Agriculture and Forestry

Tools in this group

• Chemical Application Rate (GPA) - GPA = (5940 * GPM) / (speed * spacing) and inverse for target GPA.
• Timber Cruise (Doyle / Scribner / International 1/4) - Board feet per log by Doyle, Scribner public-domain table, or International 1/4.
• Planting Density and Seed Rate - Seeds and pounds per acre from row spacing, target population, germination, and seed price.
• Tractor Drawbar Power - Drawbar HP = (pull * speed) / 375; PTO HP estimate from public benchmark.
• Irrigation Sprinkler Uniformity - Christiansen CU and Distribution Uniformity from catch-can readings; pass/fail at 85% and 75%.
• Soil Bulk Density and Compaction - Bulk density, total porosity, and compaction flag against texture-class threshold.
• Crop Yield and Harvest Loss - Yield bu/acre adjusted to standard moisture, plus optional ground-loss percent.
• Temperature-Humidity Index (Livestock) - USDA-ARS THI from temperature and RH, with species-specific heat-stress band (dairy / beef / hog / poultry / horse) and a recommended cooling intervention.
• Sprayer 1/128-Acre Calibration - USDA Extension 1/128-acre method: boom width determines travel distance, ounces collected per nozzle equals GPA, speed adjustment closes to a target rate.
• Irrigation Requirement (ET-based, acre-feet) - Crop ET demand (Kc x ET0 x days), net and gross irrigation depth after rainfall and application efficiency, and total acre-feet / gallons over the field. Per FAO Irrigation and Drainage Paper 56 and the USDA NRCS Irrigation Guide; reference ET0 from your local station.
• Cattle Stocking Rate (AUM) - Available forage (production x area x utilization), animal-unit-months of carrying capacity, head supported, and grazing days for a herd, by animal class. Per the USDA NRCS National Range and Pasture Handbook Ch. 6.
• Grain Bin Capacity (Bushels) - Cylinder plus cone volume of a round bin in cubic feet and bushels (ft^3 x 0.8036), and weight by grain test weight (corn / wheat / soybeans / oats). Bin geometry first-principles; USDA FGIS test-weight standards.
• Grain Drying Shrink and Net Bushels - Moisture shrink from wet to market moisture, dried weight, handling shrink, and net market bushels at the crop test weight (56 corn, 60 wheat/soy). The buyer contract and moisture discount schedule govern.
• Livestock Dry-Matter Intake and As-Fed Ration - Dry-matter intake (body weight x intake %) restated as as-fed bunk weight at the feed dry-matter content, and a herd total. Wet feeds weigh far more as-fed for the same nutrition. A nutritionist governs the ration.
• Nutrient-Based Manure Application Rate - Application rate (ton/acre solid or 1,000 gal/acre liquid) to meet a crop N or P2O5 need from the manure total nutrient and its first-year availability. Per NRCS Code 590; the farm nutrient-management plan governs.
• NPK Fertilizer Blend from Soil Test - Nutrient recommendation (max(0, crop demand - soil-test credit)) for N / P2O5 / K2O, solved into a three-straight blend (urea, DAP, potash) with delivered nutrients and over-application flags. Per USDA NRCS Agronomy Technical Note ranges; certified soil-test recommendation governs.
• Pesticide Tank-Mix and Acres per Tank - Acres treated per tank (tank gal / GPA), product per tank in the entered unit with gal / mL or lb / g conversions, and tanks / total product / carrier water for a field. Tank-mix math first-principles; the EPA label is the law (FIFRA).
• Pesticide REI / PHI Clock - Time remaining on the restricted-entry interval and pre-harvest interval from elapsed time since application, with early-entry / early-harvest violation flags. Per EPA WPS 40 CFR 170 and the product label (the label is the law, FIFRA).
• Growing Degree Days - Accumulated growing degree days from a daily Tmax/Tmin series, a crop base temperature, and an optional upper cutoff, by the standard or modified method.
• Pearson-Square Feed Ration - Parts and percent of two feeds to hit a target nutrient level via the Pearson square, with pounds of each for a given batch and a blend verification.
