• Authors:
    • Ossom, E.
  • Source: International Journal of Agriculture and Biology
  • Volume: 12
  • Issue: 4
  • Year: 2010
  • Summary: Sweet potato is a major root storage crop in Swaziland, whereas maize ( Zea mays L.) is the staple food crop in Swaziland. In this experiment, sweet potato cv. Kenya was grown in the field and intercropped with maize cv. SC 603 with the objective of determining the effects of crop association on soil temperature, weed infestation and crop yields. Five plant population treatments (T) were investigated: T 1, Maize alone at 40,000 plants/ha; T 2, sweetpotato alone at 33,333 plants/ha; T 3, maize at 40,000 plants/ha, intercropped with sweetpotato at 33,333 plants/ha; T 4, maize at 40,000 plants/ha, intercropped with sweet potato at 16,666 plants/ha and T 5, sweet potato alone at 16,666 plants/ha. Soil surface temperatures were generally higher than temperatures at 10 cm depth; nonetheless there were no significant differences in soil temperatures among the cropping systems. The three most dominant weed species in all plots were Bidens pilosa L. (37.5-59.3% relative abundance), followed by Cynodon dactylon L. (15.7-43.6%) and Oxalis latifolia (7.1-18.7%). Sida rhombifolia (0-0.4%); Schkuhria pinnata (0-0.4%) and Leucas martinicensis (0-0.4%) were the three least abundant weed species. Land equivalent ratio (LER) values indicated that Sweet potato-maize mixture at the recommended sole sweet potato population (33,333 plants per hectare) was a better cropping system (LER, 0.77) than intercropping at 50% of the recommended Sweet potato (LER, 0.74). Correlation data showed that maize cob yield was not significantly correlated to the 100-grain mass (r=0.508; R 2=0.2581; N, 12); the resultant correlation of determination showed that 25.8% in the variation in cob yield could be ascribed to 100-grain mass. In sweet potato, correlation data showed that the number of tubers per plant was positively correlated to tuber yield ha -1 (r=0.676; R 2=0.4570; N, 16); from the co-efficient of determination, 45.7% of tuber yield could be associated with the number of tubers per plant. In conclusion, sweet potato monocropping was the best system; nonetheless, if it has to be intercropped with maize, there should be 33,333 and 40,000 plants ha -1 of sweet potato and maize, respectively.
  • Authors:
    • Liu, Z.
    • Li, J.
    • Chen, H.
    • Chen, Y.
    • Gao, P.
    • Yang, T.
    • Huete, A.
    • Huang, J.
    • Peng, D.
  • Source: JOURNAL OF ZHEJIANG UNIVERSITY-SCIENCE B
  • Volume: 11
  • Issue: 4
  • Year: 2010
  • Summary: We developed a sophisticated method to depict the spatial and seasonal characterization of net primary productivity (NPP) and climate variables. The role of climate variability in the seasonal variation of NPP exerts delayed and continuous effects. This study expands on this by mapping the seasonal characterization of NPP and climate variables from space using geographic information system (GIS) technology at the pixel level. Our approach was developed in southeastern China using moderate-resolution imaging spectroradiometer (MODIS) data. The results showed that air temperature, precipitation and sunshine percentage contributed significantly to seasonal variation of NPP. In the northern portion of the study area, a significant positive 32-d lagged correlation was observed between seasonal variation of NPP and climate ( P
  • Authors:
    • Rosolem, C.
    • Olibone, A.
    • Olibone, D.
    • Prando, M.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 34
  • Issue: 3
  • Year: 2010
  • Summary: In soils with physical and/or physical hydric restrictions for root growth, it may be a viable strategy to increase crop productivity by increasing water storage potential through improvements in water infiltration. Accordingly, the objective of this study was to determine water infiltration in a Hapludult in three crop rotations under no-tillage, with and without initial chiseling. Crop rotations consisted of: millet/soybean/sorghum/maize/sorghum; millet/soybean/Brachiaria ruziziensis/corn/Brachiaria ruziziensis; and millet/soybean/Brachiaria ruziziensis+castor bean/corn/Brachiaria ruziziensis+castor bean. Water infiltration in soil was evaluated in the field, using concentric discs at the soil surface and at depths of 0.10 and 0.20 m, in 2006 and 2007. After the first year, chiseling led to increased infiltration of water into the soil. Water infiltration was greatest in the crop rotation system with Brachiaria ruziziensis+castor bean. The activity of root systems of crops in the plots without chiseling increased the rate of water infiltration into the soil.
