Dryland Farming Areas Research Articles

Monitoring and forecasting drought impact on dryland farming areas

AbstractFrequent drought amplifies the need for a warning system and forecasting models for damage to crop yields. This study developed an operational model to assess agricultural drought impact. The dryland areas of Kermanshah Province (Iran) were selected to test the proposed modelling system. The model predicted the consequences of drought damage on wheat crop during critical stages of growth (emergence, vegetative growth, initiation of flowering, grain filling, and maturity) as a drought loss indicator. Two types of input were evaluated to correlate climate conditions versus drought losses. The first group comprises the Palmer Drought Severity Index, Z‐index, Crop Moisture Index, Crop‐Specific Drought Index (CSDI), Standardized Precipitation Index, and Effective Drought Index with one‐ to three‐month timescales used as meteorological indices. The second group, which is consistent of the vegetation condition index and temperature condition index, is based on satellite data. Also a new satellite‐based version of CSDI, so‐called standardized CSDI (S‐CDSI), where evapotranspiration was estimated using surface energy balance algorithm for land, is used. Adaptive Neuro‐Fuzzy Inference Systems (ANFIS) technique was used for forecasting with genetic algorithms applied to select appropriate inputs from among the large number of indices. It was concluded that the combination of meteorological and satellite indices performed best in forecasting crop yield. As expected, accuracy improved over the growth stages as the crop developed. Enhancement of the model with a GIS platform made it possible to present the results more suitably, hence helping users to make more realistic decisions. Copyright © 2012 Royal Meteorological Society

EVALUATION OF WHEAT-CHICKPEA INTERCROPS AS INFLUENCED BY NITROGEN AND WEED MANAGEMENT

Wheat and chickpea are most important crops in dryland farming areas of Iran. Weeds have major impact on chickpea grain yield. This experiment was carrie d out to increase land use efficiency and weed suppression through intercropping in dryland agricu ltural research station-Sararood, Kermanshah, Iran during 2008-10. The experimental design layout was factorial split plot based on randomized complete block design with three replications. The main plot s contained factorial plots of N fertilization with 3 levels (N1: no fertilization, N2: 60 kg.ha -1 urea for wheat and 20 kg.ha -1 for chickpea and N3: Nitragin as a biofertilizer + 30 kg.ha -1 urea for wheat and chickpea no urea); and weed con ditions with 2 levels (weed infested and weed free). The third factor as sub-pl ots arranged in main plots was cropping patterns wi th 10 levels (1: wheat Sole Crop (wh.SC), 2: chickpea Sol e Crop (ch.SC), 3: wh./ch. Mixed Intercropping (wh./ch.MIC) in 1:1 ratio, 4: wh./ch. MIC in 2:1 ra tio, Row Intercropping (RIC) 1row wh.:1row ch., 6: Strip Intercropping (SIC) 5wh.1ch.5wh.2ch, 7: SIC 7wh.:2ch., 8: SIC 2wh.:7ch., 9: SIC 9wh.:4ch. and 10: SIC 4wh.:9ch.). Weed and nitrogen factors didn’t have s ignificant effect on wheat yield and patterns numbe r 5, 8 and 10 produced highest wheat grain yield respect ively. Chickpea yield was significantly reduced by wheat when intercropped, but high Land Equivalent Ratio (LER) derived. Effect of weeds on chickpea Grain Yield (GY) was significant and GY in weed infested was nearly half of GY in weed free condition. LER in weed infested condition in both years was hi gher than weed free condition. Weed dry matter in f ive intercropping patterns clearly decreased as compare to chickpea sole crop. It is concluded that interc ropping can be used as a method to decrease the inputs of w heat and chickpea crops, especially for nitrogen fertilizing and weed control.

