INCREASE IN WHEAT YIELDS

Sun (Auckland), Volume IV, Issue 1028, 19 July 1930, Page 27

INCREASE IN WHEAT YIELDS

NECESSITY FOR SEEDING AS REGULARLY AS POSSIBLE REGUTjAR seeding of wheat land, as a means of assuring high yields, and the way in which it can be achievad, are discussed in the latest bulletin of the Canterbury Chamber of Commerce on the sowing of wheat. Particular stress is laid on the need for proper cultivation and the use of good implements.

How much wheat should be sown to the acre is a question that has been very frequently discussed, and which is put to the trial on thousands of farms cyerv season. At the moment, it is desired to pass that question by, and to draw attention to the fact that, whether the wheat is sown at 80 pounds or 120 pounds to the acre, the seeds are not distributed with absolute evenness over the area sown. On walking along any one coulter mark after the wheat has coma up, it will he found that there are thin patches and thick patches, and occasionally small lengths on which no plants at all appear. While this was known in a general way, very little importance was attached to it, until the publication, in 1928, of a paper by Mr Engledow, of Cambridge, where it was shown that these irregularities, small though they may appear, have a very definite effect upon yield. Engledow counted the plants on succes«lve foot-lengths of one coulter ol the drill, repeating the counts hundreds of times, and found irregularities that had been quite unsuspected. In a typical instance, the counts showed 20. 11, 12, 14, 5,8, 7 plants in successive footlengths. Similar counts were taken on an ordinary well-drilled field at Lincoln College, and the figures obtained on successive foot-lengths were 10, 13, 17 7,0, 3,8, 17, 14, 2, 18, 25, 18, 9, 6 and so on—thus showing that our fields were sown quite as irregularly as those in England. Now the number of plants on a footlength of one coulter may seem a trivial matter, but the whole field is made up of foot-lengths. Twenty-five plants per foot and eight plants per foot cannot both be the best thickness for the plants —one of them must be giving a decreased yield; and since such irregularies occur in thousands of thousands, of places all over the field, the aggregate loss must be very great. Tbin Seeding and Tillering. It is, of course, agreed by all that _ 'Hants will mean loss of yield but it is generally supposed that the thinner stand is compensated for by increased tillerng. __ This certainly is the case where there is an even thin seeding over the area, or where isolated plants are concerned, but it is not s< under the ordinary conditions of field irregularities. This is shown by the following averages of hundreds of counts of the number of plants and thp •’"mber of beads per foot:— Plants per ft. .. 5 0 13 *l7 21 Aver, heads per plant 1.3 1.8 1.8 1.8 1.6 Heads per ft... 9.5 1G.2 23.4 30.6 33.6 Thus, there were as many heads per plant when there were 17 plants to the foot as when there were only 9, so that the foot-lengths with only f plants did not give anything approaching the number of heads of those with 17 plants. Yield from Irregular Seeding. The whole relationship between yield and number of plants per foot ~ is brought out in the following table from Mr Engledow’s paper; a table that deserves the closest study, as it may point out one of the shortest roads to greatly increased yields of wheat. Four separate fields were chosen, anr a typical acre of each was investigated The first was a rich field, well worked and well drilled. The second and third fields were of medium quality* and the

fourth was ou poor land, insufficiently worked, and drilled with a worn-out machine.' The plants were counted on many hundreds of foot-lengths of each coulter of the drill used, the counts being made at the latest date on which the crop could be walked through without injuring it. Each foot-length was marked with the number of plants found on it, and then, at harvest-time each was separately threshed and weighed. The average weights of grain from all the foot-lengths having different numbers of plants are given ir the table, the weights being turned into bushels per acre for ease of comparison.

Here it is clearly seen that the thin parts of the rows gave reduced yields, and that, for the greater part, the yield keeps on increasing with the increased number of plants per foot. It can further be seen that in fields 2,3, and 4 the yield begins to fall off as the number of plants a foot reach the highest figures. In field 2, for instance, where there were 18 or 20 plants a foot, the olants crowded each other out, and the yield was reduced. In field 1, it is true, the yield continues to rise, even at 20 plants a foot, but this was a rich field, that could carry a great number of plants, and doubtless if the sowing had been heavier a point would have been reached where the number of plants was so great as to produce crowding and reduction of yield. Thus, either too few plants or too many plants mean loss at harvest; somewhere between there is a thickness of plants that will give the greatest yield. In tield 1, it every footlength had carried 20 plants, the yield of the observed acre would have been 80 bushels, whereas the acre yielded in fact, only 58 bushels—the irregularities in seeding producing a loss of 22 bushels an acre. Similarly, in field 2, irregularities meant a loss of 12 bushels an acre, and in Held 3 nine bushels an acre, and in field 4 eight bushels an acre. Thus, if regular seeding could be obtained, increased yields would immediately follow. While absolute regularity of seeding is, of course, an unattainable ideal, any approach to it must be advantageous, and so it is worth while to examine the causes that lead to the irregularities found in practice. Faults in the Drill. (1) On fields that are at all Jumpy, the drill swings rora side to side in its progress, and this means that each land wheel is travelling now fast, now slow. If the seed-sowing mechanism is driven by only one wheel, the seed roust be delivered by fits and starts. (2) If the train of cogs from the land wheels to the seed delivery are not closely meshed, the backlash will cause jerky delivery of the seed, and this will become worse when the cogs are worn.

No. Plants BUSHELS PER ACRE. Class of Land. Rich Med. Med. per loot. 6 .. . I. 11. III. IV. 30 2ft 18 8 .. .. 34 :to 20 10 .. .. 36 :t2 24 12 .. .. . ..52 38 34 22 14 .. .. . . . 60 42 42 32 16 .. .. 46 26 18 .. .. -48 42 — 20 .. 46 40 —