| The water resource is very insufficient in Hebei Province. In fact, water insufficientdistricts cover more than50%of the total area in Hbei Province, which have become animportant influencing factor to agriculture development. In this paper, focusing on the highefficient utilization of water resources of saline groundwater in low plain and precipitationin hilly region of Hebei Province, the study carries out control experiments and fieldexperiments in Luquan Experimental Station of Hebei Academy of Agriculture andForestry Sciences from2010to2013to reveal the farming production principle underdifferent water types of constraints and focusing on water and soil, find out an approach totechnological innovation in efficiently utilizing the regional earth-atmosphereresources.Being confronted with the resources background of shortage in fresh water andrich in mineralized shallow ground water, the experiment is designed that using salinewater irrigation, the production of salt tolerant economic crop is under environmentalcontrol. In order to achieve effective alternatives to fresh water resources, using economicbenefit compensates facilities cost. In the treatments, using different concentration saltwater and soil matric potential to research irrigate salt tolerant tomatoes at different growthstages reveals tomato sensitivity to concentration salt water irrigation and soil matricpotential in tomato’s different growth stages and finds out the threshold stage and theproper concentration of salt water irrigation. The purpose of the experiment is to supply thebase of theory and technology on saline water use and scientific irrigation in vegetableproduction under solar greenhouse in low plain area of Hebei Province.In the backgroundof rich in light and heat resources but lack of rainfall in hilly area in Hebei province, theexperiment, based on soil retention of rainfall resource, has used peritoneal and ridgeculture, water retention and catchment planting of drought resistant plants and thecompound planting of drought resistant and high-yield plants, and at the same time, takenadvantage of the differences of water ecological adaptability among different plants andthe mechanism of the complementary use of water and soil resource to achieve theeffective transformation of rainfall resource in cropland during growing stage. The paper,through researching on soil moisture and temperature effects, photo-synthetically activeradiation, dry material accumulative transfer and regularity of N, P, K absorption anddistribution, enucleates transformation mechanisms of resource soil and water andregularity of yield forming of intercropping system of spring sweet potato and spring maize under ridge tillage with plastic film mulching cultivation. It provides theoretical andtechnological supports for adjusting production structure of regional crop and utilizingefficiently farmland water and soil resources.1The results indicate that there are remarkable differences of salt-tolerance capacityat different growth periods of tomato. That means the blooming and earlier fruit periods aremore sensitive to soil matric potential and salt stress than other stages. The most adaptedone to salt stress is the harvest period. The data shows that the salinity of salt waterirrigation should be less than the3g/L at both the whole growth period and the bloomingand the fruit period, and less than5g/L at the fruit enlargement period. Relatively, highconcentration salt water irrigation of7g/l-9g/l can be used at the harvest period. The resultis different between the relationship of yield at different growing periods and the soilmatric potential, the concentration salt. The conicoid relationship was found in thetomatoes yield and the concentration salt, the soil matric potential at the whole growthperiod and the blooming and the fruit period, and the effect on the yield is significant.However, only the concentration salt has significant effects on the yield at fruitenlargement period，and there is a parabolic relation between the concentration salt and thetomatoes yield. The two factors at harvest period have no effects on the tomatoes yield.The relationship between the concentration salt, the soil matric potential and the rootweight could be expressed by a conicoid relationship. The concentration salt at wholegrowth period has significant effects on the root weight, and there is a significantinteraction between the concentration salt and the soil matric potential. Only theconcentration salt has significant effects on the root weight at the blooming period, andthere is a parabolic relation between the concentration salt and the tomatoes root weight.The effect of the tomatoes root weight is not significant at the fruit enlargement period andthe harvest period in every. The positive linear relationship is shown between the soilsalinity and the concentration salt, the soil matric potential in all growth stages. The saltcontent would increased50%～400%by using the brackish water resources with mineralconcentration between3～9g/L to irrigate. Salt water irrigation will result in the soil saltaccumulation in green house production systems. The water consumption of irrigatingtomatoes is positively correlated with the soil matric potential at every growth period,however, negatively correlated with the concentration salt. Hence, the effect of salt waterirrigation on plant growth appeared the "from control to promotion" regulating trendswhile a moderate amount is chosen, which will help reduce the water consumption andimprove tomato yield and WUE. As a result，based on the characteristics of salt toleranceof tomato at different growth periods, the use of a certain concentration of salt waterirrigation can not only replace the fresh water but also improve WUE.2The result showed that plastic mulching treatment in the early growth stage (fromsowing stage to tasseling stage) could significantly add the soil temperature at5,10,15,20 cm depths and