  • Authors:
    • Nandita, G.
    • Pratibha, S.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 137
  • Issue: 3/4
  • Year: 2010
  • Summary: Total biological productivity and soil microbial biomass are important characteristics to describe sustainable agroecosystems. We investigated the impact of herbicide, alone or in combination with soil amendments, on crop and weed productivity and microbial biomass in a rice ( Oryza sativa)-barley ( Hordeum vulgare)-summer fallow rotation in a tropical rainfed agroecosystem. Total net productivity (TNP) of crops was greater with herbicide (Butachlor)+chemical fertilizer (NPK), herbicide+farmyard animal manure, and herbicide+green manure ( Sesbania aculeata) than with herbicide+crop residue ( Triticum aestivum straw), herbicide only, and the control without amendment. Weed TNP was highest in the control, lowest in herbicide only, and intermediate in combined herbicide and amendment treatments except herbicide+crop residue. The sum of crop TNP and weed TNP was highest in herbicide+green manure and lowest in herbicide only. Microbial biomass C and N were greater with herbicide and amendment treatments than with herbicide only. Microbial biomass showed distinct temporal variation. Yearly plant input to soil had strong correlation with microbial biomass in the control and herbicide only treatments. In these agroecosystems, combining organic soil amendments with herbicide application could help sustain soil fertility and maintain higher total biological productivity.
  • Authors:
    • Prakash, H.
    • Dabbas, M.
    • Singh, R.
    • Singh, D.
  • Source: International Journal of Agricultural Sciences
  • Volume: 6
  • Issue: 1
  • Year: 2010
  • Summary: The study was carried out during 1997-98 to 2003-04 under Diversified Agricultural Support Project-a-World Bank Funded Project of Uttar Pradesh. The objective of this study was to increase the income and improve the cash flow system of small-marginal farmers, residing in the vicinity of town and urban. The pilot area was selected at Kaimganj in Farrukhabad district, having sandy loam to loam soils and maximum area cover with plantation crops viz., mango, ber and guava. Five to seven year old mango fields were selected for two tier cropping system. The alleys of mango tree intercropped with important vegetable crops like potato, brinjal, pumpkin, vegetable pea, garlic and onion, because the local market is available for the disposal of these vegetable crops. Generally, farmers planted Dashari mango at the distance of 8*8 m in rows. The associated crop of potato planted at the distance of 50 cm apart on 12 ridges between two rows of mango and adjusted 75% plant stand. Onion planted in 40 rows at 15 cm apart in the interspaces of two rows of mango and 75% plant stand was adjusted. Three rows of pumpkin were planted between two rows of mango at 200*50*75 cm apart and adjusted 75% plant population. Vegetable pea planted in 20 rows at 30 cm apart between two rows of mango and plant stand was adjusted 75%. Brinjal planted at 60 cm apart in 10 rows between two rows of mango and adjusted 72% plant population in interspaces of mango. The 75% plant stand of garlic was adjusted with plantation of 40 rows at 15 cm apart between two rows of mango. Potato, brinjal, green fruits of pumpkin, green pods of vegetable pea, garlic and onion yield 225, 218, 278, 92, 73, and 255 q/ha, respectively. The mango based cropping systems have maintained cash flow system and improved the economic status of farming community. The standards of living of small and marginal farm families scaled up and created eco-friendly environment.
  • Authors:
    • Singh, I.
    • Singh, P.
    • Yadav, D.
    • Yadav, R.
    • Singh, S.
