Effects of diversifying the planting period of maize on herbivorous and their natural enemies

Knowledge of the specific insect densities during crop development is necessary to perform appropriate measures for the control of insect pests and to minimize yield losses. In a previous study, both spatial and temporal approaches were adopted to analyse the influence of landscape structure and field variables on herbivore and predatory insects on maize. Both types of variables influenced insect abundance, but the highest effect was found with maize phenology. Given that the field planting date could modulate the influence produced by the structure of the landscape on herbivores and predatory insects, analyses of population dynamics must be performed at both the local and landscape levels. The anterior prompted us to study these aspects in the two common planting periods (early and late) in northern Spain. The present study tests the hypothesis that the period of maize planting could have a higher effect than phenology or interannual variation on the abundance of natural enemies and herbivores on maize. Our results showed that only the abundances of other herbivore thrips and Syrphidae were significantly different between the two planting periods. Moreover, we found significant effects of planting period when we performed yearly analysis in 2015 for Coccinellidae and Chrysopidae and in 2016 and 2017 for Aeolothrips sp. Most of the taxa had abundance peaks in earlier growth stages, which are related to pollination (before or during), while only Stethorus punctillum and Syrphidae increased later in the season. Furthermore, Frankliniella occidentalis, aphids, Syrphidae and Coccinellidae registered higher abundances in fields sown in the late planting period than in the rest of the insect species. The results of the present study highlight the effects of sowing dates on insect dynamics in maize.

Soil, Water, and Climate Change Integrated Impact Assessment on Yields

This article describes the potential yields of maize, wheat and barley which were modeled with climate change, soil degradation and water balance scenarios in central Mexico. Two adaptation measures were also evaluated. To estimate yields the AquaCrop-FAO model was applied. Three study cases were chosen and their climate, soil, phenological and management information was compiled. Once calibrated, the authors tested the response in yields for 28 climate change scenarios: five General Circulation Models, two RCP and three-time horizons. Two adaptation actions were evaluated: changing planting date and increase of organic mulches. Results show that yield of maize in the near future (2015-2039) would fall 50% average, barley and wheat yields would decrease in 40% and 25% respectively. If soil degradation and loss is considered, the yield will reduce considerably. Adaptation measure based on changing planting date was as effective as increasing mulches. It is necessary to consider soil together with climate change scenarios in yield modeling. It is possible to suggest wrong adaptation measures if only the climate is considered and not all the variables involved.

Planting date and fertilizer type influenced soil quality indices and soybean (Glycine max L.) yields in derived savannah of Nigeria

Soybean is grown in many parts of Northern Nigeria, with little climatic challenges and soil organic matter. There is need to investigate possible influence of planting date of the crop in Southeastern Nigeria, an environment that is rather foreign to the crop. A study was carried out in 2018 and 2019 cropping seasons at Federal College of Agriculture, Ishiagu, Ebonyi State, to evaluate the influence of different planting dates and fertilizer types on selected soil physical and chemical properties, growth and yield of soybean. A split plot in a randomized complete block design was used with planting date (May and June) as the main plots, while six fertilizer types (poultry-droppings manure 5 t ha–1, swine-droppings manure 5 t ha–1, rice-husk dust 5 t ha–1, NPK 15:15:15 at 150 kg ha–1, urea at 100 kg ha–1 and the control) constituted the sub-plots. At crop maturity, some soil quality indices and pod and grain yields (t ha–1) of soybean were assessed. Soil organic carbon (SOC) and total nitrogen contents were significantly (p < 0.05) influenced by both planting date and fertilizer type in 2018 and 2019, while soil pH was improved significantly (p < 0.05) only by fertilizer type in these two cropping seasons. Mean-weight diameter of aggregates, soil bulk density and SOC stock as well as soybean yields were significantly (p < 0.05) influenced by both planting date and fertilizer type in the two seasons. Generally, planting in May improved soil total nitrogen and soybean pod yield whereas planting in June improved the other soil quality indices and soybean grain yield, the best soil amendment in either case being poultry-droppings manure but sometimes parameter-specific. The choice of planting date (May or June) in soybean production in the derived savannah and the soil amendment to use in the enterprise thus has both agronomic and environmental implications. Such a choice would depend on the indices of soil quality and/or the aspects of soybean yields (pod or grain) whose improvements the farmer intends to achieve at crop maturity.

