• Authors:
    • Chen, L.
    • Sun, Q.
    • Li, H.
    • Fang, S.
  • Source: Agroforestry Systems
  • Volume: 79
  • Issue: 2
  • Year: 2010
  • Summary: The importance of agroforestry systems in CO 2 mitigation has become recognized worldwide in recent years. However, little is known about carbon (C) sequestered in poplar intercropping systems. This study aims compare the effects of three poplar intercropping designs (configuration A: 250 trees ha -1; configuration B: 167 trees ha -1 and configuration C: 94 trees ha -1) and two intercropping systems (wheat-maize cropping system and wheat-soybean cropping system) on biomass production and C stocks in poplar intercropping systems. The experiment was conducted at Suqian Ecological Demonstration Garden of fast-growing poplar plantations in northwestern Jiangsu, China. A significant difference in C concentration was observed among the poplar biomass components investigated ( P≤0.05), with the highest value in stemwood and the lowest in fine roots, ranging from 459.9 to 526.7 g kg -1. There was also a significant difference in C concentration among the different crop components ( P≤0.05), and the highest concentration was observed in the maize ear. Over the 5-year period, the total poplar biomass increased with increasing tree density, ranging from 8.77 to 15.12 tonnes ha -1, while annual biomass production among the crops ranged from 4.69 to 16.58 tonnes ha -1 in the three configurations. Overall, total C stock in the poplar intercropping system was affected by configurations and cropping systems, and configuration A obtained the largest total C stock, reaching 16.7 tonnes C ha -1 for the wheat-soybean cropping system and 18.9 tonnes C ha -1 for the wheat-maize cropping system. Results from this case study suggest that configuration A was a relative optimum poplar intercropping system both for economic benefits and for C sequestration.
  • Authors:
    • Shiva, D.
    • Ashok, K.
    • Jat, N.
  • Source: Indian Journal of Agronomy
  • Volume: 55
  • Issue: 4
  • Year: 2010
  • Summary: Meager information is available on the use of Sesbania in conjunction with-crop residue and N-dose in maize-wheat cropping system. Therefore, an attempt was made to substitute the fertilizer N through organic sources in maize-wheat cropping sequence. Hence a field experiment was conducted for 2 year from 2006-2008, on maize ( Zea mays L)-wheat ( Triticum aestivum L. emend. Fiori & Paol) system to evaluate the influence of four organic sources (control, Sesbania green manure (SGM), wheat straw; and the combination of SGM and wheat straw), and three fertilizer N levels (0, 60 and 120 kg/ha) on maize. The residual effect of above treatments and response of wheat to direct N application (0, 40, 80 and 120 kg/ha) were also assessed. The highest plant height, dry matter accumulation, leaf area index, yield attributes, yield (4.48 and 4.86 t/ha during each year) and N uptake by maize were recorded with the application of SGM in combination with wheat straw closely followed by SGM alone. Maize responded significantly to fertilizer N up to 120 kg/ha (4.63 and 4.96 t/ha grain yield during each year) and the residual effect of that also affected significantly the growth and yields of succeeding wheat. Statistically higher plant height, dry matter accumulation, leaf area index, effective tillers, test weight, yields and N uptake by wheat were recorded under residual fertility of organic sources. Under the influence of residual fertility of N, wheat growth and yield parameters responded significantly up to 120 kg N/ha. Wheat also responded significantly to direct N application with respect to all growth and yield parameters and N uptake by wheat. SGM and SGM+wheat straw treatments resulted in gain of N content. Regarding the effect of N levels, N gain was found with all N levels. It was concluded that conjoin use of organic and inorganic sources of N was essential for higher productivity of maize-wheat cropping sequence.
  • Authors:
    • Li, L.
    • Chen, W.
    • Sun, J.
    • Hu, H.
    • Yu, C.
    • Li, Q.
