International Journal of Plant Production
Volume:14 Issue: 2, Jun 2020

Water deficits reduce plant growth. Moisture stress affects the development of plant organs, which in turn can have very profound effects on plant growth. Initiation and differentiation of vegetative and reproductive organs, as well as cell division and cell enlargement, are very sensitive to water stress. The size of the vegetative organs in part determines the yield of grain crops, and therefore the yield is often determined before heading or flowering. Factors that determine the size of plant vegetative organs are many, and they are interrelated in a complex manner. Environmental factors rank high among those that determine vegetative growth, and among these environmental factors, nitrogen, soil temperature, and soil water play key roles. In this paper, we present a sensor-cloud based precision agriculture for intelligent water management for effective productivity in agriculture.

India is one of the largest landmasses under crop cultivation with staple consumption of food security crops. Post green revolution (since 1967), there has been a steady March towards self-sustainability in food production. Though the general trends speak of an increase in crop yields, the detailed study on decade wise trends and fast approaching state of stagnation in crop yields is largely missing. The present manuscript is the first study examining the crop yield trends of three major food crops—wheat, rice, and maize across Indian states. The four types of regression models were fitted on the annual yield data from all the 29 Indian states over the period 1967–2017. The best-fit statistical models were chosen using the Akaike information criterion. Our results suggest that (1) Wheat yields in 13 Indian states, rice yields in eleven Indian states, and maize yields in six Indian states are now not improving. (2) The yields in ~ 76% of wheat harvested area (~ 18.5 million hectares), ~ 47% of rice harvested area (~ 19.5 million hectares), and ~ 18% of maize harvested area (~ 1.2 million hectares) are not improving for the recent decade. The detailed mapping of current crop yield trends across Indian states is the first step towards achieving a bigger goal of identifying the responsible factors affecting current crop yield trends and then identifying and recommending appropriate mitigation strategies.

Organic agriculture can contribute to maintain the long-term sustainability of the agroecosystems, preserve and improve soil quality and guarantee good quality food products. The objective of this study was to investigate the effects of different organic fertilizers and a biostimulant on crop performance and soil properties. The research was performed in an experimental farm in Southern Italy and covered a 2-year rotation of lentil and durum wheat for a period of 4 years. An organic commercial fertilizer and a compost, obtained from municipal wastes, with and without a commercial biostimulant, were compared in a randomized complete block design. The results showed that compost, as the only nutrient source, did not significantly decrease lentil and wheat grain yields, even though, in 2011 and 2012, wheat grain quality was better with the organic commercial fertilizer. Probably, the mineralization rate of compost, depending also on environmental conditions, and, consequently, the nutrient availability was not enough to meet the needs of wheat crop. Biostimulant significantly increased the straw yield of lentil by 20% and the weight of 1000 seeds of wheat by 4%. At the end of the experiment, the compost, applied at low doses, significantly increased soil TOC content (+ 3.4%) compared to the organic commercial fertilizers. Conversely, the biostimulant seemed to have no effect on the soil properties. Overall, under the local Mediterranean conditions, the compost may be used as an alternative nutrient source, with positive effects for lentil and wheat productivity, economic sustainability and soil fertility.

Because of human dependence on sustainable food production, it is needed to adopt agricultural production to climate change, and their consequences on associated socioeconomic issues. Crop modelling potentially can contribute to global food and nutrition security. Therefore, in this context DSSAT (decision support system for agro-technology transfer) was validated for predicting growth and yield of wheat under a diverse semi-arid climate (2 years with diverse climates) and different irrigation strategies, planting methods, and nitrogen rates. The irrigation strategies were ordinary furrow irrigation (OFI) and variable alternate furrow irrigation (VAFI), and the planting methods were on-ridge planting (ORP) and in-furrow planting (IFP) methods. The fertilizer levels were 0 (N0), 150 (N1) and 300 (N2) kg N ha−1. Results indicated that water stress and inappropriate weather especially during the stem elongation influences the grain yield remarkably without noticeable effect on straw yield. Furthermore, VAFI strategy did not impose any limitation on top dry matter N concentration in both years. Calibration of DSSAT showed that the model underestimated the actual evapotranspiration at the end of growing season (during spring with high temperature) and resulted in overestimating the soil water content at depths under 10 cm during this period of time. Since the potential transpiration has an important role in calculating the effect of water stress factor, the model overestimated slightly the maximum leaf area index (LAI) and consequently biomass and yield in water stress condition; however, overall, model could statistically simulate LAI (NRMSE = 0.3, d = 0.96, R2 = 0.95), total dry matter (NRMSE = 0.07, d = 0.99, and R2 = 96) and grain yield (NRMSE = 0.13, d = 0.96, and R2 = 90). Model also could reasonably simulate the nitrogen components including the grain N concentration (NRMSE = 0.05, d = 0.95), above-ground nitrogen uptake (NRMSE = 0.11, d = 0.99), and soil nitrate content (NRMSE = 0.23, d = 0.86). However, evaluating the model with data set from 2015 to 2016 indicated that the model could not simulate wheat yield and nitrogen components in validation year due to strong effects of diverse weather condition and water stress on grain yield and crop development.

