Showing papers in "International Journal of Plant Production in 2021"

Rain-Fed Rice Yield Fluctuation to Climatic Anomalies in Bangladesh

Abstract: To examine the rain-fed Aman rice yield fluctuation due to climatic anomalies overtimes in Bangladesh, we used climate-induced yield index (CIYI), ensemble empirical mode decomposition (EEMD), step-wise multiple regression, isotopic signature, wavelet transform coherence (WTC) and random forest (RF) model. In this work, daily multiple source climatic data which were collected between 1980 and 2017, from 18 weather stations and five atmospheric circulation indices were used for this purpose. The key findings were as follows; by employing principal component analysis (PCA), six temporal variability modes were identified as six corresponding sub-regions with various Aman rice CIYI fluctuations. The Aman rice CIYI in different sub-regions represented a noteworthy 3–4-year quasi-oscillation using the EEMD. The key climate variables (KCVs) including the potential evapotranspiration and cloud cover in September, the minimum temperature in August, and precipitation in July, August, and October were the best rice yield prediction signals in these sub-regions. The results suggest that Aman rice yield could likely decline by 33.59%, and 3.37% in the southwestern and southeastern regions, respectively, if KCV increased by 1 °C or 1%. The RF model suggests that the Indian Ocean Dipole (IOD) significantly influenced the rice yield. Isotopic signatures were employed to confirm the fluctuation and anti-amount effect during the Aman rice-growing period in Bangladesh. The results obtained in this study could be used as a guideline for sustainable mitigation and adaptation measures in managing agro-meteorological hazards in Bangladesh.

Combined Use of Organic and Inorganic Nutrient Sources Improved Maize Productivity and Soil Fertility in Southwestern Ethiopia

Abstract: Declining soil quality is among the factors leading to low crop yields in Sub-Saharan Africa. In this study, a 2 year on farm field experiment was carried out in Ethiopia to test whether integration of organic and inorganic fertilizer inputs increases soil quality, the nutrient balance and maize yields. Treatment combinations included 2 and 4 t ha−1 of compost (Com) and farm yard manure (FYM), and 50 and 100% of the recommended inorganic fertilizer (RIF). The treatments were laid out on 11 farmer fields where each farm served as a replicate. About 40% yield increase was recorded due to the combined use of 4 t ha−1 of Com along with 50% RIF compared to the 100% RIF. Soil quality was significantly improved in the top 20 cm of the soil due to application of FYM or Com combined with 50% RIF. Carbon and Nitrogen stocks were respectively 86 and 175% higher in the 4 t Com + 50% RIF compared to the control with no significant variation between farms. Further, the N and P partial balances were between 12.2 and 41.6 kg ha−1 year−1 and 10.2 and 17.4 kg ha−1 year−1 for N and P, respectively implying that the sites showed N and P-accumulations over the study period. Results suggest that nutrient depletion can be mitigated in smallholder systems through the use of locally available organic inputs, hence longer-term productivity of smallholders can be sustained.

Mitigation of Drought Stress and Yield Improvement in Wheat by Zinc Foliar Spray Relates to Enhanced Water Use Efficiency and Zinc Contents

Abstract: Water and nutrients scarcity are the two major factors for yield reduction in many wheat-producing areas of the world. Drought stress also restricts micronutrient uptake and thus induces micronutrient deficiency. Zinc is the most important micronutrient for abiotic stress tolerance. A field trial was conducted from 2013 to 2015 to study the effect of foliar application of zinc under normal (100% field capacity) and water deficit (60% field capacity) conditions on quantitative and qualitative aspects of wheat (Triticum aestivum L. var. Faisalabad-08). Three Zn levels (0, 0.1%, and 0.2% by using ZnSO4. 7H2O) were foliar sprayed at the vegetative and reproductive stages of wheat. Obtained results revealed that the growth, yield traits, photosynthetic pigments, and WUE were negatively affected by lower water supply. Zinc foliar application did not affect yield under normal irrigation conditions, however, under water deficit foliar application of 0.2% Zn enhanced grain yield to 25–40%. Zinc foliar spray at both vegetative and reproductive stages increased the chlorophyll contents and WUE. Zinc contents of wheat grain were more when 0.1% Zn was sprayed at the reproductive stage or 0.2% Zn at the vegetative stage. Thus, the foliar application of Zn is a promising short-term approach to improve productivity and grain nutrient content in wheat under water deficit stress. Furthermore, the timing and rate of Zn application could be helpful for the efficient use of water for increasing grain yield.

Paclobutrazol Improves Sesame Yield by Increasing Dry Matter Accumulation and Reducing Seed Shattering Under Rainfed Conditions

Abstract: Several biotic and abiotic stresses significantly decrease the biomass accumulation and seed yield of sesame crops under rainfed areas. However, plant growth regulators (such as Paclobutrazol) can improve the total dry matter and seed production of the sesame crop. The effects of the paclobutrazol application on dry matter accumulation and seed yield had not been studied before in sesame under rainfed conditions. Therefore, a two-year field study during 2018 and 2019 was conducted with key objectives to assess the impacts of paclobutrazol on leaf greenness, leaf area, total dry matter production and partitioning, seed shattering, and seed yield of sesame. Two sesame cultivars (TS-5 and TS-3) were treated with four paclobutrazol concentrations (P0 = Control, P1 = 100 mg L−1, P2 = 200 mg L−1, P3 = 300 mg L−1). The experiment was executed in RCBD-factorial design with three replications. Compared with P0, treatment P3 improved the leaf greenness of sesame by 17%, 38%, and 60% at 45, 85, and 125 days after sowing, respectively. However, P3 treatment decreased the leaf area of sesame by 14% and 20% at 45 and 85 days after sowing than P0, respectively. Compared with P0, treatment P3 increased the leaf area by 46% at 125 days after sowing. On average, treatment P3 also improved the total biomass production by 21% and partitioning in roots, stems, leaves, capsules, and seeds by 23%, 19%, 23%, 22%, and 40%, respectively, in the whole growing seasons as compared to P0. Moreover, under P3 treatment, sesame attained the highest seed yield and lowest seed shattering by 27% and 30%, respectively, compared to P0. This study indicated that by applying the paclobutrazol concentration at the rate of 300 mg L−1 in sesame, the leaf greenness, leaf areas, biomass accumulation, partitioning, seed yield, and shatter resistance could be improved. Thus, the optimum paclobutrazol level could enhance the dry matter accumulation and seed production capacity of sesame by decreasing shattering losses under rainfed conditions.

