Effects Of Different Rotations Research Articles

The Effects of Different Rotations of Beans, Maize, and Cabbage on Soil Moisture and Economic Benefits

The article investigates the effects of different cropping rotations on soil moisture and economic benefit. Cabbage–maize–cabbage (CMC), beans–maize–cabbage (BMC), and cabbage–cabbage–cabbage (CCC) treatments were set up to study the effects of different crop rotation combinations on soil water storage, evapotranspiration (ET), water use efficiency (WUE), and economic benefit. The results showed that the average soil moisture content decreased initially and then increased with crop rotation, whereas it continued to decrease with continuous cabbage cropping as the crop grew. CMC reduced ET, whereas BMC increased ET from the nodulation to maturation stages of cabbage compared with CCC in the third experimental year. WUE of different crops showed that cabbage > maize > beans. The economic benefit of the CMC was higher than the other treatments in the third planting year. Therefore, the best crop rotation combination in this area is cabbage–maize–cabbage.

Simulation of carbon sequestration and timber production in Larix olgensis plantation based on CO2FIX model

Based on datasets from plot survey and bibliographic of Larix olgensis plantations in Maoer Mountain, the CO2FIX model was used to quantitatively simulate the effects of different rotations (30, 40, 50, 60 years), site indices (12, 16, 20 m), and initial densities (2500, 3333, 4444 trees·hm-2) on the stand level carbon flows among different carbon pools (i.e., biomass carbon pool, soil carbon pool, and product carbon pool). The results showed that the CO2FIX model had high reliability for simulating the processes of L. olgensis plantation, with the average relative errors of stand biomass and volume between analog and measured values being 6.4% and 3.7%. Under the baseline conditions of initial density of 3333 trees·hm-2, site index of 16 m and rotation of 40 years, the carbon stock of total and sub-pool of L. olgensis plantation changed periodically with rotation. The total stand carbon stock and volume for L. olgensis plantation increased with the extension of rotation, the improvement of site index, and the increase of initial density. The stand carbon stock and volume would be increased by 12.2% and 31.2%, 36.7% and 67.8%, respectively, when the reference rotation was correspondingly extended by 10 and 20 years. However, if the reference rotation was shortened by 10 years, stand carbon stock and volume would be correspondingly decreased by 20.9% and 40.4%, respectively. When the initial density was set as 3333 and 4444 trees·hm-2, stand carbon stock and volume were increased by 27.8% and 50.9%, 27.4% and 49.1%, respectively. When the site index was under the range of 12 to 20 m, stand carbon stock and volume could be increased by 36.0% and 40.3%, 39.3% and 44.2%, respectively, with each increase of 4 m in site index. During one rotation, 271.57 t C per hectare could be fixed into L. olgensis plantation. At the end round of the rotation, 27.47 and 56.75 t C were transferred to soil and wood product carbon pools. Therefore, when the site condition was good, the management model with a higher initial density (4444 trees·hm-2) and longer rotation (60 years) would be more beneficial to maximizing the carbon sink and timber benefits of L. olgensis plantation.

Long term effect of different crop rotations on soil physical properties in a Mollisol

The present study was conducted for the study about the effect of different rotations on physical properties in a Mollisol. The study area was located at Norman E. Borlaug Crop Research Centre, G. B. Pant University of Agriculture and Technology, Pantnagar, which lies at 290N latitude, 790 3’ E longitude and 243.84 m above the mean sea level altitude. The crop rotation selected for study were T1 (Rice- Wheat-Fallow) T2 (Rice- Vegetable pea- Summer Rice) T3 (Maize- Wheat- Cowpea) T4 (RiceWheat- Sesbania) T5 (Maize- Toria- Urd) T6 (Rice- Yellow Sarson- Grain Cowpea) T7 (Multi-Cut Sorghum- Barseem + Oat- Maize + Cowpea) T8 (Napier + Fodder cowpea- Barseem- Fodder cowpea) T9 (Basmati rice- Potato- Maize Cob) T10 (Maize- Broccoli- Okra) T11 (fallow (uncultivated land)). The soil sample was collected from 20cm depth for the study of soil physical properties (soil color, soil texture, bulk density, particle density, porosity, and water holding capacity). Among the different crop rotations, T4 treatment was obtained a significantly high value (except bulk density) of soil texture, particle density, porosity, and water holding capacity. T11 (except bulk density) treatment was obtained a significantly lowest value of soil texture, particle density, porosity and water holding capacity Results indicated that soil under Sesbania rotation was found superior with respect to soil physical properties followed by other crop rotation and the uncultivated land. By taking a crop for a long time on same and using chemical fertilizers that are decrease of soil physical properties. Therefore, in this experiment taking different crop rotations. under the different crop rotations, soil physical properties influenced positively and especially the green manure cycle has had the greatest positive impact. According to experimental data concluded that incorporation of green manure crop rotations was effect more positive an effect on soil physical properties. Crop rotations and green manure crops are improved soil physical properties and soil health.

