International Journal of Plant Production
Volume:12 Issue: 4, Dec 2018

Dry matter accumulation pattern of winter cereals and rapeseed is similar to double sigmoid growth curve and can be described by sum of two different or similar singular sigmoid (S-shape) functions (e.g., Richards, Von Bertalanffy, and other functions) that they have overlap on one point. In this study, accuracy of 49 different function compositions of double sigmoid function for describing the rapeseed dry matter based on days after planting (DAP) and growing degree days (GDD) were tested. Results of this study showed that the Beta–Richards and Richards–Gompertz functions were fitted to the measured dry matter during growing season very accurately based on DAP and GDD, respectively. Sum of two Von Bertalanffy or Weibull functions can not describe the winter rapeseed growth. Results of this investigation can be used to estimate dry matter of rapeseed during growing season and analysis of plant growth rate variation under different irrigation treatments.

Faba bean seeds are generally large which limits its adoption as cover crop and/or dual-purpose cover crop/cash crop due to the high seed cost. The purpose of this study was to evaluate six faba bean varieties for their yield and yield components, using phenology, morphology and physiological growth pattern. Faba bean varieties included Early Violletto, Aquadulce, Delle Cascine, Windsor, Early White, and D’Aquadulce, which studied in 2015 and 2016. Aquadulce produced the highest grain yield followed by Delle Casine. These two varieties also produced the highest biomass, which potentially can provide more N to the succeeding crop. Aquadulce and Delle Cascine had the highest HI (40.1 and 41%, respectively) indicating an efficient distribution of assimilates to their seeds.. Delle Cascine produced the highest number of seeds plant−1 and seed weight, respectively. Plant height variation also revealed that varieties Early White was the shortest (40.6 cm) and the tallest (76.0 cm), respectively. Significant differences were observed in regard to the growing degree days required to reach flowering and pod formation stages. Aquadulce and Delle Cascine ranked early among the tested varieties, providing the opportunity for dual purpose and double cropping in short-season areas.

Investigating the impacts of climate change and varietal replacement on winter wheat phenology is important for understanding the processes and mechanisms underlying crop responses and adaptations to ongoing climate change. Information on the impact of cultivar shifts on phenological trends based on field experiments is limited. In this study, we analyzed the impacts of climate change and varietal replacement on winter wheat phenology using historical meteorological and phenological data from the North China Plain and field experiments on wheat varieties at different times. The results showed that the sowing date of winter wheat was delayed in northern areas and advanced in southern areas, whereas the greening-up, heading, and maturity dates all advanced in the North China Plain. The lengths of the vegetative and whole growth phases were shortened at 70.00% and 83.33%, respectively, of the stations in the North China Plain; by contrast, the length of the reproductive growth phase was prolonged at 86.67% of the stations. The precipitation and mean temperature were correlated with the length of the growth phases. Varietal replacement prolonged the growth phase, especially the reproductive growth phase of winter wheat. Therefore, the winter wheat cultivars with longer full growing periods should be adopted in the North China Plain in response to phenological changes caused by climate warming, and the strategy adapted for winter wheat production should consider the crop phenology response to climate change. This study provides theoretical support and scientific evidence for the formulation of scientific management measures for the adaptation of winter wheat to climate change in the North China Plain.

Arid and semi-arid regions in the world that produce wheat (Triticum aestivum) are faced with frequent droughts in recent years. Moreover, wheat production is highly dependent on irrigation and it is essential to increase irrigation water productivity in these regions. Therefore, the aim of this study was to investigate the effects of irrigation methods, planting methods, and nitrogen application rates on yield, water and nitrogen use efficiencies of winter wheat. The experiment arranged in split–split plot with randomized blocks with two surface irrigation methods [ordinary furrow irrigation (OFI) and variable alternate furrow irrigation (VAFI)] as the main plots, two planting methods [on-ridge planting (ORP) and in-furrow planting] as the sub plots, and three nitrogen application rates (N0 = 0, N1 = 150 and N2 = 300 kg N ha−1) as the sub–sub plot. Results indicated that VAFI reduced the winter wheat grain yield, dry matter, grain number per spike, and harvest index as 12, 9, 3, and 4%, respectively; however, these reductions were not significant in comparison with OFI method with a reduction of 33% in irrigation water; as a consequence, the straw nitrogen concentration, grain protein concentration, and also water use efficiencies (WUE), irrigation water productivity (IWP), economic irrigation water productivity (EIWP) and nitrogen use efficiency (NUE) were improved in VAFI as 14, 5, 6, 26, 25, and 8%, respectively. In spite of a slight reduction in grain yield, VAFI method increased EIWP. Economic nitrogen productivity decreased about 50% by increase in N rate, and 150 kg N ha−1 was the optimum rate to apply. Furthermore, VAFI decreased the seasonal ET, thereby improved WUE and IWP. In-furrow planting increased significantly the WUES while it did not enhance significantly WUE for grain. Generally, increasing the nitrogen rate increased the grain yield; whereas, there was no significant difference between the treatments of 150 and 300 kg N ha−1. Results suggest that application of 150 kg N ha−1 combined with in-furrow planting method and variable alternate furrow irrigation is an effective way to improve WUE, yield, yield components and NUE for winter wheat in the study area.