Full Parameterisation Matters for the Best Performance of Crop Models: Inter-comparison of a Simple and a Detailed Maize Model

Abstract: Process-based crop growth models have become indispensable tools for investigating the effects of genetic, management, and environmental factors on crop productivity. One source of uncertainty in crop model predictions is model parameterization, i.e. estimating the values of model input parameters, which is carried out very differently by crop modellers. One simple (SSM-iCrop) and one detailed (APSIM) maize (Zea mays L.) model were partially or fully parameterized using observed data from a 2-year field experiment conducted in 2016 and 2017 at the UFT (Universitats- und Forschungszentrum Tulln, BOKU) in Austria. Model initialisation was identical for both models based on field measurements. Partial parameterization (ParLevel_1) was first performed by estimating only those parameters related to crop phenology. Full parameterization (ParLevel_2) was then conducted by estimating parameters related to phenology plus those affecting dry mass production and partitioning, nitrogen uptake, and grain yield formation. With ParLevel_1, both models failed to provide accurate estimation of LAI, dry mass accumulation, nitrogen uptake and grain yield, but the performance of APSIM was generally better than SSM-iCrop. Full parameterization greatly improved the performance of both crop models, but it was more effective for the simple model, so that SSM-iCrop was equally well or even better compared to APSIM. It was concluded that full parameterization is indispensable for improving the accuracy of crop model predictions regardless whether they are simple or detailed. Simple models seem to be more vulnerable to incomplete parameterization, but they better respond to full parameterization. This needs confirmation by further research.

Effect of Nitrogen Rates on Wheat Photosynthesis, Anatomical Parameters and Photoassimilate Partitioning in North China Plain

Abstract: Evaluating the effects of nitrogen (N) on photosynthesis characteristics and photoassimilate partitioning via vascular bundles (VB) under water-saving irrigation is crucial to maximum grain yield of environment-friendly wheat production in the North China Plain (NCP). Field experiments were conducted with four N application rates 0 (N0), 180 (N180), 240 (N240), and 300 (N300) kg N ha−1 under 70% and 65% relative soil water content (RSWC) at jointing and anthesis, respectively. Results showed that, compared with N0, N180 significantly improved the photosynthetic parameters and chlorophyll fluorescence of flag leaf after anthesis. N application improved the anatomical parameters both in the flag leaf and the stem. Total transverse area of VB in the flag leaf and in the stem internode below the ear under N180 was 17.95–23.70% and 37.91–43.90% larger than those of N0, respectively, due to the increased numbers and transverse area of VB. Furthermore, N180 had higher dry matter assimilation after anthesis (DMA) and its contribution to the grain. N180 increased grain yield by 14.23–23.24% compared with N0, and N supply exceeding 180 kg N ha−1 did not further increase yield. Moreover positively correlations were showed among photosynthesis characteristics after anthesis, total transverse area of VB in the flag leaf and in the stem internode below the ear, DMA and grain yield. In summary, the recommended N application rate was 180 kg N ha−1 under RSWC-based supplemental irrigation that can produce grain yield over 7500 kg ha−1 for at least 2 years in the NCP.

Quantification of Climate Warming and Crop Management Impacts on Phenology of Pulses-Based Cropping Systems

Abstract: Climate warming is impacting the phenology, growth and productivity of diverse cropping systems at local, regional and global levels. Long-term observed chickpea-mungbean system (CMS) phenological changes were used for the determination of the relationship between crop practices, climate warming and phenology for the making strategies for CMS to minimize negative climate change impacts. Observed thermal trend from sowing to maturity was ranging from 0.82 to 1.15 °C decade−1 for chickpea and 0.64 to 0.97 °C decade−1 for mungbean during 1980–2018. Observed chickpea phenology stages was earlier for mean value of 7.04 (sowing; S), 6.76 (emergence; E), 4.31 (anthesis; A), 2.15 (maturity; M) days decade−1, whereas chickpea phases were decreased averagely 2.73 (S–A), 2.16 (A–M), 4.89 (S–M) days decade−1. Mungbean, ‘S’ 6.24, ‘E’ 5.97, ‘A’ 3.76, and ‘M’ 2.01 days decade−1 were occurred earlier. Period of mungbean phenology phases were lessened with averaged 2.45 (S–A), 1.76 (S–M) and 4.23 (A–M) days decade−1, respectively. Phenological stages and phases of both crops chickpea and mungbean correlated negatively with rising temperatures at all sites studied. By using CROPGRO-Chickpea and CROPGRO-Legume models for usual chickpea and mungbean cultivars at the sites for 38 years duration indicated that model predicted phenology stages were accelerated with thermal trend more as compared with observed stages. This showed that, during last decades, growing newly evolved cultivars of pulses having more thermal time requirement have significantly offset the increased temperature induced changes in chickpea (33%) and mungbean (20%) phenology. Therefore, for the mitigation of climate warming influences, newly evolved cultivars for CMS must be familiarized that need greater demand for degree days and having higher tolerance to temperature.

