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... IAM YUNUSA 1'3, RH SEDGLEY 1 and KMH SIDDIQUE: 1Crop and Pasture Sciences Group, School of Agriculture, University of Western ... A pan (mm), Es-evaporation from uncropped soil (mm), E~c-evaporation from soil beneath... more
... IAM YUNUSA 1'3, RH SEDGLEY 1 and KMH SIDDIQUE: 1Crop and Pasture Sciences Group, School of Agriculture, University of Western ... A pan (mm), Es-evaporation from uncropped soil (mm), E~c-evaporation from soil beneath the wheat canopy (ram), ET-evapotranspiration ...
Research Interests: Environmental Science, Agronomy, Biological Sciences, Triticum Aestivum, Seasonality, and 15 moreEnvironmental Sciences, Water use efficiency, Transpiration, Water Use, Western Australia, Soil Temperature, Indexation, Anthesis, Grain Yield, Water Content, Dry Matter, Leaf Area, Soil Water, Spring Wheat, and Mulch
Research Interests: Mathematics, Agronomy, Seasonality, Water use efficiency, Soil moisture, and 15 moreWater Use, Pasture, Vigna Radiata, Plant species, Dry Matter, Agroforestry Systems, Agroforestry System, Lolium Perenne L., Pinus radiata, Radiation Use Efficiency, Land Equivalent Ratio, Growing Season, Medicago sativa, Dry Matter Yield, and Crop Coefficient
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BACKGROUND Salinity constrains agricultural sustainability and crops differ in their respond. We tested the hypothesis that contrasting responses in canopy and stomatal traits to salinity will cause convergence of water-use for okra and... more
BACKGROUND Salinity constrains agricultural sustainability and crops differ in their respond. We tested the hypothesis that contrasting responses in canopy and stomatal traits to salinity will cause convergence of water-use for okra and tomato. RESULTS Stomata were found almost exclusively (>90%) on the lower leaf surface of tomato, but okra produced ~30% of stomata on the upper leaf surface. While salinity reduced the magnitudes of canopy and stomata traits in tomato, stomata traits were either unaffected or enhanced in okra. Salinity reduced the rates and duration of stomatal conductance (gs ) in both crops, more severely in tomato in which gs was restricted to early mornings in contrast to its bell-shape trend in okra. The superiority of okra in its stomata traits was compensated by the larger plant canopies in tomato resulting in both daytime canopy transpiration and total plant water-use were within 17% and 28%, respectively, of each other for the two crops. A tight stomatal control of transpiration that minimised use of water and its uptake from the soil conferred a superior salinity tolerance on tomato over okra. In both crops, D was inversely correlated with A, while water-use was positively correlated with plant leaf area, in addition to D and A in tomato; gs was also correlated with stomata area index in tomato. CONCLUSIONS Differences in water-use for both crops were relatively narrow notwithstanding the several-fold differences in their canopy and stomata traits. Under saline conditions, irrigation intervals should be long for tomato but short for okra. This article is protected by copyright. All rights reserved.
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Impermeable subsoil is a major constraint to root growth and water infiltration in most duplex soils of Australia, but can be ameliorated by channels or biopores created by dead and decomposed roots of plant species that are adapted to... more
Impermeable subsoil is a major constraint to root growth and water infiltration in most duplex soils of Australia, but can be ameliorated by channels or biopores created by dead and decomposed roots of plant species that are adapted to these soils. In the current study, we evaluated whether a 6-year phase of native woody species planted in belts created sufficient biopores to significantly improve the soil structure of a yellow Chromosol, us (but not E. nitens) plantations in Tasmania because of low mean minimum temperatures. Conditions within 3 weeks of planting induced severe photoinhibition in non-shaded seedlings. This was associated with increased anthocyanin and photodamage in non-shaded E. nitens and E. globulus. As a result, there was 20% mortality in non-shaded E. globulus. In contrast, shaded seedlings of both species had levels of photoinhibition and anthocyanin that were largely similar to those before planting and there was no photodamage. Levels of anthocyanin i...
