111. Botanic and structural composition and nutritional value on intercropped ryegrass pastures.; Composicao botanica e estrutural e valor nutricional de pastagens de azevem consorciadas.

• 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.

112. Study on the soil temperature characteristics in early spring under apricot-wheat system in the south of Xinjiang.

• Authors:
  • Fu, L.
  • Jia, Q.
  • Yang, L.
  • Fan, D.
  • Zhang, P.
  • Lu, C.
  • Wang, F,
• Source: Xinjiang Agricultural Sciences
• Volume: 48
• Issue: 8
• Year: 2011
• Summary: Objective: According to the measured data of soil temperature and air temperature in early spring in Kashgar area of Xinjiang, the temperature change characteristic about apricot wheat interplanting and the only wheat monoculture during the 24 h was analyzed. Method: The paper took Saimaiti apricot of 8 years old and Xindong-20 as investigative objects, and carried out a study of phenophase, horizontal distance, soil depth and air temperatures at different levels under the intercrop and monoculture model by ZDR-41. Result: The results showed that: (1) the total changes of soil temperature present the onefold type of "S"; (2) there were differences in the sustained time of temperature extremum under the 20 cm soil layer of different modes. The topmost and lowermost of air temperature did not have sustained time, but it had sustained time of the topmost and lowermost under the different horizontal distance in the intercrop model; (3) in the stages in germination, temperature under monoculture model was higher than intercrop model at the same soil depth. The average temperature of the stages in apricot germination was monoculture > the distance of 2 m to stem of apricot > the distance of 1 m to stem of apricot > air temperature. Conclusion: In the stages in germination of early spring, apricot orchard inter-crop wheat have definite effect to reduce soil temperature. The time change and the soil temperature were gradually ascended. In the period of apricot bloom, the horizontal distance at different levels did not have obvious effect on soil temperature.

113. Spatial distribution and morphological variations of the fine roots in walnut-wheat intercropping agroforestry ecosystem.

• Authors:
  • Zhang, S.
  • Jiang, Z.
  • Cai, J.
  • Zhong, C.
  • Wang, L.
• Source: Journal of Northwest A & F University
• Volume: 39
• Issue: 7
• Year: 2011
• Summary: Objective: This paper studied the distribution patterns and morphological variations of fine roots in walnut ( Juglans regia)-wheat ( Triticum aestivum) agroforestry system to provide theoretical basis for the interspecific relationship research and management of agroforestry ecosystem. Method: With walnut, wheat monocropping ecosystem as control, samples were collected by soil coring method. WinRHIZO root analysis system was conducted to measure root morphology parameters. Moreover, differences of the fine roots spatial distribution and morphological variations between the agroforestry ecosystem and monocropping ecosystem were analyzed. Result: (1) The vertical gravity center of walnut fine root length in agroforestry ecosystem is 35.49 cm, compared with that in walnut monocropping ecosystem, which is 29.97 cm, moving down 5.52 cm. The distance between the radial gravity centers of walnut fine root length and the tree in agroforestry ecosystem is 0.91 m, which is 0.08 m closer to the tree than that (0.99 m) of walnut in monocropping ecosystem. The vertical gravity center of wheat root length in agroforestry ecosystem is 18.46 cm, compared with that in wheat monocropping ecosystem, which is 26.04 cm, moving up 7.58 cm. (2) The total mean root length density of walnuts in agroforestry ecosystem is 83.6 cm/dm 3, which is 135.6 cm/dm 3 in walnut monocropping ecosystem. The former decreases 38% than the latter. The total mean root length density of wheat in agroforestry ecosystem is 1.74 cm/cm 3, which is 1.22 cm/cm 3 in wheat monocropping ecosystem. The former increases 42% than the latter. (3) In 0-30 cm soil depth, the specific root length of walnut is 5 149.34 cm/g in agroforestry ecosystem, which is greater than 3 624.68 cm/g in walnut monocropping ecosystem. But in 30-100 cm soil depth, the specific root length of walnut is 2 626.59 cm/g in agroforestry ecosystem, which is smaller than the 3 906.9 cm/g in walnut monocropping ecosystem; In 0-50 cm soil depth, the specific root length of wheat is 10 019.5 cm/g in agroforestry ecosystem, smaller than the 11 811. 7 cm/g in wheat monocropping ecosystem. In 50-100 cm soil depth, the specific root length of wheat is 14 328.9 cm/g in agroforestry ecosystem, greater than the 13 389.6 cm/g in wheat monocropping ecosystem. Conclusion: In agroforestry ecosystem, most of the root competitions appear in 0-30 cm soil depth and radial 1.5-2.0 m to the tree. As responses to adapt to the competition and maximize access to resources in soils in agroforestry systems, the spatial distribution and morphology in fine roots might have a high plasticity during the growth of walnut and wheat.