Effects of Nitrogen Fertilizer Applications on Photosynthetic Production and Yield of Japonica Rice

Abstract: Nitrogen management plays important roles in high-yielding rice production. In this two-year study, four rice cultivars were used to investigate the effects of the nitrogen application regime on yields, yield components, photosynthetic characteristics, and the dry matter accumulation and transformation of rice. Under a split-plot design, the main plots were assigned to five nitrogen application strategies, of which strategies 0 (N1), 165 (N2), 195 (N3), and 225 kg N ha−1 (N4) were applied as follows: 50% at basal, 35% at tillering and 15% at panicle initiation. In addition, strategy N5 was applied with 195 kg N ha−1 by 40% at basal, 15% at green-returning, 25% at the tillering stage, 15% at the panicle initiation stage, and 5% at the spikelet differentiation stage. Each main plot was sub-plotted by four experimental rice cultivars. Our results showed that all four cultivars obtained the highest yield with 195 kg N ha−1application. The nitrogen treatments seemed to have a smaller effect on the number of spikelets per panicle and 1000-grains weight, but more influence on the number of panicles and seed-setting rate and eventually affected grain yield. Under the N5 treatment, high yield was obtained due to more effective panicles, more spikelets per panicle and a high seed-setting rate. Additionally, the N5 treatment caused a longer leaf stay-green duration and higher photosynthetic potential, and the leaf area decreased slower at the late stage. The N4 treatment increased the dry matter formation at the jointing stage and the N3 treatment accelerated the dry matter accumulation between the jointing and heading stages. The results suggested that under 195 kg N ha−1 nitrogen amount, a higher post-anthesis biomass could be gained, and the N5 treatment showed greater advantages from heading to maturity than the other treatments in the aspects of more dry matter accumulation at the late growth stage, a coordinated organ growth ratio, and a higher matter translocation rate from the stem and leaf to the panicle, thus benefiting yield formation.

Leaf Nitrogen, Based on SPAD Chlorophyll Reading Can Determine Agronomic Parameters of Winter Wheat

Abstract: Applying appropriate nitrogen (N) rates is a big challenge to farmers when they need to earn maximum yield along with lowering leached N. It is hard to synchronize soil N availability with crop N needs due to the variation of weather conditions and its effects on crop growth. In this respect, the SPAD chlorophyll meter has been used extensively to analyze rapidly leaf chlorophyll and nitrogen status. However, it has not been established how the SPAD readings are correlated with wheat grain yield and growth under variable field and weather conditions. Therefore, the objective of this study was to determine the relationship between SPAD chlorophyll readings and leaf N status along with other agronomic parameters like yield and leaf area index. Two-year field experiments were carried out in 2015–2016 and 2016–2017. Variable alternate furrow irrigation (VAFI) and ordinary furrow irrigation (OFI) were the irrigation strategies, and in-furrow planting (IFP) and on-ridge planting (ORP) defined the planting methods. Three N application rates at 0, 150, and 300 kg N ha−1 indicated N variation. Results indicated that spring cold had negative effects on SPAD readings and especially leaf N concentration in the first year. The SPAD values were homogeneous in the second year with favorable weather conditions, and it was classified in three intervals 28–35, 35–45, and 45–50 in non-fertilized, 150 kg N ha−1 and 300 kg N ha−1, respectively. Since the grain yield was similar in 150 kg N ha−1 and 300 kg N ha−1, the values of SPAD readings at 40–45 could be appropriate values for producing optimum wheat growth and grain yield. However, higher grain protein concentration might need higher leaf N concentration and subsequently higher SPAD values. Leaf N concentration positively correlated with SPAD values (R2 = 0.64). Linear relationships between grain yield and grain N% and SPAD readings showed higher accuracy in the second year (R2 = 0.71 and 0.79, respectively). Moreover, relative yield and SPAD readings resulted in a higher accurate model than the absolute values. Therefore, using this model, chlorophyll meter reading can be used by farmers as an alternative complementary tool for predicting crop N status and obtaining higher wheat grain yield.

Evaluating Precision Nitrogen Management Practices in Terms of Yield, Nitrogen Use Efficiency and Nitrogen Loss Reduction in Maize Crop Under Indian Conditions

Abstract: Nitrogen (N) losses from the N sources such as manures, fertilizers etc. applied to crops are considered as the largest non-point source of nitrogen-nitrate pollution in surface and groundwater bodies. The extent of water bodies polluted with N is worsening day by day, worldwide, with its severe impact on the quality of drinking water. This necessitates the development of crop specific N management practices to reduce N losses from crop systems. Improvements in agronomic and recovery efficiency of nitrogen in crops are regarded as promising techniques to reduce N losses. With the hypothesis that precise N supply in maize employing LCC or CCM under a critical threshold value will augment the yield performances and Nitrogen Use Efficiency (AEN and REN) of maize, while reducing N losses, a two year study was conducted at Anand, India. Fifty percent reduction in basal N application and subsequent N applications based on LCC critical value 5 resulted in 12.30 and 12.25% increment in maize grain yield over recommended practices during the year 2015 and 2016, respectively. Significant improvement for total biological yield, grain protein accumulation in maize and total N uptake by crop was observed in the direction of N application using LCC threshold point 5, CCM threshold point 40 and recommended practice. Applying nitrogen at whatever the times LCC critical point drops ≤ 5 also recorded 4.09 and 4.17 kg gain in grain produced (over recommended practice) kg−1 of N supplied (AEN), 0.16 and 0.17 kg gain in N uptake (over recommended practice) kg−1 of N supplied (REN) during 2015 and 2016, respectively and a total reduction of 51.14 kg N loss ha−1 (over recommended practice) for the entire study period. The study reveal that compared to blanket application, N fertilizers can be more efficiently managed with LCC threshold value 5 or CCM threshold value 40 for guiding N application with higher yield, NUE and reduced N losses in maize crop.