increase1~3℃, increase accumulated temperature155.2~280.9℃,lengthened growth period5.9~10.7d compared with the CK(flat with bare land). Plasticmulching treatment also could significantly add the soil water content and storage, andWUE (water use efficiency) increased by81.61%～136.43%compared with the CK in thestages from sowing to seeding. The stages from seedling to jointing coincided with thestable dry season of Northern China, as the result, layers of supply water with the plasticmulching treatment could reach0.9m soil depth and WUE decreased by16.96%～21.64%because of water stress, and luxury water consumption was observed during this stage ofplastic mulching treatment. The stage after trumpeting entered the rainy season and the soilof various treatments was rewatered in different time and the soil supersaturation inducedleakage. As a result, the soil water content and storage in the harvest stage was almostequal to that in the sowing stage so the soil water is sufficient. The yield of the ridge tillagewith plastic film mulching treatment increased by9.47%compared with the CK. The flatwith plastic film mulching treatment restrained rain water so that infiltration led towaterlog and the yield decreased by5%. However, the yield had no significant differencebetween flat with plastic film mulching and flat with bare land. The higher yield of springmaize was limited because time sequences of water supply and demand imbalanced onspring maize soil characterized by soil water shortage before the rainy season and soilwater storage after the rainy season in meteorological drought period. Plastic mulchingtreatment of sweet potato in the early growth stage (from sowing stage to tasseling stage)could significantly add the soil temperature at5,10,1520cm depths and increase1~3℃,increase accumulated temperature155.2~280.9℃, lengthened growth period5.9~10.7dcompared with the CK(flat with bare land). Plastic mulching treatment also couldsignificantly add the soil water content and storage, and WUE (water use efficiency)increased by81.61%～136.43%compared with the CK in the stages from sowing toseeding. The stages from seedling to jointing coincided with the stable dry season ofNorthern China, as the result, layers of supply water with the plastic mulching treatmentcould reach0.9m soil depth and WUE decreased by16.96%～21.64%because of waterstress, and luxury water consumption was observed during this stage of plastic mulchingtreatment. The stage after trumpeting entered the rainy season and the soil of varioustreatments was rewatered in different time and the soil supersaturation induced leakage. Asa result, the soil water content and storage in the harvest stage was almost equal to that inthe sowing stage so the soil water is sufficient. The yield of the ridge tillage with plasticfilm mulching treatment increased by9.47%compared with the CK. The flat with plasticfilm mulching treatment restrained rain water so that infiltration led to waterlog and theyield decreased by5%. However, the yield had no significant difference between flat withplastic film mulching and flat with bare land. The higher yield of spring maize was limitedbecause time sequences of water supply and demand imbalanced on spring maize soil characterized by soil water shortage before the rainy season and soil water storage after therainy season in meteorological drought period.The result showed that plastic mulching treatment in the early growth stage (beforesealing ridge period) could significantly add the soil temperature at0-25cm depths andincrease an average of1.64~3.33℃, compared with the CK (flat with bare land). However,the soil temperature did not significantly add after sealing ridge period. The temperatureincrease of plastic mulching treatment accumulated194.8℃and lengthened growth period8.2d. Plastic mulching treatment from planting stage to branching stage also couldsignificantly add the soil water content and storage, which is advantageous to the earlygrowth of sweet potato. The water consumption intensity of plastic-mulching was lower at26.9%, compared with the CK. WUE (water use efficiency) increased by104.3%,compared with the CK in the stages before branching stage. The yield of plastic filmmulching treatment has increased by49.4%compared with the CK. The waterconservation function of plastic film mulching made the daily water consumptiondecreased in26.9%, and the water consumption of sweet potato was29.8mm less than thatof CK，which was equivalent to a surplus supply of40.32mm water because of plastic filmmulching. Plastic film mulching benefited both water retention and yield-increasing.However，the dry season before the rainy season in Northern China leaded to lose largeamount of water because of fast soil evaporation. The soil relative water content was only56.1%. As the result, layers of supply water with the plastic mulching and CK treatmentcould reach100cm depth and WUE decreased by63%and27%because of water stress,and luxury water consumption was observed during this stage. The sweet potato of plasticmulching treatment rapidly grew from branching stage to sealing ridge period, and dailywater consumption significantly increased. Daily water consumption increased49.7%,which was18.9mm compared with the CK. The yield of plastic film mulching treatmenthas increased by37.6%and WUE has increased by3.87%, compared with the CK in thestages. The effect of saving water reduced. The stage after vines growth stage entered therainy season, and the soil of the two treatments was rewatered in different time and the soilsupersaturation induced leakage. Hence, the daily water consumption of the two treatmentswas up to6.9~8.0mm.d-1in vines growth stage and4.5~5.1mm.d-1in tuber growth stage.Plastic film mulching restrained evaporation of the soil water and at the same timehindered soil gas exchange. So，the yield decreased by1.78%, and WUE decreased by3.8%. Plastic film mulching treatment affected the growth of the sweet potato in