• Livestock Water Requirement - Gallons per head per day and total herd demand by temperature interpolation between user-supplied breakpoints, or the dry-matter-intake ratio method, with a lactation doubling.
• Mulch, Topsoil, and Aggregate Volume - Bulk landscape material: yd^3 = area x depth/324, bags = ceil(yd^3 x 27 / bag), tons = yd^3 x density, loads = ceil(yd^3 / load). 1000 ft^2 at 3 in topsoil (1.1 ton/yd^3) -> 9.26 yd^3, 125 bags, 10.2 tons, 1 load; lighter mulch (0.5) is 4.6 tons at the same volume. The supplier's product density governs.
• Grain Drying Energy and Fuel - Water removed = weight x (Mi - Mf)/(100 - Mf), energy = water x ~1500 Btu/lb, propane = energy/91,500. 1000 bu corn (56 lb/bu) from 20% to 15% -> 3,294 lb water, 4.94 million Btu, 54 gal; drying only to 17.5% roughly halves both. The dryer efficiency and fuel heat content govern.
• Manure Nutrient Application Rate - N-based rate = crop N need / (total N x availability), with the P2O5 and K2O delivered at that rate reported so phosphorus over-application is visible. 150 lb N/acre, 10 lb N/ton, 50% avail -> 30 ton/acre, delivering 150 lb P2O5/acre; composted manure (70%) drops it to 21.4 ton/acre. The nutrient-management plan governs.
• Center-Pivot Application Depth and Runtime - Hours per pass, gross capacity per acre, and net depth of a center-pivot irrigation system: hours = area x depth x 452.6 / flow. An 800 gpm pivot on 125 ac applying 1 in at 85% runs 70.7 hr (~3 days). The outer spans sweep more area, so the instantaneous rate under an outer span can run off even when the daily depth is right.
• Center-Pivot Outer-Span Application Rate vs Soil Intake - The runoff check center-pivot-runtime's own note warns about: the outer end sweeps the biggest circle fastest, so it dumps the whole pass depth in a few minutes. app_rate = pass_depth x 2 x pi x pivot_length / (revolution_hr x wetted_band). A 1-in pass on a quarter-mile pivot turning once a day through a 100-ft band applies 3.5 in/hr at the end tower - about 7x a silt loam's 0.5 in/hr intake, so it runs off on any slope even when the daily inch is right. Slow the pivot, narrow the band, or pick a lower-rate package. A design screen, not a runoff model.
• Center-Pivot Percent-Timer to Depth - The number the operator turns at the panel: the end-tower percent timer, converted to applied depth. revolution = revolution_100_hr x 100 / timer_pct; depth = flow x revolution / (452.6 x area). The depth is inversely proportional to the timer - dropping it from 100% to 50% does not halve the depth, it doubles it, which irrigators get backwards constantly. An 800-gpm pivot on 125 ac with a 20-hr full-speed pass lays 0.28 in at 100% but 0.57 in at 50%. Closes the loop on center-pivot-runtime. An operating aid, not a scheduling design.
• Stored-Grain Aeration Fan Airflow - The fan airflow to cool or dry stored grain: required_cfm = rate x bushels, with the ~15/rate cooling-front rule. Aeration cooling (0.1-0.25 cfm/bu) is a different job from natural-air drying (0.5-1.0). Static pressure rises steeply with depth and fan power grows ~fourfold when the rate or depth doubles, so a fan sized on cfm/bu alone stalls in a tall bin.
• Waste Storage Facility Volume (NRCS 313) - NRCS 313 waste storage sizing: total = (daily manure + wastewater + bedding) x storage_days + area x (net precip + 25-yr storm)/12 + freeboard. An uncovered pit must bank the rain and the 25-year storm on its own surface, or it overtops in a wet spring; minimum storage 120 days. A planning aid, not the engineer of record.
• Manure Storage Roof Savings (Covered vs Open) - The storage a roof buys back, the follow-on to manure-storage-volume: roof_saving = area x (net_precip + storm)/12 - the whole rainfall term an open pit must bank on its own surface. An 8,000 ft2 pit in a 10-in wet season saves 6,667 ft3 (~50,000 gal, a fifth of the facility); a 12,000 ft2 pit in a wetter climate saves 15,000 ft3 (~112,000 gal, a third). The saving is clean rainwater the operation also avoids hauling and spreading, so a roof pays back fastest where it rains most. A planning aid, not the engineer of record.