Rotation with oilseed rape as the winter crop enhances rice yield and improves soil indigenous nutrient supply

Crop yield and soil fertility are significantly influenced by crop rotation practices and plant nutrition management. A 3-year field experiment testing different fertilizer inputs under oilseed rape–rice (OR), wheat–rice (WR), and fallow–rice (FR) rotations was performed to investigate the effects of different rotations on rice yield and soil indigenous nutrient supply. Rice yield under the OR rotation was significantly higher than yields under the other two rotations, especially when no fertilizer was applied (control treatment) or when the applied fertilizer lacked N (no-N treatment). The rice grain yields of the control and no-N treatments under OR rotation exceeded those under the WR and FR rotations by 20.5 % and 14.5 % (control), and by 16.2 % and 14.9 % (no-N), respectively. The increase in rice yield was significantly related to the soil indigenous nutrient supply. Linear regression analysis showed that for every 1.0 kg increase in soil N supply, the rice yield increased by 86.2–136.8 kg ha–1. The indigenous N supply in the rice season under OR rotation was 22.0 % and 19.5 % higher than supplies under WR and FR rotations, respectively. The indigenous P and K supplies under OR were 21.9 % and 12.8 % higher, respectively, than those under WR. The highest N and P surpluses and lowest K deficits occurred under OR rotation. These effects were significantly correlated with the soil indigenous nutrient supply. Thus, a surplus of 1.0 kg N ha–1 increased the soil indigenous N supply by 0.04–0.29 kg N ha–1. Consequently, the use of oilseed rape as a previous crop in a rotation protocol could significantly increase rice yield and soil indigenous nutrient supply capacity. Inclusion of this rotation practice into agronomic systems that currently use wheat-rice and fallow-rice rotations should bring significant benefits.

Different rotations: does it have an impact on confidence of future HBP surgeons to perform complicated procedures

Presenter: Salah Abdel Jalil MD | Grand Strand Regional Medical Center Background: The pursuit of a fellowship has become increasingly popular over the past several years with >90% of graduating general surgical residents continuing their education in further subspecialties (1). The goal of the HPB fellowship is to provide the fellow with the necessary skills and expertise to be able to perform complicated procedures, which is variable between programs. Our goal of the survey is to investigate the strength and weakness areas upon participating in different rotations including Surgical Oncology, Hepatobiliary Surgery and Transplant Surgery rotation. Methods: This is a retrospective survey using an anonymous online survey of hepato-pancreato-biliary fellowship (HPB) program fellows and physicians. Statistical analysis was performed to calculate how many respondents were needed to achieve a 95% confidence level for p <0.05, as there is 220 HBP graduates since 2012. Thirty percent was the response rate needed to achieve the that power. The survey underwent face validation process with expert physicians. Also, cognitive interview was done by fellows outside of the HBP field. Respondents were asked to answer 18 questions to judge the effect of different rotations on the HBP physician’s confidence in doing complicated HBP procedures. No incentives were offered to the fellows at any stage in the study in exchange for survey completion other than the satisfaction of participating in the acquisition of knowledge and benefits of future HBP fellow’s education. The survey was posted online using Monkey survey software that allows fellow to access through the link that was distributed. Results: eight fellows responded, Our survey showed that half of the fellows completed both Transplant and HBP rotations during their fellowship, while only 25% completed surgical oncology rotations, also about 42% found that surgical oncology and Transplant rotation’s duration was about the right length, and non-thought it’s too long for both rotations, while for HBP rotation slightly more than half the reposnders found it’s about the right length while 42% responds as its too short. Slightly more than half of the fellows were comfortable performing complex bile duct excision and reconstruction, and 42% were comfortable performing hemi-hepatectomy, and complex bile duct excision and reconstruction on the other side more than 80% did not feel comfortable performing HPB-related vascular reconstruction. Conclusion: Our survey shows that most of the recently graduated fellows in HBP surgeons were not comfortable in performing HPB-related vascular reconstruction after graduation. We believe increasing the length of transplant and HBP rotations should have a positive impact on the surgeon’s ability and self-confidence to perform such procedures.

