Global agriculture is undergoing a phase of agroecological transition This transition will be characterized by adoption of agroecological cropping practices and by an increased diversity of soil management/tillage practices However, very little is known as to whether or not crop seed germination and seedling emergence (hereafter referred to as SGE) will be affected under these cropping practices This paper first proposes a conceptual scheme which integrates key abiotic and biotic factors affecting crop SGE Subsequently, the key mechanistic factors affecting SGE (ie intrinsic factors related to the seeds, and extrinsic factors related to the biotic and abiotic conditions of the seedbed), and how crop management practices can influence SGE through alterations of these direct mechanistic factors are discussed This is done with special emphasis on how agricultural practices, particularly those related to agro-ecology, may impact SGE Crop SGE are affected by five major groups of drivers, namely seed and seedling characteristics, seedbed physical components, seedbed chemical components, seedbed biological components, and cropping systems Although the crop SGE failure frequently occurs under field conditions, very little quantitative information is available in the literature on the real economic impact, the precise cause/s and ranking of factors associated with this failure Re-seeding is often practiced for a number of crops to compensate the lack of SGE with significant direct and indirect costs for farmers Little information exists in the literature concerning how SGE will be affected under agroecological cropping systems, such as conservation agriculture, or organic farming, or under climate-driven changes Field observation, experimental and modeling studies are needed to fill the current knowledge gaps on the economic impact, precise cause/s and ranking of different stress factors associated with SGE failure

Abiotic and biotic factors affecting crop seed germination and seedling emergence: a conceptual framework

Excessive reliance on chemical fertilizer (CF) in conventional farming is a serious concern owing to its negative effects on soil health, the environment, and crop productivity. Organic manure is an alternative source of fertilizer to reduce the amount of CF usage in agriculture, decrease environmental pollution, and ensure sustainable crop production. This study assessed the integrated effect of poultry manure (PM) and cattle manure (CM) with CF on soil properties, plant physiology, and rice grain yield. Additionally, the difference in pre-and post-anthesis dry matter (DM) and nitrogen (N) accumulation and their relationship with grain yield was also determined. Pot experiments were performed in the early and late growing season at the experimental station of Guangxi University, China, in 2018. A total of six treatments, i.e., T1-CF0; T2-100% CF; T3-60% CM + 40% CF; T4-30% CM + 70% CF; T5-60% PM + 40% CF, and T6-30% PM + 70% CF were used in this pot experiment. Results showed that T6 enhanced leaf photosynthetic efficiency by 11% and 16%, chlorophyll content by 8% and 11%, panicle number by 12% and 16%, and grain yield by 11% and 15% in the early and late seasons, respectively, compared to T2. Similarly1, post-anthesis N and DM accumulation, N uptake, and soil properties (i.e., soil organic carbon, total N, and bulk density) were improved with integrated CF and manure treatments over the sole CF treatments. Interestingly, increases in post-anthesis N uptake and DM production were further supported by enhanced N-metabolizing enzyme activities (i.e., nitrate reductase, glutamine synthetase, and glutamate oxoglutarate aminotransferase during the grain-filling period in combined treatments. In-addition, the linear regression analysis showed that post-anthesis DM (R2 = 0.95) and N (R2 = 0.96) accumulation were highly associated with grain yield of rice. Thus, the combination of 30% N from PM or CM with 70% N from CF (i.e., urea) is a promising option for improvement of soil quality and rice grain yield. Furthermore, our study provides a sustainable nutrient management plan to increase rice yield with high N use efficiency.

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Manure combined with chemical fertilizer increases rice productivity by improving soil health, post-anthesis biomass yield, and nitrogen metabolism.

Wheat is one of the world’s most commonly consumed cereal grains. During abiotic stresses, the physiological and biochemical alterations in the cells reduce growth and development of plants that ultimately decrease the yield of wheat. Therefore, novel approaches are needed for sustainable wheat production under the changing climate to ensure food and nutritional security of the ever-increasing population of the world. There are two ways to alleviate the adverse effects of abiotic stresses in sustainable wheat production. These are (i) development of abiotic stress tolerant wheat cultivars by molecular breeding, speed breeding, genetic engineering, and/or gene editing approaches such as clustered regularly interspaced short palindromic repeats (CRISPR)-Cas toolkit, and (ii) application of improved agronomic, nano-based agricultural technology, and other climate-smart agricultural technologies. The development of stress-tolerant wheat cultivars by mobilizing global biodiversity and using molecular breeding, speed breeding, genetic engineering, and/or gene editing approaches such as CRISPR-Cas toolkit is considered the most promising ways for sustainable wheat production in the changing climate in major wheat-growing regions of the world. This comprehensive review updates the adverse effects of major abiotic stresses and discusses the potentials of some novel approaches such as molecular breeding, biotechnology and genetic-engineering, speed breeding, nanotechnology, and improved agronomic practices for sustainable wheat production in the changing climate.

