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Proceedings of the 7 th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation AGRICULTURAL SEEDING EQUIPMENT Paper presented by Erich Schulz, C.E.T. Agricultural Engineering Technologist Ministry of Agriculture and Food Proceedings of the 7 th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation AGRICULTURAL SEEDING EQUIPMENT INTRODUCTION The basic textbook definition for the function of seeding equipment is to uniformly distribute seeds into moist soil at a prescribed rate and depth, and cover these seeds with a compacted soil layer, without damage to the seed. A large number of seeding units have been designed and built to accomplish this function, and it is our intention to review some of the various units available for agricultural practices. Before proceeding with seeding, however, one must prepare a seedbed in a soil media suitable for plant support. Over the years, you have all heard a range of topics on soil properties, characteristics, and a good seedbed for satisfactory germination? Simply put, they are: good fertility, sufficient warmth, sufficient air, adequate moisture and an adequate layer of soil between the seed and the surface which will allow penetration by the sprout of the particular seed. Seeds vary widely in their soil-moisture requirements for germination and their sprout energy. Grass seeds must be planted close to the surface as they have low sprout energy, but they also require sufficient moisture. If planted deep enough to stay moist, they may not be able to penetrate the surface. A light mulch is valuable in securing a stand of grass because it retains moisture but does not offer resistance to the sprouts. Good soil tilth, the degree of aggregation of the soil, is the most important rootbed factor. A high degree of aggregation in a soil provides: freedom of root development and penetration, maximum water storage capacity to supply plant needs, and resistance to breakdown of surface particles under rainfall, and prevention of sealing over, allowing maximum water intake and therefore reducing erosion due to runoff. CHARACTERISTICS OF SEEDERS Most seeders have some method of accurate seed metering, which comes in a variety of forms. They must have furrow openers which will place the seed at a desired depth, and some type of device which will cover the seed and compact it into the soil to allow maximum soil-seed contact. Many different methods are used to meter seeds for planting, and their use depends on the characteristics of the seed and the spacing desired. Metering mechanisms in common use are: a) agitator with adjustable hole b) fluted or external force feed 65 Proceedings of the 7 th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation c) double run or internal force feed d) cup feed e) vertical plate feed f) inclined plate g) horizontal seed plate. The mechanisms most commonly used for grass seeding are the fluted and double run force feed systems, primarily because they can accommodate a variety of seed sizes and can meter the seeds at different rates with relatively easy adjustments. Furrow openers must place the seed at the desired depth with minimum dispersion. Many types are used, the most common being: a) hoe or shovel openers b) single disc openers c) double disc openers d) shoe openers e) wheel openers. The single disc or double disc openers are most frequently used in grass seeding equipment. They can be operated at relatively high speeds and depth can be accurately controlled by gauge wheels. For proper germination, seed must be in contact with moist