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Napier grass (Pennisetum purpureum Schumach.) is an important fodder and relatively drought-tolerant crop in tropical and subtropical regions, especially in developing countries. For this and other species, tools are needed for... more
Napier grass (Pennisetum purpureum Schumach.) is an important fodder and relatively drought-tolerant crop in tropical and subtropical regions, especially in developing countries. For this and other species, tools are needed for identifying drought-tolerant cultivars to aid selection for semi-arid environments. We determined tissue water status, carbon assimilation, biomass yield and forage quality for Napier grass cvv. Bana and Atherton grown in bins and subjected to three soil-water supply levels (100, 50 or 25% of field capacity) in glasshouses set at either low (15−25°C) or high (25−35°C) temperature regimes, over three growing cycles. Our aim was to explore whether differences in leaf water potential (LWP) and carbon assimilation rates could be reliable indicators of the relative yield potential and forage quality of the two cultivars in environments prone to water and heat stresses. At the low soil-water supply of 25% and low temperature, Bana had lower (more negative) LWP and ...
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SummaryThe growth and development of maize and soya bean when grown in mixtures in different proportions and arrangements were studied at Samaru (11° 11' N, 38° E) and Yandev (07° 23' N, 09° 10' E) in the savannah belts of... more
SummaryThe growth and development of maize and soya bean when grown in mixtures in different proportions and arrangements were studied at Samaru (11° 11' N, 38° E) and Yandev (07° 23' N, 09° 10' E) in the savannah belts of Nigeria. The crops were sown in both pure and mixed stands. The pure-stand densities were 513 plants/m2 for maize and 20·15 plants/m2 for soya bean. Mixtures were made in three proportions: additive (100:100), containing 100% of the sole crop population of each crop; semi-additive (67:67), containing 67% of each crop's sole population; and replacement (67:33 and 33:67), containing 67% of one crop's population to the other's 33%. The mixtures were formed either on the same ridge (in-ridge) or on different ridges (alternate ridge).Maize grain yield at Samuru was not significantly reduced in mixtures except where its proportion was reduced to 33% of its sole crop density. Seed yields in soya bean were significantly reduced in all mixtures, and...
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With the renewed interest in the use of coal fly-ash for amendment of agricultural soils in Australia, we assessed how earthworms, as indicators of soil health, responded to this ameliorant. We assessed survival, weight, burrowing and... more
With the renewed interest in the use of coal fly-ash for amendment of agricultural soils in Australia, we assessed how earthworms, as indicators of soil health, responded to this ameliorant. We assessed survival, weight, burrowing and elemental concentrations for earthworms of a native unnamed Megascolecid species and of exotic Aporrectodea trapezoides in intact soil cores treated with an alkaline fly-ash
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... IAM YUNUSA 1'3, RH SEDGLEY 1 and KMH SIDDIQUE: 1Crop and Pasture Sciences Group, School of Agriculture, University of Western ... A pan (mm), Es-evaporation from uncropped soil (mm), E~c-evaporation from soil beneath... more
... IAM YUNUSA 1'3, RH SEDGLEY 1 and KMH SIDDIQUE: 1Crop and Pasture Sciences Group, School of Agriculture, University of Western ... A pan (mm), Es-evaporation from uncropped soil (mm), E~c-evaporation from soil beneath the wheat canopy (ram), ET-evapotranspiration ...