Effects of no-tillage management on soil biochemical characteristics in northern China

SUMMARYField experiments (15 years) were carried out to study the effects of no-tillage (NT) and conventional tillage (CT) management practices on the soil chemical properties, microbial biomass, soil enzymatic activities and winter wheat yield on a cinnamon soil in Shanxi, on the Chinese Loess Plateau. Compared to CT, NT increased soil organic carbon, soil total nitrogen and soil total phosphorus in the 0–100 mm layer by 25, 18 and 7%, respectively. Microbial biomass C and N contents under NT were 41 and 57% greater than under CT on the same layer. In general, higher enzymatic activities were found in the more superficial layers of soil under NT than under CT in the same layer. Winter wheat yield wasc. 20% higher under NT than under CT. These findings have implications for understanding how conservation tillage practices improve soil quality and sustainability in the rainfed dryland farming areas of northern China.

Soil physical properties and infiltration after long‐term no‐tillage and ploughing on the Chinese Loess Plateau

Water is the most limiting factor for crop production in dryland farming. A better understanding of the long‐term impact of tillage and residue management systems on soil structure and water infiltration is necessary for the further development of conservation tillage practice to improve water use efficiency. The objectives of this study were to assess the influence of no‐till with residue retention (NT) and conventional (plough) tillage with residue removal (CT) on soil properties and soil water transmission characteristics in a winter wheat (Triticum aestivum) monoculture system in Shanxi, on the Chinese Loess Plateau. Soil physical parameter measurements were made in the top 30 cm depth in September 2007 after 16 years under the two tillage treatments. Compared with CT treatment, NT significantly (P < 0.05) reduced soil bulk density (7.1%) in the 20–30 cm soil layer, and increased macroporosity (>60 μm, 17.0%) and saturated hydraulic conductivity (249%) in the 15–30 cm soil layer. There were no significant differences in these soil physical properties between tillage systems in the 0–15 cm layer. In addition, plant available water and water infiltration rate were greater in the NT treatment. The improved soil quality parameters and water infiltration from this long‐term experiment indicate that no‐tillage with residue retention is a promising farming system for the dryland farming areas of northern China.

Land-Use and Land-Cover Dynamics in the Central Rift Valley of Ethiopia

Understanding the complexity of land-use and land-cover (LULC) changes and their driving forces and impacts on human and environmental security is important for the planning of natural resource management and associated decision making. This study combines and compares participatory field point sampling (pfps) and remote sensing to explore local LULC dynamics. The study was conducted in two peasant associations located in the central Ethiopian Rift Valley, which is a dry-land mixed farming area exposed to rapid deforestation. From 1973-2006, the area of cropland doubled at the expense of woodland and wooded-grassland in both of the study sites. Major deforestation and forest degradation took place from 1973-1986; woodland cover declined from 40% to 9% in one of the study sites, while the other lost all of its original 54% woodland cover. Our study concludes that assessing LULC dynamics using a combination of remote sensing and pfps is a valuable approach. The two methods revealed similar LULC trends, while the pfps provided additional details on how farmers view the changes. This study documents dramatic trends in LULC over time, associated with rapid population growth, recurrent drought, rainfall variability and declining crop productivity. The alarming nature of these trends is reflected in a decrease in the livelihood security of local communities and in environmental degradation. Given these dry-land conditions, there are few opportunities to improve livelihoods and environmental security without external support. If negative changes are to be halted, action must be taken, including building asset bases, instituting family planning services, and creating opportunities outside these marginal environments.

Soil chemical properties and microbial biomass after 16 years of no-tillage farming on the Loess Plateau, China

Data from a 16-year field experiment conducted in Shanxi, on the Chinese Loess Plateau, were used to compare the long-term effects of no-tillage with straw cover (NTSC) and traditional tillage with straw removal (TTSR) in a winter wheat ( Triticum aestivum L.) monoculture. Long-term no-tillage with straw cover increased SOM by 21.7% and TN by 51.0% at 0–10 cm depth and available P by 97.3% at 0–5 cm depth compared to traditional tillage. Soil microbial biomass C and N increased by 135.3% and 104.4% with NTSC compared to TTSR for 0–10 cm depth, respectively. Under NTSC, the metabolic quotient (CO 2 evolved per unit of MBC) decreased by 45.1% on average in the top 10 cm soil layer, which suggests that TTSR produced a microbial pool that was more metabolically active than under NTSC. Consequently, winter wheat yield was about 15.5% higher under NTSC than under TTSR. The data collected from our 16-year experiment show that NTSC is a more sustainable farming system which can improve soil chemical properties, microbial biomass and activity, and thus increase crop yield in the rainfed dryland farming areas of northern China. The soil processes responsible for the improved yields and soil quality, in particular soil organic matter, require further research.