Safflower oil is a rich source of omega-3 fatty acids that is important for health. Drought stress can severely decrease the productivity and oil quality of safflower. Thus, in order to study the effect of hydropriming and melatonin-seed-priming on fatty acid composition and yield of Safflower under water deficit conditions a field experiment was carried out as split-factorial in a randomized complete block design with four replicates during 2017 and 2018 growing seasons. The oil concentration of the safflower seeds was determined by soxhlet extraction method. Fatty acids of safflower’s oilseed were transformed to their methyl esters (FAME), and a gas chromatograph equipped with a flame ionization detector (FID) was used for determination of fatty acids. The results indicated that melatonin-seed priming increased grain yield, HI and oil yield of safflower under drought condition. Drought stress led to a significant decrease in oil yield, and recently harvested seeds had higher oil yield across both years. The highest amount of oil yield was obtained by hydropriming on seeds which had been stored for 8 years, and recently harvested seeds with 576.50 and 645.57 kg.ha−1, respectively under no-stress condition. Melatonin-seed-priming improved the oil quality of safflower under drought with an increase of unsaturated fatty acids of safflower especially omega 6 and omega 3. Melatonin-seed priming increased the amount of ∑PUFA, ∑UFA/∑SFA, P/S and DBI across both years in comparison with unprimed seeds. Seed priming improved the quality of oil and productivity in both recently harvested and stored seeds. It can be concluded that melatonin-seed priming improved the productivity, oil content and composition especially in stored seeds and under drought stress.

Water productivity (WP) is becoming a key issue in understanding the relationship between water availability and rainfed sorghum (Sorghum bicolor L. Moench) yields in agricultural systems across sub–Saharan Africa. The objective of this study was to determine water productivity of three sorghum genotypes under different environmental conditions. Three sorghum genotypes, a hybrid (PAN8816), a commercial open-pollinated variety (Macia) and a landrace (Ujiba) were planted at two sites (Ukulinga and Mbumbulu) in South Africa during 2013/2014 and 2014/2015. High clay content in Mbumbulu lowered plant available water in the soil compared to Ukulinga. Sorghum adapted to low water availability by significantly (P < 0.05) lowering plant growth (green leaf number, plant height and canopy cover), crop physiology (chlorophyll content index and stomatal conductance), biomass and grain yield. Ujiba and PAN8816 genotypes hastened phenological development, whilst Macia delayed phenological development in response to low water availability. Total and grain WP were lower at Mbumbulu (14.93 and 7.49 kg/ha/mm) relative to Ukulinga (21.49 and 11.01 kg/ha/mm), respectively. Results showed that Macia had significantly higher (P < 0.05) WP (10.51 kg/ha/mm) relative to PAN8816 (9.34 kg/ha/mm) and Ujiba (7.90 kg/ha/mm). Lack of significant genotypic differences in grain WP highlights that all three genotypes are equally suitable for production under sub–optimal and dryland conditions.

