Agronomy and Crop Sciences Commons^™

Growth And Yield Of Rice (Oryza Sativa L.) Under Different Irrigation Methods In Transplanted And Direct-Seeded Systems, Wang Guirui, Crisanta S. Bueno

The Philippine Agricultural Scientist

In the face of climate change and socioeconomic transformation, there is an urgent need to save energy and enhance rice production. Direct-seeded rice (DSR) is a viable alternative to transplanted rice due to reduced water and labor requirements, potentially achieving comparable or higher yields with reduced inputs. This study was conducted in the 2025 dry and wet seasons in Los Baños, Philippines, using a 2-factorial randomized complete block design with 4 replications. The first factor was the 2 rice varieties NSIC Rc 506 (Tubigan 41, V1) and NSIC Rc 160 (Tubigan 14, V2), and the second factor was cultural management, …

Marker-Assisted Identification Of Hybrids In Polyembryonic ‘Carabao’ Mango (Mangifera Indica L.) Breeding In The Philippines, John Edward L. Felipe, Kyla Andrea G. Mendoza, Benjamin Christian J. Esguerra, Carolyn E. Alcasid, Gino R. Hernandez, Eureka Teresa M. Ocampo

The Philippine Agricultural Scientist

Varietal improvement of the Philippine ‘Carabao’ mango (Mangifera indica L.) through conventional breeding is constrained by polyembryony, which makes it difficult to distinguish zygotic hybrids from nucellar seedlings at early developmental stages. This study evaluated the utility of simple sequence repeat (SSR) markers for early and accurate identification of hybrids in polyembryonic ‘Carabao’ mango crosses. Genomic DNA was isolated from 24 parental accessions and 61 putative hybrid seedlings using a modified CTAB protocol that yielded DNA suitable for PCR-based marker analysis. Eighty-one SSR markers were screened across 29 parental combinations, of which 64 markers (79.0%) were polymorphic in at …

Crop Performance Of Aromatic Basmati Rice Grown In Tidal Lands In Indonesia [Research Note], Riza Adrianoor Saputra, Indra Jatmika Liran, Yulia Padma Sari

The Philippine Agricultural Scientist

Rice production in Banjar Regency has declined in recent years due to land-limiting factors, particularly the suboptimal conditions of tidal wetlands. Therefore, improving cultivation techniques for new superior varieties such as Aromatic Basmati is essential to enhance productivity on marginal lands. This study aimed to determine the best combination of seedling number per planting hole and seedling age, as well as to evaluate the effect of each factor on the growth and yield of Aromatic Basmati rice cultivated on tidal land. The experiment was conducted for 4 mo (August to December 2020) in the experimental paddy fields of the Agricultural …

Spatial Variation In Soil Quality Across Selected Fruit Tree Plantations In Bacnotan, La Union, Philippines, Jay Mark G. Cortado, Roberto G. Visco, Jenielyn T. Padrones, Pastor L. Malabrigo Jr

The Philippine Agricultural Scientist

Sustaining soil quality on any plantation is critical to increasing productivity and responsible land use. However, spatial variation in soil quality across fruit tree plantations under existing field and management conditions remains insufficiently documented. This study aimed to assess the soil quality of monocropped plantations of banana, calamansi, coffee, and rambutan in northern Luzon, Philippines, evaluate the extent of degradation or improvement relative to a reference forest using the Soil Quality Index (SQI) approach, and identify the soil indicators that significantly influence soil quality in these plantations. The objectives were to determine which fruit tree plantations could enhance soil quality …

Can Generative Ai Make Farming Decisions? Current Status And Future Pathways: A Case Study In Row Crop Production With Chatgpt, Nipuna Chamara, Yufeng Ge, Joe Luck, Yu Pan, Saleh Taghvaeian, Cory Walters, Christopher Proctor, Daran Rudnick, Daren Redfearn

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The agricultural decision-making process is experience-based, knowledge-dependent, time-sensitive, complex, and driven by historical data. Planting, fertilization, irrigation, and chemigation are key categories in farm decision-making, and currently there is no one-shot decision-support tool that covers all these activities. Generative Artificial Intelligence (AI) models are more advanced than traditional machine learning and deep learning models. These models have been trained on vast amounts of data from the internet, allowing them to accept unstructured data in various forms and generate human-like text, solutions to problems, and scenario predictions. Given this capability, we became interested in exploring the potential of generative AI in …

Arkansas Corn And Grain Sorghum Research Studies 2025, Jason Kelley, Travis Faske

Arkansas Agricultural Experiment Station Research Series

The 2025 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, nematode, and insect management; economics; irrigation; agronomics; soil fertility; drone use; research verification program results; and numerous miscellaneous topics. Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results. The reports inform and guide our long-term recommendations, …

Fate Of Nitrogen Applied To Grassland In Animal Wastes, M Sherwood

IGC Proceedings (1977-2023)