Effects of check dams, reforestation and land-use changes on river channel morphology: Case study of the Rogativa catchment (Murcia, Spain)

Catchment-scale land-use changes and erosion-control works have geomorphic consequences as can be seen in the morphological evolution of river channels. An analysis of the consequences of check dams and reforestation works that took place in the 1970s on the channel morphology in the Rogativa catchment (53 km 2) in SE Spain is conducted. A land-use change detection analysis of the catchment between 1956, 1981, and 1997 was performed. River channel changes were mapped between 1956 and 1997. Furthermore, morphological field mapping of river reaches, location of all check dams, and characterization of the areas upstream and downstream of them were carried out. Sediment sampling along 10.5 km of the channel and analysis of time series precipitation data were performed. A slight decreasing tendency of the annual precipitation and erosivity of rainfall since the 1940s has been detected. In addition, vegetation cover has increased enormously in the catchment since the 1950s. The dense forest has increased fivefold and the dryland farming areas have been reduced by a 57%. Of all 58 check dams, 72% are silted and 81% of them show erosion features downstream. The active channel has narrowed and many of the lateral bars have been colonized by vegetation. A lateral displacement of the active channel is also observed. Sediment supply has decreased because of the reduction of non-point sources of sediment (i.e., decrease in dryland farming areas and pasture land) and sediment retention behind check dams. Water flow with an increased transport capacity started erosion locally downstream of check dams. The decrease of sediment supply has caused a general armoring of channels. Currently, most of the check dams have lost much of their trap efficiency, erosion of the alluvial wedges upstream of dams is starting, degrading their structure and mobilizing the sediments retained during the past 30 years. Although seemingly clear that land-use changes, reforestation, and correction works affect the channel responses and sediment dynamics, the relative importance of each of these factors with respect to the morphological channel dynamics remains unclear, which is proposed for further research.

Effects of 15 years of conservation tillage on soil structure and productivity of wheat cultivation in northern China

An understanding of long-term tillage and straw management impact on soil structure and productivity is necessary for the further development of conservation tillage practice in dryland farming areas. Data from a 15-year field experiment conducted in Shanxi, on the loess plateau of northern China, were used to compare the long-term effects of no-till and residue cover (NTSC) with conventional tillage (CT) in a winter wheat (Triticum aestivum L.) monoculture. Long-term CT and straw removal resulted in poor soil structure and low productivity. Mean soil bulk density in NTSC was 1.5% less than in CT and capillary porosity (&lt;60 μm) 3.2% greater. Water stability of macro-aggregates &gt;2 mm was much greater for NTSC in the 0–0.20 m profile. Soil organic matter and total N and P were 27.9%, 25.6%, and 4.4% greater in NTSC, respectively, and earthworms (19/m2) were found only in the no tillage treatment. Crop yield and water use efficiency tended to be higher under NTSC than under CT, especially in the years of low rainfall, suggesting that the change in soil structure has provided a better environment for crop development. Our 15-year experimental data indicate that NTSC is a more sustainable farming system, which can improve soil structure, and increase productivity with positive environmental impacts in the rainfed dryland farming areas of northern China.

Agricultural intensification and loss of matrix habitat over 23 years in the West Wimmera, south-eastern Australia

