Effects Of Film And Straw Mulching On Soil Moisture, Soil Temperature And Crop Growth

There is a climatic condition in Northwest China which shows arid and large temperature diffierence between day and night. Soil moisture loss, nutrient conversion, crop nutrient absorption and crop conditions will inevitably be affected by soil water and temperature in dryland agriculture. Mulching measures as a useful means are widely valued. Mulching measures can hinder the exchange of water and energy between soil and atmosphere so that they can not only effectively suppress the evaporation of soil moisture but also increase the rate of precipitation protection, production and so on.Aimming at the actuality and the existent problems on mulching measures in the aeras where had winter wheat and summer maize two crops a year in Yangling, using the bare land without irrigation as the CK and based on soil hydrothermal data, crop growth and yield data as well as meteorological data which were successively and dynamicly measured as the stresses, this article analyzes the effects of different mulching treatments on the soil water and heat conditions, crop growth and yield and crop coefficient. The main conclusions are as follows:(1) In the wintering and reviving stage of winter wheat, mulching treatments can effectively improve topsoil moisture, while the influence of mulching treatments on topsoil moisture during the growing period of summer maize is unstable. Film mulching, compared to straw mulching, can be better to suppress the evaporation of surface soil moisture, thereby to increase the surface soil moisture, especially at the condition of higher air temperature. Mulchings have a greater impact on deep soil moisture content so that they can increases the deep soil moisture. The water storage of soil reachs to the maximum in the reviving and filling stage of winter wheat, while the minimum appears in the maturity stage. The water storage of soil slowly raises until to heading stage, then falls in the filling stage, at last maximum appears in the maturity stage.(2) At the condition of higher air temperature, soil temperature will decrease with the increase of soil depth. Air temperature has a greater influence on surface soil temperature. In the season of higher air temperature, film mulching has a obvious warming effect on topsoil, and the whole is better than the half. At the condition of lower air temperature, neither film mulching nor straw mulching has a more significant warming effect compared to bare land. Irrigation can promote the warming effect of film mulching and cooling effect of straw mulching.(3) Before the winter wheat turns green, it grows slowly. At the same time, the increace of plant height is unobvious. But it will be changed when the growth period enter into jointing and heading stage that the plant height will have a fast growing with a linearly speed. From filling stage to harvesting stage, plant height rise slowly. Mulching measures can make the plant height of winter wheat increased. The height of summer maize appears a trend of firstly increasing and then stoping growing gradually. The planting heights of NF4 and WF4 in the whole growth period were higher than other treatments. Film mulching can suppress the growth of summer maize so that to reduce its height. The leaf area index of winter wheat and summer maize presents a trend of firstly increasing and then decreasing.(4) The dry matter accumulation of winter wheat and summer maize show a trend of increasing gradually with time changing as a whole. Mulching measures improve the dry matter accumulation of winter wheat, but film mulching reduces it as for summer maize. The treatment NF3 has the highest economic yield, while CK is the least. As for WUE, NF1 is the maximum and CK is the minimum. In order to higher economic yield, NF3 is the best way for summer maize. NF1 is the best way for the purpose of higher economic coefficient. Ear length, ear diameter and ear grain number of summer maize have larger differences between the various processings than ear number and ear row number. The grain size and filling degree of maize have a higher sensitivity to irrigation and mulching treatments. In order to higher economic yield, WF1 is the best way for summer maize. WF3 is the best way for the purpose of higher economic coefficient. Straw mulching will increase WUE of summer maize, and plastic mulching had impact not so far.(5) Crop coefficients of winter wheat appear changes which expressed as bimodal during the whole growth period, while the summit appears in the tillering~wintering and heading~filling stage. At the same time, there are good forth-order-polynomial and second-order-polynomial relations between Kc and the days after sowing and the cumulative temperature above 0℃ respectively. Crop coefficients of summer maize appear changes which expressed as peak during the whole growth period, while the summit appears in the tasselling~filling stage. At the same time, there are good second-order-polynomial and third-order-polynomial relations between Kc and the days after sowing and the cumulative temperature above 10℃ respectively.