soil and covered with a layer of soil which the seed sprout can penetrate. Some of the devices used to provide the proper seed environment are: a) drag chains b) covering blades c) covering shovels d) disc covers e) press wheels. The press wheels have been found to be most effective as they gauge opener depths as well as firm the soil around the seed, so as to optimize soil-seed contact and moisture retention. SEEDING EQUIPMENT Forage stands can be established by using a variety of seeding techniques. Some are successful only during short periods when specific soil and climatic conditions exist, while others are reliable 66 Proceedings of the 7 th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation over a wide range of conditions. Hydroseeding and helicopter seeding have been discussed in earlier papers. These methods are very expensive for most agricultural enterprises. Seeding by airplanes however, can have a place in agriculture. This method can be used effectively in rather rough terrain conditions or when fields are too muddy for vehicles. It should be anticipated that not all seed spread will germinate, as no proper seed placement or compaction occurs and therefore aerial seeding requires application of more seeds per hectare. Wind can seriously effect the even distribution of the seed. In range conditions, the seed is usually broadcast on snow. As the snow melts, the seed is carried down to the ground, and with some frost action, will be carried into a suitable environment for germination. There is a danger of seeds being carried away with the runoff and the practice is therefore prone to spotty forage establishment. Spinner spreaders have a similar problem of seed placement and soil compaction, but they can be effective in well-prepared seedbeds. The seeds will drop into openings of a rough seedbed, and wind and raindrop splash action will cover these seeds to stimulate germination. Again, a higher rate of seeding per hectare is required. As a method of seeding, broadcasting is not as efficient as drilling because of the variable depth of coverage, some seeds being too deep and others too shallow. Small farm operations have used and are still using the Brill ion type seeder. An excellent seedbed must be prepared. The first set of rollers breaks up large clots and creates small ridges and depressions. The seed is then dropped and a second set of packer rings presses the seed into the ground. The ridge formation from the first packer rings is displaced by the second set of rings. This will ensure that some soil covers the seed and good seed-soil contact is achieved. A more advanced step in seeding equipment is one in which the equipment does some of the soil tillage, drops the seed in a well- tilled soil, covers the seed with a second set of discs and ultimately packs the soil with press wheels. This ensures that the seed is positively covered and well compacted into the soil. The field is left in a smooth condition for subsequent harvesting operation. The small ridges created can catch any moisture that becomes available due to rain. The Australian hoe drill, after primary tillage and seed placement, firms the seed into the soil and then loosens the surface soil layer 67 Proceedings of the 7 th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation with hoes to allow the young seed sprouts to penetrate the soil surface more easily. This leaves the soil surface very loose and can become a soil erosion problem under windy conditions. Attempts have been made over the years to reduce the pre-seeding tillage required; not only to reduce the overall