The global trend toward more intensive forms of agriculture is changing the nature of matrix habitat in agricultural areas. Removal of components of matrix habitat can affect native biota at the paddock and the landscape scale, particularly where intensification occurs over large areas. We identify the loss of paddock trees due to the proliferation of centre pivot irrigation in dryland farming areas as a potentially serious threat to the remnant biota of these areas. We used a region of south-eastern Australia as a case study to quantify land use change from grazing and dryland cropping to centre pivot irrigation over a 23-year period. We also estimated rates of paddock tree loss in 5 representative landscapes within the region over the same period. The total area affected by centre pivots increased from 0 ha in 1980 to nearly 9000 ha by 2005. Pivots were more likely to be established in areas which had originally been plains savannah and woodlands containing buloke ( Allocasuarina luehmannii), a food source for an endangered bird. On average, 42% of paddock buloke trees present in 1982 were lost by 2005. In the two landscapes containing several centre pivots, the loss was 54% and 70%. This accelerated loss of important components of matrix habitat is likely to result in species declines and local extinctions. We recommend that measures to alleviate the likely negative impacts of matrix habitat loss on native biota be considered as part of regional planning strategies.

Land use changes detection and spatial distribution using digital and satellite data, case study: Farim drainage basin, Northern of Iran

Land use change may influence many natural phenomena and ecological processes, including runoff, soil erosion, sedimentation and soil conditions. Decreasing of forest area in the North of Iran is one of the critical problems in recent years. The aims of this study are to detect land use changes between 1967 to 2002 using satellite images of Land Sat 7 ETM+ (2002), aerial photos and digital topographic maps (1967 and 1994) and to investigate the effect of some physical and socio economical factors on land use dynamic. The forest maps of 1967 and 1994 were collected from 1:25000 digital maps in Micro Station and then Arc/View 3.2 software. The interpretation of the maps of other land uses were derived using aerial photos. ETM+ satellite data were used to generate land use map dated 2002. The images quality assessment and georeferencing were performed on images. Different suitable spectral transformations such as rationing, PCA, Tasseled Cap transformation and data fusion were performed on the images in ENVI and IDRISI software. Image classification was done using supervised classification maximum likelihood and minimum distance classifier utilizing original and synthetic bands resulted from diverse spectral transformation and the forest area was separated from non forest area. Unsupervised classification was used to separate other types of land use. Change detection has shown that the forest area decreased between 1967 and 2002 by 2.99% from 7322.22 to 6947.23 ha. Also, the area with irrigated land farms have been increased to 202.01 ha (1.61%) and the dry land farming area decreased to 9.2%. Overlaying the map of land use change with roads and residential maps showed that by increasing the distance from roads and residential areas and villages, deforestation rate and conversion of forest to arable lands were reduced, but conversion of arable lands to released lands increased. Also, the most quantity of deforestation was observed in lower slope angle, but the dry land farming converted to release lands was observed in higher slope angle.

Dust storm erosion and its impact on soil carbon and nitrogen losses in northern China

There is increased awareness of the environmental impacts of soil carbon (C) and nitrogen (N) losses through wind erosion, especially in areas heavily affected by dust storm erosion. This paper reviews the recent literature concerning dust storm-related soil erosion and its impact on soil C and N losses in northern China. The purpose of our study is to provide an overview of the area of erosion-affected soils and to estimate the magnitude of soil C and N losses from farmland affected by dust storm erosion. According to the second national soil erosion remote-sensing survey in 2000, the area affected by wind erosion was 1.91 million km 2, accounting for 20% of the total land area in China. This area is expanding quickly as the incidence of heavy dust storms has greatly increased over the last five decades, mainly as a result of the intensification of soil cultivation. The economic and ecological damage caused by wind erosion is considerable. Heavily affected areas show a loss of nutrients and organic carbon in soils and the heavily degraded soils are much less productive. Compared with the non-degraded soil, the C and N contents in degraded soils have declined by 66% and 73%, respectively. The estimated annual losses per cm toplayer of soil C and N by dust storm erosion in northern China range from 53 to 1044 kg ha − 1 and 5 to 90 kg ha − 1 , respectively. Field studies suggest that soil losses by wind erosion can be reduced by up to 79% when farmers shift from conventional soil tillage methods to no-till. Thus shifting to no-till or reduced tillage systems is an effective practice for protecting soil and soil nutrients. Our study indicates that soil conservation measures along with improved soil fertility management measures should be promoted in dry-land farming areas of northern China. As erosion is a major mechanism of nutrient withdrawal in these areas, we plead for the development of accurate methods for its assessment and for the incorporation of erosion, as a nutrient output term, in nutrient budget studies.

