Soil erosion on farmland is a critical environmental issue and the main source of sediment in the Yellow River, China. Thus, great efforts have been made to reduce runoff and soil loss by restoring vegetation on aband...Soil erosion on farmland is a critical environmental issue and the main source of sediment in the Yellow River, China. Thus, great efforts have been made to reduce runoff and soil loss by restoring vegetation on abandoned farmland. However, few studies have investigated runoff and soil loss from sloping farmland during crop growth season. The objective of this study was to investigate the effects of soil management on runoff and soil loss on sloping farmland during crop growth season. We tested different soybean growth stages (i.e., seedling stage (R1), initial blossoming stage (R2), full flowering stage (R3), pod bearing stage (R4), and initial filling stage (R5)) and soil management practice (one plot applied hoeing tillage (HT) before each rainfall event, whereas the other received no treatment (NH)) by applying simulated rainfall at an intensity of 80 mm/h. Results showed that runoff and soil loss both decreased and infiltration amount increased in successive soybean growth stages under both treatments. Compared with NH plot, there was less runoff and higher infiltration amount from HT plot. However, soil loss from HT plot was larger than that from NH plot in R1–R3, but lower in R4 and R5. In the early growth stages, hoeing tillage was effective for reducing runoff and enhancing rainfall infiltration. By contrast, hoeing tillage enhanced soil and water conservation during the late growth stages. The total soil loss from HT plot (509.0 g/m2) was 11.1% higher than that from NH plot (457.9 g/m2) in R1–R5. However, the infiltration amount from HT plot (313.9 mm) was 18.4% higher than that from NH plot (265.0 mm) and the total runoff volume from HT plot was 49.7% less than that from NH plot. These results indicated that crop vegetation can also act as a type of vegetation cover and play an important role on sloping farmland. Thus, adopting rational soil management in crop planting on sloping farmland can effectively reduce runoff and soil loss, as well as maximize rainwater infiltration during crop growth peri展开更多
Ground cover management and farmyard manure （FYM） management have important roles in organic lettuce production. However, there is not enough information about their combined effects. In order to assess the effects ...Ground cover management and farmyard manure （FYM） management have important roles in organic lettuce production. However, there is not enough information about their combined effects. In order to assess the effects of individual and combined ground cover and FYM management on soil mineral N （NH4-N and NO3-N） dynamics, lettuce yield and economics in organic farming, a two-year field experiment was conducted on a certified organic farm in Kisa6 （Vojvodina, Serbia）. The experiment had a two-factorial split-plot completely randomized block design. FYM was applied on the half of the experimental field as a whole-plot factor, while ground cover management included the following four treatments： （I） control, without ground cover management （0）; （11） hoeing （H）; （111） agrotextile cover; （IV） straw mulch （SM）, which were applied on split plots. The applied SM and AT increased soil moisture by 12.83 and 3.73%, respectively, compared to the control treatment. FYM increased soil mineral N concentration, the lettuce fresh matter （FM） yield and nitrate concentration in lettuce. However, nitrate concentration in lettuce in all treatments was below the limit required by the European Commission （EC） （2001）. The highest lettuce yield was obtained by AT （39 122 kg）, followed by SM （33 925 kg）, and it was higher with FYM application by 16.85%. Hoeing did not positively affect the yield, probably due to its negative effect on soil moisture. Additional profit was higher with FYM, showing the following decreasing order： AT〉H〉SM〉Ф. However, value/cost ratio （VCR） was in the order Ф〉H〉SM〉AT on FYM fertilized plots. FYM application led to higher lettuce yield and higher profit and VCR. In case a farm does not have FYM, SM is the best alternative due to its positive effect on the yield and low investment costs. Keywords： hoeing, agrotextile cover, straw mulch, farmyard manure, FYM, mulch展开更多
Parthenium poses serious threat to modern crop production system and necessitate evaluating control practices for its effective management.Efficacy of different weed control practices for controlling parthenium was ex...Parthenium poses serious threat to modern crop production system and necessitate evaluating control practices for its effective management.Efficacy of different weed control practices for controlling parthenium was explored in conventional and deep tillage systems in the field conditions.Hand hoeing(20 and 35 days after emergence),S-Metolachlor(pre-emergence herbicide),sorghum straw mulch@5 tons ha-1 and combination of hand hoeing and sorghum straw mulch(hand hoeing at 20 and straw mulch at 35 days after emergence)were used as weed control practice.Weedy check where no weed control measure was applied was also included in this experiment for comparison.Results concluded that the all weed management treatments significantly reduced parthenium density,its fresh and dry biomass during both the years of study as compared to weedy check.Maximum sunflower achene yield was recorded in hand hoeing(20 and 35 days after emergence)in combination with deep tillage.So,mold bold plough used for the purpose of deep tillage should be encouraged for better control of parthenium and higher achene yield of sunflower crop(3293.3 kg ha^(-1) in 2017 and 3221.3 kg ha^(-1) in 2018).Moreover,is also inferred that total dose of herbicide might be reduced by using hoeing and mulching in an integrated way.展开更多