114. Economic analysis of soil fertility restoration options in potato - bean of gardening intercropping in south - rift, Kenya.

• Authors:
  • Kipsat, M.
  • Chepngeno, W.
  • Rop, W.
  • Langat, B.
  • Vincent, N.
• Source: Journal of Development and Agricultural Economics
• Volume: 3
• Issue: 10
• Year: 2011
• Summary: Soil fertility management options to restore soil fertility depletion have been developed and these consist of inorganic and organic fertilizer applications. However, the adoption rates by smallholder farmers for these soil fertility management options are negligible. The overall aim of this study was to evaluate side-by-side economic aspects of different soil fertility improvement options, which have been tested in the region. Field experiments were carried out to evaluate soil fertility management options on potato-bean production in five districts in south-rift, Kenya (Narok, Bomet, Bureti, Kericho and Konoin). It appeared that application of organic residues is a more feasible and sustainable alternative to the recommended fertilizers. However, for long term yield improvement, fertilization with these recommended fertilizers would only be profitable if applied seasonally.

115. Analysis of the nitrogen uptake and utilization efficiency and N fertilizer residual effect in the wheat-maize-soybean and wheat-maize-sweet potato relay strip intercropping.

• Authors:
  • Yang, W.
  • Liu, W.
  • Wan, Y.
  • Zhang, J.
  • Xiang, D.
  • Yong, T.
• Source: Acta Prataculturae Sinica
• Volume: 20
• Issue: 6
• Year: 2011
• Summary: The aim of this paper was to study the mechanisms of interspecific nitrogen facilitation and transfer in the relay strip intercropping systems of "wheat/maize/soybean" and "wheat/maize/sweet potato". The methods of root barrier and 15N-isotope dilution were used to investigate the nitrogen transfer, nitrogen uptake and residual effect in the two relay strip intercropping systems. Comparing the no barrier with solid barrier, the results showed that in-season 15N uptake and 15N recovery efficiency of wheat increased remarkably, and 15N% abundance left in soil and total N content reduced obviously. In the "wheat/maize/soybean" system, the in-season 15N uptake and 15N recovery efficiency, 15N% abundance left in soil and total N content of maize with no barrier increased by 25.16%, 25.16%, 13.89% and 10.15%. But in the "wheat/maize/sweet potato" system, the value of above indices reduced by 15.98%, 15.99%, 17.37% and 5.19%. For soybean, the in-season 15N uptake and 15N recovery efficiency, 15N% abundance left in soil reduced, the soil total N content increased by 3.03%. For sweet potato, the in-season 15N uptake and 15N recovery efficiency increased, 15N% abundance left in soil and total N content reduced by 0.91% and 4.95%. In the "wheat/maize/soybean" system, the 15N uptake and 15N recovery efficiency of wheat and maize obtained from previous wheat, maize and soybean were higher than that of the "wheat/maize/sweet potato" system. The 15N uptake and 15N recovery efficiency of soybean obtained from previous wheat or maize were lower than that of sweet potato, but that from previous soybean was higher than that from previous sweet potato. The "wheat/maize/soybean" system was more beneficial to increase annual nitrogen uptake, nitrogen residual effect and maintaining soil fertility.

116. Testing analysis on anti-erosion capability of conservation tillage strip surface in agro-pastoral mixed regions of Yinshan Mountain.

• Authors:
  • Wang, R.
  • CHEN-Zhi
  • Sun, Y.
  • Zhao, Y.
• Source: Journal of Northwest A & F University - Natural Science Edition
• Volume: 39
• Issue: 4
• Year: 2011
• Summary: Objective: The paper uncovered the wheat and potato strip intercropping farmland's resistance effects to wind erosion in the agro-pastoral ectone in order to provide theoretical foundation and techonological direction. Method: Based on agro-pastoral mixed areas of Yinshan Mountain in Inner Mongolia, soil-erosion testing experiments were conducted on three stubble coverage farmland (wheat stubble coverage, coverage 65% and 76%, stubble height 20 cm and 30 cm; naked oats stubble coverage, coverage 90%, stubble height 30 cm) under 5 scheduled velocities (6, 9, 12, 15 and 18 m/s) by means of the movable wind tunnel and its suited velocity and sand sampling equipments. The author analyzed the change disciplinarian of the surfaces' aerodynamic roughness and wind erosion amount with the increasing distance of tested points (3, 3.75, 4.5, 5.25 and 6 m) from wind tunnel experiment section entrance (Simulating conservation tillage farmland's stubble widths). Result: The roughness of three kinds of surface showed early increasing and subsequent decreasing trend with the increasing distance of tested points from wind tunnel experiment section entrance under different velocities and the majority reached the max when the distance was 5.25 m; The wind erosion amount revealed rapid decreasing trend with the increasing distance of tested points from wind tunnel experiment section entrance under different velocities, the decreasing trend of wind erosion amount was gentle when the distance reached 5.25 m. Conclusion: Conservation tillage farmland's stubble height and vegetation coverage increase anti-wind erosion significantly. Anti-wind erosion effect of conservation tillage farmland tends to be more steady and significant when conservation tillage farmland effective width reaches 5.25 m.

