Cereal Cropping Systems Research Articles

Development approach and evaluation of the Nutrient Expert software for nutrient management in cereal crops

Meeting the demand for more food in the next 20–30years requires intensifying cereal cropping systems and increasing current yields to about 70–80% of the genetic yield potential. A dynamic and robust nutrient management approach such as site-specific nutrient management (SSNM) will be essential to increase yields and optimize profits while maintaining the productivity of these intensive cropping systems. SSNM has increased yield and profit in rice, maize, and wheat in major cropping systems in Asia; but, crop advisors have found it complex and difficult to implement in the field. Nutrient Expert (NE) was developed to provide crop advisors with a simpler and faster way to use SSNM. NE enables crop advisors to develop SSNM recommendations using existing site information. Nutrient Expert for Hybrid Maize (NEHM) increased yield and profit of farmers in Indonesia and the Philippines. In Indonesia, NEHM increased yield by 0.9tha−1, which increased profit by US$ 270ha−1 over farmer’s fertilizer practice (FFP). Compared with FFP, NEHM recommendations reduced fertilizer P (−4kgha−1), increased fertilizer K (+11kgha−1), and did not significantly change fertilizer N. In the Philippines, NEHM increased yield by 1.6tha−1 and profit by US$ 379ha−1 compared with FFP. Compared with FFP, NEHM gave higher rates of all three nutrients (+25kgNha−1, +4kgPha−1, and +11kgKha−1), which substantially increased fertilizer costs (US$ 64ha−1) but still increased profit by about six times the additional investment in fertilizer. NE accounts for the important factors affecting site-specific recommendations, which makes it a suitable starting point for developing nutrient management tools to reach more users.

Grass-clover undersowing affects nitrogen dynamics in a grain legume–cereal arable cropping system

A field experiment was carried out in an arable organic cropping system and included a sequence with sole cropped fababean (Vicia faba L.), lupin (Lupinus angustifolius L.), pea (Pisum sativum L.), oat (Avena sativa L.) and pea–oat intercropping with or without an undersown perennial ryegrass (Lolium perenne L.) – white clover (Trifolium repens L.) catch crop followed by a first crop of spring wheat (Triticum aestivum L.) and second crop of winter triticale (Triticale hexaploide L.). The rotation sequence was repeated twice. Natural 15N abundance techniques were used to determine grain legume N2 fixation and 15N labeling technique to determine the fate of pea and oat residue N recovery in the subsequent crop. The subsequent spring wheat and winter triticale crop yields were not significantly affected by the previous main crop, but a significant effect of catch crop undersowing was observed. A higher soil mineral N content in the soil profile without undersown grass-clover increased the spring wheat yield. This effect was circumvented in the subsequent winter triticale, where yields in the treatments with catch crops undersown were significantly greater. The grass-clover catch crop after grain legumes had a higher grass proportion before incorporation as compared to grass-clover after oat, which had the greatest clover proportion. The dynamic response of interspecific interactions in the catch crop to the soil mineral N levels is moderating the preceding effect of main crops in the subsequent cereal – and sometimes to a higher degree than the main crop effect. For research involving rotation principles it is recommended to evaluate cumulative effects over several years and not only single seasons.

Shifts in comparative advantages for maize, oat and wheat cropping under climate change in Europe

Climate change is anticipated to affect European agriculture, including the risk of emerging or re-emerging feed and food hazards. Indirectly, climate change may influence such hazards (e.g. the occurrence of mycotoxins) due to geographic shifts in the distribution of major cereal cropping systems and the consequences this may have for crop rotations. This paper analyses the impact of climate on cropping shares of maize, oat and wheat on a 50-km square grid across Europe (45–65°N) and provides model-based estimates of the changes in cropping shares in response to changes in temperature and precipitation as projected for the time period around 2040 by two regional climate models (RCM) with a moderate and a strong climate change signal, respectively. The projected cropping shares are based on the output from the two RCMs and on algorithms derived for the relation between meteorological data and observed cropping shares of maize, oat and wheat. The observed cropping shares show a south-to-north gradient, where maize had its maximum at 45–55°N, oat had its maximum at 55–65°N, and wheat was more evenly distributed along the latitudes in Europe. Under the projected climate changes, there was a general increase in maize cropping shares, whereas for oat no areas showed distinct increases. For wheat, the projected changes indicated a tendency towards higher cropping shares in the northern parts and lower cropping shares in the southern parts of the study area. The present modelling approach represents a simplification of factors determining the distribution of cereal crops, and also some uncertainties in the data basis were apparent. A promising way of future model improvement could be through a systematic analysis and inclusion of other variables, such as key soil properties and socio-economic conditions, influencing the comparative advantages of specific crops.

