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1.
James K. Mutegi Daniel N. Mugendi Louis V. Verchot James B. Kung’u 《Agroforestry Systems》2008,74(1):37-49
We established hedges/barriers of calliandra (Calliandra calothyrsus Meissner), leucaena (Leucaena trichandra (Zucc.) Urban)) and napier grass (Pennisetum purpureum Schumach) and combination hedges of either calliandra or leucaena with napier grass on slopes exceeding 5% to study the effect
of vegetative barriers on productivity of arable steep-lands in central Kenya. Hedges/barriers were pruned regularly and biomass
incorporated into the plots. Hedge plots were monitored for soil fertility, soil losses and maize crop yield changes. Inorganic-N
concentration in the tree hedge plots was higher than in the control and napier barrier plots after 20 months. Napier grass
barriers were the most effective in reducing erosion losses across the two seasons. The effectiveness of napier grass to significantly
reduce soil erosion was detectable in one year old napier barriers. Soil loss from all the other one year old vegetative treatments
was similar to soil loss from the control. Seventeen month old combination hedge plots recorded lower soil losses than tree
hedges of the same age (P = 0.012). Maize crop yields throughout the trial period were high and similar for leguminous and combination hedge plots,
but lower in the napier grass and control plots. Overall, we observed that the combination hedges seemed to provide a win-win
scenario of reduction in soil erosion combined with improvement of maize crop yields and soil fertility enhancement. We conclude
that vegetative hedges have a potential for improving soil productivity in arable steep-lands of the central highlands of
Kenya, and that in adoption of vegetative hedges for this purpose there are trade-offs between soil conservation, soil fertility
and maize crop yields to be considered.
Throughout the text, tree hedges and leguminous hedges are used interchangeably to imply calliandra and leucaena hedges while
use of barrier/s to refer to a treatment is restricted to monospecific grass strips 相似文献
2.
采用径流小区实验的方法,在李子口小流域设立了6个不同植被类型的径流小区,研究径流小区不同植被条件下降雨对土壤侵蚀的影响,结果如下:(1)不同植被条件下,降雨对土壤侵蚀的影响可表现为撂荒地小区>农耕地小区>林地小区,降雨对林地的土壤侵蚀弱,林地对当地水土的保持能力强,最适合作为当地水土保持的植物措施。(2)总体上,6个径流小区的降雨量、降雨侵蚀力与地表径流量、径流深、土壤流失量之间的相关性均表现为显著正相关的关系,表明降雨对当地土壤侵蚀作用强,需重点防护。研究揭示了研究区降雨与土壤侵蚀的相关性,比较了不同植被条件下降雨对土壤侵蚀的影响,为水土保持的相关研究提供参考与借鉴。 相似文献
3.
4.
P. B. Dharmasena 《Agroforestry Systems》1994,28(3):203-212
Traditional agricultural villages in the dry zone of Sri Lanka are minor watersheds where small earth bank reservoirs provide water for irrigation and domestic purposes. The farmers practise rainfed farming on a shifting basis called chena in the reservoir catchments, which are being degraded due to soil erosion. The consequent sedimentation in reservoirs has reduced the extent of irrigation, and the total farming system has lost its ecological balance and economic sustenance. The present study aimed at identifying suitable farming methods for reservoir catchments in order to prevent further deterioration.The investigation was carried out on plot basis to assess soil loss and runoff from forest, scrub and cultivated lands as well as from four other types of farming lands namely plough-farming, bund-farming and two conservation farming practices: strip mulch and graded hedgerow farming. In graded hedgerow farming hedgerow trees are planted across the slope with a mild gradient of 0.4–0.5%. The study was carried out in a reservoir watershed at Maha Illuppallama, Sri Lanka during 1989/90 major rainy season.Results indicated that the two conservation farming practices generate 33–34% annual runoff while replenishing soil moisture of the watershed. Soil loss data showed that the conservation farming practices provide more than 80% protection against soil erosion while bunding can provide only 40% protection compared to existing shifting cultivation practices. 相似文献
5.
Sloping Agricultural Land Technology (SALT): a sustainable agroforestry scheme for the uplands 总被引：2，自引：0，他引：2
H. D. Tacio 《Agroforestry Systems》1993,22(2):145-152
Soil erosion due to deforestation and heavy rains presents an extremely serious problem in many parts of Southeast Asia, particularly in the upland Philippines. The Mindanao Baptist Rural Life Center (MBRLC), a non-government organization based in the southern part, has developed and spread an agroforestry scheme called Sloping Agricultural Land Technology (SALT) to help control soil erosion and increase crop yields. Basically, SALT utilizes nitrogen-fixing trees as soil binder, fertilizer generator, and livestock feed source. The system also includes annual and perennial diversified food crops grown in the spaces between the hedgerows. The SALT model has been tested both in demonstration plots and farmers' fields, and has proven to be appropriate for use by typical hilly-land farmers. The system can reduce soil erosion and restore moderately degraded hilly lands to a profitable farming system. 相似文献
6.