Improved Crop Management Achieved High Wheat Yield and Nitrogen Use Efficiency

Abstract: Approaches to meet increasing demand for cereals while improving agricultural resource use efficiency have been extensively studied. However, the dominant intensive agricultural paradigm still considers high yield and increased nitrogen use efficiency (NUE) to be contradictory goals. The objective of this study was to determine whether increased yield requires a proportional increase in N application. Two groups of N treatments were compared at 33 field sites in four wheat producing provinces of China. With a high-yield system (HY), the average yield, PFPN and AEN were 42.3, 37.6 and 38.7% higher than current farming practice (CP), respectively. The average estimated maximum grain yield for HY was 8563 kg ha–1 over 2 years, 2007 and 2008, which was 44.2% higher than under CP (5938 kg ha–1). The optimal N rate for HY was 185 kg ha−1, which was significantly higher than that under CP (149 kg ha−1). The increased wheat yield with HY was accompanied by 24.1% increase in optimal N rate. Significant relationships were found between 0-N (unfertilized control) yield and the estimated maximum yield and AEN with HY and CP. There were also decreasing trends for PFPN and AEN with increasing N rate in HY and CP. These on-farm observations indicate that achieving increased yield does not require a proportional increase in the amount of N fertilizer, which provides a win–win opportunity to meet food demand while improving NUE.

Corn (Zea mays L.) Growth, Yield and Nutritional Properties Affected by Fertilization Methods and Micronutrient Use

Abstract: With respect to the significance of finding methods, which may improve corn (Zea mays L.) yield and quality in the semi-arid areas of the world, an improved method and type of fertilization has been suggested and tested. A two-year field experiment (2016–2017) (split plot) was conducted in the Research Station of Safi-Abad, Dezful, Iran to test the effects of fertilization methods (soil application of fertilizer (N1), foliar application (N2), and fertigation (N3)) and micronutrient use (Fe and Zn at 3 gL−1) on the yield and quality of corn plants. Cob (CH) and plant height (PH), weight of 1000 grains (W), corn yield (Y), weight of cob wood (CobWood), cob weight (CobW), number of rows in a cob (NR), number of grains in a row (NG), plant nutrient uptake of Fe and Zn, and grain protein (Pro) were determined. The single or combined effects of the experimental treatments significantly affected the measured parameters. The fertilization method significantly affected corn growth (CH), yield (W, Y, CobWood, and NR) and plant Fe uptake. However, micronutrients were significant on all the measured parameters except Pro. Although the soil method significantly increased plant uptake of Fe and Zn, the foliar application and fertigation methods significantly enhanced corn growth and yield. The combined use of the tested methods may enhance corn yield and quality in the arid and semi-arid areas of the world.

Comparing the Corn, Millet and Sorghum as Silage Crops Under Different Irrigation Regime and Nitrogen Fertilizer Levels

Abstract: The present study carried out to evaluate the effects of irrigation regimes (control and water stress) and two nitrogen levels (0, and 112.5 kg ha−1) on dry matter yield and silage quality of proso millet, sorghum and corn plants in 2015–2016. Results showed that dry matter (DM) yields of millet, sorghum and corn plants decreased as a result of water shortage. Under both irrigation regimes, the highest DM yields were observed in sorghum. Water stress also reduced irrigation water use efficiency (IWUE) in millet and corn, while it had no significant effect on that of sorghum. Water shortage led to increases in acid detergent fiber (ADF) and neutral detergent fiber (NDF) in corn and sorghum, whereas no significant differences were observed in millet. Furthermore, water deficit resulted in decreased digestibility in corn and sorghum, while increased it in millet. Under normal irrigation, maximum digestibility was observed in corn, while under water stress, no significant difference was observed between corn and millet. Accordingly, it can be said that sorghum is the best option for planting in arid areas, which has the highest yield and is also acceptable in terms of quality. In addition, nitrogen application is recommended to improve IWUE and forage quality. But, because of its insignificant effect on DM yield under stress conditions, application of nitrogen under stress conditions should be tested at more levels to find out optimum amount of nitrogen use and prevent fertilizer loss.

Sowing Dates and Cultivars Mediated Changes in Phenology and Yield Traits of Cotton-Sunflower Cropping System in the Arid Environment

Abstract: Cotton-sunflower cropping system is a unique oilseed-based rotation. The real problem is overlapping sunflower-maturity with cotton-sowing. Investigations aim to tackle cotton-late-sowing through sowing-time-adjustment and cultivar-selection at cropping-system-level. Cotton (May 10th to June 24th) and sunflower (December 20th to February 03rd) sowing-dates were maintained biweekly. Maturity-time based cultivars were selected (early, medium, late) and variations in ambient-temperature through sowing-dates from 33.2 to 33.9 °C, 32.2 to 33.6 °C and 29.2 to 32.6 °C, length of emergence-squaring, squaring-flowering and flowering-maturity differed by 3.1, 1.5 and 5.1 days, respectively. Likewise, sunflower-sowing-dates based ambient-temperature ranged 13.7–18.1 °C, 16.3–17.5 °C and 23.8–28.5 °C at emergence-budding, budding-anthesis and anthesis-maturity, resulted in a difference of 13.5, 4.8 and 1.0 days. Results revealed that cotton late-sowing (May 10th to June 24th) and sunflower (December 20th to January 19th) resulted in reduces seedcotton, lint and achene yield by 19.9, 8.2 and 8.8 kg ha−1 day−1. Oil productivity was the highest in cotton vide June 24th and in sunflower 04th January. In this cropping system, cotton is highly sensitive to sowing-dates for yield losses (35%) and sunflower less sensitive (14.4%). Meanwhile, yield variations in cotton-cultivars (12.5%) and sunflower-hybrids (10.0%). It was realized that sunflower December 20th hold great importance to assure minimum cotton yield-losses than looking for hybrids.

