Deriving PAR use efficiency of wet season rice from bright sunshine  hour data and canopy characteristics

The input-intensive rainfed tropical ecosystem, where wet season (WS) rice (Oriza sativa L.) – dry season (DS) diversified high-value upland crops like vegetables predominate, has resulted in a problem of a large leakage of N into the environment, thereby polluting the water. Excessive use of N fertilizer in high-value crops grown in DS is economically motivated. Out of twenty water sources evaluated in a watershed with a total area of 265 ha located in Magnuang, Ilocos Norte, Philippines, twelve had near or above the World Health Organization’s (WHO) NO3-N limit for drinking water of 10 ppm. Soil mineral N (upper 100 cm) observed in seven rice-sweet pepper (Capsicum annuum L.) farmers’ fields ranged from 111 to 694 kg ha-1 which decreased by 10 to 68% in plots with dry-to-wet (DTW) crops like indigo, indigo+mungo and corn. In fallow plots where mineral N was either maintained or increased, it showed movement to lower soil profiles demonstrating NO3 leaching without a crop. On average, maize (Zea mays L.) captured 176 kg N ha-1 and indigo (Indigofera tinctoria L.) 194 kg N ha-1. In both fallow and planted plots, mineral N declined to low levels at 100% water-filled pore spaces (WFPS) before rice transplanting. A strategy for including indigo plus maize as a N-catch crop is proposed to decrease NO3 leaching and maximize N use efficiency in a rice-sweet pepper cropping system.

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Dry-matter partitioning and radiation-use efficiency in cowpea cultivars (Vigna unguiculata (L.) Walp. cvs TC-9-6 and M-28-6-6) during consecutive seasonal courses in the Orinoco llanos

The Journal of Agricultural Science ◽

10.1017/s0021859604003922 ◽

2004 ◽

Vol 142 (2) ◽

pp. 163-175 ◽

Cited By ~ 3

Author(s):

J. J. SAN JOSÉ ◽

R. A. MONTES ◽

N. NIKONOVA ◽

N. VALLADARES ◽

C. BUENDIA ◽

...

Keyword(s):

Vigna Unguiculata ◽

Mass Production ◽

Harvest Index ◽

Dry Mass ◽

Radiation Use Efficiency ◽

Wet Season ◽

Early Maturing ◽

Use Efficiency ◽

Radiation Use ◽

Mass Accumulation

Field work on rainfed cowpea (Vigna unguiculata (L.) Walp. cvs TC-9-6 and M-28-6-6) was conducted in the Orinoco lowlands to explain the changes in dry-mass partitioning and radiation-use efficiency (RUE) as compared with other cultivars over four consecutive seasons. Growth features were assessed in early-maturing, prostrate-canopy (TC-9-6), and medium-maturing, erect-canopy (M-28-6-6) cowpeas. These cultivars were sown in consecutive middle-wet and late-wet seasons in double peak rainfall conditions. Dry mass accumulation by cultivars was assessed as a function of leaf-area duration and the efficiency with which radiation was converted into dry mass throughout the season (i.e. radiation-use efficiency). Cultivar differences in canopy architecture and duration of leaf area had a minor effect on the total dry mass production. In the early-maturing TC-9-6, RUE for a middle-wet and a late-wet season was 0·90±0·04 and 0·65±0·05 g/MJ, respectively. In the medium-maturing M-28-6-6, the values were 0·97±0·05 and 0·72±0·03 g/MJ, respectively. A season with rainfall below 100 mm had a negative effect on phenology and RUE. When average rainfall was above 100 mm, the total dry mass accumulation was not affected by differences in cultivars and seasons. The rate of harvest index (HI) changes was negatively related to pod-filling duration. The changes in assimilation distribution depended on the process of partitioning as modulated by the limited pod-sink and the photosynthate supply. However, the photosynthate source was not depressed by the sink activity of the pod-filling. Partitioning to non-reproductive sinks was maintained. M-28-6-6 with high dry-mass production and delayed senescence did not effectively divert a large amount of assimilate to pod-filling. Pod sink activity in cowpea was limited by genotype. Harvest index in M-28-6-6 decreased with the increasing dry mass. The final HI and rate of linear increase in HI differed between cultivars and were lower in M-28-6-6. The results of the present work in the Orinoco lowlands are relevant for a wide range of savannahs with a late wet season.