cost of seeding, but also to retain some of the trash cover to improve soil surface tilth and help to prevent soil erosion. Disc tiller seeders were developed that mounted conventional seed hoppers on a one-way disc tiller with the seed-delivery tubes dropping the seed between the discs at a location where it will be covered at the desired depth. Seed depth placement, however, is not very accurate and no provision was made for compaction. A similar method was developed by John Deere and Company using two sets of discs, one to rough-till the soil, the other to cover the seed. Again, accurate seed placement and compaction were not dealt with. This equipment would be applicable in grain seeding where the seeds have considerable energy to germinate and grow under more adverse depth-of-placement conditions; however, for grasses, results are questionable. Minimum tillage was pursued as time went on and the introduction of the Versatile-Noble hoe drill achieved this. The coulters are widely spaced on three separate rows to prevent trash build-up. Approximately 20 kg of downward force is required to penetrate the soil. The hooked toe on the coulters assists in keeping the shanks in the ground. Seed is metered out and firmed into the ground by press wheels which are in-line with the coulters. The Amazon Zero-Till, an experimental model from Germany, has angled cutting coulters that disturb the soil. Seed and fertilizer are dropped on the back side of the coulters. Two ranks of coulters and packer wheels firm the seed into the soil. There is considerable soil disturbance and the term zero-till seeding is rather misleading; however, it is a once-over operation and the residue is left at the surface. Triple disc zero-till requires up to 100 kg downpressure to penetrate the soil and establish a seedbed. The advantage of this unit is that it can cut through field residue, place fertilizer below the seed level, and distribute the seed at a desired depth in the soil that will enhance seed germination. 68 Proceedings of the 7 th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation The introduction of John Deeres Power-Till seeder brought minimum tillage or zero tillage to its highest point. A set of spinning discs cut a very narrow slot in the sod or soil. This creates an excellent seedbed. The seed is dropped into this tilled soil and pressed into the soil. Since only a limited amount of the vegetation is disturbed, it is necessary to apply a herbicide to spray the unwanted vegetation. When only inter-seeding for pasture renovation, no chemical sprays are required. It was found, however, that the spinning discs would wear very quickly and had to be hard-surfaced frequently. Secondly, the discs would almost self-destruct in rocky soils. Air seeders are a relatively new introduction to seeding equipment. Forced air delivers the seed from a seed box and distributes it to the seed delivery tubes. The seedbed is prepared with the equipment, seed is placed into the soil with special coulters and by running a short diamond harrow behind the unit, the soil is partially compacted and the field is left in a very smooth condition. A liquid fertilizer tank can be pulled behind the whole unit. The fertilizer is injected before seed placement and deeper than the seed. In this way, a once-over operation in stubble fields can be achieved; that is, it achieves soil cultivation or seedbed preparation, fertilizer application and seed piacement. B.C. RANGELAND SEEDING EQUIPMENT In 1975, the B.C. Ministry of Agriculture and Food embarked on a program to develop seeding equipment that could