Phenotypic Traits, Grain Yield and Yield Components of Maize Cultivars Under Combinations of Management Practices in Semi-arid Conditions of Iran

Abstract: In semi-arid regions, selecting cultivars and planning management practices are critical issues for improving yields and reducing risks of maize cultivation in the short summer cropping season. This study aimed to assess the responses of grain yield (GY) and important phenotypic characteristics of maize cultivars from different maturity groups under various irrigation regimes, planting dates, and nitrogen rates, in a 2-year experiment. According to the clusters identified in the loading plot, stover yield, radiation use efficiency (RUE), height, leaf greenness index, stem weight, and ear size during flowering (VT/R1) were strongly correlated with GY, yield components and harvest index. Based on analysis of variance, more irrigation or N, or their interaction often increased GY, rows ear(-1), grains row(-1) and hundred-grain weight. Late planting decreased GY of KSC704 (late maturity cultivar). KSC260 (early maturity cultivar) had greater flexibility in planting time, required less days for maturity, and had less water consumption. The findings highlight the physiological basis of the relationship between the different phenotypic characteristics and how they affect GY and its components. They were in line with the established theories that higher RUE, biomass and sink activity (e.g. grain weight and numbers, and larger ear size) are associated with better genetic gains to produce high GY. Although the results were not consistent between years, findings suggested the good performance of recently released early maturity cultivars for use during the summer growing season.

Characterizing Differences in Soil Water Content and Wheat Yield in Response to Tillage and Precipitation in the Dry, Normal, and Wet Years at the Loess Plateau

Abstract: Changes in precipitation and drought are major threats to rainfed wheat production in drylands. Understanding the impacts of precipitation fluctuations on wheat production can provide insight into future crop production under climate change. We conducted an eight-year field experiment to estimate the effect of tillage (no-tillage, NT; deep tillage, DT; subsoiling, SS) system on the soil water consumption and nitrogen translocation to the wheat grains. Furthermore, we accessed the variation in wheat yield according to the wet, dry, and normal precipitation years in the Loess Plateau, China. The tillage improved the soil water content, N remobilization, and grain yield in comparison to NT. The soil water storage was significantly higher in 0–300 cm depth under DT than NT and SS. The changes in soil water content were highest in the years which received higher precipitation. The translocation and accumulation of N were higher in the normal years than the dry and wet years and more under DT and SS than the NT. Furthermore, pre-anthesis N translocation contributed more to grain N, whereas post-anthesis N accumulation did not significantly vary with the years and tillage. Thus, increasing soil moisture or precipitation rate compared to normal does not increase the soil water storage, N accumulation, and grain yield. Therefore, tillage proved beneficial in increasing yield by improving the soil water storage and N availability.

The Use of Stability Statistics to Analyze Genotype × Environments Interaction in Rainfed Wheat Under Diverse Agroecosystems

Abstract: Due to environmental diversity, genotype performance for yield and stability is essential for crop improvement. The GGE biplot, and 11 parametric and non-parametric stability models were employed to evaluate 23 wheat (Triticum aestivum L.) genotypes, tested in randomized complete block trials across two contrasting fields (sandy and loamy) and four seasons. The sandy field yielded half compared to the loamy field, reflecting relatively low- and high-input environments, respectively. Analysis of variance showed significant differences between genotypes for grain yield and crossover genotype ranking across environments; the loamy field was more representative of an overall genotype performance. The stability models resulted in diverse genotype classification and were distinguished into two separate groups. The first group comprised measures that consider both G and GE focusing on the agronomic aspect of stability and high-yielding ability. The second group included tools that consider only GE focusing on the static aspect of stability and characterized most of the high-performing genotypes as undesirable. The GGE biplot highlighted genotypes that were characterized as either desirable or undesirable following most models in both groups. Therefore, the GGE biplot presented an effective statistical tool for assessing wheat genotypes in terms of general and specific adaptation without overlooking yielding ability. It is suggested the preference of favorable experimental conditions and application of the GGE model to identify genotypes that are more promising for stable performance across wide agroecosystems.

Interactive Influences of Elevated Atmospheric CO2 and Temperature on Phosphorus Acquisition of Crops and its Availability in Soil: A Review

Abstract: Global climate change escalates the rise of atmospheric CO2 concentration and temperature, which impact crop production in agricultural ecosystems. As the second important macronutrient, phosphorus (P) fundamentally mediates the crop adaptability to climate change. An overview on previous work on crop P acquisition and soil P dynamics in responses to elevated CO2 and temperature would be critical for further advancing our knowledge on P cycling under climate change and its management to maintain agroecosystem sustainability. This review focuses on the effects of elevated CO2 and temperature on root morphology, root exudation, and associated biochemical properties in the rhizosphere in relevant to crop P acquisition and soil P availability. Studies indicate that elevated CO2 and temperature could increase P uptake of crops, such as rice and soybean when crops are grown within the range of optimal growth temperature. Elevated CO2 and temperature not only alter root exudates and changes the activity of soil enzymes and microbes the in rhizosphere environment, but also directly influence soil chemical and biochemical processes and thus the bioavailability of P. It is worth to focus on P-solubilizing microbial community composition, and microbial function on soil P mobilization in the rhizosphere of crops grown under climate change.

