Water management in wheat using non-traditional techniques

Water is one of the most limiting resources for agricultural production. Due to uneven distribution of rainfall, supplemental irrigation is often required to produce sustainable yield level. Timing and frequency of irrigation is one of the most important tactical decisions, which a farmer has to make to maximize profit from limited water availability. Computer based dynamic simulation models have the capability to assess management options under different environments to help in decision making. In this study, CRESS-Wheat Model V-3.5 has been utilized to quantify the optimum utilization of limited water for popular wheat genotypes of NW India for operational use in Agrometeorological Advisory services with routinely measured weather parameters.

Trends in Pacific Canadian groundfish stock status

We assembled estimated biomass (B) time series from stock assessments for 24 Pacific Canadian groundfish stocks and modelled average and stock status through 2020 based on biomass relative to each stock's (1) Limit Reference Point (B/LRP), (2) Upper Stock Reference (B/USR), and (3) biomass at maximum sustainable yield (B/BMSY). The overall mean B/LRP in 2020 was 3.2 (95% credible interval [CI]: 2.6-3.9). The overall mean B/USR and B/BMSY in 2020 was 1.5 (95% CI: 1.3-1.9) and 1.4 (95% CI: 1.1-1.7), respectively. Average stock status declined from 1950 to around 2000 and has remained relatively stable since then. The change around 2000 followed the implementation of ITQs (individual transferable quotas) for the trawl fleet and the commencement of the synoptic trawl surveys. As of their last assessment, four stocks (Strait of Georgia Lingcod [Area 4B], coastwide Bocaccio, and inside and outside Quillback Rockfish) had a greater than 5% probability of being below their LRP (i.e., in the "critical zone"); Pacific Cod in Area 3CD had a 4.6% probability. Roughly one-third of stocks had a greater than 1 in 4 chance of being below their USR (i.e., in the "cautious zone"). Conversely, two-thirds of assessed groundfish stocks had a high (>75%) probability of being above the USR (i.e., in the "healthy zone").

Maximum Sustainable Yield Estimates from Lake Nasser Fisheries, Egypt with Special Reference to Nile Tilapia Oreochromis niloticus using ASPIC Software

The lakes’ fisheries play an important role in the Egyptian economy. Egyptian lakes face many challenges such as over-fishing, illegal and destructive fishing methods, human activities and pollution which affected the fish production from it. The lakes’ contribution to the Egyptian fish production decreased from about 50% in 80’s to the only 10% during 2017. Lake Nasser, as one of the largest artificial lakes in the world, plays a significant role in Egyptian fisheries. Its mean annual fish production is about 28,000 ton, this constituted 18% of the total fish harvested from Egyptian lakes. The catch and effort data over 15 years were collected from the lake and analyzed to assess its status and to summerize the main problems facing its development and management. Maximum Sustainable Yield of Nasser lake with special reference to the Nile tilapia, the main species in the lake, is estimated based on catch and effort data from 2003 to 2017. The computer software packages of ASPIC had been used. The surplus production model of Schaefer was applied in this study. The obtained results proved the over exploitation situation for the lake fishery and to achieve the sustainability many applicable measures are recommended.

The different responses of rice genotypes to heat stress associated with morphological, chlorophyll and yield characteristics

Sixteen rice genotypes were planted under normal and high temperature during 2018 and 2019 seasons to understand the mechanisms that make plants tolerant or susceptible to heat stress and methods which may lead to generate new varieties with sustainable yield production. The combined analysis showed significant differences at the level of probability 0.05 and 0.01 among years for all characters except, chlorophyll content and leaf rolling which would indicate wide differences among the weather of both years. Environment’s variance was significant at the level of probability 0.01 over all characteristics. The significant differences at the level of probability 0.01 were recorded among genotypes and G x E interaction variances for all characteristics. The highest values of panicles number plant-1 were obtained from ‘Giza 178’ and ‘Hybrid 2’, however, the highest values of 100-grain weight were recorded with ‘Giza 179’ and ‘Egyptian Yasmine’. The minimum values of sterility% were recorded with ‘Sakha 107’ and ‘IET1444’. Concerning the cultivars performance across two environments, the cultivars ‘Giza 178’, ‘Giza 179’, ‘Sakha 107’ and ‘IET 1444’ gave the best desirable values over natural and heat stress so, those cultivars are considered to play a vital role in breeding program to enhance heat stresses tolerance accompanied with high yield potential.