Research Interests: Environmental Science, Agronomy, Biological Sciences, Triticum Aestivum, Seasonality, and 15 moreEnvironmental Sciences, Water use efficiency, Transpiration, Water Use, Western Australia, Soil Temperature, Indexation, Anthesis, Grain Yield, Water Content, Dry Matter, Leaf Area, Soil Water, Spring Wheat, and Mulch
Quantifying water use of native vegetation is an important contribution to understanding landscape ecohydrology. Few studies provide long‐term (more than one growing season) estimates of water use and even fewer quantify interseasonal and... more
Quantifying water use of native vegetation is an important contribution to understanding landscape ecohydrology. Few studies provide long‐term (more than one growing season) estimates of water use and even fewer quantify interseasonal and interannual variation in transpiration. Globally, changes in land use are significantly altering landscape ecohydrology, resulting in problems such as dryland salinity and excessive groundwater recharge. Estimating stand water use is complex in multispecies forests, due to the differences in relationships among sapwood area, basal area and tree size for co‐occurring species. In this article, we examine seasonal and interannual variation in transpiration rate of the tree canopy of two co‐occurring species (a conifer Callitris glaucophylla J. Thompson & L.A.S. Johnson and a broad‐leaved Eucalyptus crebra F. Muell.) in an open woodland in eastern Australia. Evapotranspiration of understorey species was measured using an open‐top chamber, and tree wate...
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Research Interests: Environmental Science, Agronomy, Irrigation, Seasonality, Water use efficiency, and 15 moreEvapotranspiration, Water balance, Environmental Variables, Vineyard, Penman Monteith, Vitis Vinifera, Water Use, Vine, Pasture, Indexation, Soil Profile, Soil Water, Furrow irrigation, Cover Crop, and Growing Season
... These were followed with two recent ones by Jala and Goyal 13 13. Jala, S. and Goyal, D. 2006. Fly ash as a soil ameliorant for improving crop production—a review. ... [CrossRef], [PubMed], [Web of Science ®] View all references The... more
... These were followed with two recent ones by Jala and Goyal 13 13. Jala, S. and Goyal, D. 2006. Fly ash as a soil ameliorant for improving crop production—a review. ... [CrossRef], [PubMed], [Web of Science ®] View all references The more recent review by Jala and Goyal 13 13. ...
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Cropping of acid sulfate soils requires effective treatment of their inherently low pH. We evaluated the efficacy of applications of two levels of lime (0 or 2 Mg/ha), two levels of organic fertiliser (0 or 5 Mg/ha), and three levels of... more
Cropping of acid sulfate soils requires effective treatment of their inherently low pH. We evaluated the efficacy of applications of two levels of lime (0 or 2 Mg/ha), two levels of organic fertiliser (0 or 5 Mg/ha), and three levels of biochar (0, 10 or 30 Mg/ha) in a factorial design for ameliorating acidity in an acid sulfate soil, and measured the subsequent growth and yield of baby corn (Zea mays L.). Lime increased soil pH(H2O) from 3.75 to 4.12, salinity from 1.72 to 1.95 dS/m, and cob yield by 30%. None of the amendments significantly altered total organic carbon or total nitrogen concentrations in the soil. Biochar additions increased cob yields by an average of 28% on both unlimed and limed soil. Addition of organic fertiliser increased cob yield by 45% on unlimed soil but had no significant effect on yields on limed soil. The yields obtained with liming were similar to the highest yields achieved with biochar or organic fertiliser applied either separately or in combinati...
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This was a trial on evaluating Napier grass cultivars performance under two contrasting environments (lowlands and highlands) in Kenya.
Research Interests: Geography, Agronomy, Productivity, Grasses, Yield, and 5 moreForage, Dry Matter, Gramineas, Rendimiento, and Napier Grass
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Summary This study was undertaken to obtain an increased understanding of how current water management practices affect fruit yield in olives (Olea europaea L.) in Australian groves, in order to identify opportunities for improvement. We... more
Summary This study was undertaken to obtain an increased understanding of how current water management practices affect fruit yield in olives (Olea europaea L.) in Australian groves, in order to identify opportunities for improvement. We assessed the relationships between seasonal water supply and fruit yield on a range of olive groves that were either irrigated or rain-fed. All the groves experienced inadequate water supply at the start of the season until early Summer (December). This limited the transpiration (T) component of evapotranspiration (ET) and certainly constrained fruit yield. Seasonal averages for the crop coefficient (Kc) ranged between 0.30 for the lightly irrigated groves, to 0.40 for the well-irrigated groves, but fluctuated during the season from as high as 0.7 during wet periods to as low as 0.2 during extended dry periods. Peak rates for daily T in Summer ranged from 1.0 mm (53 l d–1 tree–1) for the rain-fed grove, to 4.0 mm (196 l d–1 tree–1) for groves that were regularly irrigated. We observed indications for advective enhancement of T to levels higher than the expected theoretical maxima. Transpiration accounted for between 35 – 67% of seasonal ET in the rain-fed and well-irrigated groves, respectively. Water-use efficiency for fruit was between 3.2 – 32.1 kg ha–1 mm–1 of ET, and between 3.1 – 58.1 kg ha–1 mm–1 of T. These were equivalent to a range of 1.2 – 4.2 g of fruit produced tree–1 l–1 of water transpired. We found no yield advantage with irrigation that did not raise seasonal ET well above 600 mm, and T above 300 mm. The late commencement of irrigation constrained T in Spring and early Summer, the avoidance of which should increase fruit yield.
