LAND EXHAUSTION.—No. 2. By R. W. Emerson MacIvor, F.I.C. F.C.S., &c. Author of" The Chemistry of Agriculture." STATION, FARM AND GARDEN. BY AN OLD COLONIST. CROPS THAT COULD BE INCREASSED WITH ADVANTAGE. Tobacco—Slcond Paper.

Waikato Times, Volume XIX, Issue 1583, 26 August 1882, Page 2 (Supplement)

LAND EXHAUSTION.— No. 2. By R. W. Emerson Maclvor, F.I.C. F.C.S., &c. Author of" The Chemistry of Agriculture ."

STATION, FARM AND GARDEN. BY AN OLD COLONIST. CROPS THAT COULD BE INCREASSED WITH ADVANTAGE. To bacco— Slcond Paper.

,Thcs we are onablcd.to explain the discordant result* obtained by the application of the same manure to different soils, i On aotne soils a manure may preduce liighly profitable results, and on others prove an utter failure. In the one case the soils were deficient in the constituents .! of plant-food present in the manure, -while in the other 6oila no such deficiency existed. We are also euabled to comprehend why the second and third application •of the same manure is often without much offect on the yield of produce ; the land bad by the first dressing become sufficiently rich in the principle constituent of the manure, so that further applications ■were useless as they simply " added their sum of more to that which had already too much." When this point has been reached a change of the manure will generally be found profitable, as some constituent not contained in the fertiliser previously applied, may have become deficient in the soil and will be restored by the employment of a manure in which the , deficient element of plant-food is the chief constituent. The principles involved in land exhaustion and in judicious manuring are summed up in Liebig's law of minimum : Erery field contains a maximum of one or several, and a minimum of one or several of the elements of plant-nutriment. It is by the minimum that the crops are governed, be it lime, potash, nitrogen, phosphoric acid, magnesia, or any other constituent ; it regulates and determines the amount or continuance of the crops. Most soils contain a good deal more potash than phosphoric acid ; and, as the latter is removed in large proportion by crops, it stands to reason that it will be withdrawn sooner than the former. Hence, so far as these Bubstances are concerned, the fertility of the land is not dependent on tho abundant potash present, bufc on tliolebs abundant phosphoric acid, which, in thia case, is the minimum constituent. Assuming tbis substance to be restored in the thape of niannre to the soil after the removal of each crop, it would in time become relately more abundant than the available potash, which, being constantly removed in large quantities, and not returned in manure, would become the minimum constituent, and as such regulates and determines the yield of produce. But, suppc«e both of thefao substances were returned in proper porportion to the land, then magnesia, or some other constituent not restarted in the manure employed, would in time take tho minimum position. Our colonial fanners leuow that a rotation of crops is often more profitable than growing, say — wheat year after year on tho same land — but they must not forget that a rotation of manuies is even mode essential to successful cultivation. Of "general" manures, well-prepared farmyard manure is the best, as it returns to the soil every constituent removed in our crops and animal produce. ' ' It acts,' ' says Leibig 1 , "upon ii field deficient in potash, by the potash it contains ; upon a soil poor in magnesia or lime ; upon one poor in silica by the Straw in it ; upon land poor in chlorine or iron by choloride of sodium (salt), chloride o potassium, or iron contained therein." This simply means that the manure is able to give back t© the land a supply of the minimum constituent, no matter what they may be. %o detcrmino the artifical manure best suited for a particular soil, the agriculturist should institute a scries of field experiments with manurei of known composition, and, according to tho results thus obtained, guide his practices on a largo scale.

Tobacco is a hearty, strong-growing plant, and it requires good soil. A rich loam, not having 1 too much sand is likely to give beat results. It will do very well where there is a somewhat free admixture of clay, anJ especially so in districts ■whore strong winds prevail, as, being a branching and heavy plant, it requires a somewhat firm hold of the soil. For reasons that will appear, it is necessary to have the land so clean that, even in the event of heavy rain coining upon the plants at the early stages of growth, they must not be chocked with weeds. This condition in connection with tho making of a successful tobacco-crop, is well understood by the Chinese, who have taken to its cultivation in the colonies, and they make preparations for it accordingly. This they do by leaving the land without crop through the preceding autumn and winter. During that time they hoc it over frequently, and so get rid of the more active-growing weeds that may bo in the land. They also -water the land freely, and so induce tho weeds to spring more readily ; and in this way they secure very clean soil in which to get out their tobacco plants. The watering part of the process is not likely to be followed by white men until irrigation can bo secui'ed ; but the cleaning 1 of tho land during two or three months before setting out tobacco plants, is an important part of the process. The season for sowing tobacco -seed extends from the end of April to the end of July, iv various parts, according to the season when warm weather sets in. At the first-mentioned date the seed should he sown in seed-beds, so as to be available for setting out on the approach of , warm spring weather. If it can. be got the seed-beds should be formed of fresh new soil. The young plants are very subject to attacks from grubs and insects, and it is an object worthy of attention to see that the seed-bed is free from them. In sowing, mix the &eed with a considerable bulk of sand and ashes, or scatter it . evenly over the seed-bed. Rake it in, and if the Boil is dry, firm it slightly by pressing down with the hoe or spade ; then Bprinkle about an inch of fine loamy soil or sand over the bed. The Chinese lay one or two inches of dry cow-dung over the eeed, and then soak the whole with water, in which soot is mixed. • This proves an effective dressing, and "brings on the plants in a manner which might be copied with advantage. The young tobacco plants do not stand interference with their roots, and if they come np too thickly, the best plan is either to nip off so many as are not necessary in ' the seed-bed, or to drag a atiffish piece of imsh over the surface, destroying some, and giving the others room to grow. If grubs attack the roots of young plants in the seed bod, (and they are very common at such times), making the plants disappear^ though a fire had passed over them, a noaking of soot water may do some good, but the more certain course is to sow other bods as soon as possible. '_ Or if the season is advancing towards -warm growing weather the seed can bo * 7 £QWn jn the field where the.plants are <to - ' grow.; i Miny experieneeeLgrowers now 4'/prefer-fcoßO^r/;in the field ?at once, and *" '■'v^^x "crops are made In that way^ ku{j&faj&e<L ijov^ such iireahnent is . mixed € ."Very, freely with good B&ndy4oam, and afl boxes in a ligh|' cajt. One,