  • Source: Plant Nutrition and Fertilizer Science
  • Volume: 16
  • Issue: 4
  • Year: 2010
  • Summary: In a field micro-plot experiment in China of three intercropping systems (barley/maize, wheat/maize, faba bean/maize) and their corresponding sole cropping systems, nitrogen (N) was applied at N 0 and 225 kg/ha, and N absorption and use efficiency and its accumulation on the soil profile were investigated. The competitive ability of crops for nutrients was closely related to the concentration and accumulation of mineral nitrogen in the root zone of the plants. Accumulation of mineral nitrogen under barley or wheat strips intercropped with maize decreased by 203-282 or 107-171 kg/ha in the 0-100 cm soil profile, respectively, compared with faba bean intercropped with maize. Accumulation of mineral nitrogen under maize strips intercropped with barley or wheat was reduced by 93-120 or 56-87 kg/ha compared with maize intercropped with faba bean, respectively. Crop types, interspecific competition and soil condition affected accumulation of mineral nitrogen in the soil profile. Interspecific interaction increased nitrogen recovery efficiency for barley and wheat intercropped with maize and decreased that for maize intercropped with barley and wheat. Nitrogen use efficiency was the highest in the no-N treatment for competitive intercropping systems (barley/maize or wheat/maize). Nitrogen harvest index was reduced in barley and wheat with N fertilizer application, but increased in maize and not changed in faba bean. It is concluded that competition between crops, soil fertility status, fertilizer rate and cultural measures should be considered carefully in order to achieve intercropping advantage when associated crops are chosen. Complement systems of legumes/cereals are recommended for low soil fertility and competitive systems of cereals/cereals for high soil fertility.
  • Authors:
    • Liu Qian
    • Zhang TingWei
    • Liu ChangZhong
  • Source: Guizhou Agricultural Sciences
  • Issue: 6
  • Year: 2010
  • Summary: The results from studying the effect of inter-cropping of wheat with different crops on occurrence quantity of wheat aphid at flowering and filling stage of wheat showed that the aphid occurrence quantity of inter-cropping of wheat with maize or Helianthus annuus or soybean significantly lower than wheat single cultivation, there was significantly difference in aphid occurrence quantity among three inter-cropping patterns and the aphid occurrence quantity of wheat/maize inter-cropping pattern was the lowest, followed by wheat/ Helianthus annuus inter-cropping pattern.
  • Authors:
    • Jasso-Chaverria, C.
    • Martinez-Gamino, M.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Symposium 3.2.1 Highland agriculture and conservation of soil and water
  • Year: 2010
  • Summary: Among the main constraints to adopting conservation tillage in the semiarid zones in Mexico's north-central region are: low acceptance among farmers, need of specialized machinery, use of herbicides, and above all, the need to utilize stubble to feed animals. The objective of this study was to assess the effect of different tillage methods in an irrigated corn-oat rotation system on corn grain, stubble, and forage oat yield. Seven tillage methods were evaluated: (1) traditional plow and disk (P+D), (2) disturbing the upper 0-4 in layer (D), (3) without disturbing the upper 0-4 in layer (ND), (4) zero tillage with 0% soil cover (ZT+0%SC), (5) zero tillage with 33% soil cover (ZT+33%SC), (6) zero tillage with 66% soil cover (ZT+66%SC), and (7) zero tillage with 100% soil cover (ZT+100%SC). In each year from 1996 to 2007, corn was sowed on the spring while forage oat was grown during the fall-winter season. Corn grain yield results showed statistical differences among treatments (p≤0.05), where ZT+66%SC was the best treatment, surpassing by 90% the corn yield registered with P+D. The statistical analysis for corn stubble yield showed no differences (p≥0.05) among treatments. With ZT+66%SC, corn stubble production was increased 3.448 ton/ha compared with that of P+D, indicating that farmers can use 2.0 ton ha -1 to cover at least 33% of the soil surface. Forage oat yields within the seven treatments were not statistically different ( P≥0.05), but all ZT treatments were no-till seeded. Our conclusions are that corn and forage oat can be no-till seeded, increasing corn production and keeping stable production of forage oat. These results can be used to provide evidence to farmers of the benefits of adopting conservation tillage.
  • Authors:
    • Muchaonyerwa, P.
    • Chiduza, C.
    • Murungu, F. S.