Molecular Basis of Resistance to Herbicides Inhibiting Acetolactate Synthase in Two Rigid Ryegrass (Lolium rigidum) Populations from Australia

Acetolactate Synthase- (ALS) inhibiting herbicides are important components for the control of ryegrass species infesting cereal-cropping systems worldwide. Although resistance to ALS herbicides in ryegrasses has evolved more than 25 yr ago, few studies have been dedicated to elucidate the molecular mechanisms involved. To this end, we have investigated the molecular basis of chlorsulfuron, sulfometuron-methyl, and imazapyr resistance in AUS5 and AUS23, two ryegrass populations from Australia. Comparison between whole-plant herbicide assays and DNA sequencing results showed that resistance to the nonmetabolizable herbicide sulfometuron-methyl was associated with four different proline mutations at ALS codon position 197 (P197) in AUS23. In addition to three P197 amino acid changes impacting on the efficacies of the two sulfonylurea herbicides, the tryptophan to leucine target-site mutation at ALS codon position 574 (W574L) was present in AUS5, conferring resistance to both sulfometuron-methyl and imazapyr. The samples were also characterized by non target-site-based resistance impacting on the metabolizable herbicide chlorsulfuron only. Interestingly, compound mutant heterozygotes threonine/serine at ALS position 197, and plants with double mutations at positions 197 and 574 were detected, thus reflecting the ability of this outcrossing species to accumulate mutant alleles. Whole-plant dose-response assays conducted on predetermined wild-type and mutant genotypes originating from the same populations allowed for a more precise estimation of the dominant and very high levels of resistance associated with the proline to serine target-site mutation at ALS codon position 197 (P197S) and W574L mutations. The two highly efficient polymerase chain reaction- (PCR) based derived cleaved amplified polymorphic sequence (dCAPS) markers developed here will allow for quick confirmation of 197 and 574 ALS target-site resistance in ryegrass species field samples and also contribute to identify populations characterized by other likely resistance mechanisms in this important weed species.

Acetolactate synthase proline (197) mutations confer tribenuron-methyl resistance in Capsella bursa-pastoris populations from China

The increasing use of AHAS-inhibiting herbicides has resulted in evolved resistance in key dicot weeds infesting cereal cropping systems worldwide. Shepherd’s purse (Capsellabursa-pastoris) is a common dicot weed species in wheat in China with populations that have evolved resistance to the AHAS herbicide tribenuron-methyl. The seeds of eight resistant populations were collected from wheat fields and one susceptible population from road side in Hebei province of China. All eight populations showed high level resistance to tribenuron-methyl with resistance indices of over 100 fold based on whole plant dose response assays in the greenhouse. Comparison of the AHAS gene sequences of the susceptible and resistant populations with Arabidopsis revealed that proline at position 197 of the AHAS gene was substituted by threonine in population CAPBU-HB-2, serine in populations CAPBU-HB-3, CAPBU-HB-4, CAPBU-HB-5, and CAPBU-HB-6, leucine in population CAPBU-HB-7 and CAPBU-HB-8, histidine in population CAPBU-HB-9. The study confirmed tribenuron-methyl resistance in shepherd’s purse in Hebei province of China due to target site mutations at AHAS codon position 197.