  • Source: Experimental Agriculture
  • Volume: 46
  • Issue: 4
  • Year: 2010
  • Summary: Field experiments were conducted for the three consecutive cropping seasons of 2003-05, 2004-06 and 2005-07 at the Indian Institute of Sugarcane Research, Lucknow, India, to explore the feasibility of planting sugarcane in autumn as a relay intercrop in standing rice. The cropping systems evaluated were: (i) rice-potato-spring sugarcane; (ii) rice+autumn sugarcane (planted as a relay intercrop in every sixth row devoid (skipped) of transplanted rice)+potato after rice; (iii) rice-autumn sugarcane (planted without preparatory tillage)+potato; and (iv) rice-autumn sugarcane (planted with preparatory tillage)+potato. In each case, sugarcane was planted in rows 90 cm apart. Rice was transplanted in rows at 20-cm row spacing when followed by potato or sugarcane, but at 18-cm row spacing when intended for sugarcane planting as a relay intercrop in late September. The germination (60.4%) of cane buds, tillers (323 000 ha -1) and number (149 000 ha -1), length (225 cm), girth (2.44 cm) and weight (747 g) of millable canes were markedly better when autumn sugarcane was planted with rice as a relay intercrop in comparison to other cropping systems. Similarly, this cropping system produced the maximum cane (111.4 t ha -1) and sugar (13.2 t ha -1) along with sugarcane equivalent yield (216.4 t ha -1). In turn, relay intercropping system with maximum cane production efficiency of 420 kg ha -1day -1 fetched the highest economic returns (Rs. 258 ha -1day -1) and benefit:cost ratio (1.5). Compared with the rice-potato-spring sugarcane cropping system, the relay intercrop of autumn sugarcane in standing rice produced 35.4% more cane and 38.3% more sugar with 24.1% higher returns besides 79.1% energy saving. This practice will not only benefit cane growers and sugar mill owners in tropical and sub-tropical India, but also in other parts of the world where rice and sugarcane are extensively cultivated.
  • Authors:
    • Inomoto, M. M.
    • Asmus, G. L.
  • Source: Plant disease: an international journal of applied plant pathology
  • Volume: 94
  • Issue: 8
  • Year: 2010
  • Summary: Taking into account that information about the host status of cover crops for Pratylenchus brachyurus is scarce or contradictory, this study was undertaken to assess the host status of selected graminaceous cover crops by estimating nematode reproduction and their ability to decrease the nematode density in glasshouse conditions. Furthermore, the reproductive fitness of three P. brachyurus populations was assessed for Brachiaria grasses. Silage and forage sorghum proved to be good hosts for P. brachyurus; consequently, they should be avoided in fields infested with this lesion nematode, mainly before susceptible crop such as soybean, common bean, cowpea, and cotton. Dictyoneura grass, the pearl millet cv. ADR 300, and black oat were poor hosts for P. brachyurus but may increase densities of this nematode over time. Consequently, these cover crops might be used in infested fields for only short periods, because they could increase the P. brachyurus population density slowly but progressively.
  • Authors:
    • da Rocha, M. R.
    • Reinert, D. J.
    • Carneiro Amado, T. J.
    • Nicoloso, R. da S.
    • Foletto Eltz, F. L.
    • Lanzanova, M. E.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 34
  • Issue: 4
  • Year: 2010
  • Summary: No-tillage associated to cover crops may maintain soil quality, improving or preserving favorable soil physical conditions for plant growth. This study assessed soil bulk density, porosity, penetration resistance, and water infiltration of a PALEUDALF, in the Experimental Area of the Soil Science Department of the Federal University of Santa Maria, in Santa Maria, RS, Brazil, in an experiment started in 1991, with the following crop successions and rotations: (1) Corn/Soybean - Jackbean - MFP; (2) Bare soil - SDES; (3) Corn/Soybean - Fallow - POU; (4) Corn / Soybean - Ryegrass + Vetch - AZEV; (5) Corn / Soybean - Mucuna - MUG; (7) Natural Grass - CNA; (6) Corn/Soybean - Oilseed radish - NFO. Soil bulk density was affected in the 0-0.10 in layer; values were highest in the SDES. Total soil porosity and soil macroporosity were closely correlated to a depth of 0.10 m. Major restriction to root penetration occurred in the surface layer (0-0.03 m) in the SDES treatment, and NFO had greatest values at 0.16-0.18 m depth. The water infiltration rate was lowest in SDES and CNA treatments in all evaluations, while in the others infiltration was constant and statistically equal. Constantly uncovered soil induces degradation in soil physical properties. The studied cropping systems confirmed significant benefits in soil density, porosity, resistance, and water infiltration rate under long term no-tillage.
