A Study On The Theory And Technics Of Cultivation Of Cotton With High-density In North Xinjiang

To further steadily promote the yield of cotton in North Xinjiang, it is necessary to study the technique of cotton high-density- cultivation and the relations between yield and cultivation- density with experiments on small plots and investigation of high-yield farms as its basis .In 2003 we went about the experiments on small plots at Shihezi University Agriculture College experimental station, systematically testing different densities with modern sophiscated apparatus, observing their characteristics so as to find out the most reasonable density for cultivating cotton .Also investigation has been made on large farms in Shihezi agriculture cultivation area which is a representation of North Xinjiang.The result of research shows that the more the density of planting is the more the dry matter accumulates before full-blooming stage. In the later period, the accumulation of dry matter will drop down with the increase of density, which explains why over-dense planting is not advantageous to yield. After the stage of full-blooming and boll-opening cotton enters the period of reproduction, the rate of dry matter accumulation to yield is positive especially in the stage of full-boll-opening (r=0.9263)The statistics analysis shows that close relations between yield and planting density , the equation as follows: y=5.266x~2+250.58x+178.7 (r=0.9773). Theoretically when density reaches 237,900 plants/hm~2(2.38 × 10~4 plants) the yield will be the highest. For the time-being the density set for North Xinjiang is 2.3-2.6 × 10~4 plants/hm~2.The changing of planting density has much effect on cotton canopy structure both individually and wholly, The height of plant is 55-65cm, and the stem grows 0.9-1.1cm higher each day. LAI is 1.97-2.25 in full-blooming stage 3.88-4.13 in boll forming stage, 2.45-2.64 in full boll opening. The space of individual plants reduce while the total plants increase, and the corresponding measures should be taken such as reasonable and timing irrigation, fertilizing, pruning etc. to control LAI and guarantee high yield through high density planting.