117. Stability analysis of farmer participatory trials for conservation agriculture using mixed models.

• Authors:
  • Raman, A.
  • Ladha, J. K.
  • Kumar, V.
  • Sharma, S.
  • Piepho, H. P.
• Source: Field Crops Research
• Volume: 121
• Issue: 3
• Year: 2011
• Summary: Normally, the data generated from farmer participatory trials (FPT) are highly unbalanced due to variation in the number of replicates of different treatments, the use of different varieties, farmers’ management of the trials, and their preferences for testing different treatments. The incomplete nature of the data makes mixed models the preferred class of models for the analysis. When assessing the relative performances of technologies, stability over a range of environments is an important attribute to consider. Most of the common models for stability may be fitted in a mixed-model framework where environments are a random factor and treatments are fixed. Data from on-farm trials conducted in the Indo-Gangetic Plain (IGP) of South Asia under the umbrella of Rice–Wheat Consortium (RWC) were analyzed for grain yield stability using different stability models. The objective was to compare improved resource management technologies with farmers’ practice. The variance components of an appropriate mixed model serve as measures of stability. Stability models were compared allowing for (i) heterogeneity of error variances and (ii) heterogeneity of variances between environments for farmers-within-environment effects. Mean comparisons of the treatments were made on the basis of the best fitting stability model. Reduced-till (non-puddled) transplanted rice (RT-TPR) and reduced-till drill-seeded wheat using a power tiller – operated seeder with integrated crop and resource management RTDSW(PTOS)ICRM ranked first in terms of both adjusted mean yield and stability.

118. Evaluation of some soil quality indices under two soil tillage systems in a tropical region of south east Mexico.

• Authors:
  • Campos-Magana, S. G.
  • Cadena-Zapata, M.
• Source: Campos-Magana, SG
• Volume: 42
• Issue: 4
• Year: 2011
• Summary: A five year field experiment was conducted to assess the interaction between soil tillage levels, maize-sorghum-legume rotation and two levels of chemical fertilization at the rain feed tropical region of southeast Mexico. The purpose of this research work was to asses this interaction over the variation of some soil quality indices and the effect on the productivity of the soil-grain yield. The treatments for soil tillage were zero till and the intensive traditional soil tillage of the region. Crop rotations employed were five years maize (mmmmm), five years sorghum (sssss), two rotations; (smsms) and (msmsm) and two intercropping of legumes (f)-cereals, (fsfsf) and (fmsmf). Ninety two and 136 units of nitrogen were the two levels of fertilization and were applied only to the cereals. The evaluated soil index in the first and fifth year were organic matter (mo), water infiltration rate (ir), aggregate stability (as), ph, biomass microbiana (mb), nitrogen soluble nitrogen, soil density (sd), soil depth (sd), electrical conductivity (ec) and availability of nutrients. In general terms, the best grain yield for both sorghum and maize were obtained with the no till treatment although no big differences were observed between them. The five year sorghum mean yield under no till with fertilization levels 1 and 2 were 3.6 and 4.5 Mg/ha, whereas, with conventional tillage these were just 3.1 and 4.1 Mg/ha, respectively. The grain yield of maize with level 2 of nitrogen, with zero and traditional till were 5.1 and 4.6 Mg/ha; however, with nitrogen level 1 there were no apparent advantages of the first treatment (3.8 Mg/ha in both cases). The type of crop rotation and soil tillage level mainly affected the chemical soil index at 0 to 5 cm depth. However, no effect occurred with the way of handling crop residues and with the levels of chemical fertilization. The main values of electrical conductivity were attributed to an increase in the solubility of some elements. It was also observed that, under no till, there was an increase of the levels of soluble carbon.