https://www.mdpi.com/2073-4395/11/2/241/pdf

Consequences and Mitigation Strategies of Abiotic Stresses in Wheat (Triticum aestivum L.) under the Changing Climate

The use of controlled-release urea (CRU) has been recommended over that of conventional urea to improve rice grain yield and nitrogen use efficiency. However, the underlying agronomical and physiological mechanisms need to be better understood. In this study, field trials over four site-years, and a big container experiment were carried out to explore CRU effects on rice yield and NUE, with the main aims to identify the key yield components contributing to the superior rice yield with CRU use, and to evaluate differences in dry matter, nitrogen (N) accumulation, translocation and yield formation with different N fertilizer practices. Four N treatments were investigated: control with 0 kg N ha-1 (CK), farmers' fertilizer practice (FFP) with 150 kg N ha-1 as urea basal application, modified fertilizer practice (MFP) with 150 kg N ha-1 as split urea application (40% at transplanting, 30% at tillering and 30% at the panicle stages), and CRU treatment with 150 kg N ha-1 as CRU basal application. Results showed that the CRU increased rice yields by 10.8 and 5.6% over FFP and MFP, respectively. The N recovery efficiency and N agronomic efficiency for CRU were significantly higher than that obtained from MFP and FFP treatments. The analysis of yield components revealed that the higher grain yields using CRU were accounted for mainly by increased panicle and spikelet numbers per m2, which resulted from higher N uptake. In addition, results from the container experiment with comparable experimental design to field trials illustrated that both post-anthesis dry matter production and translocation were critical for high grain yields using CRU, while the former seemed more important. Relative to MFP and FFP, CRU maintained higher flag leaf SPAD and photosynthetic rate, as well as higher root oxidation activity (ROA) and N uptake during grain filling. Furthermore, CRU increased the activities of key enzymes involved in N assimilation in flag leaves, including GS, GOGAT, and NR. CRU effects on such underground and aboveground processes were proposed to contribute to high rice yield.

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Application of Controlled-Release Urea Enhances Grain Yield and Nitrogen Use Efficiency in Irrigated Rice in the Yangtze River Basin, China.

Smart agriculture – Urgent need of the day in developing countries

Impact of sowing date on yield, dry matter and nitrogen accumulation, and nitrogen translocation in dry-seeded rice in North-West India

Plant hormones influence various physiological processes during the growth and development of plants, but their critical roles in influencing yield and antioxidant activities in dry-seeded rice (DSR) have not been adequately explored. This study aims to analyze the performance and antioxidant activity of contrasting genotypes of DSR in response to soil moisture regimes and foliar-applied hormones. The study comprised sixteen treatments that were evaluated under field conditions as per split-plot design in three replications. Treatments comprised combinations of two soil moisture tension regimes (10 kPa and 20 kPa) and two genotypes (PR-111, non-stay-green type and PR-123, stay-green type) applied to the main plots and foliar application of three hormones (gibberellic acid (GA3) 40 mg kg-1, abscisic acid (ABA) 20 mg kg-1, and cytokinin (CK) 40 mg kg-1)) and a control (unsprayed) to subplots. The non-stay-green genotype (PR-111) resulted in 34.6% more grain yield (6.48 t ha-1) than the stay-green genotype (PR-123) at the lower soil moisture tension regime (SMTR) (10 kPa) due to the increased number of filled grains per panicle and improvement in harvest index (HI). At the higher SMTR (20 kPa), the stay-green genotype (PR-123) produced 26.4% more grain yield (5.21 t ha-1) than non-stay green genotype (4.12 t ha-1) and showed enhanced superoxide dismutase (SOD) and peroxide dismutase (POD) activity that may have contributed in maintaining sink size through improved chlorophyll content. Grain yield (6.35 t ha-1) with foliar-applied GA3 (40 mg kg-1) at SMTR of 10 kPa was higher by 12.2% and 24.0% than with foliar-applied ABA (20 mg kg-1) and unsprayed treatments, respectively. Irrigation application at SMTR of 20 kPa and foliar application of ABA gave 24.1% higher grain yield (5.15 t ha-1) than the unsprayed treatment, but it was similar to foliar-applied GA3 and CK. This study implied that the stay-green genotype (PR-123) was more suitable under moisture stress conditions (20 kPa) in DSR, as it maintained sink size even under moisture stress conditions by improving dry matter translocation and enhancing SOD and POD activity. The study suggests the need to find out the endogenous level of these plant hormones in rice genotypes under a range of water regimes to develop high yielding and water use efficient genotypes of DSR.

