Effects of coated-compound fertilizer on the growth and nutrition characteristics of double cropping rice (Oryza sativa L.)

Field experiment was conducted to study the characteristics of growth and nutrition physiology of test plants treated with different dosages of self-developed and lower cost coated-compound fertilizer(N: P2O5:K2O = 17% :7%: 12%)(coated F) . Uncoated-compound fertilizer with same nutrient contents was selected as control (uncoated F) . Experimental materials are double cropping rice ( Oryza sativa L.) varieties named as Zaofan No. 5 being early season rice and Xinxiangyou 80 being late season rice, respectively. Three treatments were set up for early season rice including two treatments for coated F with dosages of 480kg/hm2 and 360kg/hm2 separately and one treatment for uncoated F as control with the dosage of 600 kg/hm2 . Four treatments were set up for late season rice including two coated F treatments with a dosage of 800 kg/hm2, 600 kg/hm2 separately and two treatments of uncoated F with the dosages of 0 kg/hm2, 800 kg/hm2 separately. Different parameters of growth and nutrition physiology were investigated including dry matter accumulation, chlorophyll content, tiller growth, yield and its components. The nutrient contents of test plant and soil nutrition properties were tested as well. Field plots adapted randomized complete block design with three replications. The area of each plot was 30m2 . The results showed that tillers increased gently with a higher percentage of effective tillers for each treatment of coated F. While for the rice treated with uncoated F, tillers increase rapidly with more unproductive tillers. After heading stage, the chlorophyll content and measured value of SPAD (tested by chlorophyll meter SPAD 502) in flag leaves were markedly higher in Coated F treatment than uncoated F treatment. Comparing to the treatment with isometric or decrement 20%-25% of uncoated F, the yield increased by 5.0%-12.8% for early season rice and by 7.5%-13.6% for late season rice. It can be concluded that coated F could control the release of N, P, K; made the rice grow sturdily during the early growth period. Meanwhile, coated F could supply more nutrientsduring the meddle-late growth periods; prolong the photosynthesis time of the function leaves; accelerate the translocation of the photosynthesis product to panicles and grains, and increase the total dry matter production and the grain yield.