• Authors:
    • Jandrey, D.
    • Strieder, M.
    • Minetto, T.
    • Silva, P.
    • Silva, A.
    • Endrigo, P.
  • Source: Ciencia Rural
  • Volume: 38
  • Issue: 3
  • Year: 2008
  • Summary: The growing of winter crop species results in benefits on soil characteristics, and can present economic advantages. Thus, it is important to introduce winter species that, besides straw, produce grains to increase the performance and the sustainability of agricultural activity. The objective of this research was to evaluate, in three growing seasons, the agronomic and economic performance of maize crop grown in succession to five winter cover crops and/or for grain production, cultivated under two rates of side dressing N fertilization. The experiment was carried out in the growing seasons of 2003/04, 2004/05 and 2005/06, in the state of Rio Grande do Sul, Brazil. In the three years, the treatments consisted of irrigated maize crop grown in succession to five winter cover crops species and to a control without cover crop. The maize cost production in succession to common vetch is lower than in succession to black oat and to wild radish. Comparing the winter cover crops for grain production, the gross income was higher when wheat was grown in relation to oat. The economic advantages of the use of wild radish and common vetch as previous crops to irrigated maize in relation to the poaceae species are only evident under conditions of low N availability in the soil.
  • Authors:
    • Jandrey, D.
    • Strieder, M.
    • Piana, A.
    • Sangoi, L.
    • Silva, P.
    • Silva, A.
    • Endrigo, P.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 43
  • Issue: 8
  • Year: 2008
  • Summary: The objective of this work was to evaluate the productivity of irrigated maize, grown using several rates of nitrogen sidedress, in succession to different winter crops. The experiment was carried out in Eldorado do Sul, RS, Southern Brazil, during the 2003/2004, 2004/2005 and 2005/2006 growing seasons. Maize was sown in succession to five winter crops: black oat, common vetch, wild radish (straw production), white oat and wheat (grain and straw production), and to a control treatment, where the spontaneous vegetation was controlled by successive desiccant application. Maize grain yield was higher than 8 Mg ha -1 and was not affected by the specie of preceding winter crop, when nitrogen sidedress was applied. Maize grain yield was higher, when it succeeded wild radish and in the treatment without N in side-dressing. White oat and wheat added more than 3 Mg ha -1 of straw and produced more than 1.5 Mg ha -1 of grain. With supplementary irrigation and side-dress nitrogen application, it is possible to obtain high grain yield, when corn is cultivated as a sequential crop, independently of winter cover species.
  • Authors:
    • Singer, J.
  • Source: Agronomy Journal
  • Volume: 100
  • Issue: 6
  • Year: 2008
  • Summary: Surveying end-users about their use of technologies and preferences provides information for researchers and educators to develop relevant research and educational programs. A mail survey was sent to Corn Belt farmers during 2006 to quantify cover crop management and preferences. Results indicated that the dominant cereal cover crops in Indiana and Illinois are winter wheat ( Triticum aestivum L.) and cereal rye ( Secale cereale L.), cereal rye and oat ( Avena sativa L.) in Iowa, and oat in Minnesota. Legumes were used more frequently in Indiana and Illinois, and red clover ( Trifolium pratense L.) was the dominant choice across the region. Farmers relied solely on herbicides 54% of the time to kill cover crops. Ninety-three percent of respondents indicated that they received no cost sharing for using cover crops and 14% indicated that they would plant cover crops on rented land. Corn Belt farmers prefer cover crops that overwinter (68%) and fix N (64%). The information provided in this survey supplements existing knowledge that can be used to develop relevant research and educational programs to address agronomic production systems that include cover crops.
  • Authors:
    • Moorman, T.
    • Cambardella, C.
    • Singer, J.
  • Source: Agronomy Journal
  • Volume: 100
  • Issue: 6
  • Year: 2008
  • Summary: Coupling winter small grain cover crops (CC) with liquid manure injection may increase manure nutrient capture. The objectives of this research were to quantify manure injection effects using target swine ( Sus scrofa) manure N rates of 112, 224, and 336 kg N ha -1 on CC plant density, fall and spring shoot biomass, N, P, and K uptake and subsequent corn ( Zea mays L.) yield. A winter rye ( Secale cereale L.)-oat ( Avena sativa L.) CC was established before fall manure injection. Manure injection lowered mean CC plant density 25% because of CC mortality in the injection zone. Fall CC dry matter (DM) was 26% lower in the manure treatments than the no manure CC control, although no difference was detected for N (9.4 kg ha -1) or P (1.4 kg ha -1) uptake. No difference was detected for spring DM between CC no manure and manure treatments. Shoot DM, N, P, and K uptake increased 29, 41, 31, and 25% from the CC manure 112 to CC manure 224 with no increase above CC manure 224. Cover crop N uptake was higher in CC manure vs. no manure (60.1 vs. 35.6 kg ha -1). Cover crop P and K uptake were also higher in CC manure vs. no manure (9.2 vs. 6.6 kg P ha -1 and 41.3 vs. 30.0 kg K ha -1). Corn grain yield was unaffected by CC and responded positively to manure application (11,022 with manure vs. 9,845 kg ha -1 without manure). Coupling manure injection and cover crops can increase nutrient capture without lowering corn yield.
