Water content, resorption of N and P, and the growth of teak Tectona grandis L.f. seedlings on four types of growing media under drought stress

Growing media that contain organic materials can provide nutrients and water for plants. This study analyzed the availability and effects of nutrients and water, N and P resorption, and growth of teak seedlings under drought stress. The growing medium was made from ultisol soil (M1), ultisol soil with husk charcoal (M2), ultisol soil with chicken manure (M3), and ultisol soil with compost (M4), then planted with teak seeds. Maintenance was conducted by field capacity watering for 30 days. Teak seedlings were treated with drought stress for 90 days. Based on the analysis, growing media total N ranged from 0.19 to 0.28%, total P ranged from 0.10 to 0.17%, and water ranged from 11.40 to 16.20%. Teak seedling leaves contain N nutrient ranging from 0.34 to 0.95 % and P nutrient ranging from 0.04 to 0.16 %. The N resorption ability of teak seedlings ranged from 26 to 31%, and P resorption was around 20 to 25 %. The height growth of teak seedlings ranged from 80 to 115cm, the stem diameter from 1.4 to 1.8cm, the leaf area from 630 to 650cm2, and the thickness of the leaves from 545 to 462µm. Growing media made from ultisol soil and chicken manure (M3) produced the best water content, N and P resorption, and the growth of teak seedlings after 3 days of drought stress.

Mycorrhizal Fungi Inoculation Improves Capparis spinosa’s Yield, Nutrient Uptake and Photosynthetic Efficiency under Water Deficit

Agricultural yields are under constant jeopardy as climate change and abiotic pressures spread worldwide. Using rhizospheric microbes as biostimulants/biofertilizers is one of the best ways to improve agro-agriculture in the face of these things. The purpose of this experiment was to investigate whether a native arbuscular mycorrhizal fungi inoculum (AMF-complex) might improve caper (Capparis spinosa) seedlings’ nutritional status, their morphological/growth performance and photosynthetic efficiency under water-deficit stress (WDS). Thus, caper plantlets inoculated with or without an AMF complex (+AMF and −AMF, respectively) were grown under three gradually increasing WDS regimes, i.e., 75, 50 and 25% of field capacity (FC). Overall, measurements of morphological traits, biomass production and nutrient uptake (particularly P, K+, Mg2+, Fe2+ and Zn2+) showed that mycorrhizal fungi inoculation increased these variables significantly, notably in moderate and severe WDS conditions. The increased WDS levels reduced the photochemical efficiency indices (Fv/Fm and Fv/Fo) in −AMF plants, while AMF-complex application significantly augmented these parameters. Furthermore, the photosynthetic pigments content was substantially higher in +AMF seedlings than −AMF controls at all the WDS levels. Favorably, at 25% FC, AMF-colonized plants produce approximately twice as many carotenoids as non-colonized ones. In conclusion, AMF inoculation seems to be a powerful eco-engineering strategy for improving the caper seedling growth rate and drought tolerance in harsh environments.

Feasibility study on hexacopter UAV based sprayer for application of environment-friendly biopesticide in guava orchard

Aim: To study the feasibility of hexacopter UAV based sprayer for application of environment-friendly biopesticide in guava orchard. Methodology: Field experiments were conducted in Punjab (India) during 2020. UAV was evaluated for spraying environment-friendly bio-pesticidein guava orchard. UAV was operated at 2.0 m height above the tree top.The water and oil sensitive papers were fixed on the outer side as well as inside of selected guava trees at four different canopies. Organic neem seed kernel based azadirachtin 0.15% EC biopesticide was used at recommended dose. After spraying, all water and oil sensitive papers were collected for further laboratory analysis. All spray quality parameters, i.e., coverage (%), droplet density (droplets cm-2), droplet size (µm) and uniformity coefficient were determined. For the efficacy of drone sprayer insects were counted before and 1, 2, 7 days after spray (DAS) and reduction in number of insects was calculated. Results: The on-flight field capacity of spraying with UAV was 3.0-3.3 ha h-1 whereas actual field capacity was found to be 2.0-2.3 ha h-1. The total mean coverage area was found in the range of 2.67-10.67%. The maximum coverage was at the top canopy (inner and outer) of tree which was significantly higher than all other observation points on the canopy. The mean droplet density was found in the range of 14.67-28.33 droplets cm-2. The highest droplet density (28.33 droplets cm-2) was found at the top outer side of the tree canopy. The volume median diameter was found in the range of 208.0-418.3 µm whereas, number median diameter was in the range of 138 to 269 µm. The percent reduction in aphid population 1, 2 and 7 days after spray (DAS) was 38.06, 68.28 and 62.69%, respectively whereas it was 47.95, 78.69 and 70.90% with knapsack sprayer. Interpretation: Hexacopter UAV sprayer is effective in terms of quality of spray and effective control of aphid population.