Sewage Sludge Impacts on Yields, Nutrients and Heavy Metals Contents in Pearl Millet–Wheat System Grown Under Saline Environment

Abstract: Salinity prompts heavy metals accumulation and adversely affects nutrient contents in soil and plants, thereby reducing crop yields. The assessment of domestic sewage sludge (SS) under saline conditions to boost crop productivity has become crucial. A field trial was conducted for two consecutive years (2017–2019) with three irrigation levels [canal water (0.35 dS m−1), I1; 8 dS m−1, I2; and 10 dS m−1 saline water, I3]; and five fertilization levels [control, F1; SS (5 t ha−1), F2; SS (5 t ha−1) + 50% RDF, F3; SS (5 t ha−1) + 75% RDF, F4; and RDF, F5]. The results revealed that treatment I3 (10 dS m−1) reduced the grain yield of pearl millet and wheat by an average of 31.2 and 32.6%, respectively, compared to I1 (0.35 dS m−1). However, among fertilizer treatments, F5 obtained significant highest grain and straw yields statistically at par with F4 treatment. Also, in the context of nutrients content in crops, a similar trend has been reported. In the addition, with the usage of saline irrigation (EC 8 and 10 dS m−1) and SS (5 t ha−1), the availability of heavy metals in crops and soil had increased (p = 0.05). The soluble ions in soil increased with increasing salinity levels of irrigation water. The extractability series of heavy metals were: Pb > Co > Ni > Cr > Cd. The addition of SS, however, recorded a higher concentration of DTPA-extractable metals in soil over control. The heavy metals content did not exceed toxicity levels in soil and plants. Hence, the incorporation of SS (5 t ha−1) resulted in saving 25% mineral fertilizers and, also combined use of SS with mineral fertilizers proved to be economically beneficial for crop production.

Optimizing the Wheat Seeding Rate for Wide-Space Sowing to Improve Yield and Water and Nitrogen Utilization

Abstract: Coordinated uptake and utilization of water and nitrogen (N) is important for high-yield and high-efficiency cultivation of winter wheat. The relationship between soil water consumption and N uptake and utilization has not previously been widely investigated. The purpose of this study was to examine the regulatory effects of different seeding rates with wide-space sowing on water consumption and N accumulation and translocation of winter wheat. A field experiment was conducted in the southeastern part of the Loess Plateau between 2016 and 2018, in which winter wheat was sown using the wide-space method (row spacing: 22–25 cm, and seedling bandwidth: 5–8 cm) and five seeding rates: 150, 225, 300, 375, and 450 kg seeds ha−1. The results showed that soil water consumption increased significantly with an increase in the seeding rate from 150–300 kg seeds ha−1, especially from the jointing to maturity stage of wheat growth. At 300 kg seeds ha−1, N translocation from the leaf and stem + sheath to the grains was significantly enhanced, which increased grain N accumulation. The maximum tiller number, water use efficiency, N uptake efficiency, and partial factor productivity from applied N were all recorded at a seeding rate of 300 kg seeds ha−1, thus, grain yield increased significantly by 6–18%. Correlation analysis showed that N accumulation from the sowing to anthesis stage, pre-anthesis N translocation, and the grain yield of winter wheat were closely related to total soil water consumption. Overall, the findings of this study have demonstrated that wide-space sowing of winter wheat at a 300 kg seeds ha−1 seeding rate improved the water use efficiency and N uptake efficiency, which in turn increased the tiller number and grain yield.

Identification of Maize Yield Trend Patterns in the North China Plain

Abstract: Yield growth stagnation in grain crops has been reported worldwide over recent decades. To understand this recent crop yield trend and its causes in China, we conducted an analysis of maize (Zea mays L.) in the North China Plain (NCP) as a case study. First, we analyzed the change characteristics of maize yield for the whole region during 1998–2015, then identified trend patterns at county level via an approach based mainly on the Mann–Kendall and Sen’s slope methods, and finally, analyzed the contribution of major causal factors to maize yield changes based on multiple linear regression (MLR) function. The results indicated that regional mean maize yield in the whole NCP increased by 0.02–2.03% per year before 2011, then declined by—0.83% during 2011–2015. Regionally, maize yield in the southern NCP did not improve greatly; in the north, it increased before 2011, then declined or stagnated thereafter. Only 40 counties showed a continuous increasing trend (IN), whereas 180 counties displayed an increasing–stagnating trend (IN-ST); 52 and 40 counties showed trend patterns of stagnating (ST) and decreasing (DE) in yield, respectively. On the whole, the maize yield in 87.8% of the counties tended to stagnate or even decrease. The reason was mainly attributed to the reduced net returns due to the quickly rising costs of labor and production material. To stimulate yield growth, it is essential to increase the profitability of maize by adopting appropriate policy measures to improve production efficiency.