Erosion losses were investigated in a field experiment, from 90 × 15 m erosion plots at 4% slope in the western Himalayan
valley region of India. The plots were planted with Leucaena leucocephala and Eucalyptus hybrid, either as block plantation
or in alley farming with maize (Zea mays), Chrysopogon fulvus grass or turmeric (Curcuma longa). The treatments also included
contour planting of sole maize, sole Chrysopogon fulvus grass and a clean weeded cultivated fallow. During the nine year study
period, the average annual monsoon rainfall was about 1000 mm and it caused 347 mm runoff and 39 Mg ha-1 soil loss per year from fallow plots. The runoff and soil loss were reduced by 27% and 45% by contour cultivation of maize.
Contour tree-rows or leucaena hedges reduced the runoff and soil loss by 40% and 48%, respectively, over the maize plot, reducing
soil loss to about 12.5 Mg ha-1. This reduction in erosion was primarily due to the barrier effect of tree or hedgerows and micro-terraces formed through
sediment deposition along the contour barriers. Such vegetative measures, that are productive while being protective, offer
viable alternative for erosion control in areas with gentile slopes of the valley region. High density block plantations of
eucalyptus and leucaena almost completely controlled erosional losses and can be recommended for steeper slopes that are vulnerable
to heavy erosion.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
7.
R. A. Nelson P. G. Grist K. M. Menz R. A. Cramb E. P. Paningbatan M. A. Mamicpic 《Agroforestry Systems》1996,35(2):203-220
Soil erosion in the Philippine uplands is severe. Hedgerow intercropping is widely advocated as an effective means of controlling soil erosion from annual cropping systems in the uplands. However, few farmers adopt hedgerow intercropping even in areas where it has been vigorously promoted. This may be because farmers find hedgerow intercropping to be uneconomic compared to traditional methods of farming. This paper reports a cost-benefit analysis comparing the economic returns from traditional maize farming with those from hedgerow intercropping in an upland community with no past adoption of hedgerows. A simple erosion/productivity model, Soil Changes Under Agroforestry (SCUAF), is used to predict maize yields over 25 years. Economic data were collected through key informant surveys with experienced maize farmers in an upland community. Traditional methods of open-field farming of maize are economically attractive to farmers in the Philippine uplands. In the short term, establishment costs are a major disincentive to the adoption of hedgerow intercropping. In the long term, higher economic returns from hedgerow intercropping compared to open-field farming are realised, but these lie beyond farmers limited planning horizons. 相似文献
8.
Sesbania [Sesbania sesban (L.) Merr.] fallows are being promoted as a means for replenishing soil fertility in N-depleted soils of small-scale, resource-poor
farmers in southern Africa. Knowledge of soil water distribution in the soil profile and water balance under proposed systems
is important for knowing the long-term implications of the systems at plot, field and watershed levels. Soil water balance
was quantified for maize (Zea mays L.) following 2-year sesbania fallow and in continuous maize with and without fertilizer during 1998–1999 and 1999–2000 at
Chipata in eastern Zambia. Sesbania fallow increased grain yield and dry matter production of subsequent maize per unit amount
of water used. Average maize grain yields following sesbania fallow, and in continuous maize with and without fertilizer were
3, 6 and 1 Mg ha−1 with corresponding water use efficiencies of 4.3, 8.8 and 1.7 kg mm−1 ha−1, respectively. Sesbania fallow increased the soil-water storage in the soil profile and drainage below the maximum crop root
zone compared with the conventionally tilled non-fertilized maize. However, sesbania fallow did not significantly affect the
seasonal crop water use, mainly because rainfall during both the years of the study was above the normal seasonal water requirements
of maize (400 to 600 mm). Besides improving grain yields of maize in rotation, sesbania fallows have the potential to recharge
the subsoil water through increased subsurface drainage and increase nitrate leaching below the crop root zone in excess rainfall
seasons.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
梁山慈竹在退耕还林中的水土保持效应研究 总被引：5，自引：0，他引：5
利用小型径流观测场对比观测降雨时间集中的梁山慈竹林和未退耕种植红薯的耕地的17次降雨、10次水土流失过程进行效益对比,分析侵蚀量、径流量与降雨因子的关系。结果表明,退耕还梁山慈竹林的穿透降水率为89.14%,茎流率平均为1.57%,林冠截持降水率为9.29%;凋落物层的最大持水量约为27.54 t.hm-2,相当于水深2.4～3.3 mm,占降水量的14.46%～19.88%;与未退耕地相比,梁山慈竹林的平均径流量比耕地减少24.6%,而耕地侵蚀量约是林地的4.7倍,林地降水的泥沙侵蚀平均减少量达到78.56%。梁山慈竹有较好的水土保持作用,能够明显地减少地表径流和泥沙侵蚀。 相似文献
10.
