Use of older age seedlings of rice often decreased the yield in transplanted rice systems. However, the response of rice seedlings at different ages in transplanting system under alternate wetting and drying (AWD) is not well documented. Therefore, this study was endeavored to identify the suitable seedling age of fine rice cultivars in transplanted rice systems under AWD. Four seedling age treatments (20, 25, 30, and 35 days), and three fine rice cultivars (Chenab, Punjab, Kissan basmati) were arranged under randomized complete block design (RCBD). Two years (2017–2018) of studies demonstrated that overall younger seedlings (20 days old) increased rice growth phase (days taken to reach physiological maturity) after transplantation with less mortality rate, and quantified with higher water productivity. Younger seedlings (20 days old) produced 14.69% and 13.36% longer panicle, 19.36% and 18% more filled grains panicle⁻¹ in both years (2017 and 2018) respectively as compared to the older seedlings (35 days old). Moreover, younger seedling (20 days) produced 22% and 22.92% kg ha⁻¹ more yield in comparison to (35 days) older seedling in both years, respectively. However, cultivars also had significant differences in growth and yield production, and Chenab basmati showed vigorous growth and produced higher yield than Punjab and Kissan basmati. Furthermore, agronomic traits such as, productive tillers, panicle length, number of branches, and filled grains in panicle significantly contributed for grain yield formation. Overall, our results revealed that younger seedlings of fine rice could be a better option to obtain optimum fine rice yield under AWD.

Japonica rice has been considerably impacted from climate change, mainly regarding temperature variations. Adjusting the crop management practices based on the assessment of adaptability mechanisms to take full advantage of climate resources during the growing season is an important technique for japonica rice adaptation to climate changed conditions. Research based on the adaptability mechanisms of japonica rice to temperature and other environmental variables has theoretical and practical significance to constitute a theoretical foundation for sustainable japonica rice production system. A contrived study was arranged with method of replacing time with space having four different japonica cultivars namely Longdao-18, Longdao-21, Longjing-21, and Suijing-18, and carried out in Harbin and Qiqihar during the years 2017–2019 to confer with the adaptability mechanisms in terms of growth, yield and quality. The formation of the grain-filling material for superior and inferior grains was mainly in the middle phase which shared nearly 60% of whole grain-filling process. Maximum yield was noticed in Longdao-18 at Harbin and Qiqihar which was 9500 and 13,250 kg/ha, respectively. The yield contributing components fertile tillers, number of grains per panicle, and 1000-grain weight were higher at Qiqihar; therefore, there was more potential to get higher yield. The data for grain-filling components demonstrated that the filling intensity and duration at Qiqihar was contributive to increase the grain yield, whereas the limiting agents to limit yield at Harbin were the dry weights of inferior grains. The varietal differences in duration and time of day of anthesis were small. Across all cultivars and both study sites, nearly 85% of the variation of the maximum time of anthesis could be justified with mean atmospheric temperature especially mean minimum temperature. Mean onset of anthesis was earliest in Longdao-21 at Harbin, whereas it was latest in Longdao-18 at Qiqihar. The maximum time to end anthesis and the longest duration of anthesis were taken by Longdao-18, i.e., 9.0 hasr and 4.2 h, respectively. Chalkiness and brown rice percentages were elevated at Qiqihar showing Harbin produced good quality rice. This study investigated the adaptability mechanisms of japonica rice under varying temperature conditions to distinguish the stress tolerance features for future sustainability and profitability in NEC. It was concluded that there is an adaptive value for anthesis especially regarding T_min and, moreover, earlier transplantation may produce tall plants. The results demonstrated that high temperature at the onset of anthesis at the start of the day enhanced the escape from high temperature later during the day. Early transplantation is recommended in NEC because earlier anthesis during humid days rendered for potential escape from high ambient temperature later during that day. Temperature influenced japonica rice significantly and coherently, whereas the influence of growing season precipitation was not significant. Daily mean sunshine influenced the japonica rice significantly, but the impact was less spatially coherent. The results foregrounded the response of the japonica rice to external driving factors focusing climate, but ignored socioeconomic suggesting emphasis on both driving factors to target future research and render important insights into how japonica rice can adapt in mid-high-latitude regions.