  • Authors:
    • Pereira, M.
    • Torres, J.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 32
  • Issue: 4
  • Year: 2008
  • Summary: A study with eight cover crops types was developed: pearl millet ( Pennisetum americanum [ Pennisetum glaucum] syn. tiphoydes), brachiaria grass ( Brachiaria brizantha [ Urochloa brizantha]), sorghum ( Sorghum bicolor), pigeonpea ( Cajanus cajan), sunn hemp ( Crotalarea juncea) and black oat ( Avena strigosa [ Avena nuda]), fallow land and conventional culture (control) in the experimental area of CEFET-Uberaba-MG, in a cerrado area to evaluate K accumulation and release. The dry mass production, crop residue decomposition in litter bags and K release were evaluated. A mathematical model was used to describe residue decomposition and K release, which calculates the decomposition constant (k) and half-time life. Pearl millet, sorghum and the sunn hemp were the cover crops that produced most dry matter while K accumulation was highest in the grasses. K release was highest in pearl millet, oats, brachiaria grass and sunn hemp in the first 42 days after handling. Brachiaria grass had the shortest half-time life and the highest K release rate.
  • Authors:
    • Fabian, A.
    • Pereira, M.
    • Torres, J.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 43
  • Issue: 3
  • Year: 2008
  • Summary: This study investigated dry biomass production, decomposition rate and macronutrients release (N, P, Ca, Mg and S) of cover crops cultural residues, in a no-till savanna soil in Minas Gerais, Brazil. The cover crops tested were: pearl millet ( Pennisetum americanum syn. typhoides), brachiaria grass ( Brachiaria brizantha [Urochloa brizantha] cv. Marandu), sorghum ( Sorghum bicolor), pigeon pea ( Cajanus cajan), sunn hemp ( Crotalaria juncea) and black oat ( Avena nuda), compared to a fallow plot (control). The experiment was carried out in an Oxisol, medium texture. A randomized block design, in a split-plot array in time, with four replications, was used. Dry biomass production was evaluated 110 days after sowing. Decomposition rate was evaluated by litter bags containing cultural residues. Millet and sunn hemp were the cover crops (grass and legume) with the highest dry biomass production and N accumulation, in the two evaluation periods. The highest decomposition rate and nutrient release occurred at 42 days after desiccation. The highest values of half life were observed in dry period.
  • Authors:
    • Finger, J.
    • Gobbi, F.
    • Souza, J.
    • Conti, C.
    • Fey, E.
    • Vanin, J.
  • Source: Central theme, technology for all: sharing the knowledge for development. Proceedings of the International Conference of Agricultural Engineering, XXXVII Brazilian Congress of Agricultural Engineering, International Livestock Environment Symposium - ILES V
  • Year: 2008
  • Summary: The soil tillage is one of the most important agricultural operations, when used crops which the root depends system directly from the physical conditions of the soil. Aiming higher soil conservation, the use of plants of covering becomes an alternative to the maintenance of soil moisture and aggregates, improving too, characteristics such as resistance to penetration. The objective of the present work was evaluate properties of the soil and cultivation of cassava on different tillages and plants of covering. The experiment was conducted in the western region of Parana in Latosol red eutrophic. The experimental design was completely randomized in split plot, and 6 main plots of soil management systems: disk plow, chisel plow and offset disk harrow (followed by an offset leveling) in the months of April and August. The sub-plots were formed by plants of covering oat, Forage turnip and Without crop. The tillages with disk plow and chisel plow in August showed greater depth of furrow and seed cuttings of cassavas. Behavior similar happened to the soil moisture of 10 to 20 cm for the disk plow and the chisel plow in August. The tillages did not influence the final population of plants, number of stems per plant and percentage of plants fall. For plants of covering, the oats presented biggest difference in the soil moisture from 0 to 10 cm.
  • Authors:
    • Stoffella, P.
    • Bayer, C.
    • Wilson, P.
    • He, Z.
    • Vieira, F.
    • Baligar, V.