Alleviating the adverse effects of deficit irrigation in Flame seedless grapevine via Paulsen interstock

Using interstock with a potential genetic base is considered more recent and sustainable strategy for mitigating the water deficit. This investigation was carried out on transplant of Flame seedless (Vitis vinifera) grapevine grafted onto two rootstocks namely; Freedom (Vitis champinii x 1613C) and 1103Paulsen (vitis berlandieri x Vitis rupestris) with or without 1103Paulsen as interstock to determine its performance under deficit irrigation condition (50% of field capacity). The results indicated that Paulsen as rootstock or as interstock significantly increased the growth vigor of Flame seedless scion as well as the leaf content of total proline, phenols and sugars. Paulsen rootstock has decreased stomatal conductance, leaf transpiration rate and increased diffusion resistance under 50% deficit irrigation compared with grafting on Freedom rootstock. Moreover, Paulsen as interstock for Flame seedless grafted onto Freedom rootstock significantly increased relative water content accompanied by an increase in thickness of leaf anatomical characters such as midvein, lamina, palisade, xylem and phloem tissue under deficit irrigation compared with grafts without Paulsen interstock. This study suggests that using Paulsen as interstock, can be an adaptation strategy for water stress through controlling in some morphological, chemical physiological and anatomical responses of scion.

Impact of Extreme Temperature and Soil Water Stress on the Growth and Yield of Soybean (Glycine max (L.) Merrill)

Climate change is a major environmental stressor that would adversely affect tropical agriculture, which is largely rain-fed. Associated with climate change is an increasing trend in temperature and decline in rainfall, leading to prolonged and repeated droughts. The purpose of this study was to determine the effect of climate variables such as temperature, relative humidity, vapor pressure deficit (VPD), and soil water on the phenology, biomass, and grain yield of soybean crops. A greenhouse experiment was set in a split plot design with three average environmental conditions as the main plots: E1 (36 °C, RH = 55%), E2 (34 °C, RH = 57%) and E3 (33 °C, RH = 44%). Additionally, there were three water treatments: W1 (near saturation), W2 (Field capacity), and W3 (soil water deficit) and two soybean varieties (Afayak and Jenguma). These treatments were replicated nine times. The results showed that high temperatures (E1) accelerated the crop development, particularly at flowering. Additionally, increased atmospheric demand for water under a high temperature environment resulted in high evapotranspiration, leading to high transpiration which probably reduced photosynthetic activity of the plants and thereby contributing to biomass and grain yield loss. Biomass and yield were drastically reduced for the combined effect of high temperature (E1) and drought (W3) as compared to combined effect of ambient temperature (E3) and well-watered condition (W1). Increasing temperatures and erratic rainfall distributions associated with climate change poses a potential threat to the soybean production in Ghana.

Capacidade de Armazenamento de Água no Solo (CAD) e Características Físicas dos Solos na Avaliação da Distribuição da Água das Chuvas na Alta Bacia do Ribeirão Santo Antônio