The experiment was designed to determine the effects of land spreading of animal manures on the nutrient content of surface runoff water and infiltrating soil water. This report deals only with nitrogen (N) and attempts to quantify the losses through runoff, leaching, and volatilization of ammonia (NH3) as well as N uptake in the grass over a 3-year period. Experimental plots sited on grassland, on two soil types (a moderately drained loam and an impermeable gley), were equipped to collect surface runoff water. Ceramic probes were installed in each plot at 15-, 30-, 60-, and 100-cm depths to extract in­filtrating …

Annual Losses Of Ammonia From A Grazed Pasture Fertilized With Urea, V R. Catchpoole, L A. Harper, R J.K Keyers

IGC Proceedings (1977-2023)

Nitrogen-balance studies have shown losses of applied nitrogen (N) from grazed pastures in southeastern Queensland. Losses as high as 80% have been observed from urea N broadcast at 376 kg N/ha/yr over 8 years on a Setaria sp1uu:elata cv. Nandi pasture. Management techniques aimed at reducing this loss and thereby increasing the efficiency of use of N by pastures cannot be devised until the pathways of loss are known. The objective of this research was to estimate the annual ammonia (NH3) loss by convective transport from a urea-fertilized pasture at Samford Pasture Research Station in southeastern Queensland. Urea was broadcast …

Nitrogen Losses From Urine-Affected Areas Of A New Zealand Pasture, Under Contrasting Seasonal Conditions, P R. Ball, D R. Keeney

IGC Proceedings (1977-2023)

Grazing ruminants aggregate large quantities of forage nitrogen (N) into urine patches. Pasture plots treated with urine N were studied to assess its fate under contrasting seasonal conditions: cool-moist (representing winter-spring); warm-moist (late spring-early summer), and warm-dry (late summer-autumn). A permanent ryegrass (Lolium perenne L.)-white clover (Trifolium repens L.) sward on free-draining alluvial soil was studied. 'freatments were replicated in randomized blocks. Urine N was applied at 30 or 60 g N/m2• Relevant measurements were then continued until treatment differences disappeared. Apparent N balances for urine treatments were compiled. Fixation by white clover was always greatly reduced in …

Effects Of Grazing Management On Seasonal Variation In Nitrogen Fixation, J L. Brock, J H. Hoglund, R H. Fletcher

IGC Proceedings (1977-2023)

Using the acetylene reduction assay, field studies in recent years have investigated the variation in N fixation in grazed systems, and some of the principles involved in the interaction with available soil N have been described. This experiment ex­tends this work to include the effect of grazing management on the factors influencing N fixation. Two self-contained sheep-grazed units, one a 10-paddock rotationally grazed system and the other set stocked, were estab­lished on a high-fertility ryegrass-white clover pasture, with a basic stocking rate of 22 sheep/ha. Over the 1975-1978 period, both units were monitored for pasture growth, N fixation, and associated …

Symbiotic Nitrogen Fixation Of Alfalfa, Birdsfoot Trefoil, And Red Clover, G H. Heichel, C P. Vance, D K. Barnes

IGC Proceedings (1977-2023)

Forage legumes such as alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus comiculatus L.), and red clover (Trifolium pratense L.), grown in crop rotations, can provide an inexpensive source of nitrogen (N) to succeeding crops. Few quantitative measurements of seasonal patterns of N fixation in managed communities of perennial forage legumes have been undertaken, chiefly because of the lack of satisfactory methods. Therefore, there is little knowledge of how N fixation varies with crop development, yielding ability, and weather patterns. Quantitative measurements of N fixation are important in choosing the appropriate legume for use in a crop rotation and for …

Photosynthate Supply And Nitrogen Fixation In Forage Legumes, P M. Murphy

IGC Proceedings (1977-2023)

Photosynthate supply is known to limit nitrogen fixation in legumes, and the resulting shortfall in energy supply necessary for maximum crop production may be aggravated by the energy-wasteful process of hydrogen (H2) evolution by the legume N2 fixing system. There is less information available on these aspects of the nitrogen-fixing process in forage legumes, such as white clover (Trifolium repens). The objectives of the present work were to determine how N2(C2H2) fixation and H2 production are in­fluenced by carbohydrate supply in forage legumes.

Plants were grown under controlled environmental conditions, and nodule energy supply was varied by adjusting …

Selection Of Rhizobium Strains For Enhanced Dinitrogen Fixation In Forage Legume Production, C Hagedorn, W E. Knight

IGC Proceedings (1977-2023)

A set of procedures for the selection of Rhizobium strains for enhanced dinitrogen fixation in forage legumes is presented. Although forage legumes are among the most efficient members of the Leguminosae regarding biological nitrogen fixation (BNF), they are generally neither productive nor persistent without effective nodulation by appropriate rhizobia. The following methods define a selection and evaluation process to obtain appropriate Rhizobium strains. These include (1) regional survey of the production area, (2) strain collection and soil analyses, (3) strain characterization, (4) strain selection and manipulation, and (5) field evaluation of strains. The initial procedure is to survey the region …