  • Source: African Journal of Agricultural Research
  • Volume: 5
  • Issue: 13
  • Year: 2010
  • Summary: Production of large biomass yields and weed suppression from cover crops have been major constraints affecting success and uptake of conservation agriculture technologies by smallholder irrigation farmers. A field study was undertaken to evaluate biomass accumulation and N uptake by oats ( Avena sativa), grazing vetch ( Vicia dasycarpa), faba bean ( Vicia faba), forage peas ( Pisum sativum) and Lupin ( Lupinus angustifolius) and their winter weed suppression efficacy in the 2007 and 2008 winter seasons. Cover crops were grown at two fertiliser levels: no fertiliser and fertilized. Control plots were included where no cover crop was grown. At the end of each winter season, glyphosate was applied to kill the cover crops and maize planted. Oats, grazing vetch and forage pea's cover crops produced mean dry weights of 13873, 8945.5 and 11073 kg ha -1 respectively while lupin had the lowest dry weight of 1226 kg ha -1. Oats responded to fertilisation while, there was little or no response from the other cover crops. Oats and grazing vetch also reduced weed density by 90 and 80% respectively while lupin only reduced weed density by 23% compared with the control plots. Grazing vetch fixed a mean of 112 kg N ha -1. The results suggest that legumes such as grazing vetch and forage peas may be grown to maximise biomass yields with minimal fertilizer inputs. Amount of biomass produced was a major factor in controlling winter weeds, while there was a progressive decline in the winter weed burden from the first to the second season. The low C:N ratio of grazing vetch (
  • Authors:
    • Chai, Q.
    • Qi, W.
  • Source: Chinese Journal of Eco-Agriculture
  • Volume: 18
  • Issue: 1
  • Year: 2010
  • Summary: A field experiment was conducted in China to investigate the effect of different root partition patterns on wheat/maize competitiveness under intercropping system and how it affects yield. Two root partition patterns (plastic film and nylon mesh partition patterns) were used. Results showed that wheat/maize competitiveness in intercropping system steadily increased from sowing to flowering stage of wheat and then decreased the competitive advantage of wheat over maize under intercropping decreases by root partitioning. Intercropping system without root partition increased the competitive advantage of wheat by 20.5 and 4.9% respectively, compared to those with plastic film and nylon mesh partitions. The land equivalent ratios of intercropping systems without root partition, with plastic film partition and nylon mesh partition were 1.46, 1.20 and 1.39, respectively. Yield for the intercropping system was quadratically correlated with wheat competitiveness to maize. Improving wheat/maize competitiveness in intercropping systems increased yield. The stage of wheat flowering was critical for optimizing wheat competitiveness.
  • Authors:
    • Silva, R.
    • Rosolem, C.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 41
  • Issue: 1
  • Year: 2010
  • Summary: Cation mobility in acidic soils with low organic-matter contents depends not only on sorption intensity but also on the solubility of the species present in soil solution. In general, the following leaching gradient is observed: potassium (K +) > magnesium (Mg 2+) > calcium (Ca 2+) > aluminum (Al 3+). To minimize nutrient losses and ameliorate the subsoil, soil solution must be changed, favoring higher mobility of M 2+ (metal ions) forms. This would be theoretically possible if plant residues were kept on the soil surface. An experiment was conducted in pots containing a Distroferric Red Latosol, with soil solution extractors installed at two depths. Pearl millet, black oat, and oilseed radish residues were laid on the soil surface, and nitrogen (as ammonium nitrate) was applied at rates ranging from 0 to 150 mg kg -1. Corn was grown for 52 days. Except for K + and ammonium (NH 4+), nitrogen rates and plant residues had little effect upon the concentrations and forms of the elements in the soil solution. Presence of cover crop residues on soil surface decreased the effect of nitrogen fertilizer on Ca leaching. More than 90% of the Ca 2+, Mg 2+, and K + were found as free ions. The Al 3+ was almost totally complexed as Al(OH 3) 0. Nitrogen application increased the concentrations of almost all the ions in soil solution, including Al 3+, although there was no modification in the leaching gradient.
  • Authors:
    • Dube, R.
    • Dhyani, S.
    • Ratan, S.
    • Sharma, A.