Interactions between the root pathogen Rhizoctonia solani AG‐8 and acetolactate‐synthase‐inhibiting herbicides in barley

The widespread acceptance of reduced-tillage farming in cereal cropping systems in the Pacific Northwest of the United States has resulted in increased use of herbicides for weed control. However, soil residual concentrations of widely used imidazalone herbicides limit the cultivation of barley, which is more sensitive than wheat. In addition, increased severity of the root rot disease caused by Rhizoctonia solani is associated with reduction in tillage. Many crops exhibit altered disease responses after application of registered herbicides. In this study, the injury symptoms in barley caused by sublethal rates of two acetolactate synthase (ALS)-inhibiting herbicides, imazamox and propoxycarbazone-sodium, were assessed in factorial combinations with a range of inoculum concentrations of the root rot pathogen Rhizoctonia solani AG-8. Both herbicides and pathogen had negative impacts on plant growth parameters such as root and shoot dry weight, shoot height and first leaf length, and interactions between pathogen and herbicide were detected. The results suggested that sublethal rates of herbicides and R. solani could alter severity of injury symptoms, possibly owing to the herbicide predisposing the plant to the pathogen.

Impacts of projected maximum temperature extremes for C21 by an ensemble of regional climate models on cereal cropping systems in the Iberian Peninsula

Abstract. Crops growing in the Iberian Peninsula may be subjected to damagingly high temperatures during the sensitive development periods of flowering and grain filling. Such episodes are considered important hazards and farmers may take insurance to offset their impact. Increases in value and frequency of maximum temperature have been observed in the Iberian Peninsula during the 20th century, and studies on climate change indicate the possibility of further increase by the end of the 21st century. Here, impacts of current and future high temperatures on cereal cropping systems of the Iberian Peninsula are evaluated, focusing on vulnerable development periods of winter and summer crops. Climate change scenarios obtained from an ensemble of ten Regional Climate Models (multimodel ensemble) combined with crop simulation models were used for this purpose and related uncertainty was estimated. Results reveal that higher extremes of maximum temperature represent a threat to summer-grown but not to winter-grown crops in the Iberian Peninsula. The study highlights the different vulnerability of crops in the two growing seasons and the need to account for changes in extreme temperatures in developing adaptations in cereal cropping systems. Finally, this work contributes to clarifying the causes of high-uncertainty impact projections from previous studies.

Soil organic carbon dynamics in a dryland cereal cropping system of the Loess Plateau under long-term nitrogen fertilizer applications

Aims Concerns over food security and global climate change require an improved understanding of how to achieve optimal crop yields whilst minimizing net greenhouse gas emissions from agriculture. In the semi-arid Loess Plateau region of China, as elsewhere, fertilizer nitrogen (N) inputs are necessary to increase yields and improve local food security.

Soil Nitrogen and Nitrogen-Use Efficiency under Long-Term No-till Practice

Land-use change from perennial grasslands to cultivated croplands leads to reduced soil organic C (SOC) and total N. Among other factors, introduction of annual crops and soil disturbance by tillage may account for reduced amounts of SOC and total N. However, agricultural practices of no-till and N fertilizer application may maintain soil N in cropped soils. We measured soil N changes and N-use efficiency in a fi eld experiment initiated in 1968, consisting of completely randomized tillage practices (conventional mechanical till [CT], and no-till [NT]), crop residue management (residue burned [RB], and residue retained [RR]), and N fertilization (0, 30, and 90 kg N ha ) on a Vertisol (Ustic Pellusert) over 40 yr. Crops grown were mainly wheat (Triticum aestivum L.) except for fi ve barley (Hordeum vulgare L.) crops early in the experiment. Significant effects of treatments on soil total N were primarily confined to the top 0.1-m depth. Soil total N exponentially declined in all treatments even though apparent fertilizer N recoveries during this period (1969-2008) were only 46 and 59% of N applied at 90 and 30 kg N ha , respectively. Mineral N in the soil profi le (0-1.2 m) ranged from 68 to 496 kg N ha . Nitrogen-use efficiency was similar (P = 0.13) under CT and NT in this Vertisol. However, crop residue retention and a low rate of N application had greater N-use efficiency (35-40%) than RB and a high rate of N application (21-25%) under the annual cereal grain cropping system. If perennial grasslands are considered ecological benchmarks for agricultural sustainability, primarily through large root biomass that utilizes water and nutrients efficiently, then the challenge remains to develop cropping systems that successfully mimic grassland ecosystems.