Response of yam varieties to soil moisture regime in Southwestern Nigeria

A field experiment was conducted on varietal response of white yam to moisture regime in Abeokuta. The experiment comprised three varieties of yam (Efuru, Ise-osi and Oniyere), three mulching options (grass, polythene and unmulched), and two planting dates (early and late). Treatments were replicated three times using RCBD lay-out. Model for selecting planting date involved relating potential evapotranspiration (PE) to precipitation (P) in the form of 0.1PE<P < 0.5PE, partitioned for attaining optimal planting date into early {T1= Σ(P-0.1PE) ≤ 0} and late {T2 = Σ(P-0.5PE) ≤ 0}, respectively. For humid period defined by P> PE, the physiological parameters and moisture agro-climatic indices measured during phenological stages of yam grown were analyzed with respect to treatments. Result showed that T1 defined as Σ(P-0.1PE) ≤ 10 mm appeared as the best model that significantly (P < 0.05) influenced emergence rate, phenological growth and tuber yield. All yam varieties evaluated were suitable for planting with respect to yield. Efuru and Ise-osi synchronized perfectly with Actual Water Availability and produced good vegetative growth with LAI of 1.08 and 0.91 leading to higher tuber yield of 12 and 11.64 tonnes ha-1, respectively. Grass mulch had tuber yield, 4-6 tonnes ha-1greater than the polythene and unmulched plots in all varieties. Mulching significantly (P< 0.05) increased tuber yield, 6-8 tonnes ha-1than the unmulched. Conclusively, early planting with grass mulch increased tuber yield.

Modeling Basin-Scale Impacts of Cultivation Practices on Cotton Yield and Water Conservation under Various Hydroclimatic Regimes

The SWAT model equipped with an improved auto-irrigation function was used to assess the impacts of cultivation practices on irrigated and dryland cotton yield and water conservation in the Texas Panhandle. Results showed the largest irrigation depth led to reductions in irrigation and crop evapotranspiration (ETc) with slightly increased cotton yields compared to the baseline scenarios under different hydroclimatic regimes. However, soil water content and surface runoff values were increased when using the largest irrigation depth. The opposite results were observed for the small irrigation depth. Early planting of cotton resulted in decreased irrigation and ETc, and increased cotton yields under both irrigated and dryland conditions, particularly in normal and wet years. By contrast, the late planting scenarios indicated the opposite for those variables. Simulated hydrologic variables were relatively stable using various maturity cultivars. Nevertheless, greater than 10% reductions in irrigated cotton yield under diverse hydroclimatic years and dryland yields during normal and wet years were identified in the long-season cotton. The opposite was determined for the short-season cotton. These outcomes suggest that a larger irrigation depth, earlier planting date, and short-season cultivar are promising cultivation practices for improving cotton yield and water conservation in the Texas Panhandle.

Planting dates and seedling age of red cabbage during the spring season in Uzbekistan

The importance of red cabbage for expanding the range of vegetable crops in Uzbekistan is highlighted in this paper. The results of three-year (2018-2020) studies on the comparative assessment of the effectiveness of three spring planting dates (March 5-9, 13-16 and 25-27) at three seedling ages (70, 60 and 50 days) at each planting date were presented. It was revealed that the later the seeds are sown to obtain seedlings for spring culture, the faster the seedlings appear and the more the seedlings form leaves. With the postponement of the timing of planting seedlings, the survival rate of seedlings increases. It has been established that the later the seedlings are planted, the higher the temperatures are the growth of plants and the formation of heads. The most unfavorable temperature conditions are formed when the seedlings are planted on March 25-27, which causes a delay at the beginning of the formation of heads of cabbage, an increase in the number of leaves of a root rosette, a decrease in the setting and average weight of heads of cabbage and their marketability. The best indicators of head set-up, their average weight and marketability, yield per unit area are provided when planting on March 14-16, 70 and 60-day old seedlings. Planting seedlings on March 25-27, seedlings of any age, due to the formation of heads of cabbage at excessively high temperatures, delays the flow of products, reduces the setting, average weight and marketability of heads of cabbage and significantly reduces the yield per unit area. It is recommended for a spring culture to plant on March 14-16 with 70 and 60-day old seedlings and not allow planting at the end of March.