person opens shallow holes, from two to four feet apart each way, according to the variety of tobacco grown. The other scatters in a handful of the loamy soil in which the seed is mixed, and covers it over. If dry he further, with a hoe, presses the soil upon the seed. This style of planting can only be carried on as the spring and warm weather are advancing. If it fails there is but little opportunity for a further sowing. About the same time, the plants in the seed-bed should be fit for setting out. This is done during cloudy weather, or as late as possible in the afternoon. The plants in tho beds are loosened by inserting a flat-tyned fork or a spade under them, and raising up a mass of plants and soil. The former aro separated carefully, each having as much soil as possible about it, and in that state they are set out as rapidly as possible Tho distances usually allowed aro four feet by three feet apart for the German, Connecticut, and Kentucky sorts. They are the largest growers, and in rich soil require all the space mentioned. For Turkish, Havannah, Zarra, Virginia, Cuba, Golden Drop, and other smaller growing sorts, three feet by two feet suffices, giving a little more or loss according to the condition of the soil, the richer soil producing the stronger plants which require most space. As stated, the young plants do not stand knocking about. When their roots aro injured they are very likely to die off. In setting out it is absolutely necessary to be careful and put the plants into the ground in such a manner as shall not crowd or break the roots ; then press the soil over the roots carefully, adding a little water if the soil is dry, and that part of tho cultivation is finished. It is absolutely necessary, however, to give the water if tho soil lequires it to make sure that misseu do not occur with the plants. The after cultivation is not difficult. The necessity of having the land very clean has been mentioned, and it is an important feature in dealing with a tobacco crop. Numbers of plants are destroyed both in thinning out fiom those sown in tho field, and from hoeing down weeds about those that have planted out. The plants should have made decided growth and established themselves firmly ere tho soil about them is disturbed |by the hoe. In this respect, the cultivation of toobacco offers a marked difference to that of corn or cabbage, both of which , its treatment resembles in other respect. As can be seen in the Chinese farms, where the culture of tabocco is becoming an extensive product, though they water the plant regularly, they do not disturb tho soil about them, even when weeds me growing strongly, until the plants aro strong, are shooting out leaves, and arc from six inches to a foot in height. Then they oan be clearned around with safety, aud thinned out until they stand th» necessary distauoeß apart. When the plants havo started growing freely after the hoe is operating amongst them, the lower leaves aro pinched off— that is, all the leaves that are likely to touch the ground. The soil is then gradually drawn towards the plants until each haa a little flattish-topped hillock about it. By that time the flower buds begin to appear, and the tops of the plants are then pinched off, so as to leave from eight to twelve leaves upon each plant. Buda will then be thrown out from the leaf stalks, but they have to be pinched out aB they appear. And this hoeing of the soil and pinching of the buds continues until the leaf shows signs of ripeness. When the growth has been regular and pretty sftong from the outset, tobacco loaf ripens to the greatest perfection during dry weather, and tho crop is more likely to be good and heavy when gathered during such weather than when showors aro falling and the season is damp. There is a gummy substance in the leaf ; and, strange though it may seem, this gum rises and becomes most decided in the leaf during dry weather : and it is more decided in dry, well- drained .soils than where the roots aro wet. It tjives tho leaves a sticky feel to the touch, aud they become thicker and more fleshy. They also change in color, losing tho green tinge, and becoming brownish or yellowish, according to the variety. Some leaf becomes speckled, and small holes form in in. It is a feature towards the succes&ful harvesting and curing of tho crop to cut the leaf at such time as will retain tho gum in its. If this ia not done, the leaf cures dry, harsh, and brittle, instead of being floxible and tough. Those who have grown tobacco some seasons will be awaie of what we refer to, and how, in spite of all the care they devoted to it, the leaf was dry and brittle as stated, and did not sell nearly so well as when in the more tough and flexible state. The difference arises largely from the cutting process. In fact, no caro in cuiing can make up for the want of gum in the leaf, and no small portion of the ill name too often given to colonial tobacco leaf arises from this very cause. In the next paper, this process of cutting and curing will bo dealt with more fully.