Attempts were made to study effects of planting techniques on crop dry matter (DM), intercepted photosynthetically active radiation (fIPAR), tuber yield (y), evapotranspiration (ET), water-use efficiency and y–ET relationship of potato under varying irrigation regimes. Field experiments were conducted for three seasons with four irrigation regimes: 2, 3, 4 and 5 numbers of irrigation per season (I1, I2, I3 and I4, respectively), and three planting methods S1-normal single row planting with 50-cm row-to-row and 15-cm plant-to-plant spacing with 50-cm furrow spacing; S2-paired-row planting at 25-cm spacing, 75-cm furrow spacing; and S3-paired-row planting at 50-cm spacing with 100-cm furrow spacing. Though the highest tuber yield was recorded in I4, it was marginally higher than that in I3; whereas the highest WUE was obtained with I3. Optimum irrigation in I3 and I4 maintained higher crop DM, greater fIPAR, ET and better tuber formation than in I1 and I2. No significant yield reduction occurred due to paired-row method (S2); however, irrigation volume reduced by 21%; crop WUE increased by 8.2% and irrigation WUE increased by 21% in S2 compared with S1. The y–ET functions were found quadratic with downward concave; and elasticity of water production functions (Ewp) were used to reveal the dynamic relationship of y, ET and WUE. Findings suggest that the ET of 348 mm would be required to achieve maximum WUE of 44.11 kg ha−1 mm−1 with paired-row furrow irrigated system; and this would result in tuber yield of 15.42 t ha−1. Crop response factor (Ky) values indicated that tuber yield reduction would be directly proportional to reduced irrigation. Therefore, it is concluded that potato could be grown with paired-row method of planting at 75 × 20 cm spacing, and the ET demand of 348 mm should be met to achieve maximum tuber yield and increased WUE. The study could be an important reference for water-saving of potato production in tropical sub-humid conditions.

Maize (Zea Mays) is the major food crop in Kenya. Its production variation has devastating consequences on people’s basic food availability. This study will investigate the relationships between climate variability and maize yield using observed weather data from Kenya Meteorological Department and national annual maize yield data from the Ministry of Agriculture for the period 1979–2012. Mann–Kendall test was used to detect a trend in precipitation, minimum, and maximum temperature. Location-wise correlation method was performed between each climate variable and maize yield in every station. Stations which had significant correlations were aggregated to form climate indices which were used to build multiple linear regression model. The results revealed that maize yield in Kenya was significantly decreasing at a rate of 0.07 tons/ha/decade at the 95% confidence level accompanied by high inter-annual variation, while world average was increasing at a rate of 0.6 tons/ha/decade. This reduction was accredited to a significant increasing temperature and reduction in seasonal rainfall. Empirical relationship derived from multiple regression models indicates that 67.53% of yield variance was attributed to varying seasonal climate indices. Precipitation is the dominant predictor accounting to 49.73% of yield variance. There is a significant correlation of 0.78 between the modeled and observed yield hence high credibility of the statistical model. A Continuous decrease of maize yield is expected under the influence of climate change which threatens national food security if effective measures to raise maize production are not endorsed. These findings form a framework for designing policies geared towards the reduction of climate-related vulnerability in many parts of the world.

Winter pastures nitrogen fertilization in crop-livestock systems may provide effects not only on animal production during winter season, but also on corn grain yield and in its nutritive value cultivated after the grazing period. This paper assessed the effect of nitrogen levels and its management in a crop-livestock system with and without grazing by sheep on corn yield and its nutritive value. The experiment was established in 2006 in Guarapuava, PR, Brazil. Oats (Avena spp.) and ryegrass (Lolium multiflorum) were grown during winter season and corn and beans during summer season over the years, being this paper related to the 2009/2010 corn crop period. Treatments were composed of four nitrogen levels at the winter pasture (0, 75, 150 and 225 kg ha−1), with and without grazing by sheep, and five nitrogen levels on corn (0, 75, 150, 225 and 300 kg ha−1). Corn yield was positively influenced by nitrogen fertilization performed in the pasture, what characterized a residual effect of nitrogen applied in winter. Corn crude protein levels from the grazed areas were higher than ungrazed areas, and its levels increased as nitrogen levels increased.