旱作水稻水肥耦合模型及经济效应

为了探讨膜下滴灌旱作水稻水分、肥料与产量之间的关系,采用通用旋转组合设计试验方法,进行膜下滴灌旱作水稻水肥耦合模型试验,并对其应用前景进行了比较分析.在供试土壤膜下滴灌条件下,灌溉定额、氮、磷与水稻产量之间符合三元二次回归模型,其一次项、二次项及水氮交互项回归系数均达显著水平,三因素的增产作用从大到小依次为灌溉定额、施氮量、施磷量.采用此模型计算的预测产量与实际产量之间呈高度正相关,预测准确度达99%.由此计算得出最高产量灌溉定额及其施肥量、经济最佳灌溉定额及其施肥量.提出实现目标产量的水肥最优组合方案:若以9 300~9 600 kg/hm²为目标产量,则灌溉定额、氮、磷用量分别为9 730~10 500 m³/hm²,272~363 kg/hm²,136~147 kg/hm²;若同时考虑经济效益,则最佳的灌溉定额、氮、磷肥用量分别为8 500~9 015 m³/hm²,225~240 kg/hm²,90~120 kg/hm².对比不同种植模式表明,膜下滴灌旱作水稻的产量与播后上水直播基本持平,其成本与育秧移栽种植持平,但水分生产效率(1.06 kg/m³)远远高于其他3种种植方式.与传统育秧移栽种植相比较,膜下滴灌旱作水稻节水50%,节约肥料30%以上.

Economic effects and coupling models of water and fertilizer of rice cultivated in aerobic soil

To probe the relations of water and fertilizer with the yield, the field experiment on the mo-del of water and fertilizer coupling of rice cultivated in aerobic soil by mulch drip irrigation was carried out by a current rotary combination design, and its application prospect was comparatively analyzed. The relation between irrigation quota, nitrogen, phosphorus and rice yields was in line with the ternary quadratic regression model under the tested soil by mulch drip irrigation. The regression coefficients of the first term, the second term and the water-nitrogen interaction term have extremely significant level. The roles of increasing yields of the three factors were in order as follows: irrigation quota> nitrogen> phosphorus. There was a highly positive correlation between the estimating yields calculated by the model and harvest yields, of which predictive accuracy was up to 99%. Thus the irrigation quota and fertilizer application with maximum yield and their maximum yields were calculated by the regression model. On the basis of this, the optimum schemes of water and fertilizer to achieve target yields were proposed. If target yields were 9 300-9 600 kg/hm², the irrigation quota, nitrogen and phosphorus application were from 9 730-10 500 m³/hm², 272-363 kg/hm² and 136-147 kg/hm², respectively. If the economic benefits were considered, the optimum irrigation quota, nitrogen and phosphorus application were 8 500-9 015 m³/hm², 225-240 kg/hm² and 90-120 kg/hm², respectively. The results from the different planting patterns showed that the yields of rice cultivated in aerobic soil by mulch drip irrigation were hardly different from those by the irrigation after direct seeding, which has roughly the same production costs as the rice seedlings transplanting cultivation, but, of which water use efficiency was much higher than that of the other three planting patterns(about 1.06 kg/m³ on average). Compared with the conventional transplanting seedlings cultivation, the planting way to rice cultivated in aerobic soil by mulch drip irrigation saves about 50% water and about 30% fertilizer.