Effects of different rotations on carbon sequestration in Chinese fir plantations

Effects of different rotations on carbon sequestration in Chinese fir plantations

Soil mineral N dynamics and maize grain yields following Centrosema macrocarpum and Stylosanthes guianensis: effects of different rotations and varying levels of N fertiliser

In order to contribute to improved utilisation of herbaceous legumes, in particular Centrosema macrocarpum and Stylosanthes guianensis for crop-livestock systems, the present study explored a number of management options to improve the effect of legumes on subsequent maize yield. The objectives of the studies were to investigate the soil nitrogen dynamics and response of maize after different periods of legume growth and in a separate experiment to investigate the effect of inorganic N fertiliser on the maize grown after the selected legumes. In one experiment, the two herbaceous legumes were grown using two rotations—short (12 months) with a single forage harvest and followed by early maize; or long (15 months) with two forage harvests followed by late maize. More N was removed in the S. guianensis forage (140 kg N ha −1) compared to C. macrocarpum (90 kg N ha −1) although more N accumulated in the regrowth after harvest of C. macrocarpum (about 100 kg N ha −1—almost twice that of S. guianensis). Subsequently, the N status of maize plants (estimated using chlorophyll readings) in the first 37 days after sowing was higher for C. macrocarpum. Soil N min also tended to be higher after C. macrocarpum (maximum of 70 μg N g −1) compared to S. guianensis (maximum of 50 μg N g −1). This was not consistently reflected in maize grain yields. Under the experimental conditions, nitrogen appeared to be immobilised in the soil during the initial stage of legume decomposition, although this was less pronounced after S. guianensis. In a second experiment, first wet season (early) maize was grown after the same two legume species, and the interaction of preceding legumes with three levels of fertiliser N (0–30–60 kg N ha −1) applied to maize was assessed. Increasing fertiliser N levels had no clear impact on N min dynamics. Increased grain yield of maize in response to N addition was measured only after S. guianensis which may have been related to site characteristics . With respect to their potential to contribute to crop-livestock production, the two species differed in that S. guianensis was better with respect to year-round forage production, but C. macrocarpum had a greater effect on the subsequent maize yield. In order to improve the legume N contribution to maize at similar sites, the role of delayed N release during leguminous residue decomposition is emphasised.

Effect of Temporal Deployment of Different Sources of Resistance to Soybean Cyst Nematode

Thirteen rotation treatments consisting of 'Bedford', a soyabean cultivar resistant to Heterodera glycines (SCN) races 3 and 14, 'Forrest' resistant to races 1 and 3, susceptible 'Essex', and a nonhost crop (cotton [Gossypium hirsutum]) were evaluated in an SCN infested field for 4 yr in Portageville, Missouri. Yields of soyabean cultivars in continuous production systems were compared with those in rotation with the nonhost, resistant, and susceptible cultivars. Bedford and Forrest yields, over the 4 yr, were less variable than Essex yields. Forrest and Essex produced similar yields in 3 out of 4 yr, and yields of Essex were significantly lower than Bedford yields in 2 out of 4 yr. Beneficial effects of different rotations on cultivar performance were not very conspicuous, however, yields of Essex were increased with rotation in 5 of the 6 comparisons compared with continuous Essex, whereas Bedford in rotation was significantly higher than continuous Bedford in 2 of the 5 comparisons. Grain yields of Forrest were not affected by rotation systems. The nematode density, after 4 yr, was lowest in cotton-Forrest-Bedford-cotton system and greatest in Bedford-cotton-Essex-Forrest system. The preceding crop had a greater influence on the nematode population density than the rotation system per se. Treatments with cotton as the preceding crop had lower nematode population densities than resistant or susceptible soyabean. Rotating cultivars caused changes in SCN race structure. SCN race 14 was present in almost all rotations including Essex and Forrest. Bedford tended to increase the population with genes for parasitism on PI 88788, resulting in a shift to race 4. The shift to highly pathogenic race was slower in rotations that included susceptible Essex and Forrest as a component crop. Inclusion of susceptible soyabean lines in rotations may delay, but not prevent, the development of highly virulent races of SCN. Rotation of soyabean cultivars was found to be a useful practice in the management of SCN-caused losses.