Purple soils are widely distributed in the Sichuan Hilly Basin and are highly susceptible to erosion, especially on the cultivated slopes. Quantitative assessment of the erosion rates is, however, difficult due to sma...Purple soils are widely distributed in the Sichuan Hilly Basin and are highly susceptible to erosion, especially on the cultivated slopes. Quantitative assessment of the erosion rates is, however, difficult due to small size of the plots of the manually-tilled land, the complex land use, and steep hillslopes. ^137Cs and ^210Pbex （excess ^210Pb） tracing techniques were used to investigate the spatial pattern of soil erosion rates associated with slope-land under hoe tillage in Neijiang of the Sichuan Hilly Basin. The ^137Cs and ^210Pbex inventories at the top of the cultivated slope were extremely low, and the highest inventories were found at the bottom of the cultivated slope. By combining the erosion rates estimates provided by both ^137Cs and 21~Pbex measurements, the weighted mean net soil loss from the study slope was estimated to be 3 100 t km^-2 year^-1, which was significantly less than 6 930 t km^-2 year^-1 reported for runoff plots on a 10° cultivated slope at the Suining Station of Soil Erosion. The spatial pattern of soil erosion rates on the steep agricultural land showed that hoe tillage played an important role in soil redistribution along the slope. Also, traditional farming practices had a significant role in reducing soil loss, leading to a lower net erosion rate for the field.展开更多
Mobile ad hoc networks are particularly vulnerable to denial of service （DOS） attacks launched through compromised nodes or intruders. In this paper, we present a new DOS attack and its defense in ad hoc networks. T...Mobile ad hoc networks are particularly vulnerable to denial of service （DOS） attacks launched through compromised nodes or intruders. In this paper, we present a new DOS attack and its defense in ad hoc networks. The new DOS attack, called AA hoc Flooding Attack（AHFA）, is that intruder broadcasts mass Route Request packets to exhaust the communication bandwidth and node resource so that the valid communication can not be kept. After analyzed AM hoc Flooding Attack, we develop Flooding Attack Prevention （FAP）, a genetic defense against the AM hoc Flooding Attack. When the intruder broadcasts exceeding packets of Route Request, the immediate neighbors of the intruder record the rate of Route Request. Once the threshold is exceeded, nodes deny any future request packets from the intruder. The results of our implementation show FAP can prevent the AM hoe Flooding attack efficiently.展开更多
基金financially supported by the National Natural Science Foundation of China (41390464, 41571130083, 41271288)
文摘Soil erosion on farmland is a critical environmental issue and the main source of sediment in the Yellow River, China. Thus, great efforts have been made to reduce runoff and soil loss by restoring vegetation on abandoned farmland. However, few studies have investigated runoff and soil loss from sloping farmland during crop growth season. The objective of this study was to investigate the effects of soil management on runoff and soil loss on sloping farmland during crop growth season. We tested different soybean growth stages (i.e., seedling stage (R1), initial blossoming stage (R2), full flowering stage (R3), pod bearing stage (R4), and initial filling stage (R5)) and soil management practice (one plot applied hoeing tillage (HT) before each rainfall event, whereas the other received no treatment (NH)) by applying simulated rainfall at an intensity of 80 mm/h. Results showed that runoff and soil loss both decreased and infiltration amount increased in successive soybean growth stages under both treatments. Compared with NH plot, there was less runoff and higher infiltration amount from HT plot. However, soil loss from HT plot was larger than that from NH plot in R1–R3, but lower in R4 and R5. In the early growth stages, hoeing tillage was effective for reducing runoff and enhancing rainfall infiltration. By contrast, hoeing tillage enhanced soil and water conservation during the late growth stages. The total soil loss from HT plot (509.0 g/m2) was 11.1% higher than that from NH plot (457.9 g/m2) in R1–R5. However, the infiltration amount from HT plot (313.9 mm) was 18.4% higher than that from NH plot (265.0 mm) and the total runoff volume from HT plot was 49.7% less than that from NH plot. These results indicated that crop vegetation can also act as a type of vegetation cover and play an important role on sloping farmland. Thus, adopting rational soil management in crop planting on sloping farmland can effectively reduce runoff and soil loss, as well as maximize rainwater infiltration during crop growth peri
基金supported by the Ministry of Education,Science and Technological Development,Republic of Serbia(TR 31027)