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Interactions of Biochar Briquette with Ammonium Sulfate Fertilizer for Controlled Nitrogen Loss in Soybean Intercopping with Melaleuca cajuputi

Legume Research - An International Journal ◽

10.18805/lr-586 ◽

2021 ◽

Author(s):

T. Alam ◽

P. Suryanto ◽

D. Kastono ◽

E.T.S. Putra ◽

S. Handayani ◽

...

Keyword(s):

Ammonium Sulfate ◽

Reductase Activity ◽

Nitrogen Loss ◽

Block Design ◽

Wet Season ◽

Independent Variables ◽

Melaleuca Cajuputi ◽

Randomized Complete Block Design ◽

Use Efficiency ◽

Different Levels

Background: Nutrient briquette and biochar are used to reduce nitrogen loss and improve soil fertility. This study aimed to evaluate the interaction of biochar briquette with ammonium sulfate fertilizer for controlled nitrogen loss in soybean intercropping with Melaleuca cajuputi.Methods: The study was conducted in the wet season from November to February 2020 at Menggoran Forest Resort, Playen Forest Section, Yogyakarta Forest Management District, Indonesia. The experiment was using a randomized complete block design factorial with three blocks as the response surface methodology. The treatments included different levels of biochar briquette from Melaleuca cajuputi waste (0, 2 and 4 grain plant-1 or 0, 5 and 10 tons ha-1) and nitrogen fertilizer supplied by ammonium sulfate (0, 50 and 100 kg ha-1) as independent variables. The observation parameters were nitrate reductase activity (NRA), total chlorophyll (TC), leaf photosynthesis rate (LPR), nitrogen loss (NL), nitrogen use efficiency (NUE) and seed yield (SY).Result: The optimum values of 3.70 grain plant-1 or 9.25 tons ha-1 biochar briquette with 76.31 kg ha-1 ammonium sulfate fertilizer decreased NL by 38.25% and increased SY by 13.02% compared with single ammonium sulfate fertilizer.

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Effect of spacing and seedling age on yield, quality and heat use of scented rice in lower gangetic plains of West Bengal

ORYZA- An International Journal on Rice ◽

10.35709/ory.2021.58.1.8 ◽

2021 ◽

Vol 58 (1) ◽

pp. 49-54

Author(s):

Shilpi Bera ◽

Mrityunjay Ghosh ◽

S Banerjee ◽

S Mondal ◽

MK Nanda

Keyword(s):

Grain Yield ◽

Protein Content ◽

West Bengal ◽

Elongation Ratio ◽

Wet Season ◽

Milled Rice ◽

Maximum Heat ◽

Seedling Age ◽

Use Efficiency ◽

Yield Quality

A traditional scented rice (cv. Radhunipagal) was tested under varied spacing (20 cm × 20 cm, 20 cm × 15 cm, 15 cm × 15 cm and 20 cm × 10 cm) and seedling age (25, 35 and 45 days) during wet (kharif) season of 2018 at B.C.K.V., Nadia, West Bengal. Seedling age caused significant variation in life duration and summed GDD from 147.9 days and 2436°C day (25-day aged) to 162.0 days and 2753°C day (45-day aged), but with maturity in same meteorological week. Square planting (15 cm × 15 cm or 44 hills m-2) resulted in highest grain yield (2.52 t ha-1), which was 2.85, 11.01 and 4.56% greater over wider (20 cm × 15 cm and 20 cm × 20 cm) and closer spacings (20 cm × 10 cm). Radhunipagal rice raised with 25-days old seedlings recorded the highest grain yield (2.53 t ha-1) and maximum heat use efficiency (0.90 kg ha-1 °C day-1), and that yield was 0.12 and 0.22 t ha-1 greater over the crops planted with 35 and 45-days old seedlings during wet season. Spacing could not influence the cooking and processing quality (gelatinization temperature, kernel elongation ratio and aroma) except protein content of milled rice in the study. Radhunipagal paddy planted with 45-day aged seedlings recorded maximum protein content (6.36%) and alkali spreading value (score 3.27).