Global Sensitivity Analysis and Evaluation of the DSSAT Model for Summer Maize (Zea mays L.) Under Irrigation and Fertilizer Stress

Abstract: Sensitivity analysis (SA) can identify the most critical parameters for crop growth model output, thus helping to improve model calibration efficiency. However, when combined with different production conditions, especially adverse conditions such as water stress and fertilizer stress, parameter sensitivity remains unclear. This study (i) assessed the sensitivity of the output response of the CERES-Maize model to the input parameters, particularly the effect of water and fertilizer stress on the SA results and (ii) evaluated the model performance based on the SA results. The results indicated that water stress had a considerable effect on SA, whereas nitrogen stress had little effect on SA. P5, G3, and P2 had significant effects on yield, maximum aboveground biomass (AGB), daily AGB, daily leaf area index (LAI), and daily actual evapotranspiration (ETc). Under water stress, soil drainage rate, soil runoff curve number, and photosynthesis factor greatly affected the output response of CERES-Maize. Compared with the calibration of maize cultivar coefficients, CERES-Maize with additional consideration of soil parameter calibration was more accurate. The model evaluation results revealed that the simulated LAI, yield, and soil water content were consistent with the actual measured values. These findings can provide a reference for the calibration of CERES-Maize model parameters under water and fertilizer stress.

The Impact of Climate Change on Wheat, Barley, and Maize Growth Indices in Near-Future and Far-Future Periods in Qazvin Plain, Iran

Abstract: The current noticeable climate change that has a significant impact on the environment and agricultural systems has become a serious concern for human society. Followed by the industrial activities of the global community and increased concentrations of greenhouse gases in the atmosphere, these changes are still considered as a threat to food safety and the environment. Changes in minimum and maximum temperature, rainfall amounts, and precipitation pattern, changes in CO2 concentrations, and complex interactions between these factors and different crops are studied in the form of different probabilistic scenarios to get a glimpse of the future cultivation situation. Agriculture in Qazvin Plain is based on the water transferred from Taleqan Dam and groundwater. Since today these resources are facing issues like restriction on transfer and draw off, which is because of growth of interest in city dwelling, inappropriate water consumption patterns and over-exploitation, agriculture is sensitive to probable changes in water requirements and it is necessary to predict these changes for better management in the future. This study was carried out to investigate the effect of climate change on growth indices for three crops including wheat, barley, and maize in Qazvin Plain with different possible climate change scenarios, in the form of five large-scale climate models and three greenhouse gas emissions scenarios in 30 years’ time from 2021 to 2050 as well as from 2051 to 2080. Results showed that biomass production, grain yield, and water use efficiency in three crops of wheat, barley, and maize have increased up to 20–40% in future periods in Qazvin region climate. Growing degree-days (GDD) of these three crops have increased by 20%. Transpiration has risen by 10% in wheat and maize; however, it was stable on average in the first period and slightly decreased in the second period in barley. The transpiration coefficient has reduced by 5% for wheat and barley and has increased by 15% for maize. Results are valid as long as the initial growing conditions of these three plants are done as before, and the irrigation scheduling is performed according to the present period in spite of climate change.

Persistent Indifference of Emmer Wheats Grain Yield and Physiological Functions to Nitrogen Supply: Evidence from Two Irrigation Regimes and Dryland Conditions

Abstract: Scientific data on emmer wheat’s response to N and water supplies is scarce. Two field experiments were conducted on a group of five emmer wheat landraces (Joneghan, Zarneh, Singerd, Shahrekord, Khoygan), a durum, and a bread wheat genotype. In the first experiment, the genotypes were subjected to 30 (N-limited) and 100 kg N ha–1 (N-supplied) at non-stress and drought stress conditions. In the second experiment, responses of these genotypes to the mentioned N supplies were studied under dryland and dryland + terminal complementary irrigation conditions. Water deprivation (being either due to the imposed drought stress or the dryland condition) led to decreases in chlorophyll concentration, maximum quantum efficiency of photosystem II, relative water content, grains/spike, spikes/plant, 1000-grains weight, grain yield, plant above-ground dry mass, and N use efficiency of the examined wheat genotypes. However, emmer wheat genotypes tended to vary less in response to water supply at least in terms of a majority of the traits, including grain yield (28–30% vs 40–58% drought-induced decreases for emmer and improved wheats, respectively) and above-ground dry mass (12–17% vs 23–40% drought-induced decreases for emmer and improved wheats, respectively). Increase in N supply led to decreases in grains/spike, spikes/plant, 1000-grains weight, and grain yield of the emmer wheats, despite increases in these grain yield attributes and grain yield of the durum and bread wheats. Results were indicative of greater protein content (15.7 vs 12.4% for non-stressed emmer and improved wheats, respectively) but a smaller grain yield (2985 vs 7275 kg ha−1 for non-stressed emmer and improved wheats, respectively), harvest index, and N use efficiency in the emmer wheats, compared to the durum and bread wheats, across different N and water supplies. Our findings were novel in that the emmer wheat was found more sustained across different water availabilities and no responsive to N levels that are beneficial to the durum and bread wheats.

Optimizing Planting Density and Impact of Panicle Types on Grain Yield and Microclimatic Response Index of Hybrid Rice (Oryza sativa L.)

Abstract: The architecture of rice plant represents important and complex agronomic traits, such as panicles morphology, which directly influence the microclimate of rice population and consequently grain yield. To enhance yield, modification of plant architecture to create new hybrid cultivars is considered a sustainable approach. The current study includes an investigation of yield and microclimate response index under low to high plant density of two indica hybrid rice R498 (curved panicles) and R499 (erect panicles), from 2017 to 2018. The split-plot design included planting densities of 11.9–36.2 plant/m2. The results showed that compared with R498, R499 produced a higher grain yield of 8.02–8.83 t/ha at a higher planting density of 26.5–36.2 plant/m2. The response index of light intensity and relative humidity to the planting density of R499 was higher than that of R498 at the lower position of the rice population. However, the response index of temperature to the planting density of R499 was higher at the upper position (0.2–1.4%) than at the lower position. Compared with R498, R499 at a high planting density developed lower relative humidity (78–88%) and higher light intensity (9900–15,916 lx) at the lower position of the rice population. Our finding suggests that erect panicles are highly related to grain yield microclimatic contributors under a highly dense rice population, such as light intensity utilization, humidity, and temperature. The application of erect panicle rice type provides a potential strategy for yield improvement by increasing microclimatic conditions in rice.