Farmers face increased risks and vulnerability to the effects of climate change and land degradation on crop production due to the lack of information and impact assessment. This is especially true in the Khorezm, an irrigated agricultural region near the Aral Sea Basin (Uzbekistan) which represents eight million of irrigated land in Central Asia. Water scarcity requires research and introduction of alternative crops into a common winter wheat–cotton rotation. Mung bean (Vigna radiata) is considered as a drought-tolerant crop that could be implemented in Khorezm and other similar drought prone areas. The main objective of this study was modeling the triple rotation sequenced the winter wheat (WW), summer mung bean (MB) and cotton (C) as a single cropping system. Specific objectives were to (1) update the parameterization of the irrigated winter wheat and cotton modules in CropSyst to identify the key variables impacting the triple rotation (WW–MB–C) on overall crop yield; (2) to parameterize and validate the developed (CropSyst-based) model using controlled triple rotation data and (3) carry out scenario analyses to capture the influence of soil fertility levels and irrigation water shortage on crops growth, development and yields. The results revealed, for the first time, the impact of different soil-ecological factors such as high soil fertility (HSF) and low soil fertility (LSF) varying levels of irrigation water availability on crops in the triple crop rotation. Compared to LSF simulated yields of winter wheat and cotton under HSF were increased with 0.58 Mg ha−1 for WW grain and 0.21 Mg ha−1 for cotton while mung bean grain yields were not affected by different soil fertility levels. Scenario analyses showed the possibility of reduced (by 20%) irrigation for triple crop without the effect on yield. However, compared to full irrigation scenario, reduction of irrigation for 40 and 60% could decrease the rotation crops yields up to 33% and 40%, respectively. The developed model could be useful to increase the understanding of the nexus of food, energy and water in Khorezm and comparable regions of Central Asia, and to inform decision-making about sustainable use of available water resources.

Plant species may be subject to Allee effect if individuals experience a reduction in fitness when population biomass is small. The instances of Allee effect are fewer in number for plants than the animals and the consequences are not substantially explored for the field crops. Here Allee effects on three winter crops, viz. Barley (Hordeum vulgare Sensulato), Wheat (Triticum aestivum L. emend. Fiori and Paol.) and Indian mustard [Brassica juncea (L.) Czernj. And Cosson] have been studied in sub-tropical sub-humid agro-ecosystem through field experiment and mathematical model formulation. The field experiment was conducted during the winter seasons of 2014–2015 and 2015–2016 at the Agricultural Experiment Farm of the Indian Statistical Institute, Giridih, Jharkhand under rainfed conditions. The underlying experimental design is a split-plot design with three replications for each winter crop. Two varieties of each winter crop were randomly allocated in the main plots. In sub-plots, four weed treatments are applied, viz. Weed-free control, other weeds except M. denticulata, M. denticulata alone, unweeded. We illustrate the mathematical models for the crop—weed interactive dynamics through the total biomass yield (in kg/ha) of the three winter crops. The existence of weak Allee effect in Barley and Wheat is established particularly in the presence of Medicago, but Indian mustard exhibits no such evidence. The importance of this dynamic process in plant ecology has been under appreciated and recent evidence suggests that it might have an impact on the population dynamics of many plants. A practical agro-economic benefit of M. denticulata has also been revealed.

Rational fertilizer management is crucial in the efficient use of resources that are basically non-renewable and that can have a great environmental impact when used without scientific basis. The availability of scientifically sound decision-making tools for rational fertilization is scarce. We have developed a Windows program to calculate the required seasonal N, P and K rates, and the most cost-effective combination of commercial fertilizers. The tool also provides estimates of the Ca, Mg and S balances in the field resulting from the fertilizer program chosen. Novel aspects of the calculations include the development of stochastic flexible fertilizer programs for N and the calculation of acidification and N losses. Regarding P and K, estimations are provided on the grounds of threshold values of usual availability indexes, something frequently unknown by final users. Also, it allows the users to determine the best complex fertilizer for pre-plant applications to avoid blending of simple fertilizers at the farm, a task usually complex for farmers. The application may be useful both to the fertilizer supply and demand sides. In addition, it may be used for teaching as it helps understanding the rationale behind this management practice.

