Abstract:The conprehensive arrangoment technical system that takes the rotation of grain - bean -grass as a center has been developed in semiarid areas with soil and water loss of South Ningxia。The system is able to make the rotation into systematization, the culture into standardization andmanure application into patternization, the efficiency of energy transformation, crop yield and to-tal yield in this system can be increased by 14. 7 percent, 1. 2 time and 1 time respectively。Among those the balanced manure spreading in rotation can not only coordinate the balance of major nu-trients and periodicity between need and supply,but also improve the ability and stability of ad-justment and control for soil nutrients in this system.

Abstract:There is a slow speed of developing agricultural production in loess hilly gully areas ofDingxi. The major reasons that influence the speed are drought, less precipitation and soil andwater loss. Through the experiments,it was shown that the tillage measures which collect runofffor infiltrating into the hole can not only retain rainfall,but also increase the depth of infiltrationand decrease evapotranspiration of soil surface in order to improve the utilization of rainfall andsoil moisture. The objectives that preserve the soil,increase the yield and return,and utilize na-ture resources rationally can be achieved。

Abstract:The location experiments have been carried out to study soil moisture balance of farmland under different rota-tion systems in loess hilly areas of South Ningxia。The results show that the rotation between grain and bean (i. e.,spring pea - spring wheat-spring wheat-broom corn millet )could adjust soil moisture and maintain the soilmoisture in basic balance within the rotation 's period;alfalfa can be taken as a part in the rotation of grass-crop。The soil moisture in layer of 1 m is adaptative to plant drought -resistance crops,such as millet,after the alfalfagrows 5-6 years;the soil moisture in layer of 2 m can be repenlished after the drought-resistance crops wereplanted for 2-3 years。The long-term continuous cropping of spring wheat can lead to the decreasing of soil fer-tility,the extending of pest and diseases,the breeding of weeds and the reducing of productivity,but can not causeheavy problem for soil moisture。

Abstract:The experiments to transform slope land into terrace have been made in mountain and hilly areas of granite-gneiss. The results show that the narrow-level terrace which is built up in one time can easily control slope land,save on investment and achieve good benefits. Compared with the usual one in slope land of 5°and 10°,the aboveway can save on labour forces and investment by 25 percent and by 30 percent respectively. The narrow-level ter-race can enhance the benefits of soil and water conservation by more than 75 percent,the soil moisture by 15 to 20percent in rainfall season,the crop yield by 20 percent to 35 percent,and land utilization by 40 percent to 50 per-cent. The fertility loss on narrow-level terrace is little compared with that one on slope fields.

Abstract:The experiments of improving slope land have been carried out. The building techniques of slope terrace andits benefits have been approached. The results show that the hillside fields is able to be built into slope terracefirstly,and then be changed into level terrace. It is a feasible way to have been testified by practice and is a betterway to improve hillside fields,and,it has a good adaptability in a large range. At the same time,the labours,earth-work amount and investment for building slope terrace could be reduced by 80 percent, 75 percent and 73 percentrespectively compared with the construction of level terrace. Furthermore,crop yield will not reduce in the sameyear and will increase in the second year. The crop yield may increase by 10 percent after the third or fourth year.

Abstract:According to the national environment,social and economical situation in loess hilly areas,the suitable tillagetechniques with soil and water conservation have been taken. The objectives of storing water,conservating soil,in-creasing fertility and yield,decreasing field in order to plant trees and grasses on slope land,and making the a-griecosystem into favourable circle cap be achieved through applving these techniques. Therefore,on the basis ofplanting. in level furrow in a large range,the experiments have been made to study tillage techniques with soil andwater conservation,which includes covering soil with film;reserving stubble for inversing ridge; putting soil blockin furrow; intercropping and rotation of grass and grain in belt shape and intercropping of grain and grass as well asbush in wider belt on slope land,etc. The benefits of storing water,retainning soil,increasing fertility and yield andincreasing return for every technical measures have been evaluated.

Abstract:According to the agricultural conditions in different regions,the productive potentials and e-cological adaptability of crops in arid farmland were analysed. The largest productive potentials ofcrops in eight typical counties have been estimated. The limitative factors for productive forceshave been determined. Finally, the authors put forward the major ways and measurements for in-creasing-yield in different regions.

Abstract:Through the preliminary study of soil moisture in loess hilly areas of the West Inner Mongo-lia, it was concluded that the dynamic distribution of soil moisture in vertical direction can be di-vided into three section, i. e., the fluctuation section (0 - 40cm), the middle transformation section(40- 100cm), the relative stable section (100 - 200cm). There is agreement between the dynamicchanges in soil moisture and the changes in rainfall in arid farmland.

Abstract:The location observation of soil moisture at different layers from 0 cm to 200 cm have beenmade. It was concluded that the soil moisture dynamics within a year can be divided into four peri-ods in arid plain, i. e.,intensive consuming period in late spring and early summer,resuming andreplenishing peroid in rainfall season,slow consuming period in late autumn,relative stable periodin winter and early spring. The vertical distribution of soil moisture can be divided into three sec-tion,i. e.,quickly changing layer (0-20cm),brisking layer (20-100cm) and relative stable layer(100-200cm). On the basis of these results,special subjects have been taken to study tillagetechniques of storing Water and conservating soil in arid plain. The results were shown as fol-lows,in arid plain,the intercropping of sun flower and soybean in belt shape produces remarkablebenefits for soil and water conservation and economy;the objectives of saving on manure,improv-ing the utilization of manure and increasing yield could be obtained by popularizing the techniquesthat make up a prescription for manure-spreading.

Abstract:The contrast experiments have been carried out to study the differences between level plant-ing , furrow and ridge planting,ridge planting and pile planting, intercropping and planting of thesame crop. The results were shown as follows: the marked increasing yield benefits of storingwater and retaining soil will be achieved after ridge planting and intercropping have been appliedin hillside fields. However, at present, there are 300 thousand mu hillside fields in this county,the authors suggested that the tillage techniques of storing water and retanining soil,such as fur-row and ridge planing.intercropping should be actively popularized before the slope land is ter-raced.

Abstract:The field experiments for rotation of grass-crop and belt intercropping have been taken inExperimental Station of Soil and Water Conservation of Heligeer in Inner Mongolia. Three kindsof grasses, i. e., Vicia sativa L,Melilotus suaveolens Ledeb,Vicia villosa Roth which have grownfor two years,were rotated and intercropped with the local major crops. The results show that therotation of grass-crop and belt intercropping are not only an important way to recover fertility,to rich soil and to increase yield of crops and grass,but also a scientific planting system that con-servates soil and water,and utilizes and protects land because of the remarkable benefits of soiland water conservation.