• Authors:
    • Goncalves, M.
    • Vitorino, A.
    • Souza, L.
    • Silva, D.
  • Source: Bragantia
  • Volume: 70
  • Issue: 1
  • Year: 2011
  • Summary: Soil physical degradation, like compaction, reduces water movement and root development. Soil structure is considered one of most importance to agriculture and closely related to it are other fundamental properties in soil-plant relationship. The objective of this study was to evaluate the effect of crop sequences on physical attributes. The research was realized in 2004/05 and 2005/06 growing seasons, in a Typic Clayey Rhodic Hopludox, under eight years of no-tillage system, at Dourados (MS). The experiment was a randomized complete block design, with three replications. Treatments were constituted by cover crops: sunflower ( Helianthus annuus L.), sunnhemp ( Crotalaria juncea L.), hairy vetch ( Vicia villosa Roth), mixture of sunnhemp+black oat ( Avena strigosa Schreb), and mixture of black oat+hairy vetch+oilseed radish ( Raphanus sativus L. Var. oliferus Metzg). Differences were not observed in soil density, porosity and aggregation rate when it was cultivated with sunflower, hairy vetch, sunnhemp, or the mixtures. Differences were observed in soil physical properties between 0-5 cm layer and 5-10 cm-10-20 cm layers, but no differences between 5-10 cm and 10-20 cm layers. Soil carbon trend to higher contents in crops with high production of surface residues, although differences in carbon contents were insufficient to modify aggregation.
  • Authors:
    • Garcez, F.
    • Bacchi, L.
    • Gavassoni, W.
    • Silva, F.
  • Source: Summa Phytopathologica
  • Volume: 37
  • Issue: 3
  • Year: 2011
  • Summary: The effects of crop residues and their extracts on Sclerotinia sclerotiorum are not well documented. Three experiments were conducted with crop residues and their ethanol and partition extracts. Oat, vetch, bean, pearl millet, corn and wheat were assessed under controlled conditions. Sclerotia covered with oat, vetch, bean and pearl millet residues did not germinate carpogenically. Ethanol extracts of oat and vetch residues were efficient in inhibiting carpogenic germination whereas pearl millet and wheat did not differ from control. All partitioned ethanol extracts inhibited germination. Crop residues negatively affected the number of apothecia per sclerotium.
  • Authors:
    • Alok, T.
    • Sarawgi, S.
    • Shrikant, C.
    • Singh, M.
    • Vijendra, J.
  • Source: Journal of Soils and Crops
  • Volume: 21
  • Issue: 2
  • Year: 2011
  • Summary: Field experiment was conducted on different intercropping under irrigated condition during rabi season of 2009-10 at Indira Gandhi Krishi Vishwavidyalaya, Raipur to evaluate the yield, economics and to undertake weed studies of intercropping in rabi cereal, legume, oilseeds and spices in rice based cropping system in inceptisols. Maximum wheat equivalent yield, (65.55 q ha -1) of rabi crops was recorded in onion+coriander system over all the other intercropping treatment. Wheat+fenugreek intercropping was next in order which has also recorded significantly higher WEY (36.58 q ha -1) overwheat followed by rice, the existing cropping system (30.61 q ha -1), castor+lentil (32.78 q ha -1) and wheat+lentil (28.18 q ha -1). The highest net returns (Rs.65,292 ha -1) from rabi crops were recorded with onion+coriander because of higher value of the produce. The highest B:C ratio of rabi intercrops was recorded in onion+coriander (1.98) followed by mustard+lentil (1.90) and wheat (1.89). On the other hand, the highest weed population (172.33 and 147.00 m -2) and dry matter production (7.8 and 194 g m -2) was observed in mustard+lentil at 30 and 60 DAS. The lowest weed dry production was found in onion+coriander (1.8 g m -2) at 30 DAS, and under wheat+fenugreek (82.07 g m -2) at 60 DAS. On an average, the available N, P, K and organic carbon content were increased by 6.1, 3.6, 11.8, and 4.2%, respectively over initial values in soil after the harvest of the rabi crop.
  • Authors:
    • Costa, O.
    • Ziech, M.
    • Nornberg, J.
    • Bermudes, R.
    • Viegas, J.
    • Skonieski, F.
    • Meinerz, G.
  • Source: REVISTA BRASILEIRA DE ZOOTECNIA-BRAZILIAN JOURNAL OF ANIMAL SCIENCE
  • Volume: 40
  • Issue: 3
  • Year: 2011
  • Summary: The objective of this work was to evaluate the influence of species intercropped with ryegrass on the botanical and structural composition and the nutritional values of pastures in an agroecological transition system. It was evaluated ryegrass ( Lolium multiflorum Lam.) intercropped with black oats ( Avena strigosa Schreb.), white clover ( Trifolium repens L.) and forage peanut ( Arachis pintoi Krapov. & Gregory). It was used a complete random design with three treatments and three repetitions. The first grazing was done 21 days after emergence of the plants on the pastures with ryegrass and black oats and ryegrass and forage peanuts and 28 days after emergence on the pasture of ryegrass+white clover. The second grazing, on the pasture with ryegras+black oats, occurred 30 days after the first one, whereas on the other pastures, grazing occurred 37 days later. The rates of dry matter (DM) accumulation, from the beginning of period of exclusion until maximal production of dry matter were: 77.7; 75.0 and 71.3 kg/ha/day of DM for the pastures intercropped with white clover, forage peanut and black cover, respectively. Leaf/culm ratio until second grazing, was high on all pastures. Reduction on contents of crude protein according to exclusion days on ryegrass+black oat pasture is lower than on pastures of ryegrass intercropped with white clover or forage peanut.