Maize is sown during spring and autumn seasons in Pakistan; however, studies on inter-seasonal variability on maize productivity, agronomic and nitrogen use efficiencies (NUEs) are limited. Therefore optimization of nitrogen (N) rate and hybrids selection for each season is critical to harvest better yield in maize–maize cropping system. Two independent field experiments were conducted to optimize N rates for different hybrids to improve maize productivity and NUEs in spring and autumn seasons during 2016 and 2017. During spring season, three spring-hybrids (P-33M15, M-DK6525 and S-NK8441) and during autumn season, three autumn-hybrids (P-30R50, M-DK6714 and S-NK6621) were sown under five N levels i.e., 0, 80, 160, 240 and 320 kg ha−1. Maize yield and related traits, and NUEs were improved with each higher level of N application. Highest and lowest grain yield, agronomic and economic NUEs were recorded at 320 kg N ha−1 and without N application, respectively in both seasons. Likewise, highest grain yield and NUEs were observed by spring-hybrid P-33M15 and autumn-hybrid P-30R50, while lowest were obtained by spring hybrid S-NK8441 and autumn hybrid S-NK6621 during both years. Nonetheless, maximum net income and benefit: cost ratio was observed by spring-hybrid P-33M15 and autumn-hybrid P-30R50 at higher N level (320 kg ha−1) and maize cultivation without N was not profitable in both seasons. Maize cultivation with N application at 320 kg ha−1 seemed a viable option to get maximum productivity, economic returns and NUEs of maize–maize cropping system in irrigated arid environment of southern Punjab, Pakistan and might be for other areas having similar environmental conditions.

Wheat sowing often gets delayed and the crop faces terminal heat stress, which is severely impacting the crop productivity. Synthetic osmolytes maintain structural integrity of cell membrane and protect oxidative damage of cells under stress conditions. Hence, foliar application of these compounds is likely to alleviate the negative effects of high temperature on crop plants. However, field response of these chemicals on late-sown wheat in the subtropical environment (eastern Indo–Gangetic Plain) is still uncertain. A field experiment was conducted for three years (2013–2016) to envisage the field efficacy of two synthetic compounds viz., potassium nitrate (KNO3) (1.0 and 0.5%) and glycine betaine (GB) (100 and 50 mM), each sprayed either at respective higher dose at booting or anthesis, or at half the dose at both booting and anthesis for improving grain yield of two contrasting wheat cultivars (DBW14 and K307) facing terminal heat stress. Foliar application of 0.5% KNO3 at both booting and anthesis stages resulted in the maximum increase (13–16%) in grain yield over no-spray treatment closely followed by 1% KNO3 at anthesis (10–14%), and 50 mM GB at both booting and anthesis stages (6–9%). However, foliar spray of KNO3 and GB at only booting stage had a non-significant effect on grain yield. The increase in grain yield with the osmolytes application was attributed to an increase in the number of grains ear− 1 (9–16%) and thousand-grain weight (3–10%), demonstrating an increased sensitivity of sink capacity and grain development of wheat to terminal heat stress. The degradation of flag leaf chlorophyll content (34–36%) and increase in the relative membrane permeability (29–52%) during anthesis to grain filling period was observed as the critical yield-limiting factors in late-sown wheat. Foliar spray of osmolytes had a regulatory effect on these physiological anomalies being highest with the treatment 0.5% KNO3 foliar spray at both booting and anthesis stages followed by 1% KNO3 foliar spray at anthesis. At the grain filling stage, significant relationships between grain yield and flag leaf chlorophyll (r = 0.43–0.68) and relative membrane permeability (r = − 0.47 to − 0.53) were observed. Thus, foliar application of 0.5% KNO3 at both booting and anthesis stages could be recommended to alleviate the adverse effect of terminal heat stress and improve productivity of late-sown wheat in subtropical environments.

In view of the expected increase in drought periods, researchers and breeders are searching for forage grasses that are more tolerant to drought stress. This study wanted to examine the physiological and biochemical reactions of nine forage grass varieties belonging to Festuca, Lolium and Festulolium under mild drought stress conditions in a semi-controlled field experiment. A mild drought stress treatment was applied in the period between cut II and cut III using three large mobile rain-out shelters equipped with sprinkler irrigation systems. The experiment consisted of two soil moisture treatments: (1) control where a soil moisture level of around 20% v/v was maintained and (2) drought stress where the soil moisture level decreased to 7.5% v/v. The experiment was cut 5 times in 2014 and 4 times in 2015. A total of nine varieties from five species of forage grasses were evaluated: L. perenne, L. multiflorum, F. pratensis, F. arundinacea and F. braunii. Dry matter yield, gas exchange parameters and chlorophyll fluorescence were significantly lower in drought stress than under control conditions and the physiological parameters reacted within 2 weeks after the start of the drought treatment in all species. In contrast, drought stress significantly increased water use efficiency, the content of proline, phenolic acids, flavonoids, water soluble carbohydrates and decreased neutral and acid detergent fibre on both years. Based on total dry matter yield and tolerance indices the most drought tolerant species were L. multiflorum in the first and F. arundinacea in the second investigated year.