Soil properties governing soil erosion affected by cropping systems in the U.S. Pacific Northwest

In the low-precipitation zone (<300mm annual precipitation) of the inland US Pacific Northwest, no-tillage spring cereal rotations are being examined as alternatives to the traditional winter wheat–summer fallow rotation to control wind erosion. There is limited information, however, regarding the effects of no-tillage cropping systems on soil physical properties and surface characteristics that govern wind erosion in this semiarid region. The objective of this research was to characterize soil aggregates, wetness, strength, roughness, crusting, and crop residue cover and biomass of a silt loam that had been subject to various crop rotations for 11 years in east-central Washington. Crop rotations examined included no-tillage spring barley–spring wheat (NTSB/SW), no-tillage spring wheat–chemical fallow (NTSW/CF), and winter wheat–summer fallow (WW/SF). Soil physical properties were measured in spring 2006 after sowing wheat in the NTSB/SW rotation and in late summer 2006 after sowing winter wheat in the WW/SF and NTSW/CF rotations. In spring, the NTSB/SW and NTSW/CF rotations were characterized by a wetter soil as compared with the WW/SF rotation. In late summer, the NTSB/SW rotation was characterized by a soil surface with more standing stubble and greater crust cover and soil strength as compared with the WW/SF and NTSW/CF rotations. Our results suggest that spring-sown cereal and chemical fallow cropping systems result in wetter soils in spring and retain more surface residue in the late summer that will reduce the risk for wind erosion as compared with the traditional WW/SF rotation in the Pacific Northwest.

An aspartate to glycine change in the carboxyl transferase domain of acetyl CoA carboxylase and non‐target‐site mechanism(s) confer resistance to ACCase inhibitor herbicides in a Lolium multiflorum population

The increasing use of ACCase-inhibiting herbicides has resulted in evolved resistance in key grass weeds infesting cereal cropping systems worldwide. Here, a thorough and systematic approach is proposed to elucidate the basis of resistance to three ACCase herbicides in a Lolium multiflorum Lam. (Italian rye grass) population from the United Kingdom (UK24). Resistance to sethoxydim and pinoxaden was always associated with a dominant D2078G (Alopecurus myosuroides Huds. equivalent) target-site mutation in UK24. Conversely, whole-plant herbicide assays on predetermined ACCase genotypes showed very high levels of resistance to diclofop-methyl for all three wild DD2078 and mutant DG2078 and GG2078 ACCase genotypes from the mixed resistant population UK24. This indicates the presence of other diclofop-methyl-specific resistance mechanism(s) yet to be determined in this population. The D2078G mutation could be detected using an unambiguous DNA-based dCAPS procedure that proved very transferable to A. myosuroides, Avena fatua L., Setaria viridis (L.) Beauv. and Phalaris minor Retz. This study provides further understanding of the molecular basis of resistance to ACCase inhibitor herbicides in a Lolium population and a widely applicable PCR-based method for monitoring the D2078G target-site resistance mutation in five major grass weed species.

Long‐Term Manure Application and Forages Reduce Nitrogen Fertilizer Requirements of Silage Corn–Cereal Cropping Systems