  • Authors:
    • Guglielmini, A. C.
    • Abelleyra, D. de
    • Kruk, B. C.
    • Verdu, A. M. C.
    • Mas, M. T.
    • Satorre, E. H.
  • Source: Weed Research
  • Volume: 50
  • Issue: 4
  • Year: 2010
  • Summary: Weed surveys were performed in commercial no-till glyphosate-tolerant soyabean crops in southern Entre Rios province (Mesopotamic Pampas of Argentina) in 2005 and 2007, during the soyabean grain filling to maturity growth stages. The objectives were to describe the weed communities in fields recently introduced to crop production and to analyse the effect of the new cropping patterns on assemblages. The fields surveyed varied in the length of the no-till period (1-11 years), the previous crop and the soil productivity rating. Weed communities were described in terms of composition, constancy, life forms, morphotypes and (only during 2007) frequency. Tragia geraniifolia, Bidens subalternans, Sida spinosa, and Eryngium horridum were species associated with fields with more than 5 years of no-till glyphosate-tolerant crops. These fields had a significantly higher relative abundance of perennials (52% versus 32%) and of dicotyledons (66% versus 39%) than fields with less than 5 years of no-till. Previous crop and soil productivity affected weed community structure. Six species, five of them annuals, were associated with fields that had high yields and maize as the previous crop. In contrast, perennials and dicotyledons had the highest relative abundance when wheat-soyabean double cropping was the previous crop. The results show that changes in cropping systems acted as filters on functional traits, modifying the previous weed community assemblage. The information may be used to develop integrated crop-weed management strategies, leading to a reduction in the assemblage of highly competitive weed communities.
  • Authors:
    • Delve, R. J.
    • Zingore, S.
    • Nyawasha, R. W.
    • Nyamangara, J.
    • Masvaya, E. N.
    • Giller, K. E.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 88
  • Issue: 1
  • Year: 2010
  • Summary: This paper examines a number of agronomic field experiments in different regions of sub-Saharan Africa to assess the associated variability in the efficiencies with which applied and available nutrients are taken up by crops under a wide range of management and environmental conditions. We consider N and P capture efficiencies (NCE and PCE, kg uptake kg(-1) nutrient availability), and N and P recovery efficiencies (NRE and PRE, kg uptake kg(-1) nutrient added). The analyzed cropping systems employed different soil fertility management practices that included (1) N and P mineral fertilizers (as sole or their combinations) (2) cattle manure composted then applied or applied directly to fields through animal corralling, and legume based systems separated into (3) improved fallows/cover crops-cereal sequences, and (4) grain legume-cereal rotations. Crop responses to added nutrients varied widely, which is a logical consequence of the wide diversity in the balance of production resources across regions from arid through wet tropics, coupled with an equally large array of management practices and inter-season variability. The NCE ranged from 0.05 to 0.98 kg kg(-1) for the different systems (NP fertilizers, 0.16-0.98; fallow/cover crops, 0.05-0.75; animal manure, 0.10-0.74 kg kg(-1)), while PCE ranged from 0.09 to 0.71 kg kg(-1), depending on soil conditions. The respective NREs averaged 0.38, 0.23 and 0.25 kg kg(-1). Cases were found where NREs were > 1 for mineral fertilizers or negative when poor quality manure immobilized soil N, while response to P was in many cases poor due to P fixation by soils. Other than good agronomy, it was apparent that flexible systems of fertilization that vary N input according to the current seasonal rainfall pattern offer opportunities for high resource capture and recovery efficiencies in semi-arid areas. We suggest the use of cropping systems modeling approaches to hasten the understanding of Africa's complex cropping systems.