  • Source: Indian Journal of Agronomy
  • Volume: 55
  • Issue: 4
  • Year: 2010
  • Summary: A field experiment was conducted at Selakui, Dehradun from 2001 to 2004 to study the effect of tillage, viz. conventional tillage (CT) and minimum tillage (MT); and weed-control practices, viz. chemical and mechanical weeding along with legume mulching, viz. in situ grown sunnhemp ( Crotalaria juncea L) and subabul [ Leucaena leucocephala (Lam.) de Wit] on soil moisture conservation, crop productivity and soil health in maize ( Zea mays L)-wheat ( Triticum aestivum L. emend Fiori & Paol.) cropping system. CT gave higher grain yield of maize (+0.11 to 0.17 t/ha), but wheat performed equally well under CT (2.48 t/ha) and MT conditions (2.36 t/ha). Chemical weeding with herbicides (alachlor in maize and isoproturon in wheat) resulted in 7.8 and 9.9% higher yield of maize and wheat, respectively over mechanical weeding. Beneficial effect of live mulching with sunnhemp or Leucaena was similar (12.3-14.7%), while their combined application increased the maize yield by 19.1% over no mulching. Further, enhanced soil moisture conservation due to mulching at maize harvest led to greater productivity of wheat by 16.1% with sunnhemp or Leucaena, and 27.0% with sunnhemp+ Leucaena. Nitrogen uptake of maize and wheat increased significantly with chemical weeding and legume mulching, but tillage practices made no effect on wheat while in maize it was lower under MT. Wheat gave 4-5 times more net returns than maize, and the net B:C ratio of the system was >1.0 with chemical weeding and legume mulching. Tillage and weed-control practices made no effect on organic C and total N status of soil but legume mulching improved these parameters and reduced bulk density associated with increased infiltration rate. It was concluded that CT along with legume mulching in maize and MT in wheat, and chemical weeding of both the crops was beneficial for improving moisture and nutrient conservation, and achieving higher productivity and profitability of maize-wheat cropping system under Doon valley conditions.
  • Authors:
    • Dube, R.
    • Dhyani, S.
    • Singh, R.
    • Sharma, A.
  • Source: NUTRIENT CYCLING IN AGROECOSYSTEMS
  • Volume: 87
  • Issue: 2
  • Year: 2010
  • Summary: Mulching with vegetative materials is a highly beneficial and widely-investigated agro-technique in rainfed areas but the adoption of this practice has been constrained due to non-availability of mulch biomass locally. Live mulching with fast-growing annual green manure legumes like sunnhemp ( Crotalaria juncea) or prunings of Leucaena leucocephala grown as hedge rows can be done for moisture conservation as well as nutrient cycling in the maize-wheat cropping system, which is predominantly followed in the high rainfall sub-mountainous region of north-western India. A field experiment was conducted at Selakui, Dehradun during 2000-2004 to study the effect of legume mulching, viz. in situ grown sunnhemp and Leucaena prunings, along with varying N levels, viz. 0, 30, 60 and 90 kg N ha -1 (to maize), and 0, 40 and 80 kg N ha -1 (to wheat) on productivity, soil moisture conservation and soil physico-chemical properties. Intercropped sunnhemp added 0.75-1.45 t dry matter and 21.6-41.3 kg N ha -1 at 30-35 days, while Leucaena twigs added 1.89-4.15 t dry matter and 75.2-161.3 kg N ha -1 at 60-65 days of maize growth. Live mulching with sunnhemp or Leucaena biomass improved soil moisture content at maize harvest (+1.15-1.57%) and crop productivity by 6.8-8.8% over no mulching. Combined use of both the mulching materials was more effective in improving the soil moisture content (+2.08-2.29%) and grain yield (15.1%) over their single application. Response of maize to N fertilizer application was significant up to 90 kg N ha -1, and it was relatively more pronounced under the mulching treatments. Residual effect of mulching on wheat showed an increase in yield of 10.2% with sunnhemp or Leucaena, and 27.9% with sunnhemp+ Leucaena. There was an improvement in organic C and total N status of soil, and a decrease in bulk density associated with an increase in infiltration rate due to mulching at the end of 4 cropping cycles. It was concluded that legume mulching is a highly beneficial practice for enhanced moisture and nutrient conservation, leading to increased productivity and soil health of maize-wheat cropping system under Doon valley conditions of north-western India.