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.
• Fertigation / Chemigation Injection Rate - The injection-pump rate to apply a liquid fertilizer or chemical through an irrigation system: total product = the per-acre rate x the acres; injecting it evenly over the irrigation SET means the pump runs at total / set time. Applying 5 gal/acre over 40 acres in a 6-hour set is 200 gal total at 33.3 gph (0.56 gpm). Set the metering pump to that, start after the system reaches pressure and the last emitter flows, then flush with clear water. For a stock solution the resulting concentration is the injection flow / system flow x the stock strength. CRITICAL: an EPA-required anti-siphon/check-valve/interlock package must protect the water source from backflow whenever a chemical is injected. A rate estimate; the product label (FIFRA), the state chemigation rules, and a drawdown calibration govern.
• Available Water and MAD Irrigation Trigger - When to irrigate and how much, from the soil water reservoir (FAO-56 / NRCS). Total available water TAW = (field capacity - wilting point) x root depth (water contents in in/in); readily available water RAW = MAD x TAW is what you let deplete before the crop stresses, MAD ~0.5 (0.3-0.6 by crop). A silt loam at FC 0.30, PWP 0.12, 24 in root zone holds 4.32 in; at MAD 0.5 you irrigate after 2.16 in is used, an 8.6-day interval at ETc 0.25 in/day, and the net refill is that 2.16 in (gross adds the application efficiency -- see irrigation-requirement). Hotter weather (higher ETc) shortens the interval, a deeper/finer soil lengthens it. A scheduling aid; the field-measured soil moisture, the actual root depth and ETc, and the agronomist govern.
• 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).
• Two-Stroke Mix Ratio Check - The inverse of the two-stroke mix tile: the gas:oil ratio you ACTUALLY made from the oil you poured, ratio = fuel volume / oil volume, flagged against a target. 2.56 oz in a gallon is 50:1; 3.2 oz is 40:1 (richer). A LEAN mix (higher X:1, too little oil) starves the bearings and risks seizure - the dangerous error; a RICH mix (lower X:1) smokes and fouls but protects the engine. First-principles volume arithmetic; the equipment manual's ratio governs.
• 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.
• Tractor Drawbar Pull from Power - The inverse of the drawbar-power tile: the drawbar pull a tractor develops at a working speed for a given power, pull = 375 x drawbar_hp / speed (a PTO rating converts first with drawbar_hp = pto_hp x tractive efficiency). A 75 PTO-hp tractor at 4.5 mph on firm soil (efficiency 0.72) pulls about 4,500 lb; on sand (0.50) only 3,125 lb, because slip wastes power. Answers 'how much can it pull' instead of the power from a measured pull. Traction can limit the usable pull below this; ballast and tires govern.
• Anhydrous Ammonia Rate from Target Nitrogen - The anhydrous ammonia product a nitrogen target needs: anhydrous is 82-0-0 (82% N), so product = target N / 0.82, and at about 5.15 lb/gal that is the gallons per acre; a nurse-tank's gallons over that is the acres it covers. A 180 lb N/acre target is about 219.5 lb (42.6 gal) of anhydrous per acre, so a 1,000-gal tank covers about 23.5 acres. Anhydrous is a pressurized, hazardous liquid -- set the applicator with a flow monitor, calibrate against a weigh/flow check, allow for temperature and vapor, and follow the label and safety (PPE, water, closed transfer) requirements. A rate estimate; the applicator calibration, the soil-test N recommendation, and the co-op / label govern. Distinct from the NPK blend (npk-blend), which solves into urea/DAP/potash.
• Tractor Ballast for a Target Weight-to-Power Ratio - The ballast to add or remove to hit a target weight-to-power ratio: target weight = ratio x power (hp), and ballast change = target - current. A 180 hp tractor at 125 lb/hp targets 22,500 lb, so an 18,000 lb machine adds 4,500 lb; a 120 hp tractor at 130 lb/hp targets 15,600 lb, so a 16,000 lb machine removes 400 lb. Field draft and tillage want about 120 to 145 lb/hp, higher-speed transport 90 to 110 (target 8 to 15% wheel slip): too much ballast wastes fuel to rolling resistance, too little spins the tires. The ratio, the front/rear split, and the tire and inflation ratings come from the operator's manual and the implement; a wrong number is a re-ballast.