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Effect of tillage, clipping and climate on grass phytomass in a Zambian savanna

Journal of Tropical Ecology ◽

10.1017/s0266467403003456 ◽

2003 ◽

Vol 19 (4) ◽

pp. 407-415 ◽

Cited By ~ 8

Author(s):

Emmanuel N. Chidumayo

Keyword(s):

Dry Season ◽

Permanent Plots ◽

Wet Season ◽

Current Season ◽

Grass Production ◽

Previous Season ◽

Use Efficiency ◽

Complex Relationships ◽

Harvest Method ◽

Precipitation Use Efficiency

The effect of tillage, clipping, precipitation and temperature on above-ground grass production was investigated in permanent plots at a Zambian savanna site for 5 y (1996^2001) by the harvest method. Mean species richness was 4.6 species m-2 with a total of 15 species at the study site. Mean end-of-season grass phytomass was 464 g m-2 with no statistically significant differences among years in control quadrats. Grass phytomass recovered within two wet seasons after tillage and a similar trend was observed after cessation of a 2-y monthly harvesting regime. However, in experimental quadrats, plot, treatment and year had significant effects on grass production. Previous- and current-season precipitation had no significant effect on end-of-wet-season grass phytomass but phytomass of the previous season explained 27-53% of the variation in end-of-wet-season phytomass. Grass production peaked in the wet season and declined sharply as the dry season progressed. The interaction between precipitation, temperature, harvesting and duration of the dry season explained 81-91% of the variation in daily grass production but the significance of the interactions varied with season and duration of harvesting. Precipitation-use efficiency (PUE) of grasses declined from 2.25 g m-2 mm-1 at the start of the wet season in December to 0.25 g m-2 mm-1 at the end of the season in March. Monthly harvesting for 1 y reduced PUE to less than 25%. The results indicate very complex relationships between above-ground grass production (dependent variable) and climate and land-use (independent) factors that makes the prediction of grass production in central southern African savannas difficult.

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Influence of Rainshelter and Irrigation Method on Yield, Water, and Fertilizer Use Efficiency of Chili Pepper

HortScience ◽

10.21273/hortsci.40.4.1143a ◽

2005 ◽

Vol 40 (4) ◽

pp. 1143A-1143

Author(s):

Manuel Palada ◽

Deng Lin Wu

Keyword(s):

Drip Irrigation ◽

Chili Pepper ◽

Nutrient Loss ◽

Vegetable Production ◽

Wet Season ◽

Marketable Yield ◽

Fertilizer Use ◽

Irrigation Method ◽

Irrigated Crops ◽

Use Efficiency

Chili pepper (Capsicumannuum cv. Delicacy) was grown in single- and double-bed rainshelters and irrigated using furrow and drip irrigation to determine effect on yield and efficiency of water and nutrient application in the lowland tropics of southern Taiwan during the hot wet season. The experiment was laid out using a split-plot design with four replications. The main plots were rainshelters (single, double, open field) and the two irrigation methods (furrow and drip) were the subplots. Grafted chili seedlings were transplanted in double rows on raised beds at row spacing of 80 cm and plant spacing of 50 cm. The furrow-irrigated crop was applied with basal N-P2O5-K2O at the rate of 180–180–180 kg·ha-1 and 240–150–180 kg·ha-1 of N-P2O5-K2O as sidedressing. The drip-irrigated crop received half of the total rate applied for the furrow-irrigated crop. Significant differences (P < 0.05) in marketable yield were observed between rainshelter treatments. Highest yield (42.2 t·ha-1) was produced from the single-bed rainshelter, and crops grown under double-bed rainshelters produced the lowest marketable yield. Irrigation method did not significantly influence marketable yield, but crops grown under drip irrigation produced a higher yield than furrow-irrigated crops. Nutrient uptake by plants grown under drip irrigation was also higher (P < 0.05) than for furrow-irrigated crops. Water use efficiency was 60.7% higher in drip-irrigated plots. Results indicate that in high rainfall vegetable production areas, drip irrigation minimizes nutrient loss through leaching and maximizes efficiency of fertilizer use.