• Two-Stroke Fuel Mix - Oil to add for a two-stroke gas:oil mix (chainsaws, trimmers, outboards): oil volume = fuel volume / ratio, reported in fl oz and mL with the per-gallon and per-liter dose (first-principles volume arithmetic).
• Green Log and Limb Weight - Green weight and volume of a log or limb from its butt / top diameter, length, and species green density - the static load every rigging number starts from.
• Tree Rigging Shock (Dynamic) Load - Estimated peak dynamic load and the multiplier over static weight when a piece is dropped and caught on a lowering line, from the drop, rope length, and elongation.
• Felling Notch and Hinge Geometry - Recommended open-face notch depth, hinge thickness, and hinge width from the felling-cut diameter, with the ANSI Z133 cautions. A qualified faller governs.
• Friction-Device Hold Force by Wraps - Hand-side hold force for 1 to 4 wraps on a porta-wrap or lowering bollard by the capstan equation, so one groundie can pick the right wrap count.
• Brush Chip Volume and Haul Loads - Loose chip volume and the number of chip-truck or dump loads from the green weight of the wood and the chip bulk density.
• Basal Area per Acre (Prism Cruise) - Stand basal area per acre from a variable-radius (prism / angle-gauge) point sample: BAF x the count of trees 'in', plus the per-tree basal area (0.005454 x DBH^2) and the trees-per-acre one in-tree represents. The prism counts by angular size, not distance -- the basal area per acre is independent of any plot radius.
• Reineke Stand Density Index - The thin-now metric: SDI = TPA x (QMD/10)^1.605 and its percent of the species maximum (35% onset of competition, 55-60% lower management zone, ~100% self-thinning). Uses the QUADRATIC mean diameter (the diameter of the tree of average basal area, always >= the arithmetic mean); a plain average understates density and thins too late.
• Thinning Target TPA From a Target SDI - The residual-stand number the prescription needs: TPA_target = (SDI_max x target%) / (QMD/10)^1.605, the trees to cut from the current TPA, and the residual basal area. A ponderosa stand (SDI_max 450) thinned to the 35% competition floor at a 10 in QMD keeps 157 trees per acre - a 300-TPA stand marks 143 for cutting at about 86 ft2/acre residual. The inverse of reineke-sdi; thinning from below raises the QMD, so the residual lands conservatively below the target. A management aid, not a prescription.
• Quadratic Mean Diameter (from a Tally) - The QMD reineke-sdi requires, straight from the tally sheet: QMD = sqrt(sum(count x DBH^2) / trees). Enter a diameter tally (one token per tree "12" or per class "12:40") and get the QMD, the arithmetic mean beside it (so the gap is visible), the tree count, and the tallied basal area. QMD is the diameter of the tree of average basal area, always at or above the arithmetic mean - the number a plain average gets wrong. A mensuration helper, not a cruise compilation.
• Hollow / Decayed Trunk Strength Loss - A tree-risk screen for a standing tree with internal decay: the Wagener strength loss (hollow_d^3 / D^3) x 100 from a central hollow, plus the Mattheck t/R ratio and the t/R < 0.30 concern flag. The cube law keeps loss small until the hollow is large -- a trunk can be two-thirds hollow and keep most of its strength. An open cavity is far weaker.
• Open-Cavity Trunk Strength Loss (Smiley & Fraedrich) - The open-cavity correction trunk-decay-strength's note warns about: an open face (wound, seam, fire scar) makes the ring a broken tube, far weaker than the closed-hollow Wagener estimate. loss = (hollow_d^3 + R x (D^3 - hollow_d^3)) / D^3 x 100, where R is the opening arc / circumference (Smiley & Fraedrich 1992). Collapses to Wagener at R = 0; validated against the paper's example (4-in stem 70% hollow, 2-in opening -> 45%). A 24-in trunk with a 3-in wall and an 8-in opening loses 48% vs the 42% a closed hollow shows. A screen, not a load rating.