  • Authors:
    • Urashima, A.
    • Silva, C.
  • Source: Journal of Phytopathology
  • Volume: 159
  • Issue: 11/12
  • Year: 2011
  • Summary: Blast caused by Magnaporthe grisea ( Pyricularia grisea) is a disease that occurs in many important gramineous plants in Brazil such as rice, wheat, triticale and barley. In 2005, the presence of this disease was reported on black oat ( Avena strigosa) at different locations of Parana state. Due to little information of M. grisea that is infecting this host, this work aimed to characterize it at molecular, sexual and pathogenic level. DNA analysis showed that M. grisea from black oat formed a homogenous and genetic distinct group of its own, different from other hosts, including rice, wheat, triticale and barley. Isolate 15720 was an exception, because it was similar to wheat isolate. There was no sexual compatibility between M. grisea from oat and other tested hosts. In pathogenic terms, isolates of M. grisea from oat infected triticale, wheat, rye, millet, barley, sorghum and rice; cross-inoculation was positive with wheat, triticale, rice and barley.
  • Authors:
    • Norris, B.
    • Harkins, H.
    • Burmester, C.
    • Santen, E.
    • Curtis, L.
    • Dougherty, M.
    • Fulton, J.
    • AbdelGadir, A.
  • Source: Crop Management
  • Issue: August
  • Year: 2011
  • Summary: Fluctuations in dryland cotton yield in the Tennessee Valley region of northern Alabama are common and are usually related to irregular drought periods during the growing season. Subsurface drip irrigation (SDI) has gained popularity as a water delivery system for small, irregular-shaped cotton fields. A seven-year study was conducted with the objective to determine the response of seed cotton yield to SDI tape orientation relative to crop row direction and different irrigation rates under dryland conditions of the Tennessee Valley. Seven treatments were tested in a randomized incomplete block design which consisted of three irrigation treatments (33%, 66%, and 99% pan evaporation), two SDI tape orientations (parallel and perpendicular), and a dryland control. All SDI treatments produced yields significantly higher than non-irrigated, dryland cotton in four out of seven years. Maximum yield was obtained at a median pan evaporation water replacement value of 74%. No statistical differences were observed between SDI tape orientations on seed cotton yield in all years except in 1999 when parallel out yielded perpendicular at lower irrigation rates. Results confirm the long-term efficacy of supplemental irrigation to increase seed cotton yield irrespective of SDI tape placement during sporadic periods of drought. These results are applicable only for fields with the same soil type or with similar water movement characteristics.
  • Authors:
    • Munindra, B.
    • Ajanta, N.
  • Source: Journal of the Indian Society of Agricultural Statistics
  • Volume: 65
  • Issue: 3
  • Year: 2011
  • Summary: It is an attempt to draw a clear picture of development disparities among the districts of Assam in agriculture with the help of composite index. Eighty-three indicators are considered here which are directly related to the agriculture. On the basis of these indicators Nagaon, Borpeta, Dhubri and Kamrup are developed districts but Karbi Anglong, Hailakandi, Dhemaji and N.C. Hills are low developed districts. The developed districts cover 18.31 percent areas and 30.47 percent population of the state whereas low developed area covers 25.35 percent areas and 7.94 percent population of the state. The entire agriculture sector is divided into seven sub sectors namely Production of miscellaneous crops, Production of pulse, cereals and oil seeds, Fertilizer used, and Percentage of livestock population, Rice production, Fish production and Infrastructure facilities. In each sector developed and low developed districts have been identified. In crop production Kokrajar, Dhubri and Sonitpur are high-developed, Jorhat, N.C. Hills and Nagaon are low developed. In production of pulse, cereal and oilseeds Goalpara, Sonitpur, Bongaigaon and Karbi Anglong are developed districts and Nagaon, Tinsukia, Karimganj, Jorhat and Morigaon are low developed districts. In case of livestock population Jorhat is the developed district and Dhemaji, Hailakandi and N.C. Hills are low developed district. In fish production Nagaon, Borpeta, Cachar and Karimganj are developed districts and Karbi Anglong and N.C. Hills are low developed districts. In case of rice production Golaghat, Karimganj, Hailakandi, Sibsagar, Dibrugarh and Cachar are high developed and Bongaigaon, Borpeta, Nalbari, Dhemaji and Lakhimpur are low developed. In case of infrastructure facilities e.g. irrigation, use of electricity in agriculture etc. are availed by the districts Nagaon, Nalbari, Borpeta and Kamrup are high developed and Hailakandi, Dhemaji, N.C. Hills are low developed. From the study it also reveals that the districts, which are low developed in overall agriculture sector they are also low developed in using infrastructure facilities essential for agriculture except Karbi Anglong. For bringing the uniform development in the state, model districts and potential target for low developed districts have been identified.