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Climate Sensitivity of Tropical Trees Along an Elevation Gradient in Rwanda

Forests ◽

10.3390/f9100647 ◽

2018 ◽

Vol 9 (10) ◽

pp. 647 ◽

Cited By ~ 1

Author(s):

Myriam Mujawamariya ◽

Aloysie Manishimwe ◽

Bonaventure Ntirugulirwa ◽

Etienne Zibera ◽

Daniel Ganszky ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Climate Sensitivity ◽

Elevation Gradient ◽

High Elevation ◽

Dry Season ◽

Nutrient Ratios ◽

Wet Season ◽

Elevation Gradients ◽

Use Efficiency

Elevation gradients offer excellent opportunities to explore the climate sensitivity of vegetation. Here, we investigated elevation patterns of structural, chemical, and physiological traits in tropical tree species along a 1700–2700 m elevation gradient in Rwanda, central Africa. Two early-successional (Polyscias fulva, Macaranga kilimandscharica) and two late-successional (Syzygium guineense, Carapa grandiflora) species that are abundant in the area and present along the entire gradient were investigated. We found that elevation patterns in leaf stomatal conductance (gs), transpiration (E), net photosynthesis (An), and water-use efficiency were highly season-dependent. In the wet season, there was no clear variation in gs or An with elevation, while E was lower at cooler high-elevation sites. In the dry season, gs, An, and E were all lower at drier low elevation sites. The leaf-to-air temperature difference was smallest in P. fulva, which also had the highest gs and E. Water-use efficiency (An/E) increased with elevation in the wet season, but not in the dry season. Leaf nutrient ratios indicated that trees at all sites are mostly P limited and the N:P ratio did not decrease with increasing elevation. Our finding of strongly decreased gas exchange at lower sites in the dry season suggests that both transpiration and primary production would decline in a climate with more pronounced dry periods. Furthermore, we showed that N limitation does not increase with elevation in the forests studied, as otherwise most commonly reported for tropical montane forests.

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Patterns and implications of Plant-soil δ13C and δ15N values in African savanna ecosystems

Quaternary Research ◽

10.1016/j.yqres.2008.11.004 ◽

2010 ◽

Vol 73 (1) ◽

pp. 77-83 ◽

Cited By ~ 45

Author(s):

Lixin Wang ◽

Paolo D'Odorico ◽

Lydia Ries ◽

Stephen A. Macko

Keyword(s):

Woody Plants ◽

Rainfall Regime ◽

Vegetation Composition ◽

Wet Season ◽

Δ13c And Δ15n ◽

Plant Soil ◽

Climatic Scenarios ◽

Use Efficiency ◽

The Relationship ◽

Composition Changes

Southern African savannas are mixed plant communities where C3 trees co-exist with C4 grasses. Here foliar δ15N and δ13C were used as indicators of nitrogen uptake and of water use efficiency to investigate the effect of the rainfall regime on the use of nitrogen and water by herbaceous and woody plants in both dry and wet seasons. Foliar δ15N increased as aridity rose for both C3 and C4 plants for both seasons, although the magnitude of the increase was different for C3 and C4 plants and for two seasons. Soil δ15N also significantly increased with aridity. Foliar δ13C increased with aridity for C3 plants in the wet season but not in the dry season, whereas in C4 plants the relationship was more complex and non-linear. The consistently higher foliar δ15N for C3 plants suggests that C4 plants may be a superior competitor for nitrogen. The different foliar δ13C relationships with rainfall may indicate that the C3 plants have an advantage when competing for water resources. The differences in water and nitrogen use likely collectively contribute to the tree–grass coexistence in savannas. Such differences facilitate interpretations of palaeo-vegetation composition variations and help predictions of vegetation composition changes under future climatic scenarios.

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