Forested land cleared for agriculture in the Blue Mountains of Jamaica rapidly loses its productivity leading to further slash-and-burn cultivation and the degradation of more forest. Contour hedgerows of Calliandra calothyrsus Meissner have been shown to reduce water runoff and soil erosion, and products of the species have a wide range of uses in the local farming community. A trial was established at 1550 m in which the locally naturalised population of C. calothyrsus was compared with seven provenances from across the species' ecological range. There was considerable variation between provenances of C. calothyrsus in all the above-ground growth variables measured and, although the local provenance performed moderately well, it was clear that there is potential to improve the suitability of the species for a range of local uses by the introduction of new provenances. One provenance combined high above-ground productivity with low fine root-length density, especially in the inter-hedgerow area: it offers particular potential for use in simultaneous agroforestry systems providing wood and foliage products whilst not imposing high levels of competition with crop plants for below-ground resources. Although there were significant differences between provenances in the distribution of roots between the hedgerow and inter-row areas, they did not differ in the distribution of roots between soil depths. There were only limited differences between provenances in the response of their subsequent growth to harvesting. However, significant block × provenance interactions suggested that the performance of C. calothyrsus provenances may be difficult to predict between sites and farmers should be encouraged to carry out trial planting of a number of provenances to find those which best match their farm environment and needs.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
11.
Kotaro Zushi 《Journal of Forest Research》2006,11(5):351-358
Digital terrain modeling was used to evaluate landscape-level spatial variation of soil C and N storage and site productivity
in Japanese cedar (Cryptomeria japonica D. Don) stands. Soil C and N storage were measured in samples from surface soils (0–25 cm depth) of 29 Japanese cedar stands
in the 205-ha Myougodani watershed, Toyama Prefecture. The site index (C. japonica tree height at age 40 years) was used as a measure of forest productivity. Seven terrain attributes (elevation, slope gradient,
aspect, profile curvature, plan curvature, openness, and wetness index) were calculated from a digital elevation model. Soil
C and N storage were negatively correlated with slope gradient and positively correlated with openness. Variation in the site
index was closely related to the wetness index. The prediction models using terrain attributes as explanatory variables explained
50% of the variability in soil C storage, 53% of the variability in soil N storage, and 75% of the variability in site index.
This result demonstrated that this technique is useful for estimating the spatial distribution of soil properties and productivity
in forest landscapes. On the other hand, there was no correlation between site index and soil C and N storage. Use of the
prediction models in a geographic information system revealed that the spatial distribution of forest productivity differed
considerably from those of soil C and N storage. 相似文献
12.
Productivity of annual cropping and agroforestry systems on a shallow Alfisol in semi-arid India 总被引：6，自引：0，他引：6
An experiment was conducted at ICRISAT Center, Patancheru, India from June 1984 to April 1988 on a shallow Alfisol to determine whether the productivity of annual
crop systems can be improved by adding perennial species such as Leucaena leucocephala managed as hedgerows. Except in the first year, crop yields were suppressed by Leucaena due to competition for moisture. The severity of competition was high in years of low rainfall and on long-duration crops
such as castor and pigeonpea. Based on total biomass, sole Leucaena was most productive; even on the basis of land productivity requiring both Leucaena fodder and annual crops, alley cropping had little or no advantage over block planting of both components. Application of
hedge prunings as green manure or mulch on top of 60 kg N and 30 kg P
2
O
5ha−1 to annual crops did not show any benefit during the experimental period, characterized by below average rainfall. Indications
are that (i) alley cropping was beneficial in terms of soil and water conservation with less runoff and soil loss with 3 m
alleys than with 5.4 m alleys, and (ii) root pruning or deep ploughing might be effective in reducing moisture competition. 相似文献
13.
14.
W. Pansak T. Hilger B. Lusiana T. Kongkaew C. Marohn G. Cadisch 《Agroforestry Systems》2010,79(2):123-144
Soil conservation approaches and agroforestry systems can play an important role in controlling erosion from tropical hillside
cropping systems. Experimental testing of their potential application domain and design, however, is costly and time consuming.