work in some of the rough, rocky range conditions of B.C. To effectively renovate some of the depleted range, the equipment would have to have the capability of: -providing good tillage of the top 8-to-15 centimetres of soil, -eliminating undesirable vegetative competition such as -placing seed accurately at no more than 1 to 2 centimetres below the soil surface and maximum contact and moisture retention. A great deal of equipment has been developed in many parts of the world. In most cases, the conditions in which that equipment had to work were not as difficult as those existing on B.C.s rangeland. 69 -providing adequate packing to firm the seed into the soil for sagebrush, Proceedings of the 7 th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation One of the more promising pieces of equipment was the U.S.D.A. Rangeland drill. The unit would do a fair job on relatively easy going ground, however, the heavy sagebrush could not be effectively killed and severe plugging occurred. It was almost impossible to ask one machine to provide the four main feeding requirements, namely, soil tillage, elimination of vegetation competition, accurate seed placement and packing. The range seeding equipment developed by the B.C. Ministry of Agriculture and Food consists of two units: a flexible, heavy-duty double offset disc to provide vegetation control and soil tillage, and a free-floating seeder-packer to compact the soil and place the seed accurately. The two units are pulled in tandem for a once-over operation. The unique features of the 10 tonne disc are in the design of the sub- gangs that are individually controlled and loaded by a hydraulically- operated cylinder. This individually variable loading of the sub- gangs gives good flexibility on uneven terrain and obstacles such as boulders and outcroppings, as well as improved durability by having each sub-gang absorb the impact loads, rather than trying to lift the entire machine. The 11-tonne seeder-packer consists of two sets of four specially- designed cast rollers which can travel up and down to follow the contour and traverse obstacles. Seed is broadcast between the rollers from a standard seed box. The second set of rollers is positioned in such a way that shallow ridges formed by the front rollers are split and the soil is formed around the seed for maximum soil-seed contact. In most cases, one pass is adequate, however, on heavy sods, double discing is sometimes necessary. One thing that cannot be over-emphasized is the fact that the equipment must be built strongly. Constant pounding over rocky soils and undulating terrain is probably the most severe operating condition any machine can be subjected to. Germination is uniform and because the soil surface is left in a ridged fashion, any moisture, either through snow or rainfall, can be effectively used by the new seedlings. The success in establishing a uniform stand of grass is directly related to good soil tillage, seed placement and packing. Over the last five years over 10,000 hectares of range have been seeded. Yield data were taken on many of these sites and a four to five-fold increase over native production was recorded. 70
農(nóng)業(yè)播種設(shè)備
論文由
埃里希·舒爾茨,C.E.T.
農(nóng)業(yè)工程技術(shù)人員
農(nóng)業(yè)食品部發(fā)表
農(nóng)業(yè)播種設(shè)備
介紹
播種設(shè)備的功能的基本定義是:以規(guī)定的速度和深度將種子均勻的分布在潮濕的土壤中,然后壓實(shí)土壤層以覆蓋這些種子,并且不能損壞種子。大量的播種單元被設(shè)計(jì)和制造來完成這一功能,我們的目的是總結(jié)一些可供選用的農(nóng)業(yè)實(shí)踐行為。
進(jìn)行播種前,我們必須準(zhǔn)備合適的土壤介質(zhì)以供支持植物。這些年來,我們都聽聞了一系列的關(guān)于土壤性質(zhì),特性和怎樣獲取滿意的苗床發(fā)芽的研究報(bào)告。簡單的說,它們是:好的肥力,合適的溫度,足夠的空氣,充足的水分與種子和土壤表面之間的一個(gè)適當(dāng)?shù)脑试S由特殊種子萌發(fā)的滲透土壤層。
