Water Consumption and Use Efficiency of Main Crops on Semi-drought Area of Western Liaoning Province

The laws of water consumption in corn,peanuts and millet on the semi-drought area of western Liaoning Province were studied through the FAO-Penman Monteith method and the water balance method.Among three corps,the amount of the day water demand,the whole growth period water demand and the soil water deficit of corn were all the largest.At the same time,its degree of agreement between the water demand and the level of precipitation was the worst,and its average in crop coefficient was larger.The amount of th...

PRODUCTIVITY AND WATER UTILITY FOR MAIN CROPS IN LOESSAL HILL.REGION, SOUTHERN NINGXIA

The loessal hill region in southern Ningxia is a semiarid and severe eroded area with developed agriculture and animal husbandry. It has long been an argument whether there might be more potentiality of farming and whether food production can be sustained at a level of local sufficiency.

Optimal management of nitrogen fertilizer in the main rice crop and its carrying-over effect on ratoon rice under mechanized cultivation in Southeast China

This study attempted to clarify the carrying-over effect of different nitrogen treatments applied to the main crop on the crop population growth and yield formation of ratoon rice under mechanized cultivation in Southeast China.Based on the constant total nitrogen application amounts(225.00 kg ha;)in the main crop,an experiment with different ratios of basal and topdressing nitrogen fertilizer(the ratio of basal fertilizer:primary tillering fertilizer:secondary tillering fertilizer:booting fertilizer at 3:1:2:4(N1),3:2:1:4(N2),3:3:0:4(N3),and 4:3:0:3(N4),respectively,and a control without nitrogen treatment(N0))was set up across two consecutive years in field using hybrid rice variety Yongyou 1540 as the test materials.The results showed that the total tiller number and effective tillering percentage increased in the main crop under the N1 treatment,more nitrogen fertilizer applied in late growth stage of the main crop,and its effective tillering percentage of the main crop was the highest at up to 70.18%,which was 9.15%higher than that of conventional fertilization treatment(N4),more nitrogen fertilizer applied in early growth stage of the main crop.The same tendency was observed in leaf area index(LAI)value of the main crop and its subsequent ratoon rice,which were 16.52 and 29.87%higher,respectively,in the N1 treatment than that in the N4 treatment at the full heading stage.The same was true in the case of the transport rates of stem and sheath dry mater and the canopy light interception rates in both the main and its ratoon crops.The transport rate of stem and sheath in main crop rice under N1 treatment increased by 50.57%compared with N4 treatment.The canopy light interception rate of N1 treatment increased by 5.07%compared with N4 treatment at the full heading stage of the ratoon crop.Therefore,the total actual yield was the highest in the main and its ratoon crops under N1 treatment,averaging 17351.23 kg ha;in two-year trials,which was 23.00%higher than that in the conventional fertilization treatment(N4).The results showed that appropriate nitrogen treatment was able to produce a good crop stand in the main crop,which was essential for producing a good ratoon crop population and high yield especially under mechanized cultivation with low stubble height of the main crop.The study suggested that shifting the proper nitrogen application amounts to the late growth stage of the main crop,such as N1 treatment,not only had a higher productive effect on ensuring the yield of the main crop,but also had a positive effect on the axillary bud sprouts from the stubbles for ratoon rice,resulting in an increased percentage of productive panicles and achieving the goal of one planting with two good harvests under the conditions of our study.

Effects of nitrogen management on the ratoon crop yield and head rice yield in South USA

Ratoon rice cropping is an important component of the rice cropping system in Texas and south Louisiana,USA,and expanded to Asian countries in 1970.Two field studies were conducted with widely planted rice(Oryza sativa L.)cultivars at Eagle Lake,Texas,USA to determine the effects of nitrogen(N)management in main(first)crop(MC)and ratoon(second)crop(RC)on RC yield.In 2012 and 2013,one cultivar(Presidio)was adopted to determine the effects of RC N management on ratoon yield and head rice yield.In 2016 and 2017,CL153,CL163 and CL272 in addition to Presidio were adopted to examine the effect of MC N management on ratoon yield and head rice yield.N applied at preflood after MC harvest considerably improved RC yield.Application of 99 kg N ha^(–1)at preflood after MC harvest was practically adequate for RC regrowth,development and approaching the yield potential for Presidio.RC could produce quite high average grain yields of 5.90 to 6.53 t ha–1 in 2012 and 2013,respectively.Main crop N rate only significantly affected MC yield;however,given N applied of 99 kg ha^(–1)at preflood after MC harvest,ratoon yield was not significantly affected by MC N rate.Neither the main nor ratoon crop N management had a significant effect on RC head rice yield.Considerable RC head rice yields(55–65%)were observed in all of the four cultivars and 4 years except for CL272 in 2016.These results indicat that without very high N fertilizer application,rice ratoon crop could produce a considerable grain yield and an expectative head rice yield.Rice ratooning could be a practical way to increase rice yields with the minimal input in south Texas and regions with a similar climate.

Chemical fertilizer rate, use efficiency and reduction of cereal crops in China, 1998–2018

This paper studied the fertilizer rate(FR), fertilizer use efficiency(FUE) and fertilizer overuse rate(FOR) of rice, corn and wheat in China from 1998 to 2018 and briefly analysed the reasons why farmers were willing to apply more fertilizers.(1) The FR of grain in China reached 373.7 kg/ha in 2018, an increase of 26.8% compared to that in 1998. In 2018, the FR for corn was the highest, at 411.2 kg/ha, compared to the values of 338.3 kg/ha for rice and 371.7 kg/ha for wheat.(2) In recent years, the FUE of grain in China has obviously improved, with values of 32.9% in 1998, 36.7% in 2008, and 39.3% in 2018. In 2018, the FUE for rice was the highest(41.2%), followed by that for corn(39.9%), and the FUE for wheat was the lowest(36.0%).(3) By 2018, fertilizer was overused in all zones of rice, corn and wheat. In 2018, the average FOR for wheat reached 69.0%, which was 35.9% higher than that for corn and 42.8% higher than that for rice.(4) The lower price of chemical fertilizers was the main reason leading to overapplication.(5) Establishing market mechanisms and adjusting regional planting structures can be effective in reducing the application of chemical fertilizers.