The potential role of sheep in dryland grain production systems

In dryland farming areas of Montana, annual precipitation is not sufficient for annual planting of cereal grains. Instead, a crop-summer fallow farming system is used to conserve soil moisture and increase available nitrogen for subsequent crop growth. Managing this summer fallow, either by mechanical means or with herbicides, is the highest variable cost associated with dryland grain production in Montana. Wheat stem sawfly, Cephus cinctus (Hymenoptera: Cephidae) is the most damaging insect pest to Montana’s US$ 1 billion per year grain industry. Weed management is the largest variable cost associated with drylandgrain production andsummerfallow management. Sixfields, located onfour commercial Montana grainoperations,were grazedbysheepandgoatsfromOctober2002toMay2003todeterminetheimpactgrazinghasonC.cinctuspopulations,weedand volunteer cereal growth, soil compaction, and gravimetric water concentrations. Percent C. cinctus larval mortality and percent reduction of weed biomass was greater in grazed compared to non-grazed areas (P 0.01). No differences in soil bulk density or gravimetric water concentrations were found between treatments (P > 0.11). Grazing fallow with sheep and goats appears to successfully improve C. cinctus and weed management in grain production systems without impacting soil compaction. # 2005 Elsevier B.V. All rights reserved.

Optimizing the Management of Soil Erosion

Abstract To reduce the environmental and economical impact of soil erosion resulting from improper management of land-use activities, a study was initiated by the Iranian Ministry of Construction on Syahrood, one of the sub-basins of the Damavand watershed in Iran. Land-use optimization is one of the appropriate strategies for soil conservation. It can empower the decision maker or watershed manager to choose from different land-use scenarios to reach the best decision with the different combinations of variables. The output results of the sediment yield model, including the integration of the Modified Universal Soil Loss Equation (MUSLE) with Spatial Analysis System-Geographic Information System (SPANS-GIS), along with the net income of each land use were used as input in the land-use optimization model for minimizing the sediment yield and maximizing farm production of each land use. The multi-objective linear programming simplex method of Steuer (1995) was used to solve the problem. The optimization process allocated dryland farming areas to rangelands if no changes were made to the current supporting practice system. The expected annual sediment yield from the entire sub-basin was reduced by 2420 tonnes/year (or by 5%) and the annual net farm income was increased by 3.99 billion Iranian Rial/year (or by 134%).

Water management and grain production in dryland farming areas in China

SUMMARY The grain production from dryland farming areas of China has great potential. At present, water utilized for grain production is only 37% of the potential. The potential yield per unit is 2.7 times that of current yield on dryland farming. Obtaining higher grain output and water use efficiency will involve many techniques including traditional farming systems, mulching tillage, water harvesting and water-saving irrigation engineering. From present agricultural production situations of the arid and semi-arid areas, rain-fed agriculture should be developed to a reasonable extent to meet the requirements of increasing grain production and economic growth. The approach for sustainable development should be adopted to strengthen international exchange and cooperation so as to enhance comprehensive sustainable development of dryland farming in China.

Increased Dryland Cropping Intensity with No‐Till Barley

For most of a century, the wide spread practice of growing only one crop every other year in a tillage‐based wheat (Triticum aestivum L.)–fallow rotation has degraded soils and contributed to environmental problems in low‐precipitation (&lt;350 mm annual) dryland regions of the inland Pacific Northwest of the USA. Many growers in this 2‐million‐ha cropland area are increasing the intensity of cropping with spring crops, but most use conventional tillage (CT) for seedbed preparation. The agronomic performance of spring barley (Hordeum vulgare L.), sown into CT seedbeds with double‐disk drills or into standing stubble with several types of no‐till (NT) drills (hoe, single disk, and notched coulter), was determined in two experiments conducted both in 1996 and 1997 where the previous crop was either winter wheat or spring barley. We measured stand establishment, seed‐zone temperature, soil water, dry biomass accumulation, rhizoctonia root rot, surface residue retention, and grain yield components. Plant stand , dry biomass accumulation , and spike density as single independent variables, and combined in a multiple regression model , were strongly correlated (P &lt; 0.001) to grain yield. Early‐season seed‐zone temperatures were cooler under NT, but seed‐zone water was slightly higher with CT. Low spike density consistently occurred in a wide row spacing (406 mm) NT drill treatment, and the highest overall yields were obtained with NT drills with rows spaced 255 mm or less. Rhizoctonia root rot was severe on seminal roots in all treatments in three out of four trials, but did not appear to limit yields, possibly due to healthy crown roots and favorable growing conditions. No‐till spring sowing into undisturbed standing stubble (2420–5230 kg ha−1) can produce grain yields equal to or exceeding those under CT and can provide environmental and potential soil quality benefits for low‐precipitation dryland farming areas in the inland Pacific Northwest.