Performance of Dry-Seeded Rice Genotypes under Varied Soil Moisture Regimes and Foliar-Applied Hormones.

Sugarcane is one of the most suitable alternative crops to predominant rice–wheat cropping system in indo-Gangetic plains of India. However, grand growth period of this crop coincides with hot and dry summer months having higher evaporative demands which raise the crop water requirement during this period, thus narrowing its scope of being an alternative to rice–wheat cropping system. To enhance water productivity of sugarcane field, experiments were conducted at Punjab Agricultural University, Regional Research Stations, Faridkot and Kapurthala during spring 2016, 2017 and 2018 on planting methods and irrigation scheduling. Four planting methods comprised of P1: conventional flat (75 cm apart) with mulching @ 6 ha−1, P2: conventional flat without mulch, P3: paired row trench planting (30:120 cm) with mulch and P4: paired row trench planting without mulch as main plots and three irrigation schedules, i.e., irrigation at 0.60, 0.80 and 1.00 IW/CPE as subplots factors in split plot design. The results revealed that paired row trench planting (30:120 cm) with mulch @ 6 t ha−1 resulted into 162% and 123% higher apparent water productivity than conventional flat planted crop without mulch at Faridkot and Kapurthala, respectively. In paired row trench planting, irrigation water application was 58.4% and 52.0% lesser than conventional flat planted crop at Faridkot and Kapurthala, respectively, as water was applied only in trenches which actually curtailed the wettable area to 40%. Mulching in conventional flat planted crop improved the cane yield by 10.3% over non-mulch flat planted crop at Kapurthala, but this difference was only 6.1% in paired row trench planted crop at Faridkot. At Kapurthala, mulching in paired row trench planted crop enhanced the cane yield by 8.8%, but in conventional flat planted crop, this increase was up to 6.9%. On the basis of these results, it can be concluded that the planting sugarcane in paired row trench planting system with mulch @ 6 t ha−1 is the most viable planting system in sugarcane to attain higher crop and water productivity. Based on the availability of irrigation water, crop can either be irrigated at 0.6 or 0.8 IW/CPE for higher total and apparent water productivity and higher water-use efficiency. Higher benefit/cost ratio (mean over locations) is obtained under paired row trench planting with mulch and irrigation scheduling at 0.8 IW/CPE.

Water Productivity of Sugarcane Influenced by Planting Techniques, Mulching and Irrigation Scheduling in Indo-Gangetic Plains of India

Incidence of pokkah boeng disease on sugarcane clones and varieties in Punjab

The present study was conducted to explore the nutritional potential of different varieties of sugarcane top silages enriched with molasses or bacterial inoculants as unconventional feed resource. Tops of four sugarcane varieties, i.e., Co 118, CoJ 88, CoPb 93 and CoPb 92, recommended for cultivation in India were collected and evaluated for their chemical composition. Results revealed that tops of sugarcane variety CoPb 93 were lower in crude protein and ether extract content, whereas variety CoPb 92 had lower acid detergent lignin as compared to all tested varieties. Similarly, neutral detergent fiber was lower in variety Co 118 and CoPb 92 as compared to varieties CoJ 88 and CoPb 93. Collected sugarcane tops were ensiled with bacterial inoculants (1 g/ton) and molasses (95:5) for 45 days in low-density polypropylene tubes. The all sugarcane tops varieties with molasses and bacterial inoculants produced good quality silage with pH  4.0% DM and ammonical-N < 10% of total nitrogen. Although molasses-based sugarcane top silages had overall good ensiling potential as compared to bacterial treated silages, overall from the present study, it can be concluded that the molasses-based silages with sugarcane tops variety CoPb 92 followed by variety CoPb 93 have higher potential as unconventional feed resource for livestock.

Harnessing the In Vitro Nutritional Potential of Different Varieties of Sugarcane Tops Silages Enriched with Molasses and Bacterial Inoculants as an Unconventional Feed Resource

Rajinder Pal

Papers

Impact of sowing date on yield, dry matter and nitrogen accumulation, and nitrogen translocation in dry-seeded rice in North-West India

Performance of Dry-Seeded Rice Genotypes under Varied Soil Moisture Regimes and Foliar-Applied Hormones.

Water Productivity of Sugarcane Influenced by Planting Techniques, Mulching and Irrigation Scheduling in Indo-Gangetic Plains of India

Incidence of pokkah boeng disease on sugarcane clones and varieties in Punjab

Harnessing the In Vitro Nutritional Potential of Different Varieties of Sugarcane Tops Silages Enriched with Molasses and Bacterial Inoculants as an Unconventional Feed Resource