Assessment of the soil N supply capacity is essential to optimize fertilizer N use. We investigated soil N supply capacity and fertilizer N recovery for three cropping systems established in 1977: silage corn (Zea mays L.)–cereal without (CC) and with 20 Mg ha−1 yr−1 manure (CCM), and silage corn–forage (3‐yr) with manure (CFM). During the present study (2005–2008), manure applications were suspended and a silage corn–silage corn–barley (Hordeum vulgaris L.)–wheat (Triticum aestivum L.) sequence was imposed to all systems. Fertilizer (15NH415NO3, 3.1 atom % 15N) was applied in 2005 to silage corn (160 kg N ha−1) and in 2007 to barley (80 kg N ha−1). The 15N recovery in silage corn and barley ranged from 40 to 59%, with the lowest values measured in CFM. Compared to the CC systems (47 kg N ha−1) in 2005, soil‐derived N in silage corn was two times higher under CCM (98 kg N ha−1), and four times higher under CFM (208 kg N ha−1). These differences decreased over years, but were still noticeable at the end of the experiment. Twenty‐two to 58% of applied 15N was recovered in the soil at harvest. More than 50% of this residual N was present in macroaggregates (&gt;0.25 mm), whereas &lt;20% was present in particulate organic matter (POM). Up to 75% of residual 15N was lost during the winter period, and little residual N was transferred to the following crop. These findings indicate that soil macroaggregates may be a preferential sink for residual fertilizer N, but this N is not present in stable forms and is vulnerable to environmental loss.

Influence of agricultural factors on weed, carabid and bird richness in a Mediterranean cereal cropping system

Using a multimodel inference approach, the most relevant field-level and landscape context factors explaining the simultaneous variability of bird, carabid and weed species richness were identified and interpreted in a low-intensity cereal farming system in central Spain. Weed species richness was negatively influenced by sowing density, herbicides and surrounding mean field size. Carabid species richness was negatively related to applied nitrogen, but positively to surrounding land cover diversity and applied phosphorous. Bird species richness was positively influenced by focal field size, but negatively by surrounding land cover diversity, sowing density and amount of potassium applied. Although all three biological groups reflected the influence of intensification factors operating at different spatial scales, the most relevant factors were specific to each particular group. These results have implications in terms of the selection of targets for agri-environmental measures aiming at reversing the impacts of agricultural intensification on biodiversity.

Factors Affecting Stem Borer Parasitoid Species Diversity and Parasitism in Cultivated and Natural Habitats

The effects of biotic and abiotic factors on stem borer parasitoid diversity, abundance, and parasitism were studied in cultivated and natural habitats in four agroecological zones in Kenya. Comparing habitat types, we found partial support for the "natural enemy" hypothesis, whereby, across all localities, parasitoid diversity was higher in more diverse host plant communities in natural habitats, whereas parasitoid abundance was higher in cultivated habitats. For both habitats, parasitoid richness was mainly influenced by stem borer density and/or its interaction with stem borer richness, whereas parasitoid abundance was mainly affected by stem borer abundance. Parasitoid richness was higher in localities (with bimodal rainfall distribution) with increased spatial and temporal availability of host plants that harbored the borers. Across seasons, parasitoid richness was lower in both cultivated and natural habitats in the driest locality, Mtito Andei. Overall, parasitoid diversity was low in Suam and Mtito Andei, where maize cultivation was practiced on a commercial scale and intense grazing activities persist across seasons, respectively. Across localities, habitats, and seasons, stem borer parasitism was positively correlated with parasitoid richness and abundance. Furthermore, the interaction of rainfall and altitude influenced the presence and absence of parasitoids, and consequently, stem borer parasitism. Parasitism was positively and negatively correlated with temperature in cultivated and natural habitats, respectively. Overall, natural habitats seem to serve as important refugia for sustaining parasitoid diversity, which in turn can affect stem borer parasitism in the cereal cropping system.

Economic evaluation of cereal cropping systems under semiarid conditions: minimum input, organic and conventional

Cropping systems like organic farming, selling products at a higher price and promoting environmental sustainability by reducing fertilizer and pesticides, can be more profitable than conventional systems. An economic evaluation of three cropping systems in a seven year period experiment was performed, using a common rotation (fallow-barley-vetch-durum wheat) in a semi-arid rainfed field of Spain. The minimum input system included mouldboard ploughing, cultivator preparation, sowing and harvest. The conventional system involved mineral fertilizer and herbicide treatments, while the organic system involved composted manure and mechanical weed control. The resulting economic margins were highest with the minimum input system, followed by the organic and conventional systems. If the cereal grain from the minimum input system was sold at a higher price on the organic market, this system was the most profitable. Without the price difference, the organic system was as profitable as the conventional one.