Relationship Between Weather Conditions and Climate Indices with Rainfed Crop Yield

Abstract: Crop yield in rainfed conditions is greatly influenced by meteorological parameters such as rainfall and evapotranspiration. As climate indices (AO, NAO, PNA, NINO-3.4, and AAO) are available for the future months, finding the relationship between crop yield with meteorological parameters and the relationship between meteorological parameters with climate indices can be very useful in predicting annual fluctuations in rainfed crop yield. In the current study, the association between rainfall, PET, and AI with barley and wheat rainfed detrended yields (1990–2016) and the relationship between AI and climate indices (AO, NAO, PNA, NINO-3.4, and AAO) were assessed for Chaharmahal and Bakhtiari province in the west of Iran. All associations were assessed at annual and seasonal (wet and dry seasons) scale considering both concurrent and lag correlations (1-year and 2-year lag). Our results showed a significant correlation between rainfall and AI with crop yields in all study locations except Kouhrang in both annual and wet season time scales. The results indicated that except Kouhrang, where the temperature is a limiting factor to crop yields, in all Chaharmahal and Bakhtiari areas, drought is one of the key factors of annual yield variability (significant correlation between AI and crop yields). The significant correlation between AI with NINO-3.4 and AAO also was observed in both annual and wet season time scales. It seems that NINO-3.4 and AAO indices can be useful to estimate grain yield of rainfed barley and wheat, predict drought occurrence, and take possible actions to counter such conditions.

Biochar Application and Rhizobium Inoculation Increased Intercepted Radiation and Yield of Chickpea in Contrasting Soil Types

Abstract: Soil amendments such as biochar and biofertilizers may improve chickpea productivity but there is limited information on whether this response could be through an increase in soil pH and nodulation. We aimed to determine whether the previously observed positive effects of biochar and rhizobium inoculation on soil pH and chickpea nodulation would result in similar improvements in the proportion of radiation intercepted by the crop canopy, biomass accumulation, and grain yield of three desi chickpea genotypes. Field experiments were carried out in clay and loamy sand soils in two successive years. Biochar application and rhizobium inoculation increased biomass accumulation, chlorophyll content, the proportion of intercepted radiation, and decreased chlorophyll a/b ratios which suggests that biochar and rhizobium inoculation increased biomass accumulation by increasing antenna size and canopy cover. Although rhizobium inoculation increased grain yield of all genotypes, the increase was greater in the best performing genotype, Acc#6. Biomass was highest at 10 t ha−1 and 20 t ha−1 biochar in the clay and loamy sand soil, respectively, suggesting that the lighter soils require higher biochar rates compared to the heavier soils for optimal biomass accumulation.

Water Stress is a Key Factor Influencing the Parameter Sensitivity of the WOFOST Model in Different Agro-Meteorological Conditions

Abstract: Sensitivity analysis is helpful for improving the efficiency and accuracy of the calibration of crop growth models. However, parameter sensitivity is still not well understood when combined with different meteorological and production conditions, especially adverse conditions such as water stress. This study simulated the production of winter wheat in four ecological areas in Henan Province, China. The Extend Fourier Amplitude Sensitivity Test algorithm (EFAST) was used for analyzing the sensitivity of 43 crop parameters of the WOrld FOod STudies (WOFOST) model to yield, aboveground biomass, and leaf area index (LAI) with or without water-limited conditions. The results demonstrated that yield and biomass were the objective outputs, and the main limiting factors for the model results were assimilation and dry matter conversion efficiency. Under water-limited conditions, the parameter sensitivity of related extinction coefficient, early wheat leaf area, and root growth increased with increased water stress. With the process variable LAI as the target output, the parameter sensitivity varied at different growth stages, whereas the parameter sensitivity was almost the same under different agro-meteorological conditions. Under water-limited conditions, the parameter sensitivity of wheat early extinction coefficient, maximum root depth, and death rate of the leaves also increased with increased water stress. Therefore, water stress is a key factor affecting parameter sensitivity under different agro-meteorological conditions.

Phenological Changes of Soybean in Response to Climate Conditions in Frigid Region in China over the Past Decades

Abstract: Plant phenology becoming a focus of current research worldwide is a sensitive indicator of global climate change. To understand observed soybean phenology and explore its climatic determinants in frigid region (Northeast China and northeast in Inner Mongolia), we studied the phenological changes of soybean [Glycine max (L.) Merr.] for the frigid region during 1981–2017, then analyzed the contribution of major causal climate factors to phenology based on multiple stepwise regression. Altogether, the average temperature from sowing to maturity (WGP) was significant increasing, accumulated precipitation and sunshine hours were decreasing. More than 50% of observations showed delays in sowing, emergence and maturity stage and short durations of sowing to flowering (VGP), flowering to maturity (RGP) and sowing to maturity (WGP). The late sowing was getting the following phenological timing backward, but the flowering and maturity delaying trends were much less than that of sowing timing due to the warming accelerated growth of soybean. Detailed analysis indicated mean temperature and accumulated precipitation of the 1–3 months immediately preceding the mean emergence, flowering and maturity dates influenced the phenological timing in higher latitude areas (HLJ and FL), while in JL and LN, accumulated precipitation and sunshine hours(replacing mean temperature) were the climatic determinants. These results brought light the importance of research and policy to support strategies for adaptation to local condition under the climate change.