• Tree Protection / Critical Root Zone - The ANSI A300 Part 5 tree protection zone (critical root zone) to fence off during construction: radius = radius_factor x DBH (1.0 ft/in standard, 1.5 ft/in mature), area = pi x radius^2. The zone is set by the trunk diameter, NOT the canopy dripline -- a narrow-crowned tree still needs the full radius, so fencing to the visible canopy under-protects the roots.
• Critical Root Zone Encroachment Percent - The encroachment check tree-protection-zone's follow-on named: how much of the CRZ a construction limit line cuts off, judged against species tolerance. A limit line at distance d slices a segment R^2 x acos(d/R) - d x sqrt(R^2 - d^2) out of the circle; encroach = segment / (pi x R^2) x 100. A wall 5 ft from a 20-in tree (R = 20 ft) encroaches 34% - fine for a tolerant species (40%), over the line for intermediate (30%) and sensitive (20%): same cut, three verdicts. Move it to 12 ft and it drops to 14%. A planning screen, not a tree-preservation permit.
• Live Crown Removal Limit (Pruning Dose) - The ANSI A300 Part 1 live-crown removal check: removal_pct = removed / live x 100 against the maturity-class cap (mature <= 25% in a season, young ~15%, over-mature ~10%, stressed 0%). The 25% is the mature-tree MAXIMUM, not a target -- a young or stressed tree gets far less. Lion's-tailing violates A300 even under the percent cap.
• Nozzle Flow vs Pressure and Tip Selection - Flow at the operating pressure from a tip's catalog flow via the square-root law, and the pressure that would hit a target flow (flagged outside the flat-fan band). Pressure is a fine-tuning lever -- change tips to change the rate. The EPA label is the law (FIFRA).
• Downwind Spray Drift Buffer - A relative downwind no-spray buffer that scales an editable droplet-class base by wind speed and release height. A planning aid only -- the product label's mandatory buffer is the law (FIFRA); your state lead agency governs.
• Sprayer Field Capacity and Spray Time - Theoretical and effective acres per hour, the spray time for a field, and the tank loads needed, from boom width, ground speed, and the field efficiency that overlap and turns eat up. Pairs with tank-mix for the product.
• Hay Dry-Matter and Safe-Storage Weight - The dry-matter pounds in a bale (weight x (1 - moisture)), the weight restated at a target moisture for an equal-basis comparison, and a heating/mold risk flag where the measured moisture is above the safe-storage ceiling (default 18% large / 20% small, editable). The producer and local extension guidance govern.
• Sprinkler Precipitation Rate - The precipitation rate a valve zone applies, in in/hr (PR = 96.3 x zone gpm / zone area), the number that sets the runtime and the reason spray heads and rotors never share a valve. Head flows come from the manufacturer's nozzle chart; this is a design-rate estimate, not a system audit (irrigation-uniformity audits the installed result).
• Irrigation Zone Runtime and Cycle-and-Soak - The controller runtime to apply a target depth: net (depth / rate x 60), gross (net / distribution uniformity, so the dry quarter gets the target), and a cycle-and-soak split into runs short enough to beat runoff on the soil and slope. The DU comes from a catch-can audit and the soil caps the cycle length; a program aid, not a guaranteed schedule.
• Drip Zone Flow and Valve Capacity - The total emitter flow on a drip zone (gph and gpm) and its utilization against the valve / lateral flow limit, with the emitter count given directly (point-source) or derived from dripline length and emitter spacing (inline). Keep utilization under 100% or the far emitters starve; a flow-budget check, not a hydraulic pressure-loss model.
• Plant Spacing Count (Square and Triangular) - The plant count for a bed at a given on-center spacing, square (area / spacing^2) and triangular (area / (0.866 x spacing^2), the staggered 60-degree grid that packs ~15% more plants the way groundcover is actually planted). The spacing comes from the mature spread or the plan; a planting-density count, not a horticultural plan.
• Sod Takeoff (Slabs and Pallets) - The sod order from a lawn area: ordered area with a cut/edge waste allowance (in ft^2 and square yards), then slabs (sold by the piece) and pallets (sold by the skid). Slab and pallet coverage vary by farm (defaults ~10 / ~450 ft^2, editable); a material takeoff, not a site-prep or establishment plan.