The relationship between land use and organochlorine compounds in streambed sediment and fish in the Central Columbia Plateau, Washington and Idaho, USA

AbstractWe analyzeds streambed sediment and fish in the Central Columbia Plateau in eastern Washington and Idaho for or ganochlorine pesticides and polychlorinated biphenyls (ΣPCB). Our objective was to assess the effects of land use on the occurrence and distribution of these compounds; land uses in the study area included forest, dryland and irrigated farming, and urban. We detected 16 organochlorine compounds in streambed sediment and fish tissue; fish usually had more compounds and a greater frequency of detection. The most frequently detected compound was ΣDDT (sum of six isomers), which was found in 52% of bed sediment samples and 94% of whole fish composite samples. The other commonly detected compounds were dimethyl tetrachloroterephthalate (DCPA), dieldrin, hexachlorobenzene, and Σchlordane (sum of cis‐ and trans‐chlordane, cis‐ and trans‐nonachlor oxychlordane, heptachlor, and heptachlor epoxide). Forest was the only land use with no detections of organochlorine compounds in either fish or bed sediment. Hexachlorobenzene was the only organochlorine pesticide detected at concentrations that differed significantly among land uses: concentrations were higher in the dryland farming areas than in the irrigated farming or urban areas. In agricultural areas irrigated by surface water, ΣDDT concentrations in both streambed sediment and fish tissue were related to the percentage of land irrigated by water delivered via furrows (gravity irrigation), although ΣDDT was not detectable in bed sediments until gravity irrigation exceeded 30%. Because of the relation between gravity irrigation and soil erosion, our study supports the importance of controlling soil erosion in order to reduce the overall loading of organochlorine compounds to surface waters.

Growth and fodder yield of the Gliricidia sepium provenances in guardrow system in dryland farming area in Bali, Indonesia

Growth and fodder yield of the Gliricidia sepium provenances in guardrow system in dryland farming area in Bali, Indonesia

Land cover mapping in a Salinised Dryland farming area in southeastern Australia using landsat TM data

Abstract The changing patterns of dry land salinisation in the Eastern Wimmern area in Southeastern Australia are closely related to changes in regional water balance regimes. Predictive mapping of dry land salinisation in this area requires distributed water balance modelling, for which, timely and accurate information on regional land cover patterns and dynamics from computer‐assisted processing of remotely sensed digital data, although not yet routinely adoptable, is regarded as one of the key inputs. With this purpose in mind, a multispectral classification procedure based on the mosaic model (Jupp 1988) is designed, and applied to a Landsat 5 TM subimage (1024 x 960 pixels) captured on Feb. 21 1988 from the Charlton area of the Eastern Wimmera, using microBRlAN, a PC‐based digital image processing system. Results show that application of the mosaic model to TM data for the Eastern Wimmera can yield 14‐class land cover maps with classification accuracy of 83 ± 7.52 % at the 95% confidence limits.

Growth and fodder yield of the Gliricidia sepium provenances in fence system in dryland farming area in Bali, Indonesia

Growth and fodder yield of the Gliricidia sepium provenances in fence system in dryland farming area in Bali, Indonesia

Chemical composition and nutritive value of the Gliricidia sepium provenances in dryland farming area in Bali, Indonesia

Chemical composition and nutritive value of the Gliricidia sepium provenances in dryland farming area in Bali, Indonesia