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SUMMARYTen accessions of Napier grass (Pennisetum purpureum Schumach.) were evaluated for their dry matter (DM) yield and forage quality in a semi-arid lowland (Katumani) and a relatively wet highland (Muguga) over seven growth cycles... more
SUMMARYTen accessions of Napier grass (Pennisetum purpureum Schumach.) were evaluated for their dry matter (DM) yield and forage quality in a semi-arid lowland (Katumani) and a relatively wet highland (Muguga) over seven growth cycles from 2011 to 2013 in tropical Kenya. Three biomass yield clusters were identified from the 10 accessions as high-yielding (HYC), medium-yielding (MYC) and low-yielding (LYC) clusters for both sites. Total biomass (shoot and root) yields (t ha−1) over the seven growth cycles were 25.3 for HYC, 22.2 for MYC and 19.6 for LYC at Katumani and 40.0, 41.4 and 29.1 at Muguga. Total biomass yield averaged over the study period was DM 22.4 t ha−1 at Katumani and 36.8 at Muguga. Rainfall productivity was higher at Katumani (28.8 kg ha−1 mm−1) than 20.8 kg ha−1 mm−1 at Muguga. Neutral detergent fibre (NDF) was lower in LYC, which was more leafy than the other clusters and there was little difference in NDF between the two sites.
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This study was undertaken to ascertain whether pulses, instead of pasture legumes, were more beneficial to grain yields by the following cereals in ley rotation systems. We evaluated growth processes for pastures or pulses and growth and... more
This study was undertaken to ascertain whether pulses, instead of pasture legumes, were more beneficial to grain yields by the following cereals in ley rotation systems. We evaluated growth processes for pastures or pulses and growth and yields for the following sequential crops of wheat and barley in a 3-crop rotation. The pasture or pulse phase that formed the main
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In this review, we propose the use of suitable plant species, termed primer-plants, for the primary purpose of preparing soil conditions for the benefit of following crops. Such plants may be used in the temperate agricultural belts of... more
In this review, we propose the use of suitable plant species, termed primer-plants, for the primary purpose of preparing soil conditions for the benefit of following crops. Such plants may be used in the temperate agricultural belts of southern Australia, where dryland salinity is a major environmental and agricultural problem that threatens the viability of many crop production enterprises. It
Research Interests: Environmental Science, Agronomy, Biological Sciences, Environmental Sciences, Agronomy for sustainable agriculture, and 12 moreCrop Production, Water Table, Water Use, Soil Structure, Plant species, FARMING SYSTEM, Native Species, Soil Water, Subsoil, Dryland salinity, Root growth, and nutrient cycle
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Research Interests: Earth Sciences, Environmental Science, Soil Science, Soil Physics, Environmental Sciences, and 15 morePower Generation, Soils, Fly Ash, Sandy soil, Soil retention water, Coal Fly Ash, Aggregate Stability, Mean Weight Diameter, Soil Amendment, Bulk Density, Soil Water, Fine Particles, Rainfall Simulation, Agricultural Soil, and Field capacity
Soybean is little grown in the semi-arid zone of the northern fringes of the Sudan savannah belt of Nigeria despite a seemingly good potential for the early maturing varieties. To explore the potential of the crop in this region a... more
Soybean is little grown in the semi-arid zone of the northern fringes of the Sudan savannah belt of Nigeria despite a seemingly good potential for the early maturing varieties. To explore the potential of the crop in this region a determinate soybean line was sown at 2 sites in 1986 at four planting densities of 7.5, 10.0, 12.5 and 15.0 plants/m2 in three row spacings of 40, 60 and 75 cm. Both the above-ground biological and grain yields increased with planting density. Row spacing had significant effect on yield only at the early planted Site 1, where 40 cm row spacing outyielded other rows. The increase in yield at high densities and narrow row was mainly due to increased pod and grain numbers/m2 Onset of competition began to manifest as from flowering and intensified thereafter. However, the post anthesis competition did not affect grain filling and so mean grain weight and harvest index were similar in all treatments. Late planting at Site 2 reduced yield by between 20 and 30 % particularly at high densities and in narrow rows. The results indicate a fairly good potential for soybean in this region, and yield advantage due to moderately high planting densities and narrow spacing.