文摘Ground cover management and farmyard manure （FYM） management have important roles in organic lettuce production. However, there is not enough information about their combined effects. In order to assess the effects of individual and combined ground cover and FYM management on soil mineral N （NH4-N and NO3-N） dynamics, lettuce yield and economics in organic farming, a two-year field experiment was conducted on a certified organic farm in Kisa6 （Vojvodina, Serbia）. The experiment had a two-factorial split-plot completely randomized block design. FYM was applied on the half of the experimental field as a whole-plot factor, while ground cover management included the following four treatments： （I） control, without ground cover management （0）; （11） hoeing （H）; （111） agrotextile cover; （IV） straw mulch （SM）, which were applied on split plots. The applied SM and AT increased soil moisture by 12.83 and 3.73%, respectively, compared to the control treatment. FYM increased soil mineral N concentration, the lettuce fresh matter （FM） yield and nitrate concentration in lettuce. However, nitrate concentration in lettuce in all treatments was below the limit required by the European Commission （EC） （2001）. The highest lettuce yield was obtained by AT （39 122 kg）, followed by SM （33 925 kg）, and it was higher with FYM application by 16.85%. Hoeing did not positively affect the yield, probably due to its negative effect on soil moisture. Additional profit was higher with FYM, showing the following decreasing order： AT〉H〉SM〉Ф. However, value/cost ratio （VCR） was in the order Ф〉H〉SM〉AT on FYM fertilized plots. FYM application led to higher lettuce yield and higher profit and VCR. In case a farm does not have FYM, SM is the best alternative due to its positive effect on the yield and low investment costs. Keywords： hoeing, agrotextile cover, straw mulch, farmyard manure, FYM, mulch
文摘Parthenium poses serious threat to modern crop production system and necessitate evaluating control practices for its effective management.Efficacy of different weed control practices for controlling parthenium was explored in conventional and deep tillage systems in the field conditions.Hand hoeing(20 and 35 days after emergence),S-Metolachlor(pre-emergence herbicide),sorghum straw mulch@5 tons ha-1 and combination of hand hoeing and sorghum straw mulch(hand hoeing at 20 and straw mulch at 35 days after emergence)were used as weed control practice.Weedy check where no weed control measure was applied was also included in this experiment for comparison.Results concluded that the all weed management treatments significantly reduced parthenium density,its fresh and dry biomass during both the years of study as compared to weedy check.Maximum sunflower achene yield was recorded in hand hoeing(20 and 35 days after emergence)in combination with deep tillage.So,mold bold plough used for the purpose of deep tillage should be encouraged for better control of parthenium and higher achene yield of sunflower crop(3293.3 kg ha^(-1) in 2017 and 3221.3 kg ha^(-1) in 2018).Moreover,is also inferred that total dose of herbicide might be reduced by using hoeing and mulching in an integrated way.
基金Project supported by the Ministry of Science and Technology of China (No. 2003CB415201)National Natural Science Foundation of China (No. 40671120)+1 种基金the International Atomic Energy Agency (Nos. 12322/RO and UK-12094)the Young Scientist Foundation of Sichuan Province (No.06ZQ026-030)
文摘Purple soils are widely distributed in the Sichuan Hilly Basin and are highly susceptible to erosion, especially on the cultivated slopes. Quantitative assessment of the erosion rates is, however, difficult due to small size of the plots of the manually-tilled land, the complex land use, and steep hillslopes. ^137Cs and ^210Pbex （excess ^210Pb） tracing techniques were used to investigate the spatial pattern of soil erosion rates associated with slope-land under hoe tillage in Neijiang of the Sichuan Hilly Basin. The ^137Cs and ^210Pbex inventories at the top of the cultivated slope were extremely low, and the highest inventories were found at the bottom of the cultivated slope. By combining the erosion rates estimates provided by both ^137Cs and 21~Pbex measurements, the weighted mean net soil loss from the study slope was estimated to be 3 100 t km^-2 year^-1, which was significantly less than 6 930 t km^-2 year^-1 reported for runoff plots on a 10° cultivated slope at the Suining Station of Soil Erosion. The spatial pattern of soil erosion rates on the steep agricultural land showed that hoe tillage played an important role in soil redistribution along the slope. Also, traditional farming practices had a significant role in reducing soil loss, leading to a lower net erosion rate for the field.
基金This project was supported by the National"863"High Technology Development Programof China (2003AA148010) Key Technologies R&D Programof China (2002DA103A03 -07)
文摘Mobile ad hoc networks are particularly vulnerable to denial of service （DOS） attacks launched through compromised nodes or intruders. In this paper, we present a new DOS attack and its defense in ad hoc networks. The new DOS attack, called AA hoc Flooding Attack（AHFA）, is that intruder broadcasts mass Route Request packets to exhaust the communication bandwidth and node resource so that the valid communication can not be kept. After analyzed AM hoc Flooding Attack, we develop Flooding Attack Prevention （FAP）, a genetic defense against the AM hoc Flooding Attack. When the intruder broadcasts exceeding packets of Route Request, the immediate neighbors of the intruder record the rate of Route Request. Once the threshold is exceeded, nodes deny any future request packets from the intruder. The results of our implementation show FAP can prevent the AM hoe Flooding attack efficiently.