種子發(fā)芽所需要的能量在不同的土壤中存在巨大的不同。草類種子因?yàn)榘l(fā)芽所需能力很小,所以必須接近土層表面,但是它們也需要足夠的水分。如果種植的很深以便保障水分,它們可能不能發(fā)芽到土層表面。充足的陽光是有利于幼芽的直立生長的,因?yàn)樗鼙WC水分并且不對(duì)幼芽的生長產(chǎn)生阻礙。具有良好可耕性的土壤和土壤的聚集程度是最重要的基礎(chǔ)因素。土壤的高聚集程度提供了:根部的自由發(fā)育和滲透,最大化的為植物需要供應(yīng)的水分,阻止因降雨而破壞土,防御性的密封功能和允許最大的進(jìn)水量并減少由于徑流量產(chǎn)生的侵蝕。
播種機(jī)的特點(diǎn)
從各種不同的統(tǒng)計(jì)表格中可以看出,大多數(shù)播種器有著精確播種的計(jì)量方法。它們必須使用開溝器將種子放在所需的深度,有一些播種機(jī)會(huì)將種子用土壤蓋住并夯實(shí)以保證土壤和種子有最大的接觸面積。
許多不同的方法被用于計(jì)量種子的種植,它們的使用取決于種子的特性和所需的間距。常用的機(jī)械計(jì)量機(jī)構(gòu)是:
a) 可調(diào)孔式攪拌器
b) 送料槽
c) 雙向送料
d) 杯型送料
e) 垂直板送料
f) 斜板送料
g) 水平種子板
最常用的播種機(jī)制是雙向送料反饋系統(tǒng),主要是因?yàn)樗鼈兛梢赃m應(yīng)不同大小的種子和相對(duì)容易調(diào)整的速度。
開溝器必須將種子放在所需的深度并保證最小程度的分散。許多的類型被運(yùn)用到播種機(jī)當(dāng)中,最普遍的是:
a) 鋤頭和鏟子型機(jī)構(gòu)
b) 單圓盤型機(jī)構(gòu)
c) 雙圓盤型機(jī)構(gòu)
d) 模座型機(jī)構(gòu)
e) 輪型機(jī)構(gòu)
單盤或雙圓盤開溝器在播種設(shè)備中是最常用的旋耕機(jī)構(gòu),它們可以在較高的速度和較深的深度條件下通過調(diào)整輪精確的控制。
為了正常萌芽,種子必須覆蓋在一層薄薄的潮濕的土壤下,以便種子發(fā)芽的時(shí)候可以穿透土層,一些用來為種子提供適當(dāng)?shù)沫h(huán)境的設(shè)備:
a) 開槽鏈
b) 覆蓋刀片
c) 覆蓋鏟子
d) 密封盤
e) 壓土輪
壓土輪已經(jīng)被證明是最有效的計(jì)量開槽深度和鞏固種子周圍土壤的方法,這種方法可以優(yōu)化土壤與種子的接觸面積并且保持濕度。
育苗器械
飼草架可以通過使用各種播種技術(shù)建立。一些只能適用于特定的土壤和氣候條件下,其他的一些則有較為廣泛的試用范圍。噴射播種和直升機(jī)播種在前面的論文中已經(jīng)做過討論。這些方法對(duì)于大多數(shù)農(nóng)場來說都是很昂貴的。
然而通過飛機(jī)播種能夠在農(nóng)業(yè)中占據(jù)一席地位。這種方法可以有效的應(yīng)用在比較復(fù)雜的地形條件以及土地十分泥濘不便于車輛運(yùn)行的地方。能夠預(yù)見的是不是所有的種子都能夠發(fā)芽,由于沒有有效的種子放置和壓實(shí)手段,因此飛機(jī)播種每公頃需要更多的種子。在很多情況下,種子通常播種在雪地上。當(dāng)雪融化的時(shí)候,雪水可以將種子帶到地下,并且具有冷藏效果,可以使中種子在一個(gè)適合的環(huán)境下發(fā)芽。但是種子存在被徑流移動(dòng)的危險(xiǎn),在實(shí)施的時(shí)候也往往因此而出現(xiàn)肥料分布不均的情況。
分離器也有類似的問題發(fā)生在種子和土壤的接觸位置,但是它們可以有效的運(yùn)用在準(zhǔn)備好的苗床上。種子會(huì)被放入苗床一個(gè)粗糙的開口,而且風(fēng)和雨水的擊打會(huì)促進(jìn)種子的發(fā)芽。再次,需要一個(gè)更高的每公頃播種率。作為一種播種方法,廣泛播種在覆蓋的可變深度上沒有鉆孔播種的效果好,廣泛播種可能會(huì)淺一點(diǎn)或者深一點(diǎn)。
小農(nóng)村的播種依然在使用過去的布里爾離子式播種機(jī)。必須準(zhǔn)備一個(gè)優(yōu)秀的苗床,第一環(huán)節(jié)的滾筒將會(huì)打碎大塊的土地變?yōu)樾K的凹凸不平的地勢,播下種子以后第二環(huán)節(jié)的壓緊機(jī)會(huì)將種子壓入地下,第二環(huán)節(jié)覆蓋在第一環(huán)節(jié)上形成了土梗,這將確保實(shí)現(xiàn)土地能夠很好的覆蓋在種子上的目的。
播種機(jī)更先進(jìn)的體現(xiàn)是它能夠?qū)崿F(xiàn)土地的耕作,將種子播種在耕作好的土地上,然后通過第二環(huán)節(jié)的盤將土壤覆蓋在種子上,最有用壓力輪夯實(shí)土壤。這確保了種子被覆蓋好和能有擁有致密的土壤覆蓋。這種行為能夠?yàn)楹罄m(xù)的收獲提供便利,小田埂的形成能夠保留來自于雨水的水分。
澳大利亞人利用鋤頭種植,進(jìn)行初步的耕作和種子定位以后,將種子放入土壤層,然后用鋤頭松開土壤以便于種子發(fā)芽的時(shí)候更容易滲透出土壤層。這種方法使得土壤表面十分松散,在風(fēng)力作用下可能成為一個(gè)土壤流失問題。
這些年來已經(jīng)嘗試了減少播種前的耕作要求,不僅僅是減少播種的成本,而且還保留了一些垃圾覆蓋提高土壤表面耕地和防止水土流失。耕耘播種盤的發(fā)展是來自于將常規(guī)種子料斗安裝在單盤與種子輸送帶之間盤上被覆蓋所需的深度。然而,種子的深度不是很準(zhǔn)確,并且沒有達(dá)到規(guī)定的壓實(shí)程度。
類似的方法經(jīng)由約翰迪爾公司所使用開發(fā)的兩種盤套發(fā)展而來,一個(gè)粗糙的耕作土地,另一個(gè)覆蓋種子。然后,準(zhǔn)確的放置種子不是隨著壓實(shí)進(jìn)行的,這種設(shè)備適用于谷物種子發(fā)芽和生長需要風(fēng)多能量和安置條件不利的深度的播種;然而,對(duì)于草來說,結(jié)果是可疑的。
微耕的追求是隨著時(shí)間的推移和引進(jìn)的先進(jìn)的耕作技術(shù)。梨刀分布在三個(gè)不同的行是用以放置廢棄物的堆積。向下約20公斤的力需要穿透土壤。在把鉤底部設(shè)有底座有助于保持地面上把柄的穩(wěn)定。種子的計(jì)量和確定通過車輪與地面滾動(dòng)直插實(shí)現(xiàn)。
亞馬遜免耕,一種來自德國的經(jīng)典模型,通過變換梨刀角度來切割土壤。種子和肥料在梨刀的后面播下,兩級(jí)梨刀和壓力輪將種子放置在土地中。對(duì)土壤有相當(dāng)大的要求并且長期的免耕播種將產(chǎn)生影響。然而,這是一個(gè)一次性的操作并且會(huì)在土地表面產(chǎn)生殘留物。
三盤免耕需要100公斤的下壓力來實(shí)現(xiàn)滲入土壤并簡歷一個(gè)苗床。這種做法的好處是它可以減少現(xiàn)場殘留物,將肥料放置在種子下方,將種子放在預(yù)期深度的土壤中并提高種子的發(fā)芽率。
John Deere's Power-Till一書中介紹的播種機(jī)中對(duì)少耕或免耕給予了高度的評(píng)價(jià)。一組螺旋研判在地底下的土壤中剪出一個(gè)非藏狹窄的槽,這構(gòu)成了一個(gè)優(yōu)良的苗床,種子被播種到土壤中并壓實(shí)。由于只有有限數(shù)量的種子被干擾,有必要用除草劑出去不需要的植物,只有牧場培育的幼苗,不能使用化學(xué)噴劑。研究表明,旋轉(zhuǎn)盤會(huì)磨損很快,很難快速的出入土壤層,而螺旋盤的損毀機(jī)會(huì)都是因?yàn)橥寥乐械膸r石。
空氣播種機(jī)裝置是一個(gè)概念相對(duì)較為先進(jìn)的裝置。它通過壓迫空氣使之將種子從種子箱中傳送到輸種管中。苗床的準(zhǔn)備也是依靠這個(gè)設(shè)備,種子通過特殊的梨刀后的較短的菱形耙放置在土壤中,土壤壓實(shí)后表面會(huì)十分光滑。肥料箱可以放置在整個(gè)機(jī)器的后面,因?yàn)榉柿戏胖玫奈恢煤蜕疃刃枰^種子,通過這種方式,一次性的操作可以在很小的地域得以實(shí)現(xiàn)。這樣,它就實(shí)現(xiàn)了土壤的耕地,整地,施肥和播種。