  • Authors:
    • Evangelista, A.
    • Silva, T.
    • Silva, C.
    • Folegatti, M.
    • Alves Junior, J.
  • Source: Engenharia Agricola
  • Volume: 31
  • Issue: 2
  • Year: 2011
  • Summary: The aim of this study was to evaluate the effect of different irrigation levels on canopy and root growth, productivity, and fruit quality of young Tahiti acid lime trees. The experiment was installed in Piracicaba, Brazil in a 1.0-ha orchard plot with 'Tahiti' acid lime trees, grafted on Swingle citrumelo rootstock and carried out from August of 2002 to May 2005. Each treatment was assigned to a drip irrigation level, based on ETc as follows: (T1) non-irrigated, (T2) 25%, (T3) 50%, (T4) 75% and (T5) 100% of ETc determined by weighing lysimeter presented in the orchard plot. Trunk diameter and tree height were evaluated monthly. The roots were evaluated when the trees were 30 and 48 months old. The yield and fruit quality was evaluated in 2004 and 2005. The results showed that irrigation did not influence root distribution in depth, and trees irrigated with 75% and 100% ETc showed horizontal root distribution concentrated until 0.6 m from the trunk. Irrigation did not improve the quality of fruit. Yield increased in all irrigated treatment, but the most efficient yield mean per unit of water applied was the 25% ETc treatment.
  • Authors:
    • Casanova,S.
    • Garcia,C.
    • Vilaro,F.
    • Carlesso,R.
  • Source: Acta Horticulturae
  • Issue: 889
  • Year: 2011
  • Summary: The potato crop ( Solanum tuberosum L.) is of great importance in the Uruguay economy, being the major vegetable in volume of trade. Uruguay imports some amount of potato seed annually. The National Institute of Agricultural Research (INIA) has been engaged for the last decades to obtain cultivars more adapted to country agroecological conditions, easier to multiply locally for replacing imported seed cultivars such as 'Chieftain'. In this sense, promising cultivars including 'INIA-Ipora' were developed. The objective of this work was to study the morpho-physiological and yield modifications of two potato cultivars ('Chieftain' and 'INIA-Ipora') under different irrigation managements. The experiment was carried out during 2006 and 2007 growing seasons under a rainout shelter, at the Experimental Station INIA Las Brujas, in Uruguay. These two varieties were studied under two irrigation managements: (i) irrigated treatment (2003/04 rainfall+irrigation according to daily crop ETc) and; (ii) deficit irrigated treatment (2003/04 rainfall+one irrigation of 25 mm when the accumulated maximum daily crop evapotranspiration reached 90 mm). The maximum daily crop evapotranspiration was estimated using the FAO Penman-Monteith equation. The experimental design was a completely randomized split plot. The leaf area index, the total plant photosynthesis and the crop yield better responded to the irrigation regime. The two potato cultivars showed differences in length of growing season, leaf area, number of mainstems, plant height and plant transpiration rates. The yield components were modified by the irrigation managements, and differences in commercial yield and total number of plant tubers were observed between the 'Chieftain' and 'INIA-Ipora' cultivars.
  • Authors:
    • Otero, A.
    • Goni, C.
  • Source: ISHS Acta Horticulturae
  • Issue: 889
  • Year: 2011
  • Summary: Supplementary irrigation in Citrus sinensis (L.) Osbeck 'Spring' navel and Citrus unshiu Marcow trees were studied according to fruit development stages on the northwestern region of Uruguay (32S, 58W) from 2000 to 2009. The effective rainfall (Pe) variability between consecutive years is bigger than the reference evapotranspiration (ETo) variability; despite the annual water balance seems to be adequate for excellent yields. Water deficit occurs at different intensities during fruit growth stages I, II and III. Supplementary irrigation was necessary in 'Spring' navel and satsuma 'Owari' during stage I and II, although 'Spring' navel requires occasionally irrigation during stage III. The major irrigation impact was to increase the fruit weight but not the number of fruits. The increment in the marketable fruit was related to the best size distribution of the fruits, also it was verified an attenuation on the alternate bearing. An inverse and significant relationship was found between the ETo/Pe ratio and the relative yield reduction in the stage I (R 2=0.73) and in stage II (R 2=0.91); and between the ETo/Pe and the fruit weight in satsuma 'Owari', (R 2=0.56) (R 2=0.85) respectively. The yield reduction between trees without irrigation and all year irrigated represents 20% in 'Spring' navel and 40% in satsuma 'Owari'. Maximum water application of 1000-1200 m 3 ha -1 was required for irrigated trees on stage I and between 1800-2000 m 3 ha -1 for the stages I+II. In a close up view, supplementary water is required to reach maximum marketable yield and alternate bearing reduction in citrus production in temperate conditions.