We, therefore, tested the ability of the Water, Nutrient and Light Capture in Agroforestry Systems (WaNuLCAS) model. The specific
objectives of the study were: (i) to evaluate the WaNuLCAS model for predicting water induced erosion under different soil
conservation strategies, (ii) to use the model for a better understanding of various soil conservation measures in controlling
erosion, and (iii) to assess the magnitude and dynamics of key processes influencing the efficiency of soil conservation measures.
A 3-year-data set (2003–2005) from a field experiment from the Loei province in Northeast Thailand on the impact of soil conservation
(Leucaena hedgerow, Jack bean relay cropping) under minimum tillage on runoff and soil loss was tested. Results indicated
that WaNuLCAS was able to predict soil loss and runoff well at the test site; i.e. R
2 = 0.80 and 0.82, respectively. In the calibration procedure a sub data set was used, where adjusting crop development parameters
was an important step for improving simulated soil loss (R
2 = 0.75) and runoff (R
2 = 0.89). Soil conservation measures such as Leucaena hedges were effective techniques to control runoff and soil loss. Implementing
a dynamic soil structure module in combination with minimum tillage reduced runoff and soil loss via an increase in available
macropores and hence drainage over time which improved simulation results. Relay cropping with Jack bean played an important
role in the control treatment in reducing soil loss during the third year due to its additional soil cover and positive impact
on soil fertility as suggested by the model. Hence, the WaNuLCAS model is a valuable tool to study and understand processes
and to explore management options for improving tropical hillside cropping threatened by soil degradation. 相似文献
15.
Degraded Aravalli hills in western India require rehabilitation through resource conservation and afforestation for meeting the biomass needs of resource-poor tribes of the region. Rainwater harvesting treatments i.e., control, Contour trench (CT), Gradonie (G), Box trench (BT) and V-ditch (VD) were prepared in <10%, 10–20% and >20% slopes categories and Dendrocalamus strictus L. seedlings were planted in August 2005 with a view to conserve soil and water and increase the productivity of the hills. Soil water content (SWC), survival and height of D. strictus plants were highest (P < 0.05) in <10% slope and all these variables decreased with increase in slope. SWC increased by 27.45% and 25.68% in <10% and >20% slopes, respectively than in 10–20% slope. From lowest in control SWC increased by 11.95%, 20.21%, 17.61% and 11.49% in CT, G, BT and VD treatments, respectively. Growth variables were highest in VD plots but the increase in shoot number was highest (2.9-fold) in CT plots. Increase in effects of rainwater harvesting with time indicated by a change in production pattern from highest (P < 0.05) fresh and dry herbage in <10% slope in 2005 to 10–20% slope (24.66% and 26.09%) in 2006 and >20% slope (42.42% and 48.35%, respectively) in 2007. The increase in herbage was 1.17–2.40-fold in fresh and 1.20–2.52-fold in dry herbage over control. Highest (P < 0.01) production was in V-ditch plots. The treatments order for herbage production was C < CT < G < BT < VD. But the production was highest in BT in <10% and in V-ditch plots in 10–20 and >20% slopes. Conclusively, soil water status is affected by natural slope, stony soil surface and rainwater harvesting structures influencing seedling growth and herbage production. Box trench and V-ditch enhanced surface soil water facilitating herbage growth, whereas contour trench facilitated deep soil water storage, which was made available to the plants after monsoon. Thus rainwater harvesting practices enhanced vegetation cover and productivity of the degraded hills and can be replicated to conserve soil resource and increase biomass for rural poor of the region. 相似文献
16.
A study was undertaken in Ohio to determine whether the presence of black locust hedgerows would increase water shortage on crop land. Water was applied to bare soil which had carried pure stand maize in the previous growing season, and to the previously established alley cropping plots, some of which had 100 cm deep below-ground fiberglass partitions to prevent root competition for soil moisture in the alleys. Direct soil evaporation was reduced by covering the soil with a black polyethylene sheet. Soil moisture remaining in the top 45 cm soil depth was monitored for 8 days. Soil 1 had a higher organic carbon content and contained more moisture than Soil 2, which had more gravel than Soil 1. In Soil 2 there was significantly less water in alleys without below-ground partitions than on bare soil. In alleys without below-ground partitions, the hedgerows reduced soil moisture content of the alleys without below-ground partitions, the hedgerows reduced soil moisture content of the alleys by about 8% on Soil 1 and 32% on Soil 2, after 8 days following water application. In the top 45 cm depth of Soil 1, the influence of the hedgerows in the same treatment was large within 76 cm of the hedgerows but declined farther inside the alleys. For Soil 2 which had more gravel in the lower soil layers, which prevented deep growth of black locust roots, the influence of the hedgerows was pronounced throughout the alleys but was also most marked within the 76 cm distance from the hedges. 相似文献
17.