Low wheat grain yield under conservation tillage has been reported, and growth duration could determine the yield. Thus, an 11-year field experiment was conducted to assess the relationship between growth duration and grain yield under different tillage and residue managements. Four treatments were investigated: no-till with residue removal (NT0), conventional tillage with residue removal (CT0), no-till with residue retention (NTR, conservation tillage), and conventional tillage with residue incorporation (CTR). Beginning at 20 days after anthesis (DAA), NTR significantly increased physiological activities, indicating that NTR had a longer growth duration. NTR significantly prolonged growth duration by 2–3 days compared with the other treatments attributed to delayed emergence of seedlings caused by higher soil compaction and moisture under NTR. The CT0 had the highest grain yield on the standard harvest date used in the local area (36 DAA). Whereas the plants in NTR reached physiological maturity (39 DAA), the grain yield in NTR was significantly increased by 7.8–8.8% compared with yield at 36 DAA, and no significant difference was observed between NTR and CT0 due to the increased thousand kernel weight of NTR. Thus, it is practicable for harvesting at physiological maturity in NTR to obtain higher grain yield.

Adverse climatic conditions lead toward reduction in agricultural crop production that is a serious threat for global food security. Reduced irradiance in crop season affects plant physiology, growth and yield. To alleviate shade stress, foliar application of thiourea (TU) has not been comprehensively tested on maize. In this regard, a greenhouse study on maize crop was established with different TU application (as foliar) rates; CK (0 mg L⁻¹), T₄ (400 mg L⁻¹), T₈ (800 mg L⁻¹) and T₁₆ (1600 mg L⁻¹) under shaded and non-shaded conditions. The results indicated that TU increased physiologically photosynthetic rate (Pn), biochemically chlorophyll a, chlorophyll b and leaf water content. In term of nutrient concentration, stem and leaf nitrogen contents were increased by 18.30% and 23.55% respectively in T₁₆ as compared to CK. Overall, higher amount of TU (T₁₆) increased plant height (5.10%), stem diameter (11.90%), stem fresh weight (5.16%), stem dry weight (5.22%), 100-kernel weight (23.58%) and grain yield (9.08%) than that of CK. However, TU application under shaded environment could not produce similar yield as that of non-shaded plants. Overall, non-shaded plant had 9.71% higher grain yield than that of shaded conditions. But it can be concluded that foliar application of TU at higher concentration could be a promising option to maintain maize productivity under shaded conditions. Furthermore, combination of TU with other plant nutrients should be tested to improve maize growth under shaded conditions.

Tunnels construction are widely used to facilitate large transport infrastructure projects, which may lead to a significant impact on soil organic carbon (SOC) dynamics and SOC chemical stability through depleting groundwater. However, the mechanisms of the effects tunnel construction on the chemical stability of SOC remain unexplored, which has become one of the most important but the least studied field. Therefore, this study aimed to investigate how tunnel construction impacts the chemical stability of SOC in shrublands along three altitude gradients (3240, 3420 and 3600 m above sea level) in the Eastern Tibetan Plateau. The results showed that tunnel construction did not significantly change SOC and its fractions regardless of altitude levels. However, tunnel construction increased O-alkyl carbon (C) by 10-15%, and decreased alkyl C (8-13%) and aromatic C (8-12%). These changes reduced SOC disintegration (alkyl C/O-alkyl C) and increased aliphaticity (aliphatic C/aromatic C) along three altitudes, causing a decrease in the chemical stability of SOC. This phenomenon was attributed to the reduced microbial activity caused by the decrease in soil water content after tunnel construction and an increase in active functional groups due to the increase of fine root biomass revealed by structural equation model. Our finding suggests that tunnel construction had no impact on SOC content, but the reduction in chemical stability of SOC may have a profound impact on long-term SOC sequestration. These findings offered new insights in predicting long-term SOC dynamics following giant construction engineering.