the floodseason. Uncover film measures should be taken to increase yield.3Results indicated that the process of spring maize dry matter accumulation showsthe representative feature of s curve. The carbon accumulation renewedly takes the stem asgrow central in late slow increases stages. The dry matter accumulation befor tasselingstage up to47.02%～53.96%of the whole growth period. The contribution of dry matters transfer efficiency to grain yield was9.99%～23.01%.The contribution of dry matterstransfer’s amounts of bracteal leaf and ear axis reached32.84%～47.48%. The springmaize dry matter accumulation higher than the CK17.19%～23.61%,becase ofwater-retention effect of film mulching.The dry matter fast accumulation stage forewent6.4days,linear growth phase shortened2.5～1.5d compared with ck. Characteristics of Naccumulation shown that high rate renewly absorb N of soil and take stem as NEnrichment central.43.08%～48.05%of the N storage in the maize plant transferred toseeds，the contribution ratio of N transferred to seeds is49.01%~52.61%. The transportrates of N in bracteal leaf and ear axis reached32.84%～47.48%. The ridge tillage withplastic film mulching treatment nitrogen accumulation amount of stem and leaf was higherthan the control plants101.08%in seedling stage. The nitrogen stored in stem and leaf inearlier growing stage and transferred to seeds in later growing stage，which promote thegrain sink development and yield increase9.47%. Spring maize one harvest in one yearpromotes carbon and nitrogen production and released high yield potential.Plastic filmmulching treatment accelerated the process of carbon and nitrogen production but shortenthe duration of carbon linear production phase. One of the breakthroughs to enhance yieldof spring maize one harvest in one year was the breakthroughs of a larger grain sinkcultivar.The process of dry matter production of spring sweet potato shows fastaccumulation in prophase and anaphase, and slow accumulation in middle stage. Theprocess of spring sweet potato nitrogen accumulation shows accelerated accumulation inearlier stage and nitrogen loss character in later stage. Nitrogen accumulation of plasticmulching sweet potato has increased by20.56%, compared with the CK, but the transferrate decreased by7.97percentage point. Plastic mulching treatment has improvesd drymatter accumulation, but the transfer amount of dry matter accumulation decreased by63%, compared with the CK. So, the yield has decreased by1.78%.4The results showed that accumulation of p showed a single-peak curve in the wholegrowing period.The accumulation patterns of p in bract and cob is grab type at the periodfrom trumpeting to tasseling. Characteristics of P accumulation shown that high raterenewly absorb P of soil and take stem as p enrichment central at maturity period. Therules of spring maize absorbing K shown fast accumulation before the trumpeting periodand K appear losing at maturity period..The distribution rate of K is6.64%～17.87%. Leafand bracteal leaf and ear axis are the principal part of distribution to grain. The treatmentof ridge tillage with plastic film mulching distribution rate of P and K is highst comparewith other treatments.The process of spring sweet potato P accumulation shows theunimodal type and the absorption peak in tuber formation stage to sealing ridge period.The plastic mulching treatment has significantly improves the P accumulation amount inprophase period, but a little effect in anaphase period. Plastic mulching treatment hasincreased P transfer amount and transfer rate of Stem. The process of spring sweet potato K accumulation shows accelerated accumulation before Vines growth stage, however, Kloss character in harvest period. The plastic mulching treatment K accumulation amount issignificantly higher in each stage than that of the CK, and the transfer amount and thetransfer rate of the plastic mulching treatment K accumulation has increased by42.45%and9.24percentage points, but the rate of transferring to tuber root has decreased by18.22percentage point, compared with the CK.5The results from spring maize and spring sweet potato intercropping system showsthat spring maize is dominant in this intercropping system. The photosynthetically activeradiation (PAR) of maize population in intercropping models with25cm high is3.82-4.40times of monoculture, but PAR of sweet potato population in intercropped models is only68.41%-69.07%of monoculture. LER of dry matter accumulation of intercropping systemin seeding is1.19~1.32. High-density intercropping system has increased competition forwater in the community in the stable dry season. Soil water content has decreased sharplyto the lowest (which is close to the wilting coefficient), drought stress has reduced theutilization ratio of resources and LER is only0.66~0.93. Resource with water and light asthe core intense competition continues to filling stage of maize. As growth rate and LAIare decreased, the inhibition of sweet potato growth becomes weaker and intercroppingsweet potato represents over-compensatory growth. Stage WER reaches up to3.06~3.96.LER is3.30~2.08.The analysis result of spring maize and spring sweet potatointercropping system indicates that the land equivalent ratio of spring sweet potato andspring maize intercropping with plastic mulching treatment （FMT1）is2:1, which soilutilization of intercropping has increased by20%, compared with sole cropping. Landequivalent ratio（FMT2）is2:2, which soil utilization has increased by17%. Landequivalent ratio of spring sweet potato and spring maize intercropping with non mulching（BMT1）is2:1, which soil utilization has increased by9%. Land equivalent ratio withnon mulching（BMT2） is2:2, which soil utilization has increased by6%. At the sametime, water use efficiency（WER）(FMT1) has increased by12%. WER FMT2hasincreased by9%. WER (BFMT1) has increased by1%. WER (BFMT2) has decreased by5%. |
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