119. Soil emissions of NO, N2O and CO2 from croplands in the savanna region of central Brazil.

• Authors:
  • Bustamante, M. M. da C.
  • Cruvinel, E. B. F.
  • Kozovits, A. R.
  • Zepp, R. G.
• Source: Agriculture, Ecosystems & Environment
• Volume: 144
• Issue: 1
• Year: 2011
• Summary: In the last 40 years, a large area of savanna vegetation in Central Brazil (Cerrado) has been converted to agriculture, with intensive use of fertilizers, irrigation and management practices. Currently, the Cerrado is the main region for beef and grain production in Brazil. However, the consequences of these agricultural practices on NO, N 2O and CO 2 emissions from soil to atmosphere are still poorly investigated. The objectives of this study were to quantify soil emissions of NO-N, N 2O-N and CO 2-C in different no-till cultivation systems in comparison with native savanna vegetation. The agricultural areas included: (a) the maize and Brachiaria ruzizienses intercropping system followed by irrigated bean in rotation; (b) soybean followed by natural fallow; and (c) cotton planting over B. ruzizienses straw. The study was performed from August 2003 to October 2005 and fluxes were measured before and after planting, after fertilizations, during the growing season, before and after harvesting. NO-N fluxes in the soybean field were similar to those measured in the native vegetation. In the cornfield, higher NO-N fluxes were measured before planting than after planting and pulses were observed after broadcast fertilizations. During Brachiaria cultivation NO-N fluxes were lower than in native vegetation. In the irrigated area (bean cultivation), NO-N fluxes were also significantly higher after broadcast fertilizations. Most of the soil N 2O-N fluxes measured under cultivated and native vegetation were very low (<0.6 ng N 2O-N cm -2 h -1) except during bean cultivation when N 2O-N fluxes increased after the first and second broadcast fertilization with irrigation and during nodule senescence in the soybean field. Soil respiration values from the soybean field were similar to those in native vegetation. The CO 2-C fluxes during cultivation of maize and irrigated bean were twice as high as in the native vegetation. During bean cultivation with irrigation, an increase in CO 2-C fluxes was observed after broadcast fertilization followed by a decrease after the harvest. Significantly lower soil C stocks (0-30 cm depth) were determined under no-tillage agricultural systems in comparison with the stocks under savanna vegetation. Fertilizer-induced emission factors of N oxides calculated from the data were lower than those indicated by the IPCC as default.

120. Forages, cover crops and related shoot and root additions in no-till rotations to C sequestration in a subtropical Ferralsol

• Authors:
  • dos Santos, N. Z.
  • Dieckow, J.
  • Bayer, C.
  • Molin, R.
  • Favaretto, N.
  • Pauletti, V.
  • Piva, J. T.
• Source: Soil & Tillage Research
• Volume: 111
• Issue: 2
• Year: 2011
• Summary: To improve C sequestration in no-till soils requires further development of crop rotations with high phytomass-C additions. The objectives of this study were (i) to assess long-term (17 years) contributions of cover crop- or forage-based no-till rotations and their related shoot and root additions to the accumulation of C in bulk and in physical fractions of a subtropical Ferralsol (20-cm depth); and (ii) infer if these rotations promote C sequestration and reach an eventual C saturation level in the soil. A wheat (Triticum aestivum L., winter crop)-soybean (Glycine max (L.) Merr, summer crop) succession was the baseline system. The soil under alfalfa (Medicago sativa L, hay forage) intercropped every three years with maize (Zea mays L., summer crop) had the highest C accumulation (0.44 Mg C ha(-1) year(-1)). The bi-annual rotation of ryegrass (Lolium multiflorum Lam., hay winter forage)-maize-ryegrass-soybean had a soil C sequestration of 0.32 Mg C ha(-1) year(-1). Among the two bi-annual cover crop-based rotations, the vetch (Vicia villosa Roth, winter cover crop)-maize-wheat-soybean rotation added 7.58 Mg C ha(-1) year(-1) as shoot plus root and sequestered 0.28 Mg C ha(-1) year(-1). The counterpart grass-based rotation of oat (Avena strigosa Schreb., winter cover crop)-maize-wheat-soybean sequestered only 0.16 Mg C ha(-1) year(-1), although adding 13% more C (8.56 Mg ha(-1) year(-1)). The vetch legume-based rotation, with a relative conversion factor (RCF) of 0.147, was more efficient in converting biomass C into sequestered soil C than oat grass-based rotation (RCF = 0.057). Soil C stocks showed a close relationship (R(2) = 0.72-0.98, P < 0.10) with root C addition, a poor relationship with total C addition and no relationship with shoot C addition. This suggests a more effective role of root than shoot additions in C accumulation in this no-till soil. Most of the C accumulation took place in the mineral-associated organic matter (71-95%, in the 0-5 cm layer) compared to the particulate organic matter. The asymptotic relationship between root C addition and C stocks in bulk soil and in mineral-associated fraction supports the idea of C saturation. In conclusion, forages or legume cover crops contribute to C sequestration in no-till tropical Ferrasols, and most of this contribution is from roots and stored in the mineral-associated fraction. This combination of soil and rotations can reach an eventual soil C saturation.