Response of onion crop to bulb set size and planting date under mulching in dry Mediterranean environment

<p class="042abstractstekst">The present pot experiment under open field conditions was conducted to evaluate the response of onion crop to bulb set size and planting date using mulching. Two different sizes of onion sets at planting (large (6-10 g) and small (2-6 g)) and three different planting dates (February, March, and April) with two soil coverings (with and without straw mulching) were tested. Treatments were replicated three times. Onion was not exposed to any drought stress during the course of the experiment.<br />Results indicated that the larger bulb sets which were planted earlier under mulching, maximised the total bulb yield (Yield, 44.0 t ha^-1), water use efficiency (WUE, 8.37 kg m^-3), and irrigation water use efficiency (IWUE, 9.57 kg m^-3). Moreover, findings revealed that onion crop appreciably respond to smaller bulb sets when they were planted earlier under mulching. Onion bulb responses were predicted to be linearly increased with the earliness in planting date, with an obvious better preference under mulching and heavier bulb sets. Hence, adopting early planting date with mulching is suggested for sustainable crop production and for enhancing water use efficiency in dry Mediterranean area.</p>

Mitigating future climate change effects on wheat and soybean yields in Central region of Madhya Pradesh by shifting sowing dates

The present work focuses on (1) estimation of future yield of wheat and soybean crop under RCPs scenario 2.6, 4.5 and 8.5 for years 2020, 2050 and 2080 using FAO AquaCrop yield simulating model and (2) assessment of shifting planting date as adaptation measure to mitigate climate change impact for Sehore district, Madhya Pradesh. Statistically downscaled General Circulation Model CanESM2 data was used as input to AquaCrop for generation of future data. The AquaCrop yield model was first checked for its suitability and accuracy in prediction of yield for years 2000–2015, model nash sutcliffe efficiency 0.79, 0.84, RMSE 300.7, 104.4 and coefficient of determination (R2) 0.91, 0.88 were obtained for wheat and soybean crops, respectively. The results depicts that RCP 8.5 shows the highest impact with reduction in wheat and soybean yield for projected year 2080. Under the changed climate, shifting planting date from of wheat from 15th November to 30th November and 1st July to 10th July for soybean resulted in least decline in crop yields and surfaced as a practical adaptation measure for sustaining future yields.

Influence of planting date and herbicide program on Amaranthus palmeri control in dry bean

Late-emerging summer annual weeds are difficult to control in dry bean production fields. Dry bean is a poor competitor with weeds, due to its slow rate of growth and delayed canopy formation. Palmer amaranth is particularly difficult to control due to season-long emergence and resistance to acetolactate synthase (ALS)-inhibiting herbicides. Dry bean growers rely on PPI and preemergence residual herbicides for the foundation of their weed control programs; however, postemergence herbicides are often needed for season-long weed control. The objective of this experiment was to evaluate effect of planting date and herbicide program on late-season weed control in dry bean in western Nebraska. Field experiments were conducted in 2017 and 2018 near Scottsbluff, Nebraska. The experiment was arranged in a split-plot design, with planting date and herbicide program as main-plot and sub-plot factor, respectively. Delayed planting was represented by a delay of 15 days after standard planting time. The treatments EPTC + ethalfluralin, EPTC + ethalfluralin fb imazamox + bentazon, and pendimethalin + dimethenamid-P fb imazamox + bentazon, resulted in the lowest Palmer amaranth density three weeks after treatment (WAT) and the highest dry bean yield. The imazamox + bentazon treatment provided poor Palmer amaranth control and did not consistently result in Palmer amaranth density and biomass reduction, compared to the non-treated control. In 2018, the delayed planting treatment had reduced Palmer amaranth biomass with the pendimethalin + dimethenamid-P treatment, as compared to standard planting. Delaying planting did not reduce dry bean yield and had limited benefit in improving weed control in dry bean.