Research Interests: Agronomy, Biology, Agronomy/crop science, Soybean, Arid, and 5 moreGlycine, Glycine max, Sowing, Row Spacing, and Plant density
Low tillering lines of spring wheat (Triticum aestivum L.), were evaluated for their ability to conform to a high yielding ideotype in a dryland environment with spring drought. The ideotype was based on a concept of saving water as a... more
Low tillering lines of spring wheat (Triticum aestivum L.), were evaluated for their ability to conform to a high yielding ideotype in a dryland environment with spring drought. The ideotype was based on a concept of saving water as a result of reduced canopy development before anthesis; this should improve moisture supply for grain filling, thus reducing the effect of drought. Five genotypes were compared under two nitrogen (N) levels, and at similar plant densities, at a site in the drier wheatbelt area of southwestern Australia. The genotypes formed three tillering groups based on the maximum number of culms produced: a free tillering group (G1), which included the standard cultivar Gamenya, with 4.3 culms per plant, an intermediate tillering group (G2) with 3.2 culms per plant, and a low ullenng group (G3) with 2.4 culms per plant. Leaf area indices (LAI) were strongly affected by N but this was not reflected in total water use and biological yield. However, water was prematurely depleted before anthesis as a result of rapid early leaf development in response to N, and this reduced grain yield. Reduced tillering produced no significant increase in gram yield over the controls; fewer tillers per plant failed to suppress LAI development and water-use before anthesis because of a compensating increase in LAI; this resulted from a greater leaf size in the reduced tillering lines. Hence the low tillering lines did not fully conform to the requirements of the ideotype. The development of low tillering lines is seen as a significant advance towards the ideotype; with yields comparable to commercial cultivars grown in the region, their performance indicates a potential for substantially higher yields if compensating increases in leaf development can be suppressed.
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SUMMARYTwo tropical and one temperate genotypes of maize were grown during the cool dry winter seasons in northern Nigeria. The tall tropical genotypes produced a greater leaf area index and more above-ground dry matter, and so had a... more
SUMMARYTwo tropical and one temperate genotypes of maize were grown during the cool dry winter seasons in northern Nigeria. The tall tropical genotypes produced a greater leaf area index and more above-ground dry matter, and so had a higher crop growth rate, than the dwarf temperate genotype. However, the early flowering temperate genotype yielded more grain than the late flowering tropical genotypes. Although the initial low winter temperatures prolonged the preflowering growth period in the tropical genotypes, the terminal high temperatures hastened maturity and were associated with poor grain filling.Maíz de temporada seca en Nigeria
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The loss of moisture by evaporation from soil under crop canopies (Esc) has been recognized as a major cause of poor water use efficiency (WUE), and hence poor grain yield, in crops grown in environments with limited rainfall. Agronomic... more
The loss of moisture by evaporation from soil under crop canopies (Esc) has been recognized as a major cause of poor water use efficiency (WUE), and hence poor grain yield, in crops grown in environments with limited rainfall. Agronomic approaches to restrain Esc aim to reduce the transmission of solar radiation to the soil beneath the crop by improving ground cover by the crop canopy. However, the sparse canopies produced in these environments have a limited effect on evaporation during the energy dependent first stage (Es1); much of the evaporation is independent of energy at the soilsurface (Es2), and therefore less sensitive to the influence of the crop canopy. Manipulating plant arrangement, primarily by changing row spacing, may provide a simple approach for improving ground cover and restraining E,, without changing GAI, and thus improving WUE and grain yield. To explore the potential benefit of variable row spacing on Esc and grain yield in the dry (300 mm) Mediterranean env...