Sustainable crop production in sub-tropical countries is severely affected by the unscientific application of fertilizers. The SPAD based N management of the rice–wheat sequence was investigated in eastern India. Topdressing of 25 kg N ha−1 was applied at SPAD 36 and 40 (S36 and S40) for rice (Oryza sativa L.) and wheat (Triticum aestivum L.), respectively, reduced the N requirement by an average of 26.5% (33.3% in rice and 18.8% in wheat) over the fixed-time N management (FTNM) without reducing the grain yield. The 25 kg N ha−1 increased nutrient removal in the system having high agronomic N use efficiency (21.4) and nitrogen recovery efficiency (0.60) with the lower N requirement (62.5 kg N ha−1) over the FTNM. The treatment with medium SPAD (S36 for rice and S40 for wheat) under 25 kg N ha−1 increased the agronomic N use efficiency by 58% in rice and 58.5% in wheat compared to that under FTNM and recorded the highest gross (2106.1$ ha−1 Year−1) and net (1202.5$ ha−1 Year−1) returns from the rice–wheat system. The SPAD-based N management increased the water content in N-treated plots compared to that in the control plots, and the utmost moisture custody was observed when using a moderate (25 kg ha−1) N topdressing at a moderate SPAD (S36 for rice and S40 for wheat) for a given soil suction. This study suggests that using SPAD meter in rice–wheat system can cover the productive N management and profitability and can be dependably used in precision agriculture to manage the spatial variation in farmers’ field.

Limited arable land area and deteriorating soil health in smallholder farmers’ fields of subtropical regions in China have led to an urgent demand for sustainable production practices with greater land productivity and nutrients use efficiency. A group of field experiments at three locations (Yaan, Lezhi and Renshou) in two consecutive years of 2012–2013 were conducted to study crop production and nutrients recovery of maize (Zea mays L.) and soybean (Glycine max (L.) Merr.) in monocropping and additive relay intercropping systems. The results showed that the total crop yields of the 2:2 maize-to-soybean wide-narrow row spacing planting pattern (RIwn) were significantly higher than that of the 1:1 maize-to-soybean equal row spacing planting pattern (RIe), and the average land equivalent ratios (LER) of the grain yield were 1.79 and 1.49 for the RIwn and RIe, respectively. The nitrogen (N), phosphorus (P) and potassium (K) recovery efficiency calculated by the ratios of crop nutrients removed and fertilizer input indicated that the RIwn had a higher nutrients recovery than the RIe due to proper spacing between maize and soybean rows and higher soybean yield in RIwn. In terms of the amount of fertilizer applied, based on this experiment, P should be reduced in maize plantings and increased in soybean plantings to maintain the balance of soil P. Considering the higher temperatures during the soybean vegetative growth phase, N fertilizer inputs should be controlled to prevent excessive soybean growth. In addition, excess K was taken up in the crop biomass, maybe the straw should be returned to the field to maintain soil K fertility sustainable for the long term.

Because water resources for irrigation are limited worldwide, it is essential to embrace proper water-saving practices. Field studies were laid out as a factorial split experiment in a randomized complete block design with three replications in 2015 and 2016 to determine the effect of wheat straw mulch (0 and 7.5 tons ha−1) under different irrigation treatments (100%, 80%, 60%, and 40% of the required water) on the physiological characteristics, grain yield, and oil content of sesame (Sesamum indicum L.) genotypes (Borazjan 2, Halil, and Jiroft). Seed yield, 1000-seed weight, seed number, and capsule number were decreased by 64%, 65%, 60%, 70%, and 66%, respectively, as a result of increments in water deficit (from 100 to 40%). However, the application of 7.5 tons ha−1 of mulch mitigated the negative effect of water stress as said factors decreased only by 42%, 40%, 46%, 44%, and 45% as a result of increments in water deficit (from 100 to 40%). Catalase activity (CAT), superoxide dismutase (SOD) activity, proline content, and water use efficiency (WUE) increased with increases in water deficiency, while relative water content (RWC), photosynthetic pigment, and leaf area index (LAI) decreased as water stress rose from 100 to 40%. Applying 7.5 tons ha−1 of straw mulch in 60% available water can be considered a promising management strategy due to both reduction in irrigation water requirements and improvement of low-yield sesame fields in water-deficient areas.