Interactions Between Grasses And Rhizosphere Nitrogen-Fixing Bacteria, M H. Gaskins, D H. Hubbell, S L. Albrecht

IGC Proceedings (1977-2023)

Sorghum and Digitaria cultivars grown in soil or nutrient solutions were inoculated with a strain of Azospirillum in short-term greenhouse experiments. Carbon compounds lost by roots in solution culture experiments were determined in order to estimate the quantity of energy substrates that might be obtained by rhizosphere organisms from growing plants. Other plants were treated with plant growth hormones, and responses were compared to those of plants treated with killed Azospirillum cells. The similarity of the responses suggests that growth-hormone production by the inoculant organism, rather than nitrogen (N) fixa­tion, is responsible for part or all of the increase in …

Simple Computer Simulation Models For Forage-Management Applications, G W. Fick, D Onstad

IGC Proceedings (1977-2023)

Dynamic computer simulation models of forage growth can be useful in interpreting physical and biological limitations on production and in designing management systems for testing in the field. The explanatory detail of such models makes them both more reliable and more expensive to use than simple empirical formulations. Simple simulation models reduce the expense. They can also serve as reference points for designing, evaluating, or selecting more complex versions and thus provide a more ra­tional basis for using models in grassland research and management. Our objectives were to develop and to test a simple dynamic simulation model of alfalfa (Medicago …

Energy Flow And Conversion Efficiency In Grazing Grassland, T Akiyama, S Takahashi, M Shiyomi, T Okubo

IGC Proceedings (1977-2023)

Measurable energy storage on grassland ecosystems was examined for 5 years at the Fujinita site under the same rotation pro­gram with two grazing intensities. Daily global solar radiation and photosynthetic active radiation were measured as the energy sources in the ecosystem. Primary production by pasture plants and amount grazed by cattle were estimated by the biomass dif­ferences inside and outside of protection cages. For the estimation of energy produced or stored by plants or cattle, calorific values were examined for dominant plant species at the Fujinita site. Seasonal changes in digestibility were investigated to ascertain the energy of herbage digested …

A System Approach To Swedish Ley Production, J F. Angus, A Kornher, B.W R. Torssell

IGC Proceedings (1977-2023)

A simulation model for estimating yield of leys from standard meteorological observations is described. It is based on an S-shaped growth curve also accounting for phasic development and regrowth depression. Effects of temperature, radiation, and soil moisture are accounted for by a growth index. Soil moisture is simulated with a standard water budget. The parameters in the model were estimated by comparing measured with calculated growth. The model then predicted final harvest with reasonable accuracy, but with underestimate of early season growth, presumably due to mobilization of car­bohydrate from storage organs. Observed ley yields from 49 Swedish parishes (1961-1978) were …

Age, Date Of Cutting, And Temperature As Factor Affecting Chemical Composition Of Berseem (Trifolium Alexandrinum L.), F Guessous

IGC Proceedings (1977-2023)

Chemical composition ofberseem (Trifolium alexandrinumL.), produced in winter and spring under irrigation in Morocco, was investigated in a 4-year study. Berseem was planted at various dates, and after the first cut had been harvested, samples were taken from each regrowth at weekly intervals. Total plant samples and leaf and stem samples were analyzed for dry matter

(DM), ash, crude protein (CP), and crude fiber (CF). A total of 172 samples of above-ground regrowth were analyzed and used to calculate multiple regressions of chemical composition on age and date of cutting. Date of cutting was defined as number of …

Forage Quantity And Quality Contributions From A Grass-Legume-Shrub Planting On A Semi-Arid Rangeleand, D A. Johnson, M D. Rumbaugh, G A. Van Epps

IGC Proceedings (1977-2023)

Poor grazing management has led to deterioration of vast expanses of the world's semiarid rangelands. Although contem­porary thought in range-management circles suggests that combinations of grasses, forbs, and shrubs are desirable in revegetating these areas, past revegetation mainly involved the establishment of monocultures of perennial grass. The objectives of this study were to determine the forage and protein yields of a grass-legume-shrub planting in a semiarid rangeland. The study was conducted in central Utah on a rangeland receiving 32 cm of annual precipitation. Crested wheatgrass (Agropyron cristatum) was established alone and in combination with fourwing saltbush (Atriplex canescens), alfalfa (Medicago …

Effects Of Water Stress On Herbage Quality, J R. Wilson

IGC Proceedings (1977-2023)

Uncertainty exists about whether drought is detrimental to the nutritive quality of herbage. This paper tries to resolve this uncertainty by examining the influence of soil moisture on some herbage-quality characteristics. Unpublished data from my own work and review of published literature are presented. Field plots of three tropical grasses, green panic (Panicum maximum var. trichoglume), buffelgrass (Cenchrus ciliaris), and speargrass (Heteropogon contortus), were subjected to perioqs of controlled drought, and herbage from these plots was compared with that from well-watered plots. Leaf and stem dry-matter ?igestibility of water-stressed herbage was either similar to or higher than that of unstressed …