Conservation Agriculture Based Integrated Crop Management Sustains the Maize–Wheat Rotation of North-Western India: Five Years’ Impacts on Crops and Water Productivity, Economic Profitability, Sustainable Yield Index and Soil Properties

We have evaluated eight different integrated crop management (ICM) modules for five years in a maize-wheat rotation (MWR); wherein, ICM1&2- ˈbusiness-as-usualˈ (conventional flatbed maize and wheat, ICM3&4- conventional raised bed (CTRB) maize and wheat without residues, ICM5&6- conservation agriculture (CA)-based zero till (ZT) flatbed maize and wheat with the residues, and ICM7&8- CA-based ZT raised bed maize and wheat with the residues. Results indicated that the ICM7&8 produced significantly (p<0.05) the highest maize grain yield (5 years av.) which was 7.8-21.3% greater than the ICM1-6. However, across years, the ICM5-8 gave statistically similar wheat grain yield, and was 8.4-11.5% greater than the ICM1-4. Similarly, the CA-based residue retained ICM5-8 modules had given 9.5-14.3% (5 years av.) greater system yields in terms of maize grain equivalents (MGEY) over the residue removed CT-based ICM1&4. System water productivity (SWP) was the highest with ICM5-8, being 10.3-17.8% higher than the ICM1-4. Nevertheless, the highest water use (TWU) was recorded in the CT flatbed (ICM1&2), ~7% more than the raised bed and ZT planted crops with or without the residues (ICM4-8). Furthermore, the ICM1-4 had produced 9.54% greater variable production costs compared to the ICM5-8, whereas, the ICM5-8 gave 24.3-27.4% additional returns than the ICM1-4. Also, different ICM modules caused significant (p<0.05) impacts on the soil properties, such as, organic carbon (SOC), microbial biomass carbon (SMBC), dehydrogenase (SDH), alkaline phosphatase (SAP) and urease (URE) activities. In 0.0-0.15 m soil profile, residue retained CA-based (ICM5-8) modules registered a 7.1-14.3% greater SOC and 10.2-17.3% SMBC than the ICM1-4. The sustainable yield index (SYI) of MWR was 13.4-18.6% greater under the ICM7&8 compared to the ICM1-4. Hence, this study conclude that the adoption of the CA-based residue retained ICMs in the MWR could sustain the crop yields, enhance farm profits, save water and improve soil properties of the north-western plan zones of India.

Comparative Studies of Soybean (Glycine max L.) based Cropping Systems for Sustainable Production in Malwa Plateau of Central India

Background: Large area under soybean is spread over Central India. Due to short growing season, soybean fits well in a number of cropping systems and is well suited for intercropping with a number of crops resulting in better land equivalent ratio and helps in the risk aversion due to climatic uncertainties in rainfed conditions. It has increased more cropping intensity and B;C ratio (profitability). All domestic demands of the farmers pertaining to agricultural produce could not be possible to fulfill by growing crops in existing soybean-wheat/gram cropping systems. Methods: A field trial was conducted during rainy, winter and late winter seasons of the year 2015-16 and 2016-17 at the research farm of Krishi Vigyan Kendra, Dhar, M.P. to assess comparative studies of soybean (Glycine max L.) based cropping systems for sustainable production in Malwa Plateau of Central India. There were altogether16 treatments comprising of soybean sequenced with wheat, chick pea, garlic, onion, potato and garden pea with inclusion of garlic, onion in late winter and assessed in randomized block design with four replications. Result: Soybean (JS 93-05) - potato (Kufri jyoti) - onion (AFLR) cropping sequence recorded the highest system productivity 177.31 q/ha) in terms of soybean equivalent yield with greater production efficiency (56.55 kg/ha/day), land use efficiency (85.89%) and sustainable yield index (0.91) while existing crop sequence viz. T3- soybean (JS 95-60) - chickpea (JG-130) recorded minimum soybean equivalent yield (42.79 q/ha) with production efficiency (22.93 kg/ha/day), use efficiency of land (56.30%) and sustainable yield index (0.50).

Pumping Well Layout Scheme Design and Sensitivity Analysis of Total Critical Pumping Rates in Coral Island Based on Numerical Model

Groundwater on small coral islands exists in the form of freshwater lenses that serve as an important water resource for local inhabitants and ecosystems. These lenses are vulnerable to salinization due to groundwater abstraction and precipitation variation. Determination of the sustainable yield from freshwater lenses is challenging because the uncertainties of recharge and hydrogeological characteristics make it difficult to predict the lens response to long-term pumping. In this study, nine pumping well layout schemes along a line are designed using the orthogonal experimental design method, and an optimal well layout scheme is determined by multi-index range analysis and comprehensive balance analysis method. The total critical pumping rates of the freshwater lens corresponding to different schemes are calculated by numerical simulation, and the sensitivity of the total critical pumping rates to hydrogeological parameters is analyzed. The results show that the calculation of the total critical pumping rates needs to be combined with the specific well layout scheme with consideration to the length of well screens, the number of wells and the distance between wells. The difference in total critical pumping rates between different schemes can be up to three times. The uncertainty of hydrogeological parameters has a great impact on the total critical pumping rates. Within the range of a 30% reduction in parameters, α and K are the key risk factors of pumping; within the range of a 30% increase in parameters, α, ne and K are the key risk factors; α-ne combined changes had the greatest impact. The management of freshwater lenses and the assessment of sustainable yield will continue to be important tasks for coral islands in the future, and this study can help with the sustainable exploitation of island freshwater lenses.