Modelling within‐field spatial variability of crop biomass – weed density relationships using geographically weighted regression

SummaryThe objective of this study is to offer a new framework for exploring and modelling the spatial variation in crop biomass – weed density relationships, adapting geographically weighted regression (GWR) to include a non‐linear regression model. The relationship between crop biomass and weed density is usually modelled by non‐linear regression models, in which the spatial heterogeneity of the relationship is ignored, although the effect of weeds on crop can differ in relation to topographic and edaphic variability. GWR attempts to capture spatial variability by calibrating a regression model to each location in space. We show the application of the method in different cereal cropping systems, with one or two weed species. The results indicate that GWR can significantly improve model fitting over non‐linear least squares (NLS) in some situations. Furthermore, the parameter estimates can be mapped to illustrate local spatial variations in the regression relationship under study and eventually to relate the spatial variability of the model to the environmental heterogeneity. We discuss the value of the GWR for analysing the observed spatial variability and for improving model development and our understanding of spatial processes.

Changes in the diversity and geographic distribution of cultivated millet (Pennisetum glaucum (L.) R. Br.) and sorghum (Sorghum bicolor (L.) Moench) varieties in Niger between 1976 and 2003

Changes in the diversity of landraces in centres of diversity of cultivated plants need to be assessed in order to monitor and conserve agrobioversity—a key-element of sustainable agriculture. This notably applies in tropical areas where factors such as increased populations, climate change and shifts in cropping systems are hypothesized to cause varietal erosion. To assess varietal erosion of staple crops in a country subjected to various anthropogenic and natural environmental changes, we carried out a study based on a comparison of the diversity of pearl millet and sorghum varieties collected in 79 villages spanning the entire cereal-growing zone of Niger over a 26 year period (1976–2003). For these two crops, the number, name and type of varieties according to important traits for farmers were considered at different spatial scales (country, region, village) at the two collection dates. The results confirmed the high diversity of millet and sorghum varieties in Niger. No erosion of varietal diversity was noted on a national scale during the period covered. Some changes were observed but were limited to the geographical distribution of certain varieties. This highlights that farmers’ management can preserve the diversity of millet and sorghum varieties in Niger despite recurrent and severe drought periods and major social changes. It also indicates that rainfed cereal cropping systems in Niger should remain to be based on millet and sorghum, while reinforcing farmers’ seed systems.

Glyphosate‐resistant weeds of South American cropping systems: an overview

Herbicide resistance is an evolutionary event resulting from intense herbicide selection over genetically diverse weed populations. In South America, orchard, cereal and legume cropping systems show a strong dependence on glyphosate to control weeds. The goal of this report is to review the current knowledge on cases of evolved glyphosate-resistant weeds in South American agriculture. The first reports of glyphosate resistance include populations of highly diverse taxa (Lolium multiflorum Lam., Conyza bonariensis L., C. canadensis L.). In all instances, resistance evolution followed intense glyphosate use in fruit fields of Chile and Brazil. In fruit orchards from Colombia, Parthenium hysterophorus L. has shown the ability to withstand high glyphosate rates. The recent appearance of glyphosate-resistant Sorghum halepense L. and Euphorbia heterophylla L. in glyphosate-resistant soybean fields of Argentina and Brazil, respectively, is of major concern. The evolution of glyphosate resistance has clearly taken place in those agroecosystems where glyphosate exerts a strong and continuous selection pressure on weeds. The massive adoption of no-till practices together with the utilization of glyphosate-resistant soybean crops are factors encouraging increase in glyphosate use. This phenomenon has been more evident in Argentina and Brazil. The exclusive reliance on glyphosate as the main tool for weed management results in agroecosystems biologically more prone to glyphosate resistance evolution.