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The Agricultural Production Systems Simulator (APSIM) suite of models was used to predict dynamics in water and nitrogen in soil, as well as the growth and yield of sequential crops of wheat and barley in pasture–wheat–barley rotations,... more
The Agricultural Production Systems Simulator (APSIM) suite of models was used to predict dynamics in water and nitrogen in soil, as well as the growth and yield of sequential crops of wheat and barley in pasture–wheat–barley rotations, between 1995 and 1997 at Roseworthy, South Australia. The NWHEAT model satisfactorily predicted above-ground dry matter, leaf area index and grain yields for both crops in rotations with either grassy (Grass) or medic (Medic) pastures, including the lack of significant response of yield to nitrogen fertiliser applied to wheat at sowing. Simulation data for soil water, from SOILWAT2, was consistent with measured data. Simulation with SOILN2, however, largely underestimated soil nitrogen, due to excessive uptake by the simulated wheat during the season when nitrogen was abundant and water supply readily available. Thus, the soil nitrate had to be reset at sowing for the following barley crop; simulated soil nitrate agreed with the measured data in this...
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... Merredin has a dry mediterra nean climate with a MayOctober growing season. The mean annual rainfall is 310 ram, of which 68 falls between May and July, and about 22 in the last 3 months of the growing season. ... CLS consists of 0.4... more
... Merredin has a dry mediterra nean climate with a MayOctober growing season. The mean annual rainfall is 310 ram, of which 68 falls between May and July, and about 22 in the last 3 months of the growing season. ... CLS consists of 0.4 208 IAM YUNUSA ET AL. ...
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Analyses of sensitivity of Global Food Security (GFS) score to a key set of supply or demand factors often suggest population and water supply as being the most critical and on which policies tend to focus. To explore other policy... more
Analyses of sensitivity of Global Food Security (GFS) score to a key set of supply or demand factors often suggest population and water supply as being the most critical and on which policies tend to focus. To explore other policy options, we characterised the nexus between GFS and a set of supply or demand factors including defining including population, agricultural and industrial water-use, agricultural publications (as a surrogate for investment in agricultural research and development [R&D]), and corruption perception index (CPI), to reveal opportunities for attaining enduring GFS. We found that despite being the primary driver of demand for food, population showed no significant correlation with GFS scores. Similarly agricultural water-use was poorly correlated with GFS scores, except in countries where evaporation exceeds precipitation and irrigation is significant. However, GFS had a strong positive association with industrial water-use as a surrogate for overall industriali...
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In dryland regions such as the cereal zone of South Australia, the most limiting biophysical resource is water. Field experiments were conducted to quantify the use of soil-water and production of biomass in sole crops and crop mixtures... more
In dryland regions such as the cereal zone of South Australia, the most limiting biophysical resource is water. Field experiments were conducted to quantify the use of soil-water and production of biomass in sole crops and crop mixtures in a study designed to evaluate the efficiency of intercropping in the use of this natural resource. Water-use and water use efficiency (ratio of biomass to water-use) for sole wheat were greater than for sole chickpea, but were similar for sole wheat and mixture. The land equivalent ratio showed no advantage or disadvantage of intercropping over sole crops. However, the water in the soil with the mixture was greater than the sole wheat. The presence of legumes in the mixture probably increased the N pool of the soil and might enhance the growth of the current and subsequent crops in an environment where the soil is poor in nutrient content. Media summary The study showed that intercropping was as efficient as sole wheat, while a greater amount of re...