred only at B. This suggests that the addition of a low N content CC was offset by high N mineralization from the soil at A with a long organic management history (greater than 33 years). Supplemental fertilizer applications may be necessary to achieve optimal yields, but the amount needed can be reduced by cover cropping in fields with a long history of cover crop-based organic management (A) or when cover crop N content is sufficiently high to prevent immobilization (B, 2006). Soil NO 3-N patterns suggest a pre-side dress nitrate test may also be useful for N management in organic broccoli. Use of cover crops increased net return above harvest and fertility costs when the yield reduction by N immobilization did not take place. However, the net return increase by the use of cover crops tended to diminish as the rate of OF application increased.