Acidification rates in the central wheatbelt of Western Australia. 2. On a sandy duplex soil

The rate and mechanisms of acidification were determined on a sandy duplex soil (depth of sand 30-45 cm) under a cereal-annual pasture rotation in Western Australia. We also evaluated the effect of rotation (intensity of cropping) on relative acidification of a sandy duplex soil. Rate of acidification was based on a linear regression analysis between soil pH and years since clearing. Sites were sampled to a depth of 50 cm in 10-cm increments and measurements included soil pH, pH buffering capacity, and bulk density. The effect of different rotations on the acidification rate was determined by soil sampling a rotation experiment which had been established for 25 years. Sampling and measurements were similar to the regression analysis. From regression, the rate of acidification for the profile was 0.15 kmol H+/ha.year, requiring 7.7 kg CaCO3 to neutralise. Most of the acidification could be accounted for by removal of alkaline products. Acidification was occurring to a depth of 30 cm, the acidification rate decreasing with depth. In the surface 20 cm the pH decline was 0.005-0.006 units/year. In the rotation experiment, the rate of acidification relative to continuous wheat without fertiliser nitrogen (N) ranged from 0.35 kmol H+/ha .year (17.5 kg CaCO3) for continuous wheat with fertiliser N to 0.92 kmol H+/ha. year (45.8 kg CaCO3) for continuous pasture. Between these rates was 1 year pasture-1 year cereal (0.41 kmol H+/ha. year, 20.5 kg CaCO3) and 2 years pasture-1 year cereal (0.82 kmol H+/ha . year, 41.2 kg CaCO3). Acidification was occurring to 60 cm depth in all rotations, mostly due to nitrate leaching, removal of alkaline products, and build-up of organic matter.

Effects of rotation, stubble retention and cultivation on take-all and eyespot of wheat in northeastern Victoria, Australia

The effects of different rotations and methods of seed-bed preparation on take-all ( Gaeumannomyces graminis var. tritici) ( Ggt) and eyespot ( Tapesia yallundae; anomorph Pseudocercosporella herpotrichoides) of wheat ( Triticum aestivum) were investigated in 1984–1986 in a long-term field experiment (established in 1981), on a fine sandy-clay loam in northeastern Victoria. One treatment, representing the conventional practice, involved burning stubble from the preceding crop followed by four passes with a scarifier in the autumn before sowing wheat each year. Other treatments were direct drilled each year (sown without prior cultivation) and included two stubble treatments (retained or burnt) in either continuously cropped wheat or in lupin ( Lupinus angustifolius)-wheat rotations. High levels of take-all and eyespot developed in the continuously cropped wheat (up to 79% and 66% plants affected, respectively). On the other hand, the incidence of plants with either disease was very low or negligible in wheat that was preceded by lupins. In continuous wheat the incidence of plants with Ggt lesions were up to two times higher in the conventionally cultivated treatment (14% 74% and 79% plants affected in 1984, 1985 and 1986, respectively) than in direct drilled treatment (5%, 36% and 39% plants affected, respectively). Generally, the incidence of plants with Ggt lesions and the severity of root symptoms in direct drilled wheat did not differ significantly between the two stubble treatments. The incidence of eyespot in direct drilled wheat was exacerbated by the retention of wheat stubble on the uncultivated plots (3%, 46% and 66% plants affected in 1984, 1985, and 1986, respectively) but was reduced by burning the stubble (4%, 19% and 33% plants affected in 1984, 1985, 1986, respectively). However, cultivating soil after burning stubble resulted in more plants with eyespot (14%, 39% and 46% plants affected in 1984, 1985 and 1986, respectively) than did burning stubble alone, and in one year the incidence of affected plants in the cultivated treatment was as high as in wheat direct drilled into stubble. The incidence of eyespot was positively correlated ( r=0.85, 0.84 and 0.61 in 1984, 1985 and 1986, respectively) with the incidence of lodged tillers. The incidence of lodging was, generally, highest each year in wheat sown directly into wheat stubble and was reduced by burning wheat stubble or by cropping wheat after lupins. Wojnowicia graminis was frequently isolated, as was Tapesia yallundae, from eyespot lesions suggesting that perhaps not all symptoms of lodging in Victoria can be attributed to Tapesia yallundae.

The effects of different rotations on sugar beet production in land infested with the sugar beet nematode. Heterodera schachtii, in the Salinas Valley of California

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