Coarse root growth of Veronese poplar trees varies with position on an erodible slope in New Zealand
Poplars are commonly planted on moist, unstable pastoral hill country to prevent or reduce soil erosion, thereby maintaining
hillslope integrity and pasture production. Mechanical reinforcement by poplar root systems aids slope stabilisation, particularly
when the roots are anchored into the fragipan or underlying rock. Total root length, mass and distribution of coarse roots
(≥2 mm diameter) were determined for three Populus deltoides × nigra ‘Veronese’ trees in their 12th growing season after being planted as 3 m poles at upper slope (TU), mid-slope (TM) and lower
slope (TL) positions on an erodible hillslope near Palmerston North in the southern North Island. Most of the roots were distributed
in the top 40 cm of soil. Depth of penetration of vertical roots was dependent on slope position and limited by the available
depth of the soil above a fragipan (0.35 m at the upper slope to 1.4 m at the lower slope). Roots penetrated the fragipan
at the upper slope position where the soil depth was shallowest, and at the mid-slope, but not the lower slope position. Total
coarse root length was 287.9 m for TU, 1,131.3 m for TM and 1,611.3 m for TL, and total coarse root dry mass (excluding root
crown) was 8.15 kg for TU, 38.77 kg for TM and 81.35 kg for TL. 相似文献
18.
IntroductionState Forestry Administration of China issuedmanagement investigated for forest harvesting andregeneration in 1987, which included three methodsof slash disposal (State Forestry Administration1987). The first slash treatment is slash piling, whichis divided into scattered piling and strip piling. Thescattered piling is suitsble for selection cutting, stripcutting and tending cutting. Strip piling is used fOllowing clear cutting. The second slash treatment isspreading of slash. … 相似文献
19.
Cost-benefit analysis of alternative forms of hedgerow intercropping in the Philippine uplands 总被引：3，自引：1，他引：2
Considerable resources have been expended promoting hedgerow intercropping with shrub legumes to farmers in the Philippine
uplands. Despite the resources committed to research and extension, persistent adoption by farmers has been limited to low
cost versions of the technology including natural vegetation and grass strips. In this paper, cost-benefit analysis is used
to compare the economic returns from traditional open-field maize farming with returns from intercropping maize between leguminous
shrub hedgerows, natural vegetation strips and grass strips. An erosion/productivity model, Soil Changes Under Agroforestry,
was used to predict the effect of erosion on maize yields. Key informant surveys with experienced maize farmers were used
to derive production budgets for the alternative farming methods.
The economic incentives revealed by the cost-benefit analysis help to explain the adoption of maize farming methods in the
Philippine uplands. Open-field farming without hedgerows has been by far the most popular method of maize production, often
with two or more fields cropped in rotation. There is little persistent adoption of hedgerow intercropping with shrub legumes
because sustained maize yields are not realised rapidly enough to compensate farmers for establishment and maintenance costs.
Natural vegetation and grass strips are more attractive to farmers because of lower establishment costs, and provide intermediate
steps to adoption. Rural finance, commodity pricing and agrarian reform policies influence the incentives for maize farmers
in the Philippine uplands to adopt and maintain hedgerow intercropping.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
Modeling the impacts of agroforestry systems on the spatial patterns of soil erosion risk in three catchments of Claveria, the Philippines 总被引：2，自引：0，他引：2
Agroforestry is one of the preferred land-use options for smallholder farms in tropical landscapes due to its ability to increase land productivity and protect soil from erosion. We investigated the impacts of agroforestry and traditional monocropping systems on the spatial patterns of soil erosion risk in three catchment areas of Claveria, the Philippines, using WaTEM/SEDEM, a spatially distributed soil erosion model. The model predicts soil loss in catchments based on the Revised Universal Soil Loss Equation (RUSLE) by taking into account the influences of rainfall, soil erodibility, vegetation cover and 2-dimensional variations in landscape structure. The predicted soil erosion rates were transformed into risk values in order to identify areas with higher risk for erosion. Model results indicate a large spatial variability in soil erosion risk patterns, with higher risks occurring on slopes greater than 8% on land under non-agroforestry use. The soil erosion risk maps were used to formulate site-specific agroforestry recommendations for future landscape amelioration plans. 相似文献