  • Source: Australian Journal of Agricultural Research
  • Volume: 59
  • Issue: 1
  • Year: 2008
  • Summary: This study aimed to: (1) determine the effect of P depletion and presence of Al on root and shoot growth of representative cover crops, and on their nutrient uptake; (2) characterise the composition of root exudation under P and Al stress in nutrient solution; (3) evaluate the ability of aqueous extracts of composts in reducing Al phytotoxicity. Plants of cowpea ( Vigna unguiculata subsp. unguiculata), black oat ( Avena strigosa), and lablab ( Lablab purpureus) were cultivated in different nutrient solution compositions and concentrations for 3 weeks. It was found that Al at concentration of 20 and 200 mol/L increased citrate exudation at least 8 and 24 times, respectively, for cowpea and 18 and 36 times, respectively, for lablab, as compared with the blank. However, no release of organic acids occurred due to P deprivation, suggesting that citrate exudation was a specific response to excess Al. No response in organic acid release was observed for black oat under the stress of P deficiency or Al toxicity. Although the presence of Al in solution did not significantly affect chlorophyll content in leaves, it decreased root and shoot weight, as well as root length, surface area, volume, and number of tips. Organic extracts alleviated aluminum toxicity, improving plant growth and ameliorating plant nutrition status. Yard waste extract was more effective in enhancing plant growth than GreenEdge extract in plants under Al stress.
  • Authors:
    • Endale, D. M.
    • Schomberg, H. H.
    • Fisher, D. S.
    • Jenkins, M. B.
    • Sharpe, R. R.
    • Cabrera, M. L.
  • Source: Agronomy Journal
  • Volume: 100
  • Issue: 5
  • Year: 2008
  • Summary: Corn (Zea mays L.) producers in the southeastern United States must overcome soil and water limitations to take advantage of the expanding corn market. In this 2001 to 2005 study on a Cecil sandy loam (fine, kaolinitic, thermic Typic Kanhapludult) near Watkinsville, GA, we compared dry land corn biomass and yield under conventional tillage (CT) vs. no-tillage (NT) with ammonium nitrate or sulfate (based on availability) as conventional fertilizer (CF) vs. poultry litter (PL). In a randomized complete block split plot design with three replications, main plots were under tillage and subplots under fertilizer treatments. The cover crop was rye (Secale cereale L.). Over 5 yr, NT and PL increased grain yield by 11 and 18%, respectively, compared with CT and CF. Combined, NT and PL increased grain yield by 31% compared with conventionally tilled and fertilized corn. Similarly, soil water was 18% greater in NT than CT in the 0- to 10-cm depth. In 2 yr of measurements, dry matter of stalks and leaves and leaf area index under PL were an average of 39 and 22% greater, respectively, than under CF during reproduction. Values were 21 and 6% greater, respectively, under NT than CT but during tasseling. Analysis of 70 yr of daily rainfall records showed that supplemental irrigation is needed to meet optimal water requirement. Our results indicate that corn growers can use rainfall more efficiently, reduce yield losses to drought, and expect increased corn yields with a combination of no-tillage management and long-term use of poultry litter.
  • Authors:
    • Place, F.
    • Ajayi, O. C.
    • Akinnifesi, F. K.
    • Sileshi, G.
  • Source: Plant and Soil
  • Volume: 307
  • Issue: 1-2
  • Year: 2008
  • Summary: A number of studies have tested the effect of woody and herbaceous legumes on soil fertility and maize yields in sub-Saharan Africa. However, their effects on maize productivity are much debated because results have been variable. A meta-analysis was conducted with the aim of evaluating the evidence in support of yield benefits from woody and herbaceous green manure legumes. A total of 94 peer-reviewed publications from West, East and southern Africa qualified for inclusion in the analysis. Maize yield from herbaceous green manure legumes (54 publications), non-coppicing legumes (48 publications), coppicing woody legumes (10 publications), natural fallows (29 publications), and fully fertilized monoculture maize (52 publications) were compared. Mixed linear modelling using yield differences (D) and response ratios (RR) indicated that the response to legumes is positive. The mean yield increase (D) over unfertilized maize was highest (2.3 t ha-1) and least variable (CV=70%) in fully fertilized maize, while it was lowest (0.3 t ha-1) and most variable (CV=229%) in natural fallows. The increase in yield over unfertilized maize was 1.6 t ha-1 with coppicing woody legumes, 1.3 t ha-1 with non-coppicing woody legumes and 0.8 t ha-1 with herbaceous green manure legumes. Doubling and tripling of yields relative to the control (RR > 2) was recorded in coppicing species (67% of the cases), non-coppicing legumes (45% of the cases), herbaceous green manure legumes (16% of the cases) and natural fallows (19% of the cases). However, doubling or tripling of yields occurred only in low and medium potential sites. Amending post-fallow plots with 50% of the recommended fertilizer dose further increased yields by over 25% indicating that legume rotations may play an important role in reducing fertilizer requirements. Except with the natural fallow, the 95% confidence intervals of D and RR were higher than 1 and 0, respectively indicating significant and positive response to treatments. Therefore, it is concluded that the global maize yield response to legumes is significantly positive and higher than unfertilized maize and natural vegetation fallows.