• Grain Bin Wall Height for a Target Capacity - The inverse of the grain-bin-capacity tile: the eave (wall) height a round bin needs to hold a target bushel capacity, eave = (target_ft3/packing - roof_cone_ft3) / floor_area (1 ft^3 = 0.8036 bu). Storing 12,875 bu in a 30 ft bin with an 8 ft peaked fill needs a 20 ft wall; widen to 42 ft and the wall drops to about 8.9 ft, since capacity grows with the square of the diameter but only linearly with the wall. Answers 'how tall a bin' instead of the capacity of one. A geometric fill volume; the manufacturer's rated capacity and the structure govern.
• Bunker (Horizontal) Silo Forage Capacity - The forage a horizontal bunker or trench silo holds: the trapezoidal cross-section (bottom + top)/2 x average settled depth, times length, times as-fed density, over 2,000 lb/ton. A 30 ft wide, 8 ft deep, 100 ft bunker at 44 lb/ft^3 holds about 528 tons. Enter equal bottom and top widths for vertical walls, a wider top for sloped. As-fed density is an input (corn silage ~40-50 lb/ft^3); use the settled depth. A core or weigh-back governs the real inventory.
• Feed Conversion Ratio and Average Daily Gain - Two production metrics from a feeding period: average daily gain ADG = (final - initial weight)/days, and feed conversion ratio FCR = total feed / total gain (lb of feed per lb of gain). A steer going 650 to 1,250 lb over 200 days on 3,900 lb of feed gains 3.0 lb/day at a 6.5:1 FCR. Enter feed as-fed (standard); a lower FCR is more efficient, and FCR rises as an animal finishes. A benchmarking aid; the ration, breed, and environment govern.
• 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.
• Minimum Sound Shell for an Allowable Trunk Strength Loss - The inverse of the trunk-decay-strength tile: the minimum radial sound-wood shell thickness for a maximum acceptable strength loss, t = (D/2) x (1 - (loss/100)^(1/3)). A 24-in trunk held to a 29.6% loss needs a 4.0-in shell (t/R 0.33, just above the Mattheck 0.30 trigger). Because loss goes as the CUBE of the hollow ratio, the minimum shell is small - a thin shell still holds most of the strength. Flags a shell below the Mattheck t/R 0.30 concern. An open cavity is far weaker; a screen, not a load rating.
• 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.
• Clinometer Tree Height (Percent-Slope) - Tree height from a clinometer's percent scale: standing a horizontal distance D from the trunk, read the percent slope to the top and to the base, both signed (+ above eye, - below); H = D x (top% - base%)/100. At 100 ft with a +58% top and a -4% base (base below eye) the tree is 62 ft. When the base is below eye its height adds; uphill above eye it subtracts. Percent = 100 tan(angle) for a degree scale. A field estimate; lean and a hidden top add error.
• Firewood Cord Volume - How many cords a firewood stack holds: a full (standard) cord is 128 stacked cubic feet (a 4 x 4 x 8 ft rick), so cords = length x height x depth (log length) / 128. An 8 x 4 x 4 ft stack is exactly 1.00 cord; a 20 x 4 x 4 ft stack is 2.5. This is the legal cord under NIST Handbook 130 - firewood is sold by the cord, not by unregulated 'face cord', 'rick', or 'truckload'. Stacked volume includes air gaps; the state weights-and-measures office governs.
• 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).
• Sprinkler Zone Flow for a Target Precip Rate - The inverse of the sprinkler-precip-rate tile: the total zone flow a target precipitation rate needs over a covered area, gpm = PR x zone area / 96.3 -- how a designer picks nozzles to sum to the right flow. A 1.5 in/hr rate over 1,200 ft^2 needs about 18.7 gpm of heads. Answers 'how much flow for this rate' instead of the rate from a set flow. Keep sprays and rotors on separate valves; the supply and valve must pass the flow. A design estimate, not a system audit.
• 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.