O estudo avalia a capacidade de armazenamento de água dos solos (CAD), utiliza como objeto de avaliação os latossolos da alta bacia do ribeirão Santo Antônio no município de Iporá-Goiás. O objetivo do estudo foi avaliar a dinâmica da água da chuva na manutenção do fluxo de água na bacia. Utilizou de dados de umidade dos solos em período de déficit hídrico e de excedente para comparar o comportamento dos solos na retenção de água e na permeabilidade. Utilizou a metodologia padrão na definição do CAD, porém com ajustes específicos na obtenção da umidade e na capacidade de campo (CC) e no ponto de murcha permanente PMP, que aqui foi denominado de ponto de menor umidade residual (PMUR). Informações como dados de chuva do período, balanço hídrico climatológico no período analisado (maio de 2018 a abril de 2019) e valores de vazão obtidos mensalmente no exutório durante o período de referência fizeram parte da análise. Um total de 43,5% da água disponibilizada pela chuva escoam superficialmente, 9,5% escoam em subsuperfície, 47% da água infiltra e/ou permanece retida nos solos. Os solos apresentaram boa drenagem e, cerca de 42% da água das chuvas garantem a perenidade da bacia. Soil Water Storage Capacity (AWSC) and Physical Characteristics of Soils in the Evaluation of Rainwater Distribution in the High Basin of Santo Antônio Stream. A B S T R A C T The study evaluates the water storage capacity of soils (AWSC). It use like object of evaluation the oxissoils located at the high Santo Antônio basin. The objective of the study was to evaluate the dynamics of rainwater in maintaining the flow of water in the basin through laboratory evaluations, in addition to testing a new methodology to define the destinations of the water that reached the surface. Was used soil moisture data in a period of water deficit and surplus to compare the behavior of soils in water retention and permeability. It used the standard methodology in the definition of the AWSC but with specific adjustments in obtaining the humidity and in the field capacity (FC) and in the permanent wilting point PWP, which here was called the point of lowest residual moisture (PLRM). Information such as rainfall data for the period, climatological water balance in the period analyzed (May 2018 to April 2019) and flow values obtained monthly in the exutory during the reference period were part of the analysis. A total of 43.5% of the water provided by the rain run off superficially, 9.5% seeps in subsurface, 47% of the water seeps and / or remains trapped in the soil. The soils had good drainage and about 42% of the rainwater guarantees the basin's perpetuity. Keywords: AWSC. Permeability. Moisture. Storage.

DEVELOPMENT AND TESTING OF BED FORMER IMPLEMENT POWERED BY HAND TRACTORS

Soil tillage, like making raised beds, is time-consuming and labour-intensive if it is done without the help of mechanization. Therefore, this study aims to develop and test a bed former powered by a hand-tractor for upland. It was carried out in the experimental field (sandy clay loam texture) at a furrower depth of 15 cm and 20 cm with a tractor forward speed of 0.5 m/s. The bed's former design results have dimensions of length, width, and height of 1200x1000x 820 mm. The performance test results showed an increase in tillage depth resulted in increased bed height, bed width, bed width, and slip. However, field capacity decreases with increasing tillage depth. The bed former's performance was found to be satisfactory in general.

A two layer soil moisture model for estimating crop evapotranspiration and runoff

In the present study, a two layer model has been proposed to estimate evapotranspiration, soil moisture storage and runoff. For this purpose soil profile has been assumed to be composed of two layers : the top layer having a fixed field capacity of 100 mm and the underlying layer having field capacity depending on the soil texture. Normal values of rainfall and potential evapotranspiration have been used in the study. The model, applied to kharif and rabi seasons furnishes crop evapotranspiration period when soil in two layers reach wilting point and surface runoff and its duration. The model developed has been applied to 411ocations representing most of the soil types found in India. The analysis revealed that lowest ET is seen over Himalayan foothills and northeast India in kharif and rabi seasons. Enough residual soil moisture is available to the crops at the end of kharif season over NE India; most of it being in the top layer. Eastern India record largest runoff of 800-1000 mm. Arid to semi-arid region in NW India does not seem to experience much runoff.

Water extraction pattern and transpirational losses of peach trees Under well-watered and drying cycles

Mature peach trees [Prunus Persica (L.) Batsch] grown in weighing lysimeters were subjected to soil moisture stress by shutting off irrigation. Initially transpiration (T) was at potential rate when available soil moisture in the active root zone was near field capacity. Rapid changes in soil moisture under drying cycles caused gradual decrease in transpirational rate. When 0 to 60 cm soil layer reached permanent wilting point, there was a sharp decline in water use. Mature peach trees require barest minimum of 10 mm of water for their metabolic activity. A regression model has been developed to estimate transpirational loss of peach from available soil profile water.