Integrated pest management for cowpea–cereal cropping systems in the West African savannah

Cowpea Vigna unguiculata (L.) Walp. is an important component in mixed cropping systems that are appropriate to the agro-ecological characteristics of the West African savannah. However, the contribution of cowpea to overall productivity of the systems is reduced by a number of insect pest species. Compared with the humid zone, important features of insect pests in the savannah region include: (i) a tendency towards higher pest incidence during the limited growing period, (ii) a more advantageous situation for generalist and migratory pests in the scanty and unstable vegetation and (iii) lower mortality inflicted by parasitoids on the pest populations. The key pests of cowpea of importance in the West African savannah are the legume flower thrips Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), the legume pod borer Maruca vitrata (Fabricius) (Lepidoptera: Crambidae) and the pod-sucking bug Clavigralla tomentosicollis Stal (Hemiptera: Coreidae). To control these insects in a sustainable manner, pest management practices such as the use of resistant cowpea varieties, mixed cropping systems, botanical and reduced risk insecticides, and biological control assisted by pest monitoring have been developed. Nevertheless, no single component is effective when used alone, but specific combinations can work synergistically. This paper highlights recent progress in integrated pest management strategies for cowpea in cereal-based cropping systems in the West African savannah.

Yields and Nutrient Use-Efficiency in Groundnut-Sunflower Cropping System in Punjab, India

ABSTRACT Long-term continuous cereal cropping systems without returning crop residues to soil has led to depletion of inherent soil fertility in semiarid subtropical soils of South Asia. The inclusion of legumes and their residues assumes great significance to restore sustainability. Groundnut (Arachis hypogaea L.) and sunflower (Helianthus annus L.) are important oilseed crops of the region and have the feasibility to be grown in annual double crop rotation with the expansion of irrigation facilities. A 4-year field experiment with irrigated groundnut-sunflower rotation was conducted on a loamy sand soil (Typic Haplustept) to evaluate the effects of different rates of fertilizer N (0, 30 and 60 kg N ha−1) and P (0, 20, 30 and 40 kg P2O5 ha−1 corresponding to 0, 8.7, 13 and 17.5 kg P ha−1, respectively), applied either to one crop (direct for current crop and residual for succeeding crop) or to both crops (cumulative) each year, with or without 4 t ha−1 of groundnut crop residues (CR) on crop yields, nutrient uptake, fertilizer use efficiency and soil productivity parameters (pH, organic carbon, available N and P). The residual effects of P and CR were assessed on the succeeding groundnut crop. Winter-grown sunflower responded significantly and consistently to applied fertilizer N and P. Seed yield of sunflower increased significantly up to 60 kg N and 30 kg P2O5 ha−1 and there was no further increase with directly applied 40 kg P2O5 ha−1. Cumulative application of P produced sunflower yields comparable with those from direct applications. Incorporation of groundnut residue in conjunction with 30 kg N ha−1 significantly increased the sunflower yields that were statistically at par with those obtained with the lone application of 60 kg N ha−1. All through 4 years, the combined application of CR with 60 kg N ha−1 and 30 kg P2O5 ha−1 further improved the yield potential of sunflower by 10–11% and of succeeding groundnut by 10–24%, illustrating the benefit that fertilizer N and P could not achieve. Residual fertilizer P (30 kg P2O5 ha−1) produced optimum yields of groundnut, which were comparable with that from directly applied 20 kg P2O5 ha−1. After 4 years of study, soil organic carbon swelled by 22% and Olsen-P increased from initial 12 kg P ha−1 to 24–43 kg P ha−1 in fertilizer and CR-treated plots. These results illustrated that in groundnut-sunflower rotation, (1) 60 kg N and 30 kg P2O5 ha−1 are adequate for the sustaining optimal sunflower production; (2) whereas the application of fertilizer P to sunflower crop is required, P requirement of groundnut can be met from soil-derived and residual fertilizer P; and (3) incorporation of groundnut crop residues in conjunction with the adequate rates of N and P has complementary effects in maximizing the yields, uptake of N and P, and nutrient use-efficiency in sunflower as well as its residual effects on succeeding groundnut crop, and in sustaining long-term soil productivity.